refactor: migrate credit note and vendor credit services to nestjs

packages/server-nest/src/modules/App/App.module.ts

@@ -46,6 +46,9 @@ import { BillsModule } from '../Bills/Bills.module';
 import { SaleInvoicesModule } from '../SaleInvoices/SaleInvoices.module';
 import { SaleReceiptsModule } from '../SaleReceipts/SaleReceipts.module';
 import { ManualJournalsModule } from '../ManualJournals/ManualJournals.module';
+import { VendorCreditsModule } from '../VendorCredit/VendorCredits.module';
+import { CreditNotesModule } from '../CreditNotes/CreditNotes.module';
+import { VendorCreditApplyBillsModule } from '../VendorCreditsApplyBills/VendorCreditApplyBills.module';
 // import { BillPaymentsModule } from '../BillPayments/BillPayments.module';
 
 @Module({
@@ -116,7 +119,10 @@ import { ManualJournalsModule } from '../ManualJournals/ManualJournals.module';
     SaleEstimatesModule,
     SaleReceiptsModule,
     BillsModule,
-    ManualJournalsModule
+    ManualJournalsModule,
+    VendorCreditsModule,
+    VendorCreditApplyBillsModule,
+    CreditNotesModule,
     // BillPaymentsModule,
   ],
   controllers: [AppController],

packages/server-nest/src/modules/Bills/commands/BillsValidators.service.ts

@@ -6,7 +6,7 @@ import { IItemEntryDTO } from '@/modules/TransactionItemEntry/ItemEntry.types';
 import { Item } from '@/modules/Items/models/Item';
 import { BillPaymentEntry } from '@/modules/BillPayments/models/BillPaymentEntry';
 import { BillLandedCost } from '@/modules/BillLandedCosts/models/BillLandedCost';
-import { VendorCreditAppliedBill } from '@/modules/VendorCredit/models/VendorCreditAppliedBill';
+import { VendorCreditAppliedBill } from '@/modules/VendorCreditsApplyBills/models/VendorCreditAppliedBill';
 import { transformToMap } from '@/utils/transform-to-key';
 
 @Injectable()

packages/server-nest/src/modules/CreditNotes/CreditNoteApplication.service.ts

@@ -0,0 +1,57 @@
+import { Injectable } from '@nestjs/common';
+import { CreateCreditNoteService } from './commands/CreateCreditNote.service';
+import { CreateRefundCreditNoteService } from './commands/CreateRefundCreditNote.service';
+import { DeleteCreditNoteService } from './commands/DeleteCreditNote.service';
+import { EditCreditNoteService } from './commands/EditCreditNote.service';
+import { OpenCreditNoteService } from './commands/OpenCreditNote.service';
+import { GetCreditNotePdf } from './queries/GetCreditNotePdf.serivce';
+import {
+  ICreditNoteEditDTO,
+  ICreditNoteNewDTO,
+  ICreditNoteRefundDTO,
+} from './types/CreditNotes.types';
+
+@Injectable()
+export class CreditNoteApplication {
+  constructor(
+    private createCreditNoteService: CreateCreditNoteService,
+    private createRefundCreditNoteService: CreateRefundCreditNoteService,
+    private editCreditNoteService: EditCreditNoteService,
+    private openCreditNoteService: OpenCreditNoteService,
+    private deleteCreditNoteService: DeleteCreditNoteService,
+    private getCreditNotePdfService: GetCreditNotePdf,
+  ) {}
+
+  createCreditNote(creditNoteDTO: ICreditNoteNewDTO) {
+    return this.createCreditNoteService.creditCreditNote(creditNoteDTO);
+  }
+
+  editCreditNote(creditNoteId: number, creditNoteDTO: ICreditNoteEditDTO) {
+    return this.editCreditNoteService.editCreditNote(
+      creditNoteId,
+      creditNoteDTO,
+    );
+  }
+
+  openCreditNote(creditNoteId: number) {
+    return this.openCreditNoteService.openCreditNote(creditNoteId);
+  }
+
+  deleteCreditNote(creditNoteId: number) {
+    return this.deleteCreditNoteService.deleteCreditNote(creditNoteId);
+  }
+
+  createRefundCreditNote(
+    creditNoteId: number,
+    creditNoteDTO: ICreditNoteRefundDTO,
+  ) {
+    return this.createRefundCreditNoteService.createCreditNoteRefund(
+      creditNoteId,
+      creditNoteDTO,
+    );
+  }
+
+  getCreditNotePdf(creditNoteId: number) {
+    return this.getCreditNotePdfService.getCreditNotePdf(creditNoteId);
+  }
+}

packages/server-nest/src/modules/CreditNotes/CreditNotes.controller.ts

@@ -0,0 +1,52 @@
+import { Body, Controller, Delete, Param, Post, Put } from '@nestjs/common';
+import { CreditNoteApplication } from './CreditNoteApplication.service';
+import {
+  ICreditNoteEditDTO,
+  ICreditNoteNewDTO,
+  ICreditNoteRefundDTO,
+} from './types/CreditNotes.types';
+
+@Controller('credit-notes')
+export class CreditNotesController {
+  /**
+   * @param {CreditNoteApplication} creditNoteApplication - The credit note application service.
+   */
+  constructor(private creditNoteApplication: CreditNoteApplication) {}
+
+  @Post()
+  createCreditNote(@Body() creditNoteDTO: ICreditNoteNewDTO) {
+    return this.creditNoteApplication.createCreditNote(creditNoteDTO);
+  }
+
+  @Put(':id')
+  editCreditNote(
+    @Param('id') creditNoteId: number,
+    @Body() creditNoteDTO: ICreditNoteEditDTO,
+  ) {
+    return this.creditNoteApplication.editCreditNote(
+      creditNoteId,
+      creditNoteDTO,
+    );
+  }
+
+  @Post(':id/open')
+  openCreditNote(@Param('id') creditNoteId: number) {
+    return this.creditNoteApplication.openCreditNote(creditNoteId);
+  }
+
+  @Delete(':id')
+  deleteCreditNote(@Param('id') creditNoteId: number) {
+    return this.creditNoteApplication.deleteCreditNote(creditNoteId);
+  }
+
+  @Post(':id/refund')
+  createRefundCreditNote(
+    @Param('id') creditNoteId: number,
+    @Body() creditNoteDTO: ICreditNoteRefundDTO,
+  ) {
+    return this.creditNoteApplication.createRefundCreditNote(
+      creditNoteId,
+      creditNoteDTO,
+    );
+  }
+}

packages/server-nest/src/modules/CreditNotes/CreditNotes.module.ts

@@ -0,0 +1,29 @@
+import { Module } from '@nestjs/common';
+import { CreateCreditNoteService } from './commands/CreateCreditNote.service';
+import { CommandCreditNoteDTOTransform } from './commands/CommandCreditNoteDTOTransform.service';
+import { CreateRefundCreditNoteService } from './commands/CreateRefundCreditNote.service';
+import { EditCreditNoteService } from './commands/EditCreditNote.service';
+import { OpenCreditNoteService } from './commands/OpenCreditNote.service';
+import { DeleteCreditNoteService } from './commands/DeleteCreditNote.service';
+import { CreditNoteApplySyncCredit } from './commands/CreditNoteApplySyncCredit.service';
+import { DeleteCustomerLinkedCreditNoteService } from './commands/DeleteCustomerLinkedCreditNote.service';
+import { CreditNoteAutoIncrementService } from './commands/CreditNoteAutoIncrement.service';
+import { CreditNoteApplication } from './CreditNoteApplication.service';
+import { CreditNotesController } from './CreditNotes.controller';
+
+@Module({
+  providers: [
+    CreateCreditNoteService,
+    CommandCreditNoteDTOTransform,
+    CreateRefundCreditNoteService,
+    EditCreditNoteService,
+    OpenCreditNoteService,
+    DeleteCreditNoteService,
+    CreditNoteApplySyncCredit,
+    DeleteCustomerLinkedCreditNoteService,
+    CreditNoteAutoIncrementService,
+    CreditNoteApplication
+  ],
+  controllers: [CreditNotesController],
+})
+export class CreditNotesModule {}

packages/server-nest/src/modules/CreditNotes/GetCreditNoteAssociatedInvoicesToApply copy.ts

@@ -0,0 +1,42 @@
+import { Service, Inject } from 'typedi';
+import BaseCreditNotes from '../CreditNotes';
+import { ISaleInvoice } from '@/interfaces';
+import { CreditNoteWithInvoicesToApplyTransformer } from './commands/CreditNoteWithInvoicesToApplyTransformer';
+import { TransformerInjectable } from '@/lib/Transformer/TransformerInjectable';
+
+@Service()
+export default class GetCreditNoteAssociatedInvoicesToApply extends BaseCreditNotes {
+  @Inject()
+  private transformer: TransformerInjectable;
+
+  /**
+   * Retrieve credit note associated invoices to apply.
+   * @param {number} tenantId
+   * @param {number} creditNoteId
+   * @returns {Promise<ISaleInvoice[]>}
+   */
+  public getCreditAssociatedInvoicesToApply = async (
+    tenantId: number,
+    creditNoteId: number
+  ): Promise<ISaleInvoice[]> => {
+    const { SaleInvoice } = this.tenancy.models(tenantId);
+
+    // Retireve credit note or throw not found service error.
+    const creditNote = await this.getCreditNoteOrThrowError(
+      tenantId,
+      creditNoteId
+    );
+    // Retrieves the published due invoices that associated to the given customer.
+    const saleInvoices = await SaleInvoice.query()
+      .where('customerId', creditNote.customerId)
+      .modify('dueInvoices')
+      .modify('published');
+
+    // Transformes the sale invoices models to POJO.
+    return this.transformer.transform(
+      tenantId,
+      saleInvoices,
+      new CreditNoteWithInvoicesToApplyTransformer()
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/GetCreditNoteAssociatedInvoicesToApply.ts

@@ -0,0 +1 @@
+ 

packages/server-nest/src/modules/CreditNotes/commands/CommandCreditNoteDTOTransform.service.ts

@@ -0,0 +1,113 @@
+import { Injectable } from '@nestjs/common';
+import moment from 'moment';
+import { omit } from 'lodash';
+import * as R from 'ramda';
+import composeAsync from 'async/compose';
+import { ERRORS } from '../constants';
+import {
+  ICreditNote,
+  ICreditNoteEditDTO,
+  ICreditNoteEntryNewDTO,
+  ICreditNoteNewDTO,
+} from '../types/CreditNotes.types';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { ItemsEntriesService } from '@/modules/Items/ItemsEntries.service';
+import { BranchTransactionDTOTransformer } from '@/modules/Branches/integrations/BranchTransactionDTOTransform';
+import { WarehouseTransactionDTOTransform } from '@/modules/Warehouses/Integrations/WarehouseTransactionDTOTransform';
+import { BrandingTemplateDTOTransformer } from '../../PdfTemplate/BrandingTemplateDTOTransformer';
+import { assocItemEntriesDefaultIndex } from '@/utils/associate-item-entries-index';
+import { CreditNoteAutoIncrementService } from './CreditNoteAutoIncrement.service';
+import { CreditNote } from '../models/CreditNote';
+
+@Injectable()
+export class CommandCreditNoteDTOTransform {
+  /**
+   * @param {ItemsEntriesService} itemsEntriesService - The items entries service.
+   * @param {BranchTransactionDTOTransformer} branchDTOTransform - The branch transaction DTO transformer.
+   * @param {WarehouseTransactionDTOTransform} warehouseDTOTransform - The warehouse transaction DTO transformer.
+   * @param {BrandingTemplateDTOTransformer} brandingTemplatesTransformer - The branding template DTO transformer.
+   * @param {CreditNoteAutoIncrementService} creditNoteAutoIncrement - The credit note auto increment service.
+   */
+  constructor(
+    private readonly itemsEntriesService: ItemsEntriesService,
+    private readonly branchDTOTransform: BranchTransactionDTOTransformer,
+    private readonly warehouseDTOTransform: WarehouseTransactionDTOTransform,
+    private readonly brandingTemplatesTransformer: BrandingTemplateDTOTransformer,
+    private readonly creditNoteAutoIncrement: CreditNoteAutoIncrementService
+  ) {}
+
+  /**
+   * Transformes the credit/edit DTO to model.
+   * @param {ICreditNoteNewDTO | ICreditNoteEditDTO} creditNoteDTO
+   * @param {string} customerCurrencyCode -
+   */
+  public transformCreateEditDTOToModel = async (
+    creditNoteDTO: ICreditNoteNewDTO | ICreditNoteEditDTO,
+    customerCurrencyCode: string,
+    oldCreditNote?: CreditNote,
+  ): Promise<CreditNote> => {
+    // Retrieve the total amount of the given items entries.
+    const amount = this.itemsEntriesService.getTotalItemsEntries(
+      creditNoteDTO.entries,
+    );
+    const entries = R.compose(
+      // Associate the default index to each item entry.
+      assocItemEntriesDefaultIndex,
+
+      // Associate the reference type to credit note entries.
+      R.map((entry: ICreditNoteEntryNewDTO) => ({
+        ...entry,
+        referenceType: 'CreditNote',
+      })),
+    )(creditNoteDTO.entries);
+
+    // Retreive the next credit note number.
+    const autoNextNumber = this.creditNoteAutoIncrement.getNextCreditNumber();
+
+    // Detarmines the credit note number.
+    const creditNoteNumber =
+      creditNoteDTO.creditNoteNumber ||
+      oldCreditNote?.creditNoteNumber ||
+      autoNextNumber;
+
+    const initialDTO = {
+      ...omit(creditNoteDTO, ['open', 'attachments']),
+      creditNoteNumber,
+      amount,
+      currencyCode: customerCurrencyCode,
+      exchangeRate: creditNoteDTO.exchangeRate || 1,
+      entries,
+      ...(creditNoteDTO.open &&
+        !oldCreditNote?.openedAt && {
+          openedAt: moment().toMySqlDateTime(),
+        }),
+      refundedAmount: 0,
+      invoicesAmount: 0,
+    };
+    const initialAsyncDTO = await composeAsync(
+      // Assigns the default branding template id to the invoice DTO.
+      this.brandingTemplatesTransformer.assocDefaultBrandingTemplate(
+        'CreditNote',
+      ),
+    )(initialDTO);
+
+    return R.compose(
+      this.branchDTOTransform.transformDTO<ICreditNote>,
+      this.warehouseDTOTransform.transformDTO<ICreditNote>,
+    )(initialAsyncDTO);
+  };
+
+  /**
+   * Validate the credit note remaining amount.
+   * @param {ICreditNote} creditNote
+   * @param {number} amount
+   */
+  public validateCreditRemainingAmount = (
+    creditNote: CreditNote,
+    amount: number,
+  ) => {
+    if (creditNote.creditsRemaining < amount) {
+      throw new ServiceError(ERRORS.CREDIT_NOTE_HAS_NO_REMAINING_AMOUNT);
+    }
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/CreateCreditNote.service.ts

@@ -0,0 +1,83 @@
+import { Knex } from 'knex';
+import { Injectable } from '@nestjs/common';
+import {
+  ICreditNoteCreatedPayload,
+  ICreditNoteCreatingPayload,
+  ICreditNoteNewDTO,
+} from '../types/CreditNotes.types';
+import { CreditNote } from '../models/CreditNote';
+import { Contact } from '../../Contacts/models/Contact';
+import { CommandCreditNoteDTOTransform } from './CommandCreditNoteDTOTransform.service';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { ItemsEntriesService } from '@/modules/Items/ItemsEntries.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class CreateCreditNoteService {
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly itemsEntriesService: ItemsEntriesService,
+    private readonly eventPublisher: EventEmitter2,
+    private readonly creditNoteModel: typeof CreditNote,
+    private readonly contactModel: typeof Contact,
+    private readonly commandCreditNoteDTOTransform: CommandCreditNoteDTOTransform,
+  ) {}
+
+  /**
+   * Creates a new credit note.
+   * @param creditNoteDTO
+   */
+  public creditCreditNote = async (
+    creditNoteDTO: ICreditNoteNewDTO,
+    trx?: Knex.Transaction,
+  ) => {
+    // Triggers `onCreditNoteCreate` event.
+    await this.eventPublisher.emitAsync(events.creditNote.onCreate, {
+      creditNoteDTO,
+    });
+    // Validate customer existance.
+    const customer = await this.contactModel
+      .query()
+      .modify('customer')
+      .findById(creditNoteDTO.customerId)
+      .throwIfNotFound();
+
+    // Validate items ids existance.
+    await this.itemsEntriesService.validateItemsIdsExistance(
+      creditNoteDTO.entries,
+    );
+    // Validate items should be sellable items.
+    await this.itemsEntriesService.validateNonSellableEntriesItems(
+      creditNoteDTO.entries,
+    );
+    // Transformes the given DTO to storage layer data.
+    const creditNoteModel =
+      await this.commandCreditNoteDTOTransform.transformCreateEditDTOToModel(
+        creditNoteDTO,
+        customer.currencyCode,
+      );
+    // Creates a new credit card transactions under unit-of-work envirement.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Triggers `onCreditNoteCreating` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onCreating, {
+        creditNoteDTO,
+        trx,
+      } as ICreditNoteCreatingPayload);
+
+      // Upsert the credit note graph.
+      const creditNote = await this.creditNoteModel.query(trx).upsertGraph({
+        ...creditNoteModel,
+      });
+      // Triggers `onCreditNoteCreated` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onCreated, {
+        creditNoteDTO,
+        creditNote,
+        creditNoteId: creditNote.id,
+        trx,
+      } as ICreditNoteCreatedPayload);
+
+      return creditNote;
+    }, trx);
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/CreateRefundCreditNote.service.ts

@@ -0,0 +1,113 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import {
+  ICreditNoteRefundDTO,
+  IRefundCreditNoteCreatedPayload,
+  IRefundCreditNoteCreatingPayload,
+} from '../types/CreditNotes.types';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { Account } from '@/modules/Accounts/models/Account.model';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { events } from '@/common/events/events';
+import { CommandCreditNoteDTOTransform } from './CommandCreditNoteDTOTransform.service';
+import { CreditNote } from '../models/CreditNote';
+
+@Injectable()
+export class CreateRefundCreditNoteService {
+  /**
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {CommandCreditNoteDTOTransform} commandCreditNoteDTOTransform - The command credit note DTO transform service.
+   * @param {typeof RefundCreditNote} refundCreditNoteModel - The refund credit note model.
+   * @param {typeof Account} accountModel - The account model.
+   * @param {typeof CreditNote} creditNoteModel - The credit note model.
+   */
+  constructor(
+    private uow: UnitOfWork,
+    private eventPublisher: EventEmitter2,
+    private commandCreditNoteDTOTransform: CommandCreditNoteDTOTransform,
+
+    @Inject(RefundCreditNote.name)
+    private refundCreditNoteModel: typeof RefundCreditNote,
+
+    @Inject(Account.name) private accountModel: typeof Account,
+    @Inject(CreditNote.name) private creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} creditNoteId
+   * @param {ICreditNoteRefundDTO} newCreditNoteDTO
+   * @returns {Promise<IRefundCreditNote>}
+   */
+  public async createCreditNoteRefund(
+    creditNoteId: number,
+    newCreditNoteDTO: ICreditNoteRefundDTO,
+  ): Promise<RefundCreditNote> {
+    // Retrieve the credit note or throw not found service error.
+    const creditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteId)
+      .throwIfNotFound();
+
+    // Retrieve the withdrawal account or throw not found service error.
+    const fromAccount = await this.accountModel
+      .query()
+      .findById(newCreditNoteDTO.fromAccountId)
+      .throwIfNotFound();
+
+    // Validate the credit note remaining amount.
+    this.commandCreditNoteDTOTransform?.validateCreditRemainingAmount(
+      creditNote,
+      newCreditNoteDTO.amount,
+    );
+    // Validate the refund withdrawal account type.
+    this.commandCreditNoteDTOTransform.validateRefundWithdrawwalAccountType(
+      fromAccount,
+    );
+    // Creates a refund credit note transaction.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Triggers `onCreditNoteRefundCreating` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onRefundCreating, {
+        trx,
+        creditNote,
+        newCreditNoteDTO,
+      } as IRefundCreditNoteCreatingPayload);
+
+      // Stores the refund credit note graph to the storage layer.
+      const refundCreditNote = await this.refundCreditNoteModel
+        .query(trx)
+        .insertAndFetch({
+          ...this.transformDTOToModel(creditNote, newCreditNoteDTO),
+        });
+
+      // Triggers `onCreditNoteRefundCreated` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onRefundCreated, {
+        trx,
+        refundCreditNote,
+        creditNote,
+      } as IRefundCreditNoteCreatedPayload);
+
+      return refundCreditNote;
+    });
+  }
+
+  /**
+   * Transformes the refund credit note DTO to model.
+   * @param {number} creditNoteId
+   * @param {ICreditNoteRefundDTO} creditNoteDTO
+   * @returns {ICreditNote}
+   */
+  private transformDTOToModel = (
+    creditNote: CreditNote,
+    creditNoteDTO: ICreditNoteRefundDTO,
+  ): RefundCreditNote => {
+    return {
+      creditNoteId: creditNote.id,
+      currencyCode: creditNote.currencyCode,
+      ...creditNoteDTO,
+      exchangeRate: creditNoteDTO.exchangeRate || 1,
+    };
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/CreditNoteApplySyncCredit.service.ts

@@ -0,0 +1,45 @@
+import { Knex } from 'knex';
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNote } from '../models/CreditNote';
+
+@Injectable()
+export class CreditNoteApplySyncCredit {
+  constructor(
+    @Inject(CreditNote.name)
+    private creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Increment credit note invoiced amount.
+   * @param {number} creditNoteId
+   * @param {number} invoicesAppliedAmount
+   * @param {Knex.Transaction} [trx]
+   */
+  public async incrementCreditNoteInvoicedAmount(
+    creditNoteId: number,
+    invoicesAppliedAmount: number,
+    trx?: Knex.Transaction,
+  ): Promise<void> {
+    await this.creditNoteModel
+      .query(trx)
+      .findById(creditNoteId)
+      .increment('invoicesAmount', invoicesAppliedAmount);
+  }
+
+  /**
+   * Decrement credit note invoiced amount.
+   * @param {number} creditNoteId
+   * @param {number} invoicesAppliedAmount
+   * @param {Knex.Transaction} [trx]
+   */
+  public async decrementCreditNoteInvoicedAmount(
+    creditNoteId: number,
+    invoicesAppliedAmount: number,
+    trx?: Knex.Transaction,
+  ): Promise<void> {
+    await this.creditNoteModel
+      .query(trx)
+      .findById(creditNoteId)
+      .decrement('invoicesAmount', invoicesAppliedAmount);
+  }
+}

packages/server-nest/src/modules/CreditNotes/commands/CreditNoteApplySyncInvoices.service.ts

@@ -0,0 +1,48 @@
+import { Knex } from 'knex';
+import { Injectable, Inject } from '@nestjs/common';
+import Bluebird from 'bluebird';
+import { ICreditNoteAppliedToInvoice } from '../types/CreditNotes.types';
+import { SaleInvoice } from '@/modules/SaleInvoices/models/SaleInvoice';
+
+@Injectable()
+export class CreditNoteApplySyncInvoicesCreditedAmount {
+  constructor(
+    @Inject(SaleInvoice.name)
+    private readonly saleInvoiceModel: typeof SaleInvoice,
+  ) {}
+
+  /**
+   * Increment invoices credited amount.
+   * @param {ICreditNoteAppliedToInvoice[]} creditNoteAppliedInvoices -
+   * @param {Knex.Transaction} trx -
+   */
+  public incrementInvoicesCreditedAmount = async (
+    creditNoteAppliedInvoices: ICreditNoteAppliedToInvoice[],
+    trx?: Knex.Transaction
+  ) => {
+    await Bluebird.each(
+      creditNoteAppliedInvoices,
+      (creditNoteAppliedInvoice: ICreditNoteAppliedToInvoice) => {
+        return this.saleInvoiceModel.query(trx)
+          .where('id', creditNoteAppliedInvoice.invoiceId)
+          .increment('creditedAmount', creditNoteAppliedInvoice.amount);
+      }
+    );
+  };
+
+  /**
+   *
+   * @param {number} invoicesIds
+   * @param {number} amount - 
+   * @param {Knex.Transaction} knex - 
+   */
+  public decrementInvoiceCreditedAmount = async (
+    invoiceId: number,
+    amount: number,
+    trx?: Knex.Transaction
+  ) => {
+    await this.saleInvoiceModel.query(trx)
+      .findById(invoiceId)
+      .decrement('creditedAmount', amount);
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/CreditNoteApplyToInvoices.service.ts

@@ -0,0 +1,131 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import { sumBy } from 'lodash';
+import {
+  ICreditNoteAppliedToInvoice,
+  ICreditNoteAppliedToInvoiceModel,
+  IApplyCreditToInvoicesDTO,
+  IApplyCreditToInvoicesCreatedPayload,
+  ICreditNote,
+} from '../types/CreditNotes.types';
+import { ERRORS } from '../constants';
+import { PaymentReceivedValidators } from '@/modules/PaymentReceived/commands/PaymentReceivedValidators.service';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { CreditNoteAppliedInvoice } from '../models/CreditNoteAppliedInvoice';
+import { events } from '@/common/events/events';
+import { SaleInvoice } from '@/modules/SaleInvoices/models/SaleInvoice';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+@Injectable()
+export class CreditNoteApplyToInvoices {
+  /**
+   * @param {PaymentReceivedValidators} paymentReceiveValidators - The payment received validators service.
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {typeof CreditNoteAppliedInvoice} creditNoteAppliedInvoiceModel - The credit note applied invoice model.
+   */
+  constructor(
+    private readonly paymentReceiveValidators: PaymentReceivedValidators,
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(CreditNoteAppliedInvoice.name)
+    private readonly creditNoteAppliedInvoiceModel: typeof CreditNoteAppliedInvoice,
+  ) {}
+
+  /**
+   * Apply credit note to the given invoices.
+   * @param {number} creditNoteId
+   * @param {IApplyCreditToInvoicesDTO} applyCreditToInvoicesDTO
+   */
+  public async applyCreditNoteToInvoices(
+    creditNoteId: number,
+    applyCreditToInvoicesDTO: IApplyCreditToInvoicesDTO,
+  ): Promise<ICreditNoteAppliedToInvoice[]> {
+    // Saves the credit note or throw not found service error.
+    const creditNote = await this.getCreditNoteOrThrowError(creditNoteId);
+
+    // Retrieve the applied invoices that associated to the credit note customer.
+    const appliedInvoicesEntries =
+      await this.paymentReceiveValidators.validateInvoicesIDsExistance(
+        creditNote.customerId,
+        applyCreditToInvoicesDTO.entries,
+      );
+
+    // Transformes apply DTO to model.
+    const creditNoteAppliedModel = this.transformApplyDTOToModel(
+      applyCreditToInvoicesDTO,
+      creditNote,
+    );
+
+    // Validate invoices has remaining amount to apply.
+    this.validateInvoicesRemainingAmount(
+      appliedInvoicesEntries,
+      creditNoteAppliedModel.amount,
+    );
+    // Validate the credit note remaining amount.
+    this.validateCreditRemainingAmount(
+      creditNote,
+      creditNoteAppliedModel.amount,
+    );
+
+    // Creates credit note apply to invoice transaction.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Saves the credit note apply to invoice graph to the storage layer.
+      const creditNoteAppliedInvoices = await this.creditNoteAppliedInvoiceModel
+        .query()
+        .insertGraph(creditNoteAppliedModel.entries);
+
+      // Triggers `onCreditNoteApplyToInvoiceCreated` event.
+      await this.eventPublisher.emitAsync(
+        events.creditNote.onApplyToInvoicesCreated,
+        {
+          creditNote,
+          creditNoteAppliedInvoices,
+          trx,
+        } as IApplyCreditToInvoicesCreatedPayload,
+      );
+
+      return creditNoteAppliedInvoices;
+    });
+  }
+
+  /**
+   * Transformes apply DTO to model.
+   * @param {IApplyCreditToInvoicesDTO} applyDTO
+   * @param {ICreditNote} creditNote
+   * @returns
+   */
+  private transformApplyDTOToModel = (
+    applyDTO: IApplyCreditToInvoicesDTO,
+    creditNote: ICreditNote,
+  ): ICreditNoteAppliedToInvoiceModel => {
+    const entries = applyDTO.entries.map((entry) => ({
+      invoiceId: entry.invoiceId,
+      amount: entry.amount,
+      creditNoteId: creditNote.id,
+    }));
+    return {
+      amount: sumBy(entries, 'amount'),
+      entries,
+    };
+  };
+
+  /**
+   * Validate the invoice remaining amount.
+   * @param {ISaleInvoice[]} invoices
+   * @param {number} amount
+   */
+  private validateInvoicesRemainingAmount = (
+    invoices: SaleInvoice[],
+    amount: number,
+  ) => {
+    const invalidInvoices = invoices.filter(
+      (invoice) => invoice.dueAmount < amount,
+    );
+    if (invalidInvoices.length > 0) {
+      throw new ServiceError(ERRORS.INVOICES_HAS_NO_REMAINING_AMOUNT);
+    }
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/CreditNoteAutoIncrement.service.ts

@@ -0,0 +1,28 @@
+import { AutoIncrementOrdersService } from '@/modules/AutoIncrementOrders/AutoIncrementOrders.service';
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class CreditNoteAutoIncrementService {
+  constructor(
+    private readonly autoIncrementOrdersService: AutoIncrementOrdersService,
+  ) {}
+
+  /**
+   * Retrieve the next unique credit number.
+   * @return {string}
+   */
+  public getNextCreditNumber(): string {
+    return this.autoIncrementOrdersService.getNextTransactionNumber(
+      'credit_note',
+    );
+  }
+
+  /**
+   * Increment the credit note serial next number.
+   */
+  public incrementSerialNumber() {
+    return this.autoIncrementOrdersService.incrementSettingsNextNumber(
+      'credit_note',
+    );
+  }
+}

packages/server-nest/src/modules/CreditNotes/commands/CreditNoteGLEntries.ts

@@ -0,0 +1,297 @@
+// import { Inject, Service } from 'typedi';
+// import { Knex } from 'knex';
+// import * as R from 'ramda';
+// import {
+//   AccountNormal,
+//   IItemEntry,
+//   ILedgerEntry,
+//   ICreditNote,
+//   ILedger,
+//   ICreditNoteGLCommonEntry,
+// } from '@/interfaces';
+// import HasTenancyService from '@/services/Tenancy/TenancyService';
+// import Ledger from '@/services/Accounting/Ledger';
+// import LedgerStorageService from '@/services/Accounting/LedgerStorageService';
+// import { SaleReceipt } from '@/models';
+
+// @Service()
+// export default class CreditNoteGLEntries {
+//   @Inject()
+//   private tenancy: HasTenancyService;
+
+//   @Inject()
+//   private ledgerStorage: LedgerStorageService;
+
+//   /**
+//    * Retrieves the credit note GL.
+//    * @param   {ICreditNote} creditNote
+//    * @param   {number} receivableAccount
+//    * @returns {Ledger}
+//    */
+//   private getCreditNoteGLedger = (
+//     creditNote: ICreditNote,
+//     receivableAccount: number,
+//     discountAccount: number,
+//     adjustmentAccount: number
+//   ): Ledger => {
+//     const ledgerEntries = this.getCreditNoteGLEntries(
+//       creditNote,
+//       receivableAccount,
+//       discountAccount,
+//       adjustmentAccount
+//     );
+//     return new Ledger(ledgerEntries);
+//   };
+
+//   /**
+//    * Saves credit note GL entries.
+//    * @param {number} tenantId -
+//    * @param {ICreditNote} creditNote - Credit note model.
+//    * @param {number} payableAccount - Payable account id.
+//    * @param {Knex.Transaction} trx
+//    */
+//   public saveCreditNoteGLEntries = async (
+//     tenantId: number,
+//     creditNote: ICreditNote,
+//     payableAccount: number,
+//     discountAccount: number,
+//     adjustmentAccount: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     const ledger = this.getCreditNoteGLedger(
+//       creditNote,
+//       payableAccount,
+//       discountAccount,
+//       adjustmentAccount
+//     );
+
+//     await this.ledgerStorage.commit(tenantId, ledger, trx);
+//   };
+
+//   /**
+//    * Reverts the credit note associated GL entries.
+//    * @param {number} tenantId
+//    * @param {number} vendorCreditId
+//    * @param {Knex.Transaction} trx
+//    */
+//   public revertVendorCreditGLEntries = async (
+//     tenantId: number,
+//     creditNoteId: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     await this.ledgerStorage.deleteByReference(
+//       tenantId,
+//       creditNoteId,
+//       'CreditNote',
+//       trx
+//     );
+//   };
+
+//   /**
+//    * Writes vendor credit associated GL entries.
+//    * @param {number} tenantId - Tenant id.
+//    * @param {number} creditNoteId - Credit note id.
+//    * @param {Knex.Transaction} trx - Knex transactions.
+//    */
+//   public createVendorCreditGLEntries = async (
+//     tenantId: number,
+//     creditNoteId: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     const { CreditNote } = this.tenancy.models(tenantId);
+//     const { accountRepository } = this.tenancy.repositories(tenantId);
+
+//     // Retrieve the credit note with associated entries and items.
+//     const creditNoteWithItems = await CreditNote.query(trx)
+//       .findById(creditNoteId)
+//       .withGraphFetched('entries.item');
+
+//     // Retreive the the `accounts receivable` account based on the given currency.
+//     const ARAccount = await accountRepository.findOrCreateAccountReceivable(
+//       creditNoteWithItems.currencyCode
+//     );
+//     const discountAccount = await accountRepository.findOrCreateDiscountAccount(
+//       {}
+//     );
+//     const adjustmentAccount =
+//       await accountRepository.findOrCreateOtherChargesAccount({});
+//     // Saves the credit note GL entries.
+//     await this.saveCreditNoteGLEntries(
+//       tenantId,
+//       creditNoteWithItems,
+//       ARAccount.id,
+//       discountAccount.id,
+//       adjustmentAccount.id,
+//       trx
+//     );
+//   };
+
+//   /**
+//    * Edits vendor credit associated GL entries.
+//    * @param {number} tenantId
+//    * @param {number} creditNoteId
+//    * @param {Knex.Transaction} trx
+//    */
+//   public editVendorCreditGLEntries = async (
+//     tenantId: number,
+//     creditNoteId: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     // Reverts vendor credit GL entries.
+//     await this.revertVendorCreditGLEntries(tenantId, creditNoteId, trx);
+
+//     // Creates vendor credit Gl entries.
+//     await this.createVendorCreditGLEntries(tenantId, creditNoteId, trx);
+//   };
+
+//   /**
+//    * Retrieve the credit note common entry.
+//    * @param   {ICreditNote} creditNote -
+//    * @returns {ICreditNoteGLCommonEntry}
+//    */
+//   private getCreditNoteCommonEntry = (
+//     creditNote: ICreditNote
+//   ): ICreditNoteGLCommonEntry => {
+//     return {
+//       date: creditNote.creditNoteDate,
+//       userId: creditNote.userId,
+//       currencyCode: creditNote.currencyCode,
+//       exchangeRate: creditNote.exchangeRate,
+
+//       transactionType: 'CreditNote',
+//       transactionId: creditNote.id,
+
+//       transactionNumber: creditNote.creditNoteNumber,
+//       referenceNumber: creditNote.referenceNo,
+
+//       createdAt: creditNote.createdAt,
+//       indexGroup: 10,
+
+//       credit: 0,
+//       debit: 0,
+
+//       branchId: creditNote.branchId,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the creidt note A/R entry.
+//    * @param   {ICreditNote} creditNote -
+//    * @param   {number} ARAccountId -
+//    * @returns {ILedgerEntry}
+//    */
+//   private getCreditNoteAREntry = (
+//     creditNote: ICreditNote,
+//     ARAccountId: number
+//   ): ILedgerEntry => {
+//     const commonEntry = this.getCreditNoteCommonEntry(creditNote);
+
+//     return {
+//       ...commonEntry,
+//       credit: creditNote.totalLocal,
+//       accountId: ARAccountId,
+//       contactId: creditNote.customerId,
+//       index: 1,
+//       accountNormal: AccountNormal.DEBIT,
+//     };
+//   };
+
+//   /**
+//    * Retrieve the credit note item entry.
+//    * @param   {ICreditNote} creditNote
+//    * @param   {IItemEntry} entry
+//    * @param   {number} index
+//    * @returns {ILedgerEntry}
+//    */
+//   private getCreditNoteItemEntry = R.curry(
+//     (
+//       creditNote: ICreditNote,
+//       entry: IItemEntry,
+//       index: number
+//     ): ILedgerEntry => {
+//       const commonEntry = this.getCreditNoteCommonEntry(creditNote);
+//       const totalLocal = entry.totalExcludingTax * creditNote.exchangeRate;
+
+//       return {
+//         ...commonEntry,
+//         debit: totalLocal,
+//         accountId: entry.sellAccountId || entry.item.sellAccountId,
+//         note: entry.description,
+//         index: index + 2,
+//         itemId: entry.itemId,
+//         itemQuantity: entry.quantity,
+//         accountNormal: AccountNormal.CREDIT,
+//       };
+//     }
+//   );
+
+//   /**
+//    * Retrieves the credit note discount entry.
+//    * @param {ICreditNote} creditNote
+//    * @param {number} discountAccountId
+//    * @returns {ILedgerEntry}
+//    */
+//   private getDiscountEntry = (
+//     creditNote: ICreditNote,
+//     discountAccountId: number
+//   ): ILedgerEntry => {
+//     const commonEntry = this.getCreditNoteCommonEntry(creditNote);
+
+//     return {
+//       ...commonEntry,
+//       credit: creditNote.discountAmountLocal,
+//       accountId: discountAccountId,
+//       index: 1,
+//       accountNormal: AccountNormal.CREDIT,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the credit note adjustment entry.
+//    * @param {ICreditNote} creditNote
+//    * @param {number} adjustmentAccountId
+//    * @returns {ILedgerEntry}
+//    */
+//   private getAdjustmentEntry = (
+//     creditNote: ICreditNote,
+//     adjustmentAccountId: number
+//   ): ILedgerEntry => {
+//     const commonEntry = this.getCreditNoteCommonEntry(creditNote);
+//     const adjustmentAmount = Math.abs(creditNote.adjustmentLocal);
+
+//     return {
+//       ...commonEntry,
+//       credit: creditNote.adjustmentLocal < 0 ? adjustmentAmount : 0,
+//       debit: creditNote.adjustmentLocal > 0 ? adjustmentAmount : 0,
+//       accountId: adjustmentAccountId,
+//       accountNormal: AccountNormal.CREDIT,
+//       index: 1,
+//     };
+//   };
+
+//   /**
+//    * Retrieve the credit note GL entries.
+//    * @param   {ICreditNote} creditNote - Credit note.
+//    * @param   {IAccount} receivableAccount - Receviable account.
+//    * @returns {ILedgerEntry[]} - Ledger entries.
+//    */
+//   public getCreditNoteGLEntries = (
+//     creditNote: ICreditNote,
+//     ARAccountId: number,
+//     discountAccountId: number,
+//     adjustmentAccountId: number
+//   ): ILedgerEntry[] => {
+//     const AREntry = this.getCreditNoteAREntry(creditNote, ARAccountId);
+
+//     const getItemEntry = this.getCreditNoteItemEntry(creditNote);
+//     const itemsEntries = creditNote.entries.map(getItemEntry);
+
+//     const discountEntry = this.getDiscountEntry(creditNote, discountAccountId);
+//     const adjustmentEntry = this.getAdjustmentEntry(
+//       creditNote,
+//       adjustmentAccountId
+//     );
+
+//     return [AREntry, discountEntry, adjustmentEntry, ...itemsEntries];
+//   };
+// }

packages/server-nest/src/modules/CreditNotes/commands/CreditNoteWithInvoicesToApplyTransformer.ts

@@ -0,0 +1,68 @@
+import { Transformer } from "@/modules/Transformer/Transformer";
+
+export class CreditNoteWithInvoicesToApplyTransformer extends Transformer {
+  /**
+   * Include these attributes to sale invoice object.
+   * @returns {Array}
+   */
+  public includeAttributes = (): string[] => {
+    return [
+      'formattedInvoiceDate',
+      'formattedDueDate',
+      'formattedAmount',
+      'formattedDueAmount',
+      'formattedPaymentAmount',
+    ];
+  };
+
+  /**
+   * Retrieve formatted invoice date.
+   * @param {ISaleInvoice} invoice
+   * @returns {String}
+   */
+  protected formattedInvoiceDate = (invoice): string => {
+    return this.formatDate(invoice.invoiceDate);
+  };
+
+  /**
+   * Retrieve formatted due date.
+   * @param {ISaleInvoice} invoice
+   * @returns {string}
+   */
+  protected formattedDueDate = (invoice): string => {
+    return this.formatDate(invoice.dueDate);
+  };
+
+  /**
+   * Retrieve formatted invoice amount.
+   * @param {ISaleInvoice} invoice
+   * @returns {string}
+   */
+  protected formattedAmount = (invoice): string => {
+    return this.formatNumber(invoice.balance, {
+      currencyCode: invoice.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieve formatted invoice due amount.
+   * @param {ISaleInvoice} invoice
+   * @returns {string}
+   */
+  protected formattedDueAmount = (invoice): string => {
+    return this.formatNumber(invoice.dueAmount, {
+      currencyCode: invoice.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieve formatted payment amount.
+   * @param {ISaleInvoice} invoice
+   * @returns {string}
+   */
+  protected formattedPaymentAmount = (invoice): string => {
+    return this.formatNumber(invoice.paymentAmount, {
+      currencyCode: invoice.currencyCode,
+    });
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/CreditNotesExportable.ts

@@ -0,0 +1,35 @@
+// import { Inject, Service } from 'typedi';
+// import { ICreditNotesQueryDTO } from '@/interfaces';
+// import { Exportable } from '@/services/Export/Exportable';
+// import ListCreditNotes from '../ListCreditNotes';
+
+// @Service()
+// export class CreditNotesExportable extends Exportable {
+//   @Inject()
+//   private getCreditNotes: ListCreditNotes;
+
+//   /**
+//    * Retrieves the accounts data to exportable sheet.
+//    * @param {number} tenantId -
+//    * @param {IVendorCreditsQueryDTO} query -
+//    * @returns {}
+//    */
+//   public exportable(tenantId: number, query: ICreditNotesQueryDTO) {
+//     const filterQuery = (query) => {
+//       query.withGraphFetched('branch');
+//       query.withGraphFetched('warehouse');
+//     };
+//     const parsedQuery = {
+//       sortOrder: 'desc',
+//       columnSortBy: 'created_at',
+//       ...query,
+//       page: 1,
+//       pageSize: 12000,
+//       filterQuery,
+//     } as ICreditNotesQueryDTO;
+
+//     return this.getCreditNotes
+//       .getCreditNotesList(tenantId, parsedQuery)
+//       .then((output) => output.creditNotes);
+//   }
+// }

packages/server-nest/src/modules/CreditNotes/commands/CreditNotesImportable.ts

@@ -0,0 +1,44 @@
+// import { Inject, Service } from 'typedi';
+// import { Knex } from 'knex';
+// import { ICreditNoteNewDTO } from '@/interfaces';
+// import { Importable } from '../Import/Importable';
+// import CreateCreditNote from './commands/CreateCreditNote.service';
+
+// @Service()
+// export class CreditNotesImportable extends Importable {
+//   @Inject()
+//   private createCreditNoteImportable: CreateCreditNote;
+
+//   /**
+//    * Importing to account service.
+//    * @param {number} tenantId
+//    * @param {IAccountCreateDTO} createAccountDTO
+//    * @returns
+//    */
+//   public importable(
+//     tenantId: number,
+//     createAccountDTO: ICreditNoteNewDTO,
+//     trx?: Knex.Transaction
+//   ) {
+//     return this.createCreditNoteImportable.newCreditNote(
+//       tenantId,
+//       createAccountDTO,
+//       trx
+//     );
+//   }
+
+//   /**
+//    * Concurrrency controlling of the importing process.
+//    * @returns {number}
+//    */
+//   public get concurrency() {
+//     return 1;
+//   }
+
+//   /**
+//    * Retrieves the sample data that used to download accounts sample sheet.
+//    */
+//   public sampleData(): any[] {
+//     return [];
+//   }
+// }

packages/server-nest/src/modules/CreditNotes/commands/CreditNotesInventoryTransactions.ts

@@ -0,0 +1,90 @@
+// import { Inject, Service } from 'typedi';
+// import { Knex } from 'knex';
+// import { ICreditNote } from '@/interfaces';
+// import InventoryService from '@/services/Inventory/Inventory';
+// import ItemsEntriesService from '@/services/Items/ItemsEntriesService';
+
+// @Service()
+// export default class CreditNoteInventoryTransactions {
+//   @Inject()
+//   inventoryService: InventoryService;
+
+//   @Inject()
+//   itemsEntriesService: ItemsEntriesService;
+
+//   /**
+//    * Creates credit note inventory transactions.
+//    * @param {number} tenantId
+//    * @param {ICreditNote} creditNote
+//    */
+//   public createInventoryTransactions = async (
+//     tenantId: number,
+//     creditNote: ICreditNote,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     // Loads the inventory items entries of the given sale invoice.
+//     const inventoryEntries =
+//       await this.itemsEntriesService.filterInventoryEntries(
+//         tenantId,
+//         creditNote.entries
+//       );
+//     const transaction = {
+//       transactionId: creditNote.id,
+//       transactionType: 'CreditNote',
+//       transactionNumber: creditNote.creditNoteNumber,
+//       exchangeRate: creditNote.exchangeRate,
+//       date: creditNote.creditNoteDate,
+//       direction: 'IN',
+//       entries: inventoryEntries,
+//       createdAt: creditNote.createdAt,
+//       warehouseId: creditNote.warehouseId,
+//     };
+//     // Writes inventory tranactions.
+//     await this.inventoryService.recordInventoryTransactionsFromItemsEntries(
+//       tenantId,
+//       transaction,
+//       false,
+//       trx
+//     );
+//   };
+
+//   /**
+//    * Edits vendor credit associated inventory transactions.
+//    * @param {number} tenantId
+//    * @param {number} creditNoteId
+//    * @param {ICreditNote} creditNote
+//    * @param {Knex.Transactions} trx
+//    */
+//   public editInventoryTransactions = async (
+//     tenantId: number,
+//     creditNoteId: number,
+//     creditNote: ICreditNote,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     // Deletes inventory transactions.
+//     await this.deleteInventoryTransactions(tenantId, creditNoteId, trx);
+
+//     // Re-write inventory transactions.
+//     await this.createInventoryTransactions(tenantId, creditNote, trx);
+//   };
+
+//   /**
+//    * Deletes credit note associated inventory transactions.
+//    * @param {number} tenantId - Tenant id.
+//    * @param {number} creditNoteId - Credit note id.
+//    * @param {Knex.Transaction} trx -
+//    */
+//   public deleteInventoryTransactions = async (
+//     tenantId: number,
+//     creditNoteId: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     // Deletes the inventory transactions by the given reference id and type.
+//     await this.inventoryService.deleteInventoryTransactions(
+//       tenantId,
+//       creditNoteId,
+//       'CreditNote',
+//       trx
+//     );
+//   };
+// }

packages/server-nest/src/modules/CreditNotes/commands/DeleteCreditNote.service.ts

@@ -0,0 +1,124 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import {
+  ICreditNoteDeletedPayload,
+  ICreditNoteDeletingPayload,
+} from '../types/CreditNotes.types';
+import { ERRORS } from '../constants';
+import { CreditNote } from '../models/CreditNote';
+import { CreditNoteAppliedInvoice } from '../models/CreditNoteAppliedInvoice';
+import {
+  RefundCreditNote as RefundCreditNoteModel,
+} from '../models/RefundCreditNote';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { ItemEntry } from '@/modules/Items/models/ItemEntry';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class DeleteCreditNoteService {
+  /**
+   * @param {UnitOfWork} uow - Unit of work.
+   * @param {EventEmitter2} eventPublisher - Event emitter.
+   * @param {typeof CreditNote} creditNoteModel - Credit note model.
+   * @param {typeof ItemEntry} itemEntryModel - Item entry model.
+   * @param {typeof CreditNoteAppliedInvoice} creditNoteAppliedInvoiceModel - Credit note applied invoice model.
+   * @param {typeof RefundCreditNote} refundCreditNoteModel - Refund credit note model.
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+
+    @Inject(ItemEntry.name)
+    private readonly itemEntryModel: typeof ItemEntry,
+
+    @Inject(CreditNoteAppliedInvoice.name)
+    private readonly creditNoteAppliedInvoiceModel: typeof CreditNoteAppliedInvoice,
+
+    @Inject(RefundCreditNoteModel.name)
+    private readonly refundCreditNoteModel: typeof RefundCreditNoteModel,
+  ) {}
+
+  /**
+   * Deletes the given credit note transactions.
+   * @param {number} creditNoteId
+   * @returns {Promise<void>}
+   */
+  public async deleteCreditNote(creditNoteId: number): Promise<void> {
+    // Retrieve the credit note or throw not found service error.
+    const oldCreditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteId)
+      .throwIfNotFound();
+
+    // Validate credit note has no refund transactions.
+    await this.validateCreditNoteHasNoRefundTransactions(creditNoteId);
+
+    // Validate credit note has no applied invoices transactions.
+    await this.validateCreditNoteHasNoApplyInvoiceTransactions(creditNoteId);
+
+    // Deletes the credit note transactions under unit-of-work transaction.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Triggers `onCreditNoteDeleting` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onDeleting, {
+        trx,
+        oldCreditNote,
+      } as ICreditNoteDeletingPayload);
+
+      // Deletes the associated credit note entries.
+      await this.itemEntryModel
+        .query(trx)
+        .where('reference_id', creditNoteId)
+        .where('reference_type', 'CreditNote')
+        .delete();
+
+      // Deletes the credit note transaction.
+      await this.creditNoteModel.query(trx).findById(creditNoteId).delete();
+
+      // Triggers `onCreditNoteDeleted` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onDeleted, {
+        oldCreditNote,
+        creditNoteId,
+        trx,
+      } as ICreditNoteDeletedPayload);
+    });
+  }
+
+  /**
+   * Validates credit note has no associated refund transactions.
+   * @param {number} creditNoteId
+   * @returns {Promise<void>}
+   */
+  private async validateCreditNoteHasNoRefundTransactions(
+    creditNoteId: number,
+  ): Promise<void> {
+    const refundTransactions = await this.refundCreditNoteModel
+      .query()
+      .where('creditNoteId', creditNoteId);
+
+    if (refundTransactions.length > 0) {
+      throw new ServiceError(ERRORS.CREDIT_NOTE_HAS_REFUNDS_TRANSACTIONS);
+    }
+  }
+
+  /**
+   * Validate credit note has no associated applied invoices transactions.
+   * @param {number} creditNoteId - Credit note id.
+   * @returns {Promise<void>}
+   */
+  private async validateCreditNoteHasNoApplyInvoiceTransactions(
+    creditNoteId: number,
+  ): Promise<void> {
+    const appliedTransactions = await this.creditNoteAppliedInvoiceModel
+      .query()
+      .where('creditNoteId', creditNoteId);
+
+    if (appliedTransactions.length > 0) {
+      throw new ServiceError(ERRORS.CREDIT_NOTE_HAS_APPLIED_INVOICES);
+    }
+  }
+}

packages/server-nest/src/modules/CreditNotes/commands/DeleteCreditNoteApplyToInvoices.service.ts

@@ -0,0 +1,63 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { IApplyCreditToInvoicesDeletedPayload } from '../types/CreditNotes.types';
+import { CreditNoteAppliedInvoice } from '../models/CreditNoteAppliedInvoice';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { events } from '@/common/events/events';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { CreditNote } from '../models/CreditNote';
+import { ERRORS } from '../constants';
+
+@Injectable()
+export default class DeleteCreditNoteApplyToInvoices {
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+    private readonly creditNoteAppliedInvoiceModel: typeof CreditNoteAppliedInvoice,
+
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Apply credit note to the given invoices.
+   * @param {number} creditNoteId
+   * @param {IApplyCreditToInvoicesDTO} applyCreditToInvoicesDTO
+   */
+  public deleteApplyCreditNoteToInvoices = async (
+    applyCreditToInvoicesId: number,
+  ): Promise<void> => {
+    const creditNoteAppliedToInvoice = await this.creditNoteAppliedInvoiceModel
+      .query()
+      .findById(applyCreditToInvoicesId);
+
+    if (!creditNoteAppliedToInvoice) {
+      throw new ServiceError(ERRORS.CREDIT_NOTE_APPLY_TO_INVOICES_NOT_FOUND);
+    }
+    // Retrieve the credit note or throw not found service error.
+    const creditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteAppliedToInvoice.creditNoteId)
+      .throwIfNotFound();
+
+    // Creates credit note apply to invoice transaction.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Delete credit note applied to invoices.
+      await this.creditNoteAppliedInvoiceModel
+        .query(trx)
+        .findById(applyCreditToInvoicesId)
+        .delete();
+
+      // Triggers `onCreditNoteApplyToInvoiceDeleted` event.
+      await this.eventPublisher.emitAsync(
+        events.creditNote.onApplyToInvoicesDeleted,
+        {
+          creditNote,
+          creditNoteAppliedToInvoice,
+          trx,
+        } as IApplyCreditToInvoicesDeletedPayload,
+      );
+    });
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/DeleteCustomerLinkedCreditNote.service.ts

@@ -0,0 +1,26 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNote } from '../models/CreditNote';
+import { ERRORS } from '../constants';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+@Injectable()
+export class DeleteCustomerLinkedCreditNoteService {
+  constructor(
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Validate the given customer has no linked credit note transactions.
+   * @param {number} customerId - The customer identifier.
+   */
+  public async validateCustomerHasNoCreditTransaction(customerId: number) {
+    const associatedCredits = await this.creditNoteModel
+      .query()
+      .where('customerId', customerId);
+
+    if (associatedCredits.length > 0) {
+      throw new ServiceError(ERRORS.CUSTOMER_HAS_LINKED_CREDIT_NOTES);
+    }
+  }
+}

packages/server-nest/src/modules/CreditNotes/commands/DeleteRefundCreditNote.service.ts

@@ -0,0 +1,73 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { Knex } from 'knex';
+import {
+  IRefundCreditNoteDeletedPayload,
+  IRefundCreditNoteDeletingPayload,
+  IRefundVendorCreditDeletedPayload,
+} from '../types/CreditNotes.types';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export default class DeleteRefundCreditNote {
+  /**
+   * @param {UnitOfWork} uow
+   * @param {EventEmitter2} eventPublisher
+   * @param {typeof RefundCreditNoteModel} refundCreditNoteModel
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: typeof RefundCreditNote,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} refundCreditId
+   * @returns
+   */
+  public deleteCreditNoteRefund = async (refundCreditId: number) => {
+    // Retrieve the old credit note or throw not found service error.
+    const oldRefundCredit = await this.refundCreditNoteModel
+      .query()
+      .findById(refundCreditId)
+      .throwIfNotFound();
+
+    // Triggers `onCreditNoteRefundDeleted` event.
+    await this.eventPublisher.emitAsync(events.creditNote.onRefundDelete, {
+      refundCreditId,
+      oldRefundCredit,
+    } as IRefundCreditNoteDeletedPayload);
+
+    // Deletes refund credit note transactions with associated entries.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      const eventPayload = {
+        trx,
+        refundCreditId,
+        oldRefundCredit,
+      } as IRefundCreditNoteDeletedPayload | IRefundCreditNoteDeletingPayload;
+
+      // Triggers `onCreditNoteRefundDeleting` event.
+      await this.eventPublisher.emitAsync(
+        events.creditNote.onRefundDeleting,
+        eventPayload,
+      );
+
+      // Deletes the refund credit note graph from the storage.
+      await this.refundCreditNoteModel
+        .query(trx)
+        .findById(refundCreditId)
+        .delete();
+
+      // Triggers `onCreditNoteRefundDeleted` event.
+      await this.eventPublisher.emitAsync(
+        events.creditNote.onRefundDeleted,
+        eventPayload as IRefundVendorCreditDeletedPayload,
+      );
+    });
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/EditCreditNote.service.ts

@@ -0,0 +1,101 @@
+import { Inject, Injectable } from '@nestjs/common';
+import {
+  ICreditNoteEditDTO,
+  ICreditNoteEditedPayload,
+  ICreditNoteEditingPayload,
+} from '../types/CreditNotes.types';
+import { Knex } from 'knex';
+import { CreditNote } from '../models/CreditNote';
+import { Contact } from '../../Contacts/models/Contact';
+import { ItemsEntriesService } from '../../Items/ItemsEntries.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { UnitOfWork } from '../../Tenancy/TenancyDB/UnitOfWork.service';
+import { events } from '@/common/events/events';
+import { CommandCreditNoteDTOTransform } from './CommandCreditNoteDTOTransform.service';
+
+@Injectable()
+export class EditCreditNoteService {
+  /**
+   * @param {typeof CreditNote} creditNoteModel - The credit note model.
+   * @param {typeof Contact} contactModel - The contact model.
+   * @param {CommandCreditNoteDTOTransform} commandCreditNoteDTOTransform - The command credit note DTO transform service.
+   * @param {ItemsEntriesService} itemsEntriesService - The items entries service.
+   * @param {EventEmitter2} eventPublisher - The event publisher.
+   * @param {UnitOfWork} uow - The unit of work.
+   */
+  constructor(
+    @Inject(CreditNote.name) private creditNoteModel: typeof CreditNote,
+    @Inject(Contact.name) private contactModel: typeof Contact,
+    private commandCreditNoteDTOTransform: CommandCreditNoteDTOTransform,
+    private itemsEntriesService: ItemsEntriesService,
+    private eventPublisher: EventEmitter2,
+    private uow: UnitOfWork,
+  ) {}
+
+  /**
+   * Edits the given credit note.
+   * @param {ICreditNoteEditDTO} creditNoteEditDTO -
+   */
+  public async editCreditNote(
+    creditNoteId: number,
+    creditNoteEditDTO: ICreditNoteEditDTO,
+  ) {
+    // Retrieve the sale invoice or throw not found service error.
+    const oldCreditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteId)
+      .throwIfNotFound();
+
+    // Validate customer existance.
+    const customer = await this.contactModel
+      .query()
+      .findById(creditNoteEditDTO.customerId);
+
+    // Validate items ids existance.
+    await this.itemsEntriesService.validateItemsIdsExistance(
+      creditNoteEditDTO.entries,
+    );
+    // Validate non-sellable entries items.
+    await this.itemsEntriesService.validateNonSellableEntriesItems(
+      creditNoteEditDTO.entries,
+    );
+    // Validate the items entries existance.
+    await this.itemsEntriesService.validateEntriesIdsExistance(
+      creditNoteId,
+      'CreditNote',
+      creditNoteEditDTO.entries,
+    );
+    // Transformes the given DTO to storage layer data.
+    const creditNoteModel =
+      await this.commandCreditNoteDTOTransform.transformCreateEditDTOToModel(
+        creditNoteEditDTO,
+        customer.currencyCode,
+        oldCreditNote,
+      );
+    // Sales the credit note transactions with associated entries.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Triggers `onCreditNoteEditing` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onEditing, {
+        creditNoteEditDTO,
+        oldCreditNote,
+        trx,
+      } as ICreditNoteEditingPayload);
+
+      // Saves the credit note graph to the storage.
+      const creditNote = await this.creditNoteModel.query(trx).upsertGraph({
+        id: creditNoteId,
+        ...creditNoteModel,
+      });
+      // Triggers `onCreditNoteEdited` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onEdited, {
+        trx,
+        oldCreditNote,
+        creditNoteId,
+        creditNote,
+        creditNoteEditDTO,
+      } as ICreditNoteEditedPayload);
+
+      return creditNote;
+    });
+  }
+}

packages/server-nest/src/modules/CreditNotes/commands/OpenCreditNote.service.ts

@@ -0,0 +1,88 @@
+import {
+  ICreditNoteOpenedPayload,
+  ICreditNoteOpeningPayload,
+} from '../types/CreditNotes.types';
+import { Knex } from 'knex';
+import { Inject, Injectable } from '@nestjs/common';
+import { ERRORS } from '../constants';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { CreditNote } from '../models/CreditNote';
+import { events } from '@/common/events/events';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+@Injectable()
+export class OpenCreditNoteService {
+  /**
+   * @param {EventEmitter2} eventPublisher - The event publisher.
+   * @param {UnitOfWork} uow - The unit of work.
+   * @param {typeof CreditNote} creditNoteModel - The credit note model.
+   */
+  constructor(
+    private readonly eventPublisher: EventEmitter2,
+    private readonly uow: UnitOfWork,
+
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Opens the given credit note.
+   * @param {number} creditNoteId -
+   * @returns {Promise<CreditNote>}
+   */
+  public openCreditNote = async (creditNoteId: number): Promise<CreditNote> => {
+    // Retrieve the sale invoice or throw not found service error.
+    const oldCreditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteId)
+      .throwIfNotFound();
+
+    // Throw service error if the credit note is already open.
+    this.throwErrorIfAlreadyOpen(oldCreditNote);
+
+    // Triggers `onCreditNoteOpen` event.
+    this.eventPublisher.emitAsync(events.creditNote.onOpen, {
+      creditNoteId,
+      oldCreditNote,
+    });
+    // Sales the credit note transactions with associated entries.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      const eventPayload = {
+        creditNoteId,
+        oldCreditNote,
+        trx,
+      } as ICreditNoteOpeningPayload;
+
+      // Triggers `onCreditNoteOpening` event.
+      await this.eventPublisher.emitAsync(
+        events.creditNote.onOpening,
+        eventPayload,
+      );
+      // Saves the credit note graph to the storage.
+      const creditNote = await this.creditNoteModel
+        .query(trx)
+        .findById(creditNoteId)
+        .update({
+          openedAt: new Date(),
+        });
+      // Triggers `onCreditNoteOpened` event.
+      await this.eventPublisher.emitAsync(events.creditNote.onOpened, {
+        ...eventPayload,
+        creditNote,
+      } as ICreditNoteOpenedPayload);
+
+      return creditNote;
+    });
+  };
+
+  /**
+   *
+   * @param creditNote
+   */
+  public throwErrorIfAlreadyOpen = (creditNote) => {
+    if (creditNote.openedAt) {
+      throw new ServiceError(ERRORS.CREDIT_NOTE_ALREADY_OPENED);
+    }
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/RefundCreditNote.service.ts

@@ -0,0 +1,45 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { ERRORS } from '../constants';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { Account } from '@/modules/Accounts/models/Account.model';
+
+@Injectable()
+export class RefundCreditNoteService {
+  /**
+   * @param {typeof RefundCreditNote} refundCreditNoteModel - The refund credit note model.
+   */
+  constructor(
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: typeof RefundCreditNote,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} refundCreditId
+   * @returns {Promise<RefundCreditNote>}
+   */
+  public getCreditNoteRefundOrThrowError = async (
+    refundCreditId: number,
+  ): Promise<RefundCreditNote> => {
+    const refundCreditNote = await this.refundCreditNoteModel
+      .query()
+      .findById(refundCreditId);
+    if (!refundCreditNote) {
+      throw new ServiceError(ERRORS.REFUND_CREDIT_NOTE_NOT_FOUND);
+    }
+    return refundCreditNote;
+  };
+
+  /**
+   * Validate the refund account type.
+   * @param {Account} account
+   */
+  public validateRefundWithdrawwalAccountType = (account: Account): void => {
+    const supportedTypes = ['bank', 'cash', 'fixed-asset'];
+
+    if (supportedTypes.indexOf(account.accountType) === -1) {
+      throw new ServiceError(ERRORS.ACCOUNT_INVALID_TYPE);
+    }
+  };
+}

packages/server-nest/src/modules/CreditNotes/commands/RefundCreditNoteGLEntries.ts

@@ -0,0 +1,160 @@
+// import { Inject, Service } from 'typedi';
+// import { Knex } from 'knex';
+// import { AccountNormal, ILedgerEntry, IRefundCreditNote } from '@/interfaces';
+// import HasTenancyService from '@/services/Tenancy/TenancyService';
+// import LedgerStorageService from '@/services/Accounting/LedgerStorageService';
+// import Ledger from '@/services/Accounting/Ledger';
+
+// @Service()
+// export default class RefundCreditNoteGLEntries {
+//   @Inject()
+//   ledgerStorage: LedgerStorageService;
+
+//   @Inject()
+//   tenancy: HasTenancyService;
+
+//   /**
+//    * Retrieves the refund credit common GL entry.
+//    * @param {IRefundCreditNote} refundCreditNote
+//    * @returns
+//    */
+//   private getRefundCreditCommonGLEntry = (
+//     refundCreditNote: IRefundCreditNote
+//   ) => {
+//     return {
+//       currencyCode: refundCreditNote.currencyCode,
+//       exchangeRate: refundCreditNote.exchangeRate,
+
+//       transactionType: 'RefundCreditNote',
+//       transactionId: refundCreditNote.id,
+//       date: refundCreditNote.date,
+//       userId: refundCreditNote.userId,
+
+//       referenceNumber: refundCreditNote.referenceNo,
+
+//       createdAt: refundCreditNote.createdAt,
+//       indexGroup: 10,
+
+//       credit: 0,
+//       debit: 0,
+
+//       note: refundCreditNote.description,
+//       branchId: refundCreditNote.branchId,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the refudn credit receivable GL entry.
+//    * @param   {IRefundCreditNote} refundCreditNote
+//    * @param   {number} ARAccountId
+//    * @returns {ILedgerEntry}
+//    */
+//   private getRefundCreditGLReceivableEntry = (
+//     refundCreditNote: IRefundCreditNote,
+//     ARAccountId: number
+//   ): ILedgerEntry => {
+//     const commonEntry = this.getRefundCreditCommonGLEntry(refundCreditNote);
+
+//     return {
+//       ...commonEntry,
+//       debit: refundCreditNote.amount,
+//       accountId: ARAccountId,
+//       contactId: refundCreditNote.creditNote.customerId,
+//       index: 1,
+//       accountNormal: AccountNormal.DEBIT,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the refund credit withdrawal GL entry.
+//    * @param   {number} refundCreditNote
+//    * @returns {ILedgerEntry}
+//    */
+//   private getRefundCreditGLWithdrawalEntry = (
+//     refundCreditNote: IRefundCreditNote
+//   ): ILedgerEntry => {
+//     const commonEntry = this.getRefundCreditCommonGLEntry(refundCreditNote);
+
+//     return {
+//       ...commonEntry,
+//       credit: refundCreditNote.amount,
+//       accountId: refundCreditNote.fromAccountId,
+//       index: 2,
+//       accountNormal: AccountNormal.DEBIT,
+//     };
+//   };
+
+//   /**
+//    * Retrieve the refund credit note GL entries.
+//    * @param {IRefundCreditNote} refundCreditNote
+//    * @param {number} receivableAccount
+//    * @returns {ILedgerEntry[]}
+//    */
+//   public getRefundCreditGLEntries(
+//     refundCreditNote: IRefundCreditNote,
+//     ARAccountId: number
+//   ): ILedgerEntry[] {
+//     const receivableEntry = this.getRefundCreditGLReceivableEntry(
+//       refundCreditNote,
+//       ARAccountId
+//     );
+//     const withdrawalEntry =
+//       this.getRefundCreditGLWithdrawalEntry(refundCreditNote);
+
+//     return [receivableEntry, withdrawalEntry];
+//   }
+
+//   /**
+//    * Creates refund credit GL entries.
+//    * @param {number} tenantId
+//    * @param {IRefundCreditNote} refundCreditNote
+//    * @param {Knex.Transaction} trx
+//    */
+//   public createRefundCreditGLEntries = async (
+//     tenantId: number,
+//     refundCreditNoteId: number,
+//     trx?: Knex.Transaction
+//   ) => {
+//     const { Account, RefundCreditNote } = this.tenancy.models(tenantId);
+
+//     // Retrieve the refund with associated credit note.
+//     const refundCreditNote = await RefundCreditNote.query(trx)
+//       .findById(refundCreditNoteId)
+//       .withGraphFetched('creditNote');
+
+//     // Receivable account A/R.
+//     const receivableAccount = await Account.query().findOne(
+//       'slug',
+//       'accounts-receivable'
+//     );
+//     // Retrieve refund credit GL entries.
+//     const refundGLEntries = this.getRefundCreditGLEntries(
+//       refundCreditNote,
+//       receivableAccount.id
+//     );
+//     const ledger = new Ledger(refundGLEntries);
+
+//     // Saves refund ledger entries.
+//     await this.ledgerStorage.commit(tenantId, ledger, trx);
+//   };
+
+//   /**
+//    * Reverts refund credit note GL entries.
+//    * @param {number} tenantId
+//    * @param {number} refundCreditNoteId
+//    * @param {number} receivableAccount
+//    * @param {Knex.Transaction} trx
+//    */
+//   public revertRefundCreditGLEntries = async (
+//     tenantId: number,
+//     refundCreditNoteId: number,
+//     trx?: Knex.Transaction
+//   ) => {
+//     await this.ledgerStorage.deleteByReference(
+//       tenantId,
+//       refundCreditNoteId,
+//       'RefundCreditNote',
+//       trx
+//     );
+//   };
+// }

packages/server-nest/src/modules/CreditNotes/commands/RefundSyncCreditNoteBalance.ts

@@ -0,0 +1,48 @@
+import { Knex } from 'knex';
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNote } from '../models/CreditNote';
+
+@Injectable()
+export class RefundSyncCreditNoteBalance {
+  /**
+   * @param {typeof CreditNote} creditNoteModel - The credit note model.
+   */
+  constructor(
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Increments the refund amount of the credit note.
+   * @param {number} creditNoteId - The credit note ID.
+   * @param {number} amount - The amount to increment.
+   * @param {Knex.Transaction} trx - The knex transaction.
+   */
+  public incrementCreditNoteRefundAmount = async (
+    creditNoteId: number,
+    amount: number,
+    trx?: Knex.Transaction
+  ): Promise<void> => {
+    await this.creditNoteModel
+      .query(trx)
+      .findById(creditNoteId)
+      .increment('refunded_amount', amount);
+  };
+
+  /**
+   * Decrements the refund amount of the credit note.
+   * @param {number} creditNoteId - The credit note ID.
+   * @param {number} amount - The amount to decrement.
+   * @param {Knex.Transaction} trx - The knex transaction.
+   */
+  public decrementCreditNoteRefundAmount = async (
+    creditNoteId: number,
+    amount: number,
+    trx?: Knex.Transaction
+  ): Promise<void> => {
+    await this.creditNoteModel
+      .query(trx)
+      .findById(creditNoteId)
+      .decrement('refunded_amount', amount);
+  };
+}

packages/server-nest/src/modules/CreditNotes/constants.ts

@@ -0,0 +1,132 @@
+export const ERRORS = {
+  CREDIT_NOTE_NOT_FOUND: 'CREDIT_NOTE_NOT_FOUND',
+  REFUND_CREDIT_NOTE_NOT_FOUND: 'REFUND_CREDIT_NOTE_NOT_FOUND',
+  CREDIT_NOTE_ALREADY_OPENED: 'CREDIT_NOTE_ALREADY_OPENED',
+  ACCOUNT_INVALID_TYPE: 'ACCOUNT_INVALID_TYPE',
+  CREDIT_NOTE_HAS_NO_REMAINING_AMOUNT: 'CREDIT_NOTE_HAS_NO_REMAINING_AMOUNT',
+  INVOICES_HAS_NO_REMAINING_AMOUNT: 'INVOICES_HAS_NO_REMAINING_AMOUNT',
+  CREDIT_NOTE_APPLY_TO_INVOICES_NOT_FOUND:
+    'CREDIT_NOTE_APPLY_TO_INVOICES_NOT_FOUND',
+  CREDIT_NOTE_HAS_REFUNDS_TRANSACTIONS: 'CREDIT_NOTE_HAS_REFUNDS_TRANSACTIONS',
+  CREDIT_NOTE_HAS_APPLIED_INVOICES: 'CREDIT_NOTE_HAS_APPLIED_INVOICES',
+  CUSTOMER_HAS_LINKED_CREDIT_NOTES: 'CUSTOMER_HAS_LINKED_CREDIT_NOTES',
+};
+
+export const DEFAULT_VIEW_COLUMNS = [];
+export const DEFAULT_VIEWS = [
+  {
+    name: 'credit_note.view.draft',
+    slug: 'draft',
+    rolesLogicExpression: '1',
+    roles: [
+      { index: 1, fieldKey: 'status', comparator: 'equals', value: 'draft' },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+  {
+    name: 'credit_note.view.published',
+    slug: 'published',
+    rolesLogicExpression: '1',
+    roles: [
+      {
+        index: 1,
+        fieldKey: 'status',
+        comparator: 'equals',
+        value: 'published',
+      },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+  {
+    name: 'credit_note.view.open',
+    slug: 'open',
+    rolesLogicExpression: '1',
+    roles: [
+      {
+        index: 1,
+        fieldKey: 'status',
+        comparator: 'equals',
+        value: 'open',
+      },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+  {
+    name: 'credit_note.view.closed',
+    slug: 'closed',
+    rolesLogicExpression: '1',
+    roles: [
+      {
+        index: 1,
+        fieldKey: 'status',
+        comparator: 'equals',
+        value: 'closed',
+      },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+];
+
+export const defaultCreditNoteBrandingAttributes = {
+  // # Colors
+  primaryColor: '',
+  secondaryColor: '',
+  
+  // # Company logo
+  showCompanyLogo: true,
+  companyLogoKey: '',
+  companyLogoUri: '',
+
+  // # Company name
+  companyName: 'Bigcapital Technology, Inc.',
+
+  // # Customer address
+  showCustomerAddress: true,
+  customerAddress: '',
+
+  // # Company address
+  showCompanyAddress: true,
+  companyAddress: '',
+  billedToLabel: 'Billed To',
+
+  // Total
+  total: '$1000.00',
+  totalLabel: 'Total',
+  showTotal: true,
+
+  // Subtotal
+  subtotal: '1000/00',
+  subtotalLabel: 'Subtotal',
+  showSubtotal: true,
+
+  // Customer note
+  showCustomerNote: true,
+  customerNote:
+    'It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout.',
+  customerNoteLabel: 'Customer Note',
+
+  // Terms & conditions
+  showTermsConditions: true,
+  termsConditions:
+    'It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout.',
+  termsConditionsLabel: 'Terms & Conditions',
+
+  lines: [
+    {
+      item: 'Simply dummy text',
+      description: 'Simply dummy text of the printing and typesetting',
+      rate: '1',
+      quantity: '1000',
+      total: '$1000.00',
+    },
+  ],
+  // Credit note number.
+  showCreditNoteNumber: true,
+  creditNoteNumberLabel: 'Credit Note Number',
+  creditNoteNumebr: '346D3D40-0001',
+
+  // Credit note date.
+  creditNoteDate: 'September 3, 2024',
+  showCreditNoteDate: true,
+  creditNoteDateLabel: 'Credit Note Date',
+};

packages/server-nest/src/modules/CreditNotes/models/CreditNoteAppliedInvoice.ts

@@ -4,8 +4,17 @@ import { mixin, Model } from 'objection';
 // import CustomViewBaseModel from './CustomViewBaseModel';
 // import ModelSearchable from './ModelSearchable';
 import { BaseModel } from '@/models/Model';
+import { SaleInvoice } from '@/modules/SaleInvoices/models/SaleInvoice';
+import { CreditNote } from './CreditNote';
 
 export class CreditNoteAppliedInvoice extends BaseModel {
+  public amount: number;
+  public creditNoteId: number;
+  public invoiceId: number;
+
+  public saleInvoice!: SaleInvoice;
+  public creditNote!: CreditNote;
+
   /**
    * Table name
    */

packages/server-nest/src/modules/CreditNotes/models/RefundCreditNote.ts

@@ -0,0 +1,63 @@
+import { Model, mixin } from 'objection';
+// import TenantModel from 'models/TenantModel';
+// import ModelSetting from './ModelSetting';
+// import CustomViewBaseModel from './CustomViewBaseModel';
+// import ModelSearchable from './ModelSearchable';
+import { BaseModel } from '@/models/Model';
+
+export class RefundCreditNote extends BaseModel{
+  date: Date;
+  referenceNo: string;
+  amount: number;
+  currencyCode: string;
+  exchangeRate: number;
+  fromAccountId: number;
+  description: string;
+  creditNoteId: number;
+  
+  userId?: number;
+  branchId?: number;
+  
+  createdAt?: Date | null;
+
+  /**
+   * Table name.
+   */
+  static get tableName() {
+    return 'refund_credit_note_transactions';
+  }
+
+  /**
+   * Timestamps columns.
+   */
+  get timestamps() {
+    return ['created_at', 'updated_at'];
+  }
+
+  /**
+   * Relationship mapping.
+   */
+  static get relationMappings() {
+    const { Account } = require('../../Accounts/models/Account.model');
+    const { CreditNote } = require('../../CreditNotes/models/CreditNote');
+
+    return {
+      fromAccount: {
+        relation: Model.BelongsToOneRelation,
+        modelClass: Account,
+        join: {
+          from: 'refund_credit_note_transactions.fromAccountId',
+          to: 'accounts.id',
+        },
+      },
+      creditNote: {
+        relation: Model.BelongsToOneRelation,
+        modelClass: CreditNote,
+        join: {
+          from: 'refund_credit_note_transactions.creditNoteId',
+          to: 'credit_notes.id',
+        },
+      },
+    };
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/CreditNoteAppliedInvoiceTransformer.ts

@@ -0,0 +1,53 @@
+import { Transformer } from '../../Transformer/Transformer';
+import { CreditNoteAppliedInvoice } from '../models/CreditNoteAppliedInvoice';
+
+export class CreditNoteAppliedInvoiceTransformer extends Transformer {
+  /**
+   * Includeded attributes.
+   * @returns {string[]}
+   */
+  public includeAttributes = (): string[] => {
+    return [
+      'formttedAmount',
+      'creditNoteNumber',
+      'creditNoteDate',
+      'invoiceNumber',
+      'invoiceReferenceNo',
+      'formattedCreditNoteDate',
+    ];
+  };
+
+  /**
+   * Exclude attributes.
+   * @returns {string[]}
+   */
+  public excludeAttributes = (): string[] => {
+    return ['saleInvoice', 'creditNote'];
+  };
+
+  public formttedAmount = (item: CreditNoteAppliedInvoice) => {
+    return this.formatNumber(item.amount, {
+      currencyCode: item.creditNote.currencyCode,
+    });
+  };
+
+  public creditNoteNumber = (item: CreditNoteAppliedInvoice) => {
+    return item.creditNote.creditNoteNumber;
+  };
+
+  public creditNoteDate = (item: CreditNoteAppliedInvoice) => {
+    return item.creditNote.creditNoteDate;
+  };
+
+  public invoiceNumber = (item: CreditNoteAppliedInvoice) => {
+    return item.saleInvoice.invoiceNo;
+  };
+
+  public invoiceReferenceNo = (item: CreditNoteAppliedInvoice) => {
+    return item.saleInvoice.referenceNo;
+  };
+
+  public formattedCreditNoteDate = (item: CreditNoteAppliedInvoice) => {
+    return this.formatDate(item.creditNote.creditNoteDate);
+  };
+}

packages/server-nest/src/modules/CreditNotes/queries/CreditNoteBrandingTemplate.service.ts

@@ -0,0 +1,45 @@
+import { Injectable } from '@nestjs/common';
+import { defaultCreditNoteBrandingAttributes } from '../constants';
+import { GetPdfTemplateService } from '../../PdfTemplate/queries/GetPdfTemplate.service';
+import { GetOrganizationBrandingAttributesService } from '../../PdfTemplate/queries/GetOrganizationBrandingAttributes.service';
+import { mergePdfTemplateWithDefaultAttributes } from '../../SaleInvoices/utils';
+
+@Injectable()
+export class CreditNoteBrandingTemplate {
+  constructor(
+    private getPdfTemplateService: GetPdfTemplateService,
+    private getOrgBrandingAttributes: GetOrganizationBrandingAttributesService,
+  ) {}
+
+  /**
+   * Retrieves the credit note branding template.
+   * @param {number} templateId
+   * @returns {}
+   */
+  public async getCreditNoteBrandingTemplate(templateId: number) {
+    const template =
+      await this.getPdfTemplateService.getPdfTemplate(templateId);
+
+    // Retrieves the organization branding attributes.
+    const commonOrgBrandingAttrs =
+      await this.getOrgBrandingAttributes.getOrganizationBrandingAttributes();
+
+    // Merges the default branding attributes with common organization branding attrs.
+    const organizationBrandingAttrs = {
+      ...defaultCreditNoteBrandingAttributes,
+      ...commonOrgBrandingAttrs,
+    };
+    const brandingTemplateAttrs = {
+      ...template.attributes,
+      companyLogoUri: template.companyLogoUri,
+    };
+    const attributes = mergePdfTemplateWithDefaultAttributes(
+      brandingTemplateAttrs,
+      organizationBrandingAttrs,
+    );
+    return {
+      ...template,
+      attributes,
+    };
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/CreditNoteTransformer.ts

@@ -0,0 +1,194 @@
+import { AttachmentTransformer } from "@/modules/Attachments/Attachment.transformer";
+import { ItemEntryTransformer } from "@/modules/TransactionItemEntry/ItemEntry.transformer";
+import { Transformer } from "@/modules/Transformer/Transformer";
+
+export class CreditNoteTransformer extends Transformer {
+  /**
+   * Include these attributes to sale credit note object.
+   * @returns {Array}
+   */
+  public includeAttributes = (): string[] => {
+    return [
+      'formattedCreditsRemaining',
+      'formattedCreditNoteDate',
+      'formattedCreatedAt',
+      'formattedCreatedAt',
+      'formattedAmount',
+      'formattedCreditsUsed',
+      'formattedSubtotal',
+
+      'discountAmountFormatted',
+      'discountAmountLocalFormatted',
+
+      'discountPercentageFormatted',
+
+      'adjustmentFormatted',
+      'adjustmentLocalFormatted',
+
+      'totalFormatted',
+      'totalLocalFormatted',
+
+      'entries',
+      'attachments',
+    ];
+  };
+
+  /**
+   * Retrieve formatted credit note date.
+   * @param {ICreditNote} credit
+   * @returns {String}
+   */
+  protected formattedCreditNoteDate = (credit): string => {
+    return this.formatDate(credit.creditNoteDate);
+  };
+
+  /**
+   * Retrieve formatted created at date.
+   * @param credit
+   * @returns {string}
+   */
+  protected formattedCreatedAt = (credit): string => {
+    return this.formatDate(credit.createdAt);
+  };
+
+  /**
+   * Retrieve formatted invoice amount.
+   * @param {ICreditNote} credit
+   * @returns {string}
+   */
+  protected formattedAmount = (credit): string => {
+    return this.formatNumber(credit.amount, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieve formatted credits remaining.
+   * @param {ICreditNote} credit
+   * @returns {string}
+   */
+  protected formattedCreditsRemaining = (credit) => {
+    return this.formatNumber(credit.creditsRemaining, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieve formatted credits used.
+   * @param {ICreditNote} credit
+   * @returns {string}
+   */
+  protected formattedCreditsUsed = (credit) => {
+    return this.formatNumber(credit.creditsUsed, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the formatted subtotal.
+   * @param {ICreditNote} credit
+   * @returns {string}
+   */
+  protected formattedSubtotal = (credit): string => {
+    return this.formatNumber(credit.amount, { money: false });
+  };
+
+  /**
+   * Retrieves formatted discount amount.
+   * @param credit
+   * @returns {string}
+   */
+  protected discountAmountFormatted = (credit): string => {
+    return this.formatNumber(credit.discountAmount, {
+      currencyCode: credit.currencyCode,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted discount amount in local currency.
+   * @param {ICreditNote} credit
+   * @returns {string}
+   */
+  protected discountAmountLocalFormatted = (credit): string => {
+    return this.formatNumber(credit.discountAmountLocal, {
+      currencyCode: credit.currencyCode,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves formatted discount percentage.
+   * @param credit
+   * @returns {string}
+   */
+  protected discountPercentageFormatted = (credit): string => {
+    return credit.discountPercentage ? `${credit.discountPercentage}%` : '';
+  };
+
+  /**
+   * Retrieves formatted adjustment amount.
+   * @param credit
+   * @returns {string}
+   */
+  protected adjustmentFormatted = (credit): string => {
+    return this.formatMoney(credit.adjustment, {
+      currencyCode: credit.currencyCode,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted adjustment amount in local currency.
+   * @param {ICreditNote} credit
+   * @returns {string}
+   */
+  protected adjustmentLocalFormatted = (credit): string => {
+    return this.formatNumber(credit.adjustmentLocal, {
+      currencyCode: this.context.organization.baseCurrency,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted total.
+   * @param credit
+   * @returns {string}
+   */
+  protected totalFormatted = (credit): string => {
+    return this.formatNumber(credit.total, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the formatted total in local currency.
+   * @param credit
+   * @returns {string}
+   */
+  protected totalLocalFormatted = (credit): string => {
+    return this.formatNumber(credit.totalLocal, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the entries of the credit note.
+   * @param {ICreditNote} credit
+   * @returns {}
+   */
+  protected entries = (credit) => {
+    return this.item(credit.entries, new ItemEntryTransformer(), {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the credit note attachments.
+   * @param {ISaleInvoice} invoice
+   * @returns
+   */
+  protected attachments = (creditNote) => {
+    return this.item(creditNote.attachments, new AttachmentTransformer());
+  };
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNote.service.ts

@@ -0,0 +1,39 @@
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+import { ERRORS } from '../constants';
+import { CreditNoteTransformer } from './CreditNoteTransformer';
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNote } from '../models/CreditNote';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+@Injectable()
+export class GetCreditNote {
+  constructor(
+    private readonly transformer: TransformerInjectable,
+
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} tenantId
+   * @param {number} creditNoteId
+   * @returns
+   */
+  public async getCreditNote(creditNoteId: number) {
+    // Retrieve the vendor credit model graph.
+    const creditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteId)
+      .withGraphFetched('entries.item')
+      .withGraphFetched('customer')
+      .withGraphFetched('branch')
+      .withGraphFetched('attachments');
+
+    if (!creditNote) {
+      throw new ServiceError(ERRORS.CREDIT_NOTE_NOT_FOUND);
+    }
+    // Transforms the credit note model to POJO.
+    return this.transformer.transform(creditNote, new CreditNoteTransformer());
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNoteAssociatedAppliedInvoices.service.ts

@@ -0,0 +1,42 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNoteAppliedInvoiceTransformer } from './CreditNoteAppliedInvoiceTransformer';
+import { CreditNote } from '../models/CreditNote';
+import { TransformerInjectable } from '../../Transformer/TransformerInjectable.service';
+import { CreditNoteAppliedInvoice } from '../models/CreditNoteAppliedInvoice';
+
+@Injectable()
+export class GetCreditNoteAssociatedAppliedInvoices {
+  constructor(
+    private readonly transformer: TransformerInjectable,
+    private readonly creditNoteAppliedInvoiceModel: typeof CreditNoteAppliedInvoice,
+
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote
+  ) {
+  }
+
+  /**
+   * Retrieve credit note associated invoices to apply.
+   * @param {number} creditNoteId
+   * @returns {Promise<CreditNoteAppliedInvoice[]>}
+   */
+  public async getCreditAssociatedAppliedInvoices(
+    creditNoteId: number
+  ): Promise<CreditNoteAppliedInvoice[]> {
+    // Retrieve credit note or throw not found service error.
+    const creditNote = await this.creditNoteModel.query()
+      .findById(creditNoteId)
+      .throwIfNotFound();
+
+    const appliedToInvoices = await this.creditNoteAppliedInvoiceModel.query()
+      .where('credit_note_id', creditNoteId)
+      .withGraphFetched('saleInvoice')
+      .withGraphFetched('creditNote');
+
+    // Transforms credit note applied to invoices.
+    return this.transformer.transform(
+      appliedToInvoices,
+      new CreditNoteAppliedInvoiceTransformer()
+    );
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNoteAssociatedInvoicesToApply.service.ts

@@ -0,0 +1,41 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNoteWithInvoicesToApplyTransformer } from '../commands/CreditNoteWithInvoicesToApplyTransformer';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+import { SaleInvoice } from '@/modules/SaleInvoices/models/SaleInvoice';
+import { GetCreditNote } from './GetCreditNote.service';
+
+@Injectable()
+export class GetCreditNoteAssociatedInvoicesToApply {
+  constructor(
+    private transformer: TransformerInjectable,
+    private getCreditNote: GetCreditNote,
+
+    @Inject(SaleInvoice.name)
+    private saleInvoiceModel: typeof SaleInvoice,
+  ) {}
+
+  /**
+   * Retrieve credit note associated invoices to apply.
+   * @param {number} creditNoteId
+   * @returns {Promise<ISaleInvoice[]>}
+   */
+  public async getCreditAssociatedInvoicesToApply(
+    creditNoteId: number,
+  ): Promise<SaleInvoice[]> {
+    // Retrieve credit note or throw not found service error.
+    const creditNote = await this.getCreditNote.getCreditNote(creditNoteId);
+
+    // Retrieves the published due invoices that associated to the given customer.
+    const saleInvoices = await this.saleInvoiceModel
+      .query()
+      .where('customerId', creditNote.customerId)
+      .modify('dueInvoices')
+      .modify('published');
+
+    // Transforms the sale invoices models to POJO.
+    return this.transformer.transform(
+      saleInvoices,
+      new CreditNoteWithInvoicesToApplyTransformer(),
+    );
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNotePdf.serivce.ts

@@ -0,0 +1,99 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { GetCreditNote } from './GetCreditNote.service';
+import { CreditNoteBrandingTemplate } from './CreditNoteBrandingTemplate.service';
+import { transformCreditNoteToPdfTemplate } from '../utils';
+import { CreditNote } from '../models/CreditNote';
+import { ChromiumlyTenancy } from '@/modules/ChromiumlyTenancy/ChromiumlyTenancy.service';
+import { TemplateInjectable } from '@/modules/TemplateInjectable/TemplateInjectable.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { PdfTemplateModel } from '@/modules/PdfTemplate/models/PdfTemplate';
+import { CreditNotePdfTemplateAttributes } from '../types/CreditNotes.types';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class GetCreditNotePdf {
+  constructor(
+    private readonly chromiumlyTenancy: ChromiumlyTenancy,
+    private readonly templateInjectable: TemplateInjectable,
+    private readonly getCreditNoteService: GetCreditNote,
+    private readonly creditNoteBrandingTemplate: CreditNoteBrandingTemplate,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: typeof CreditNote,
+
+    @Inject(PdfTemplateModel.name)
+    private readonly pdfTemplateModel: typeof PdfTemplateModel,
+  ) {}
+
+  /**
+   * Retrieves sale invoice pdf content.
+   * @param {number} creditNoteId - Credit note id.
+   * @returns {Promise<[Buffer, string]>}
+   */
+  public async getCreditNotePdf(
+    creditNoteId: number,
+  ): Promise<[Buffer, string]> {
+    const brandingAttributes =
+      await this.getCreditNoteBrandingAttributes(creditNoteId);
+    const htmlContent = await this.templateInjectable.render(
+      'modules/credit-note-standard',
+      brandingAttributes,
+    );
+    const filename = await this.getCreditNoteFilename(creditNoteId);
+
+    const document =
+      await this.chromiumlyTenancy.convertHtmlContent(htmlContent);
+    const eventPayload = { creditNoteId };
+
+    // Triggers the `onCreditNotePdfViewed` event.
+    await this.eventPublisher.emitAsync(
+      events.creditNote.onPdfViewed,
+      eventPayload,
+    );
+    return [document, filename];
+  }
+
+  /**
+   * Retrieves the filename pdf document of the given credit note.
+   * @param {number} creditNoteId
+   * @returns {Promise<string>}
+   */
+  public async getCreditNoteFilename(creditNoteId: number): Promise<string> {
+    const creditNote = await this.creditNoteModel
+      .query()
+      .findById(creditNoteId);
+    return `Credit-${creditNote.creditNoteNumber}`;
+  }
+
+  /**
+   * Retrieves credit note branding attributes.
+   * @param {number} creditNoteId - The ID of the credit note.
+   * @returns {Promise<CreditNotePdfTemplateAttributes>} The credit note branding attributes.
+   */
+  public async getCreditNoteBrandingAttributes(
+    creditNoteId: number,
+  ): Promise<CreditNotePdfTemplateAttributes> {
+    const creditNote =
+      await this.getCreditNoteService.getCreditNote(creditNoteId);
+
+    // Retrieve the invoice template id of not found get the default template id.
+    const templateId =
+      creditNote.pdfTemplateId ??
+      (
+        await this.pdfTemplateModel.query().findOne({
+          resource: 'CreditNote',
+          default: true,
+        })
+      )?.id;
+    // Retrieves the credit note branding template.
+    const brandingTemplate =
+      await this.creditNoteBrandingTemplate.getCreditNoteBrandingTemplate(
+        templateId,
+      );
+    return {
+      ...brandingTemplate.attributes,
+      ...transformCreditNoteToPdfTemplate(creditNote),
+    };
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNoteRefunds.service.ts

@@ -0,0 +1,37 @@
+import { Inject, Injectable } from '@nestjs/common';
+import RefundCreditNoteTransformer from './RefundCreditNoteTransformer';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { IRefundCreditNotePOJO } from '../types/CreditNotes.types';
+
+@Injectable()
+export class ListCreditNoteRefunds {
+  constructor(
+    private readonly transformer: TransformerInjectable,
+
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: typeof RefundCreditNote,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} creditNoteId
+   * @returns {Promise<IRefundCreditNotePOJO[]>}
+   */
+  public async getCreditNoteRefunds(
+    creditNoteId: number,
+  ): Promise<IRefundCreditNotePOJO[]> {
+    // Retrieve refund credit notes associated to the given credit note.
+    const refundCreditTransactions = await this.refundCreditNoteModel
+      .query()
+      .where('creditNoteId', creditNoteId)
+      .withGraphFetched('creditNote')
+      .withGraphFetched('fromAccount');
+
+    // Transforms refund credit note models to POJO objects.
+    return this.transformer.transform(
+      refundCreditTransactions,
+      new RefundCreditNoteTransformer(),
+    );
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNoteState.service.ts

@@ -0,0 +1,25 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { ICreditNoteState } from '../types/CreditNotes.types';
+import { PdfTemplateModel } from '@/modules/PdfTemplate/models/PdfTemplate';
+
+@Injectable()
+export class GetCreditNoteState {
+  constructor(
+    @Inject(PdfTemplateModel.name)
+    private pdfTemplateModel: typeof PdfTemplateModel,
+  ) {}
+
+  /**
+   * Retrieves the create/edit initial state of the payment received.
+   * @return {Promise<ICreditNoteState>}
+   */
+  public async getCreditNoteState(): Promise<ICreditNoteState> {
+    const defaultPdfTemplate = await this.pdfTemplateModel.query()
+      .findOne({ resource: 'CreditNote' })
+      .modify('default');
+
+    return {
+      defaultTemplateId: defaultPdfTemplate?.id,
+    };
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/GetCreditNotes.service.ts

@@ -0,0 +1,68 @@
+// import { Service, Inject } from 'typedi';
+// import * as R from 'ramda';
+// import { ICreditNotesQueryDTO } from '@/interfaces';
+// import DynamicListingService from '@/services/DynamicListing/DynamicListService';
+// import BaseCreditNotes from './commands/CommandCreditNoteDTOTransform.service';
+// import { CreditNoteTransformer } from './queries/CreditNoteTransformer';
+// import { TransformerInjectable } from '@/lib/Transformer/TransformerInjectable';
+
+// @Service()
+// export default class ListCreditNotes extends BaseCreditNotes {
+//   @Inject()
+//   private dynamicListService: DynamicListingService;
+
+//   @Inject()
+//   private transformer: TransformerInjectable;
+
+//   /**
+//    * Parses the sale invoice list filter DTO.
+//    * @param filterDTO
+//    * @returns
+//    */
+//   private parseListFilterDTO = (filterDTO) => {
+//     return R.compose(this.dynamicListService.parseStringifiedFilter)(filterDTO);
+//   };
+
+//   /**
+//    * Retrieves the paginated and filterable credit notes list.
+//    * @param {number} tenantId -
+//    * @param {ICreditNotesQueryDTO} creditNotesQuery -
+//    */
+//   public getCreditNotesList = async (
+//     tenantId: number,
+//     creditNotesQuery: ICreditNotesQueryDTO
+//   ) => {
+//     const { CreditNote } = this.tenancy.models(tenantId);
+
+//     // Parses stringified filter roles.
+//     const filter = this.parseListFilterDTO(creditNotesQuery);
+
+//     // Dynamic list service.
+//     const dynamicFilter = await this.dynamicListService.dynamicList(
+//       tenantId,
+//       CreditNote,
+//       filter
+//     );
+//     const { results, pagination } = await CreditNote.query()
+//       .onBuild((builder) => {
+//         builder.withGraphFetched('entries.item');
+//         builder.withGraphFetched('customer');
+//         dynamicFilter.buildQuery()(builder);
+//         creditNotesQuery?.filterQuery && creditNotesQuery?.filterQuery(builder);
+//       })
+//       .pagination(filter.page - 1, filter.pageSize);
+
+//     // Transforomes the credit notes to POJO.
+//     const creditNotes = await this.transformer.transform(
+//       tenantId,
+//       results,
+//       new CreditNoteTransformer()
+//     );
+
+//     return {
+//       creditNotes,
+//       pagination,
+//       filterMeta: dynamicFilter.getResponseMeta(),
+//     };
+//   };
+// }

packages/server-nest/src/modules/CreditNotes/queries/GetRefundCreditNoteTransaction.service.ts

@@ -0,0 +1,37 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { IRefundCreditNote } from '../types/CreditNotes.types';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { RefundCreditNoteTransformer } from './RefundCreditNoteTransformer';
+
+@Injectable()
+export class GetRefundCreditNoteTransaction {
+  /**
+   * @param {RefundCreditNoteTransformer} transformer
+   * @param {typeof RefundCreditNote} refundCreditNoteModel
+   */
+  constructor(
+    private readonly transformer: RefundCreditNoteTransformer,
+
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: typeof RefundCreditNote,
+  ) {
+  }
+
+  /**
+   * Retrieve credit note associated invoices to apply.
+   * @param {number} refundCreditId
+   * @returns {Promise<IRefundCreditNote>}
+   */
+  public async getRefundCreditTransaction(
+    refundCreditId: number
+  ): Promise<IRefundCreditNote> {
+    const refundCreditNote = await this.refundCreditNoteModel
+      .query()
+      .findById(refundCreditId)
+      .withGraphFetched('fromAccount')
+      .withGraphFetched('creditNote')
+      .throwIfNotFound();
+
+    return this.transformer.transform(refundCreditNote);
+  }
+}

packages/server-nest/src/modules/CreditNotes/queries/RefundCreditNoteTransformer.ts

@@ -0,0 +1,29 @@
+import { Transformer } from "@/modules/Transformer/Transformer";
+
+export class RefundCreditNoteTransformer extends Transformer{
+  /**
+   * Includeded attributes.
+   * @returns {string[]}
+   */
+  public includeAttributes = (): string[] => {
+    return ['formttedAmount', 'formattedDate'];
+  };
+
+  /**
+   * Formatted amount.
+   * @returns {string}
+   */
+  protected formttedAmount = (item) => {
+    return this.formatNumber(item.amount, {
+      currencyCode: item.currencyCode,
+    });
+  };
+
+  /**
+   * Formatted date.
+   * @returns {string}
+   */
+  protected formattedDate = (item) => {
+    return this.formatDate(item.date);
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/CreditNoteApplySyncCreditSubscriber.ts

@@ -0,0 +1,67 @@
+import { Service, Inject } from 'typedi';
+import { sumBy } from 'lodash';
+import events from '@/subscribers/events';
+import {
+  IApplyCreditToInvoicesCreatedPayload,
+  IApplyCreditToInvoicesDeletedPayload,
+} from '@/interfaces';
+import CreditNoteApplySyncCredit from '../commands/CreditNoteApplySyncCredit.service';
+
+@Service()
+export default class CreditNoteApplySyncCreditSubscriber {
+  @Inject()
+  syncInvoicedAmountWithCredit: CreditNoteApplySyncCredit;
+
+  /**
+   *
+   * @param bus
+   */
+  attach(bus) {
+    bus.subscribe(
+      events.creditNote.onApplyToInvoicesCreated,
+      this.incrementCreditedAmountOnceApplyToInvoicesCreated
+    );
+    bus.subscribe(
+      events.creditNote.onApplyToInvoicesDeleted,
+      this.decrementCreditedAmountOnceApplyToInvoicesDeleted
+    );
+  }
+
+  /**
+   * Increment credited amount of credit note transaction once the transaction created.
+   * @param {IApplyCreditToInvoicesCreatedPayload} payload -
+   */
+  private incrementCreditedAmountOnceApplyToInvoicesCreated = async ({
+    trx,
+    creditNote,
+    tenantId,
+    creditNoteAppliedInvoices,
+  }: IApplyCreditToInvoicesCreatedPayload) => {
+    const totalCredited = sumBy(creditNoteAppliedInvoices, 'amount');
+
+    await this.syncInvoicedAmountWithCredit.incrementCreditNoteInvoicedAmount(
+      tenantId,
+      creditNote.id,
+      totalCredited,
+      trx
+    );
+  };
+
+  /**
+   * Decrement credited amount of credit note transaction once the transaction deleted.
+   * @param {IApplyCreditToInvoicesDeletedPayload} payload -
+   */
+  private decrementCreditedAmountOnceApplyToInvoicesDeleted = async ({
+    tenantId,
+    creditNote,
+    creditNoteAppliedToInvoice,
+    trx,
+  }: IApplyCreditToInvoicesDeletedPayload) => {
+    await this.syncInvoicedAmountWithCredit.decrementCreditNoteInvoicedAmount(
+      tenantId,
+      creditNote.id,
+      creditNoteAppliedToInvoice.amount,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/CreditNoteApplySyncInvoicesSubscriber.ts

@@ -0,0 +1,61 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import {
+  IApplyCreditToInvoicesCreatedPayload,
+  IApplyCreditToInvoicesDeletedPayload,
+} from '@/interfaces';
+import CreditNoteApplySyncInvoicesCreditedAmount from '../commands/CreditNoteApplySyncInvoices.service';
+
+@Service()
+export default class CreditNoteApplySyncInvoicesCreditedAmountSubscriber {
+  @Inject()
+  private syncInvoicesWithCreditNote: CreditNoteApplySyncInvoicesCreditedAmount;
+
+  /**
+   * Attaches events with handlers.
+   */
+  public attach(bus) {
+    bus.subscribe(
+      events.creditNote.onApplyToInvoicesCreated,
+      this.incrementAppliedInvoicesOnceCreditCreated
+    );
+    bus.subscribe(
+      events.creditNote.onApplyToInvoicesDeleted,
+      this.decrementAppliedInvoicesOnceCreditDeleted
+    );
+  }
+
+  /**
+   * Increment invoices credited amount once the credit note apply to invoices transaction
+   * @param {IApplyCreditToInvoicesCreatedPayload} payload -
+   */
+  private incrementAppliedInvoicesOnceCreditCreated = async ({
+    trx,
+    tenantId,
+    creditNoteAppliedInvoices,
+  }: IApplyCreditToInvoicesCreatedPayload) => {
+    await this.syncInvoicesWithCreditNote.incrementInvoicesCreditedAmount(
+      tenantId,
+      creditNoteAppliedInvoices,
+      trx
+    );
+  };
+
+  /**
+   *
+   * @param {IApplyCreditToInvoicesDeletedPayload} payload -
+   */
+  private decrementAppliedInvoicesOnceCreditDeleted = async ({
+    trx,
+    creditNoteAppliedToInvoice,
+    tenantId,
+  }: IApplyCreditToInvoicesDeletedPayload) => {
+    // Decrement invoice credited amount.
+    await this.syncInvoicesWithCreditNote.decrementInvoiceCreditedAmount(
+      tenantId,
+      creditNoteAppliedToInvoice.invoiceId,
+      creditNoteAppliedToInvoice.amount,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/CreditNoteAutoSerialSubscriber.ts

@@ -0,0 +1,30 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import BaseCreditNotes from '../commands/CommandCreditNoteDTOTransform.service';
+import { ICreditNoteCreatedPayload } from '@/interfaces';
+
+@Service()
+export default class CreditNoteAutoSerialSubscriber {
+  @Inject()
+  creditNotesService: BaseCreditNotes;
+
+  /**
+   * Attaches events with handlers.
+   */
+  public attach(bus) {
+    bus.subscribe(
+      events.creditNote.onCreated,
+      this.autoSerialIncrementOnceCreated
+    );
+  }
+
+  /**
+   * Auto serial increment once credit note created.
+   * @param {ICreditNoteCreatedPayload} payload - 
+   */
+  private autoSerialIncrementOnceCreated = async ({
+    tenantId,
+  }: ICreditNoteCreatedPayload) => {
+    await this.creditNotesService.incrementSerialNumber(tenantId);
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/CreditNoteGLEntriesSubscriber.ts

@@ -0,0 +1,113 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import {
+  ICreditNoteCreatedPayload,
+  ICreditNoteDeletedPayload,
+  ICreditNoteEditedPayload,
+  ICreditNoteOpenedPayload,
+} from '@/interfaces';
+import CreditNoteGLEntries from '../commands/CreditNoteGLEntries';
+
+@Service()
+export default class CreditNoteGLEntriesSubscriber {
+  @Inject()
+  private creditNoteGLEntries: CreditNoteGLEntries;
+
+  /**
+   * Attaches events with handlers.
+   * @param bus
+   */
+  public attach(bus) {
+    bus.subscribe(
+      events.creditNote.onCreated,
+      this.writeGlEntriesOnceCreditNoteCreated
+    );
+    bus.subscribe(
+      events.creditNote.onOpened,
+      this.writeGLEntriesOnceCreditNoteOpened
+    );
+    bus.subscribe(
+      events.creditNote.onEdited,
+      this.editVendorCreditGLEntriesOnceEdited
+    );
+    bus.subscribe(
+      events.creditNote.onDeleted,
+      this.revertGLEntriesOnceCreditNoteDeleted
+    );
+  }
+
+  /**
+   * Writes the GL entries once the credit note transaction created or open.
+   * @private
+   * @param {ICreditNoteCreatedPayload|ICreditNoteOpenedPayload} payload -
+   */
+  private writeGlEntriesOnceCreditNoteCreated = async ({
+    tenantId,
+    creditNote,
+    creditNoteId,
+    trx,
+  }: ICreditNoteCreatedPayload | ICreditNoteOpenedPayload) => {
+    // Can't continue if the credit note is not published yet.
+    if (!creditNote.isPublished) return;
+
+    await this.creditNoteGLEntries.createVendorCreditGLEntries(
+      tenantId,
+      creditNoteId,
+      trx
+    );
+  };
+
+  /**
+   * Writes the GL entries once the vendor credit transaction opened.
+   * @param {ICreditNoteOpenedPayload} payload
+   */
+  private writeGLEntriesOnceCreditNoteOpened = async ({
+    tenantId,
+    creditNoteId,
+    trx,
+  }: ICreditNoteOpenedPayload) => {
+    await this.creditNoteGLEntries.createVendorCreditGLEntries(
+      tenantId,
+      creditNoteId,
+      trx
+    );
+  };
+
+  /**
+   * Reverts GL entries once credit note deleted.
+   */
+  private revertGLEntriesOnceCreditNoteDeleted = async ({
+    tenantId,
+    oldCreditNote,
+    creditNoteId,
+    trx,
+  }: ICreditNoteDeletedPayload) => {
+    // Can't continue if the credit note is not published yet.
+    if (!oldCreditNote.isPublished) return;
+
+    await this.creditNoteGLEntries.revertVendorCreditGLEntries(
+      tenantId,
+      creditNoteId
+    );
+  };
+
+  /**
+   * Edits vendor credit associated GL entries once the transaction edited.
+   * @param {ICreditNoteEditedPayload} payload -
+   */
+  private editVendorCreditGLEntriesOnceEdited = async ({
+    tenantId,
+    creditNote,
+    creditNoteId,
+    trx,
+  }: ICreditNoteEditedPayload) => {
+    // Can't continue if the credit note is not published yet.
+    if (!creditNote.isPublished) return;
+
+    await this.creditNoteGLEntries.editVendorCreditGLEntries(
+      tenantId,
+      creditNoteId,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/CreditNoteInventoryTransactionsSubscriber.ts

@@ -0,0 +1,98 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import CreditNoteInventoryTransactions from '../commands/CreditNotesInventoryTransactions';
+import {
+  ICreditNoteCreatedPayload,
+  ICreditNoteDeletedPayload,
+  ICreditNoteEditedPayload,
+} from '@/interfaces';
+
+@Service()
+export default class CreditNoteInventoryTransactionsSubscriber {
+  @Inject()
+  inventoryTransactions: CreditNoteInventoryTransactions;
+
+  /**
+   * Attaches events with publisher.
+   */
+  public attach(bus) {
+    bus.subscribe(
+      events.creditNote.onCreated,
+      this.writeInventoryTranscationsOnceCreated
+    );
+    bus.subscribe(
+      events.creditNote.onEdited,
+      this.rewriteInventoryTransactionsOnceEdited
+    );
+    bus.subscribe(
+      events.creditNote.onDeleted,
+      this.revertInventoryTransactionsOnceDeleted
+    );
+    bus.subscribe(
+      events.creditNote.onOpened,
+      this.writeInventoryTranscationsOnceCreated
+    );
+  }
+
+  /**
+   * Writes inventory transactions once credit note created.
+   * @param {ICreditNoteCreatedPayload} payload -
+   * @returns {Promise<void>}
+   */
+  public writeInventoryTranscationsOnceCreated = async ({
+    tenantId,
+    creditNote,
+    trx,
+  }: ICreditNoteCreatedPayload) => {
+    // Can't continue if the credit note is open yet.
+    if (!creditNote.isOpen) return;
+
+    await this.inventoryTransactions.createInventoryTransactions(
+      tenantId,
+      creditNote,
+      trx
+    );
+  };
+
+  /**
+   * Rewrites inventory transactions once credit note edited.
+   * @param {ICreditNoteEditedPayload} payload -
+   * @returns {Promise<void>}
+   */
+  public rewriteInventoryTransactionsOnceEdited = async ({
+    tenantId,
+    creditNoteId,
+    creditNote,
+    trx,
+  }: ICreditNoteEditedPayload) => {
+    // Can't continue if the credit note is open yet.
+    if (!creditNote.isOpen) return;
+
+    await this.inventoryTransactions.editInventoryTransactions(
+      tenantId,
+      creditNoteId,
+      creditNote,
+      trx
+    );
+  };
+
+  /**
+   * Reverts inventory transactions once credit note deleted.
+   * @param {ICreditNoteDeletedPayload} payload -
+   */
+  public revertInventoryTransactionsOnceDeleted = async ({
+    tenantId,
+    creditNoteId,
+    oldCreditNote,
+    trx,
+  }: ICreditNoteDeletedPayload) => {
+    // Can't continue if the credit note is open yet.
+    if (!oldCreditNote.isOpen) return;
+
+    await this.inventoryTransactions.deleteInventoryTransactions(
+      tenantId,
+      creditNoteId,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/DeleteCustomerLinkedCreditSubscriber.ts

@@ -0,0 +1,48 @@
+import { Inject, Service } from 'typedi';
+import { ServiceError } from '@/exceptions';
+import TenancyService from '@/services/Tenancy/TenancyService';
+import events from '@/subscribers/events';
+import { ICustomerDeletingPayload } from '@/interfaces';
+import DeleteCustomerLinkedCreidtNote from '../commands/DeleteCustomerLinkedCreditNote.service';
+
+const ERRORS = {
+  CUSTOMER_HAS_TRANSACTIONS: 'CUSTOMER_HAS_TRANSACTIONS',
+};
+
+@Service()
+export default class DeleteCustomerLinkedCreditSubscriber {
+  @Inject()
+  tenancy: TenancyService;
+
+  @Inject()
+  deleteCustomerLinkedCredit: DeleteCustomerLinkedCreidtNote;
+
+  /**
+   * Attaches events with handlers.
+   * @param bus
+   */
+  public attach = (bus) => {
+    bus.subscribe(
+      events.customers.onDeleting,
+      this.validateCustomerHasNoLinkedCreditsOnDeleting
+    );
+  };
+
+  /**
+   * Validate vendor has no associated credit transaction once the vendor deleting.
+   * @param {IVendorEventDeletingPayload} payload -
+   */
+  public validateCustomerHasNoLinkedCreditsOnDeleting = async ({
+    tenantId,
+    customerId,
+  }: ICustomerDeletingPayload) => {
+    try {
+      await this.deleteCustomerLinkedCredit.validateCustomerHasNoCreditTransaction(
+        tenantId,
+        customerId
+      );
+    } catch (error) {
+      throw new ServiceError(ERRORS.CUSTOMER_HAS_TRANSACTIONS);
+    }
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/RefundCreditNoteGLEntriesSubscriber.ts

@@ -0,0 +1,61 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import RefundCreditNoteGLEntries from '../commands/RefundCreditNoteGLEntries';
+import {
+  IRefundCreditNoteCreatedPayload,
+  IRefundCreditNoteDeletedPayload,
+} from '@/interfaces';
+
+@Service()
+export default class RefundCreditNoteGLEntriesSubscriber {
+  @Inject()
+  refundCreditGLEntries: RefundCreditNoteGLEntries;
+
+  /**
+   * Attaches events with handlers.
+   */
+  public attach = (bus) => {
+    bus.subscribe(
+      events.creditNote.onRefundCreated,
+      this.writeRefundCreditGLEntriesOnceCreated
+    );
+    bus.subscribe(
+      events.creditNote.onRefundDeleted,
+      this.revertRefundCreditGLEntriesOnceDeleted
+    );
+  };
+
+  /**
+   * Writes refund credit note GL entries once the transaction created.
+   * @param {IRefundCreditNoteCreatedPayload} payload -
+   */
+  private writeRefundCreditGLEntriesOnceCreated = async ({
+    trx,
+    refundCreditNote,
+    creditNote,
+    tenantId,
+  }: IRefundCreditNoteCreatedPayload) => {
+    await this.refundCreditGLEntries.createRefundCreditGLEntries(
+      tenantId,
+      refundCreditNote.id,
+      trx
+    );
+  };
+
+  /**
+   * Reverts refund credit note GL entries once the transaction deleted.
+   * @param {IRefundCreditNoteDeletedPayload} payload -
+   */
+  private revertRefundCreditGLEntriesOnceDeleted = async ({
+    trx,
+    refundCreditId,
+    oldRefundCredit,
+    tenantId,
+  }: IRefundCreditNoteDeletedPayload) => {
+    await this.refundCreditGLEntries.revertRefundCreditGLEntries(
+      tenantId,
+      refundCreditId,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/subscribers/RefundSyncCreditNoteBalanceSubscriber.ts

@@ -0,0 +1,62 @@
+import { Inject, Service } from 'typedi';
+import {
+  IRefundCreditNoteCreatedPayload,
+  IRefundCreditNoteDeletedPayload,
+} from '@/interfaces';
+import events from '@/subscribers/events';
+import RefundSyncCreditNoteBalance from '../commands/RefundSyncCreditNoteBalance';
+
+@Service()
+export default class RefundSyncCreditNoteBalanceSubscriber {
+  @Inject()
+  refundSyncCreditBalance: RefundSyncCreditNoteBalance;
+
+  /**
+   * Attaches events with handlers.
+   */
+  attach(bus) {
+    bus.subscribe(
+      events.creditNote.onRefundCreated,
+      this.incrementRefundedAmountOnceRefundCreated
+    );
+    bus.subscribe(
+      events.creditNote.onRefundDeleted,
+      this.decrementRefundedAmountOnceRefundDeleted
+    );
+    return bus;
+  }
+
+  /**
+   * Increment credit note refunded amount once associated refund transaction created.
+   * @param {IRefundCreditNoteCreatedPayload} payload -
+   */
+  private incrementRefundedAmountOnceRefundCreated = async ({
+    trx,
+    refundCreditNote,
+    tenantId,
+  }: IRefundCreditNoteCreatedPayload) => {
+    await this.refundSyncCreditBalance.incrementCreditNoteRefundAmount(
+      tenantId,
+      refundCreditNote.creditNoteId,
+      refundCreditNote.amount,
+      trx
+    );
+  };
+
+  /**
+   * Decrement credit note refunded amount once associated refuned transaction deleted.
+   * @param {IRefundCreditNoteDeletedPayload} payload -
+   */
+  private decrementRefundedAmountOnceRefundDeleted = async ({
+    trx,
+    oldRefundCredit,
+    tenantId,
+  }: IRefundCreditNoteDeletedPayload) => {
+    await this.refundSyncCreditBalance.decrementCreditNoteRefundAmount(
+      tenantId,
+      oldRefundCredit.creditNoteId,
+      oldRefundCredit.amount,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/CreditNotes/types/CreditNotes.types.ts

@@ -0,0 +1,307 @@
+import { Knex } from 'knex';
+import { DiscountType, IDynamicListFilter, IItemEntry } from '@/interfaces';
+import { ILedgerEntry } from './Ledger';
+import { AttachmentLinkDTO } from './Attachments';
+import { CreditNote } from '../models/CreditNote';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+
+export interface ICreditNoteEntryNewDTO {
+  index?: number;
+  itemId: number;
+  rate: number;
+  quantity: number;
+  discount: number;
+  description: string;
+  warehouseId?: number;
+}
+export interface ICreditNoteNewDTO {
+  customerId: number;
+  exchangeRate?: number;
+  creditNoteDate: Date;
+  creditNoteNumber: string;
+  note: string;
+  open: boolean;
+  entries: ICreditNoteEntryNewDTO[];
+  branchId?: number;
+  warehouseId?: number;
+  attachments?: AttachmentLinkDTO[];
+  discount?: number;
+  discountType?: DiscountType;
+  adjustment?: number;
+}
+
+export interface ICreditNoteEditDTO {
+  customerId: number;
+  exchangeRate?: number;
+  creditNoteDate: Date;
+  creditNoteNumber: string;
+  note: string;
+  open: boolean;
+  entries: ICreditNoteEntryNewDTO[];
+  branchId?: number;
+  warehouseId?: number;
+  attachments?: AttachmentLinkDTO[];
+}
+
+export interface ICreditNoteEntry extends IItemEntry {}
+
+export interface ICreditNote {
+  id?: number;
+  customerId: number;
+  amount: number;
+  refundedAmount: number;
+  currencyCode: string;
+  exchangeRate: number;
+  creditNoteDate: Date;
+  creditNoteNumber: string;
+  referenceNo?: string;
+  // note?: string;
+  openedAt: Date | null;
+  entries: ICreditNoteEntry[];
+  isOpen: boolean;
+  isClosed: boolean;
+  isDraft: boolean;
+  isPublished: boolean;
+  creditsRemaining: number;
+  localAmount?: number;
+  branchId?: number;
+  warehouseId: number;
+  createdAt?: Date;
+  termsConditions: string;
+  note: string;
+}
+
+export enum CreditNoteAction {
+  Create = 'Create',
+  Edit = 'Edit',
+  Delete = 'Delete',
+  View = 'View',
+  Refund = 'Refund',
+}
+
+export interface ICreditNoteDeletingPayload {
+  tenantId: number;
+  oldCreditNote: CreditNote;
+  trx: Knex.Transaction;
+}
+
+export interface ICreditNoteDeletedPayload {
+  tenantId: number;
+  oldCreditNote: CreditNote;
+  creditNoteId: number;
+  trx: Knex.Transaction;
+}
+
+export interface ICreditNoteEditingPayload {
+  trx: Knex.Transaction;
+  oldCreditNote: CreditNote;
+  creditNoteEditDTO: ICreditNoteEditDTO;
+  tenantId: number;
+}
+
+export interface ICreditNoteEditedPayload {
+  trx: Knex.Transaction;
+  oldCreditNote: CreditNote;
+  // creditNoteId: number;
+  creditNote: CreditNote;
+  creditNoteEditDTO: ICreditNoteEditDTO;
+  // tenantId: number;
+}
+
+export interface ICreditNoteCreatedPayload {
+  // tenantId: number;
+  creditNoteDTO: ICreditNoteNewDTO;
+  creditNote: CreditNote;
+  // creditNoteId: number;
+  trx: Knex.Transaction;
+}
+
+export interface ICreditNoteCreatingPayload {
+  // tenantId: number;
+  creditNoteDTO: ICreditNoteNewDTO;
+  trx: Knex.Transaction;
+}
+
+export interface ICreditNoteOpeningPayload {
+  tenantId: number;
+  creditNoteId: number;
+  oldCreditNote: CreditNote;
+  trx: Knex.Transaction;
+}
+
+export interface ICreditNoteOpenedPayload {
+  // tenantId: number;
+  creditNote: CreditNote;
+  // creditNoteId: number;
+  oldCreditNote: CreditNote;
+  trx: Knex.Transaction;
+}
+
+export interface ICreditNotesQueryDTO {
+  filterQuery?: (query: any) => void;
+}
+
+export interface ICreditNotesQueryDTO extends IDynamicListFilter {
+  page: number;
+  pageSize: number;
+  searchKeyword?: string;
+}
+
+export interface ICreditNoteRefundDTO {
+  fromAccountId: number;
+  amount: number;
+  exchangeRate?: number;
+  referenceNo: string;
+  description: string;
+  date: Date;
+  branchId?: number;
+}
+
+export interface ICreditNoteApplyInvoiceDTO {
+  entries: { invoiceId: number; amount: number }[];
+}
+export interface IRefundCreditNotePOJO {
+  formattedAmount: string;
+}
+
+export interface IRefundCreditNoteDeletedPayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: RefundCreditNote;
+  tenantId: number;
+}
+
+export interface IRefundCreditNoteDeletingPayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: RefundCreditNote;
+  // tenantId: number;
+}
+
+export interface IRefundCreditNoteCreatingPayload {
+  trx: Knex.Transaction;
+  creditNote: CreditNote;
+  newCreditNoteDTO: ICreditNoteRefundDTO;
+  // tenantId: number;
+}
+
+export interface IRefundCreditNoteCreatedPayload {
+  trx: Knex.Transaction;
+  refundCreditNote: RefundCreditNote;
+  creditNote: CreditNote;
+  // tenantId: number;
+}
+
+export interface IRefundCreditNoteOpenedPayload {
+  // tenantId: number;
+  creditNoteId: number;
+  oldCreditNote: CreditNote;
+  trx: Knex.Transaction;
+}
+
+export interface IApplyCreditToInvoiceEntryDTO {
+  amount: number;
+  invoiceId: number;
+}
+
+export interface IApplyCreditToInvoicesDTO {
+  entries: IApplyCreditToInvoiceEntryDTO[];
+}
+
+export interface IApplyCreditToInvoicesCreatedPayload {
+  trx: Knex.Transaction;
+  creditNote: ICreditNote;
+  creditNoteAppliedInvoices: ICreditNoteAppliedToInvoice[];
+  // tenantId: number;
+}
+export interface IApplyCreditToInvoicesDeletedPayload {
+  trx: Knex.Transaction;
+  creditNote: ICreditNote;
+  creditNoteAppliedToInvoice: ICreditNoteAppliedToInvoice;
+  // tenantId: number;
+}
+
+export interface ICreditNoteAppliedToInvoice {
+  invoiceId: number;
+  amount: number;
+  creditNoteId: number;
+}
+export interface ICreditNoteAppliedToInvoiceModel {
+  amount: number;
+  entries: ICreditNoteAppliedToInvoice[];
+}
+
+export type ICreditNoteGLCommonEntry = Pick<
+  ILedgerEntry,
+  | 'date'
+  | 'userId'
+  | 'currencyCode'
+  | 'exchangeRate'
+  | 'transactionType'
+  | 'transactionId'
+  | 'transactionNumber'
+  | 'referenceNumber'
+  | 'createdAt'
+  | 'indexGroup'
+  | 'credit'
+  | 'debit'
+  | 'branchId'
+>;
+
+export interface CreditNotePdfTemplateAttributes {
+  // # Primary color
+  primaryColor: string;
+  secondaryColor: string;
+
+  // # Company logo
+  showCompanyLogo: boolean;
+  companyLogo: string;
+
+  // # Company name
+  companyName: string;
+
+  // # Customer Address
+  showCustomerAddress: boolean;
+  customerAddress: string;
+
+  // # Company address
+  showCompanyAddress: boolean;
+  companyAddress: string;
+  billedToLabel: string;
+
+  total: string;
+  totalLabel: string;
+  showTotal: boolean;
+
+  subtotal: string;
+  subtotalLabel: string;
+  showSubtotal: boolean;
+
+  showCustomerNote: boolean;
+  customerNote: string;
+  customerNoteLabel: string;
+
+  showTermsConditions: boolean;
+  termsConditions: string;
+  termsConditionsLabel: string;
+
+  lines: Array<{
+    item: string;
+    description: string;
+    rate: string;
+    quantity: string;
+    total: string;
+  }>;
+
+  showCreditNoteNumber: boolean;
+  creditNoteNumberLabel: string;
+  creditNoteNumebr: string;
+
+  creditNoteDate: string;
+  showCreditNoteDate: boolean;
+  creditNoteDateLabel: string;
+}
+
+export interface ICreditNoteState {
+  defaultTemplateId: number;
+}

packages/server-nest/src/modules/CreditNotes/utils.ts

@@ -0,0 +1,25 @@
+import { CreditNotePdfTemplateAttributes, ICreditNote } from '@/interfaces';
+import { contactAddressTextFormat } from '@/utils/address-text-format';
+
+export const transformCreditNoteToPdfTemplate = (
+  creditNote: ICreditNote
+): Partial<CreditNotePdfTemplateAttributes> => {
+  return {
+    creditNoteDate: creditNote.formattedCreditNoteDate,
+    creditNoteNumebr: creditNote.creditNoteNumber,
+
+    total: creditNote.formattedAmount,
+    subtotal: creditNote.formattedSubtotal,
+
+    lines: creditNote.entries?.map((entry) => ({
+      item: entry.item.name,
+      description: entry.description,
+      rate: entry.rateFormatted,
+      quantity: entry.quantityFormatted,
+      total: entry.totalFormatted,
+    })),
+    customerNote: creditNote.note,
+    termsConditions: creditNote.termsConditions,
+    customerAddress: contactAddressTextFormat(creditNote.customer),
+  };
+};

packages/server-nest/src/modules/Import/ImportableResources.ts

@@ -14,7 +14,7 @@ import { SaleEstimatesImportable } from '../Sales/Estimates/SaleEstimatesImporta
 import { BillPaymentsImportable } from '../Purchases/BillPayments/BillPaymentsImportable';
 import { VendorCreditsImportable } from '../Purchases/VendorCredits/VendorCreditsImportable';
 import { PaymentsReceivedImportable } from '../Sales/PaymentReceived/PaymentsReceivedImportable';
-import { CreditNotesImportable } from '../CreditNotes/CreditNotesImportable';
+import { CreditNotesImportable } from '../CreditNotes/commands/CreditNotesImportable';
 import { SaleReceiptsImportable } from '../Sales/Receipts/SaleReceiptsImportable';
 import { TaxRatesImportable } from '../TaxRates/TaxRatesImportable';
 

packages/server-nest/src/modules/SaleEstimates/models/SaleEstimate.ts

@@ -1,15 +1,25 @@
 import { BaseModel } from '@/models/Model';
 import moment from 'moment';
 import { Model } from 'objection';
-// import TenantModel from 'models/TenantModel';
+import { ItemEntry } from '../../Items/models/ItemEntry';
-// import { defaultToTransform } from 'utils';
+import { Customer } from '../../Customers/models/Customer';
-// import SaleEstimateSettings from './SaleEstimate.Settings';
+import { Branch } from '../../Branches/models/Branch.model';
-// import ModelSetting from './ModelSetting';
+import { Warehouse } from '../../Warehouses/models/Warehouse.model';
-// import CustomViewBaseModel from './CustomViewBaseModel';
+import { Document } from '../../ChromiumlyTenancy/models/Document';
-// import { DEFAULT_VIEWS } from '@/services/Sales/Estimates/constants';
+import { Injectable } from '@nestjs/common';
-// import ModelSearchable from './ModelSearchable';
 
+@Injectable()
 export class SaleEstimate extends BaseModel {
+  constructor(
+    private readonly itemEntryModel: typeof ItemEntry,
+    private readonly customerModel: typeof Customer,
+    private readonly branchModel: typeof Branch,
+    private readonly warehouseModel: typeof Warehouse,
+    private readonly documentModel: typeof Document,
+  ) {
+    super();
+  }
+
   exchangeRate!: number;
   amount!: number;
 
@@ -207,16 +217,10 @@ export class SaleEstimate extends BaseModel {
    * Relationship mapping.
    */
   static get relationMappings() {
-    const { ItemEntry } = require('../../Items/models/ItemEntry');
-    const { Customer } = require('../../Customers/models/Customer');
-    const { Branch } = require('../../Branches/models/Branch.model');
-    const { Warehouse } = require('../../Warehouses/models/Warehouse.model');
-    const { Document } = require('../../ChromiumlyTenancy/models/Document');
-
     return {
       customer: {
         relation: Model.BelongsToOneRelation,
-        modelClass: Customer,
+        modelClass: this.customerModel,
         join: {
           from: 'sales_estimates.customerId',
           to: 'contacts.id',
@@ -227,8 +231,7 @@ export class SaleEstimate extends BaseModel {
       },
       entries: {
         relation: Model.HasManyRelation,
-        modelClass: ItemEntry,
+        modelClass: this.itemEntryModel,
-
         join: {
           from: 'sales_estimates.id',
           to: 'items_entries.referenceId',
@@ -238,37 +241,25 @@ export class SaleEstimate extends BaseModel {
           builder.orderBy('index', 'ASC');
         },
       },
-
-      /**
-       * Sale estimate may belongs to branch.
-       */
       branch: {
         relation: Model.BelongsToOneRelation,
-        modelClass: Branch,
+        modelClass: this.branchModel,
         join: {
           from: 'sales_estimates.branchId',
           to: 'branches.id',
         },
       },
-
-      /**
-       * Sale estimate may has associated warehouse.
-       */
       warehouse: {
         relation: Model.BelongsToOneRelation,
-        modelClass: Warehouse,
+        modelClass: this.warehouseModel,
         join: {
           from: 'sales_estimates.warehouseId',
           to: 'warehouses.id',
         },
       },
-
-      /**
-       * Sale estimate transaction may has many attached attachments.
-       */
       attachments: {
         relation: Model.ManyToManyRelation,
-        modelClass: Document,
+        modelClass: this.documentModel,
         join: {
           from: 'sales_estimates.id',
           through: {

packages/server-nest/src/modules/Tenancy/TenancyModels/Tenancy.module.ts

@@ -25,7 +25,7 @@ import { BillPayment } from '@/modules/BillPayments/models/BillPayment';
 import { BillPaymentEntry } from '@/modules/BillPayments/models/BillPaymentEntry';
 import { BillLandedCostEntry } from '@/modules/BillLandedCosts/models/BillLandedCostEntry';
 import { BillLandedCost } from '@/modules/BillLandedCosts/models/BillLandedCost';
-import { VendorCreditAppliedBill } from '@/modules/VendorCredit/models/VendorCreditAppliedBill';
+import { VendorCreditAppliedBill } from '@/modules/VendorCreditsApplyBills/models/VendorCreditAppliedBill';
 import { SaleInvoice } from '@/modules/SaleInvoices/models/SaleInvoice';
 import { PaymentReceivedEntry } from '@/modules/PaymentReceived/models/PaymentReceivedEntry';
 import { CreditNoteAppliedInvoice } from '@/modules/CreditNotes/models/CreditNoteAppliedInvoice';

packages/server-nest/src/modules/VendorCredit/VendorCredits.controller.ts

@@ -0,0 +1,33 @@
+import { Body, Controller, Delete, Get, Param, Post, Put } from '@nestjs/common';
+import { VendorCreditsApplicationService } from './VendorCreditsApplication.service';
+import { IVendorCreditCreateDTO, IVendorCreditEditDTO } from './types/VendorCredit.types';
+
+@Controller('vendor-credits')
+export class VendorCreditsController {
+  constructor(
+    private readonly vendorCreditsApplication: VendorCreditsApplicationService,
+  ) {}
+
+  @Post()
+  async createVendorCredit(@Body() dto: IVendorCreditCreateDTO) {
+    return this.vendorCreditsApplication.createVendorCredit(dto);
+  }
+
+  @Put(':id') 
+  async editVendorCredit(
+    @Param('id') vendorCreditId: number,
+    @Body() dto: IVendorCreditEditDTO,
+  ) {
+    return this.vendorCreditsApplication.editVendorCredit(vendorCreditId, dto);
+  }
+
+  @Delete(':id')
+  async deleteVendorCredit(@Param('id') vendorCreditId: number) {
+    return this.vendorCreditsApplication.deleteVendorCredit(vendorCreditId);
+  }
+
+  @Get(':id')
+  async getVendorCredit(@Param('id') vendorCreditId: number) {
+    return this.vendorCreditsApplication.getVendorCredit(vendorCreditId);
+  }
+}

packages/server-nest/src/modules/VendorCredit/VendorCredits.module.ts

@@ -0,0 +1,23 @@
+import { Module } from '@nestjs/common';
+import { CreateVendorCreditService } from './commands/CreateVendorCredit.service';
+import { DeleteVendorCreditService } from './commands/DeleteVendorCredit.service';
+import { EditVendorCreditService } from './commands/EditVendorCredit.service';
+import { VendorCreditDTOTransformService } from './commands/VendorCreditDTOTransform.service';
+import { VendorCreditAutoIncrementService } from './commands/VendorCreditAutoIncrement.service';
+import { GetRefundVendorCreditService } from '../VendorCreditsRefund/queries/GetRefundVendorCredit.service';
+import GetVendorCreditService from './queries/GetVendorCredit.service';
+  
+@Module({
+  providers: [
+    CreateVendorCreditService,
+    DeleteVendorCreditService,
+    EditVendorCreditService,
+    VendorCreditDTOTransformService,
+    VendorCreditAutoIncrementService,
+    GetRefundVendorCreditService,
+    VendorCreditDTOTransformService,
+    GetVendorCreditService
+  ],
+  controllers: [],
+})
+export class VendorCreditsModule {}

packages/server-nest/src/modules/VendorCredit/VendorCreditsApplication.service.ts

@@ -0,0 +1,64 @@
+import { Knex } from 'knex';
+import { CreateVendorCreditService } from './commands/CreateVendorCredit.service';
+import { DeleteVendorCreditService } from './commands/DeleteVendorCredit.service';
+import { EditVendorCreditService } from './commands/EditVendorCredit.service';
+import GetVendorCreditService from './queries/GetVendorCredit.service';
+import { IVendorCreditEditDTO } from './types/VendorCredit.types';
+import { IVendorCreditCreateDTO } from './types/VendorCredit.types';
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class VendorCreditsApplicationService {
+  constructor(
+    private readonly createVendorCreditService: CreateVendorCreditService,
+    private readonly editVendorCreditService: EditVendorCreditService,
+    private readonly deleteVendorCreditService: DeleteVendorCreditService,
+    private readonly getVendorCreditService: GetVendorCreditService,
+  ) {}
+
+  /**
+   * Creates a new vendor credit.
+   * @param {IVendorCreditCreateDTO} dto - The vendor credit create DTO.
+   * @param {Knex.Transaction} trx - The transaction.
+   * @returns {Promise<VendorCredit>} The created vendor credit.
+   */
+  createVendorCredit(dto: IVendorCreditCreateDTO, trx?: Knex.Transaction) {
+    return this.createVendorCreditService.newVendorCredit(dto, trx);
+  }
+
+  /**
+   * Edits the given vendor credit.
+   * @param {number} vendorCreditId - The vendor credit id.
+   * @param {IVendorCreditEditDTO} dto - The vendor credit edit DTO.
+   * @param {Knex.Transaction} trx - The transaction.
+   * @returns {Promise<VendorCredit>} The edited vendor credit.
+   */
+  editVendorCredit(
+    vendorCreditId: number,
+    dto: IVendorCreditEditDTO,
+    trx?: Knex.Transaction,
+  ) {
+    return this.editVendorCreditService.editVendorCredit(
+      vendorCreditId,
+      dto,
+      trx,
+    );
+  }
+
+  /**
+   * Deletes the given vendor credit.
+   * @param {number} vendorCreditId - The vendor credit id.
+   * @param {Knex.Transaction} trx - The transaction.
+   * @returns {Promise<VendorCredit>} The deleted vendor credit.
+   */
+  deleteVendorCredit(vendorCreditId: number, trx?: Knex.Transaction) {
+    return this.deleteVendorCreditService.deleteVendorCredit(
+      vendorCreditId,
+      trx,
+    );
+  }
+
+  getVendorCredit(vendorCreditId: number, trx?: Knex.Transaction) {
+    return this.getVendorCreditService.getVendorCredit(vendorCreditId, trx);
+  }
+}

packages/server-nest/src/modules/VendorCredit/commands/CreateVendorCredit.service.ts

@@ -0,0 +1,90 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import {
+  IVendorCreditCreatedPayload,
+  IVendorCreditCreateDTO,
+  IVendorCreditCreatingPayload,
+} from '@/modules/VendorCredit/types/VendorCredit.types';
+import { VendorCredit } from '../models/VendorCredit';
+import { Vendor } from '@/modules/Vendors/models/Vendor';
+import { events } from '@/common/events/events';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { ItemsEntriesService } from '@/modules/Items/ItemsEntries.service';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+
+@Injectable()
+export class CreateVendorCreditService {
+  /**
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {ItemsEntriesService} itemsEntriesService - The items entries service.
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   * @param {typeof Vendor} vendorModel - The vendor model.
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly itemsEntriesService: ItemsEntriesService,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+
+    @Inject(Vendor.name) private readonly vendorModel: typeof Vendor,
+  ) {}
+
+  /**
+   * Creates a new vendor credit.
+   * @param {IVendorCreditCreateDTO} vendorCreditCreateDTO -
+   * @param {Knex.Transaction} trx -
+   */
+  public newVendorCredit = async (
+    vendorCreditCreateDTO: IVendorCreditCreateDTO,
+    trx?: Knex.Transaction,
+  ) => {
+    // Triggers `onVendorCreditCreate` event.
+    await this.eventPublisher.emitAsync(events.vendorCredit.onCreate, {
+      vendorCreditCreateDTO,
+    });
+
+    // Retrieve the given vendor or throw not found service error.
+    const vendor = await this.vendorModel
+      .query()
+      .findById(vendorCreditCreateDTO.vendorId)
+      .throwIfNotFound();
+
+    // Validate items should be sellable items.
+    await this.itemsEntriesService.validateNonSellableEntriesItems(
+      vendorCreditCreateDTO.entries,
+    );
+
+    // Transforms the credit DTO to storage layer.
+    const vendorCreditModel = this.transformCreateEditDTOToModel(
+      vendorCreditCreateDTO,
+      vendor.currencyCode,
+    );
+    // Saves the vendor credit transactions under UOW environment.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Triggers `onVendorCreditCreating` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onCreating, {
+        vendorCreditCreateDTO,
+        trx,
+      } as IVendorCreditCreatingPayload);
+
+      // Saves the vendor credit graph.
+      const vendorCredit = await this.vendorCreditModel
+        .query(trx)
+        .upsertGraphAndFetch({
+          ...vendorCreditModel,
+        });
+
+      // Triggers `onVendorCreditCreated` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onCreated, {
+        vendorCredit,
+        vendorCreditCreateDTO,
+        trx,
+      } as IVendorCreditCreatedPayload);
+
+      return vendorCredit;
+    }, trx);
+  };
+}

packages/server-nest/src/modules/VendorCredit/commands/DeleteVendorCredit.service.ts

@@ -0,0 +1,116 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import {
+  IVendorCreditDeletedPayload,
+  IVendorCreditDeletingPayload,
+} from '@/modules/VendorCredit/types/VendorCredit.types';
+import { ERRORS } from '../constants';
+import { VendorCredit } from '../models/VendorCredit';
+import { ItemEntry } from '@/modules/TransactionItemEntry/models/ItemEntry';
+import { VendorCreditAppliedBill } from '../../VendorCreditsApplyBills/models/VendorCreditAppliedBill';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { RefundVendorCredit } from '../models/RefundVendorCredit';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class DeleteVendorCreditService {
+  /**
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   * @param {typeof ItemEntry} itemEntryModel - The item entry model.
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {typeof RefundVendorCredit} refundVendorCreditModel - The refund vendor credit model.
+   * @param {typeof VendorCreditAppliedBill} vendorCreditAppliedBillModel - The vendor credit applied bill model.
+   */
+  constructor(
+    private vendorCreditModel: typeof VendorCredit,
+    private itemEntryModel: typeof ItemEntry,
+    private eventPublisher: EventEmitter2,
+    private uow: UnitOfWork,
+
+    @Inject(RefundVendorCredit.name)
+    private refundVendorCreditModel: typeof RefundVendorCredit,
+
+    @Inject(VendorCreditAppliedBill.name)
+    private vendorCreditAppliedBillModel: typeof VendorCreditAppliedBill,
+  ) {}
+
+  /**
+   * Deletes the given vendor credit.
+   * @param {number} vendorCreditId - Vendor credit id.
+   */
+  public deleteVendorCredit = async (
+    vendorCreditId: number,
+    trx?: Knex.Transaction,
+  ) => {
+    // Retrieve the old vendor credit.
+    const oldVendorCredit = await this.refundVendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    // Validates vendor credit has no associate refund transactions.
+    await this.validateVendorCreditHasNoRefundTransactions(vendorCreditId);
+
+    // Validates vendor credit has no associated applied to bills transactions.
+    await this.validateVendorCreditHasNoApplyBillsTransactions(vendorCreditId);
+
+    // Deletes the vendor credit transactions under UOW environment.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Triggers `onVendorCreditEditing` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onDeleting, {
+        oldVendorCredit,
+        trx,
+      } as IVendorCreditDeletingPayload);
+
+      // Deletes the associated credit note entries.
+      await this.itemEntryModel
+        .query(trx)
+        .where('reference_id', vendorCreditId)
+        .where('reference_type', 'VendorCredit')
+        .delete();
+
+      // Deletes the credit note transaction.
+      await this.vendorCreditModel.query(trx).findById(vendorCreditId).delete();
+
+      // Triggers `onVendorCreditDeleted` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onDeleted, {
+        vendorCreditId,
+        oldVendorCredit,
+        trx,
+      } as IVendorCreditDeletedPayload);
+    });
+  };
+
+  /**
+   * Validates vendor credit has no refund transactions.
+   * @param {number} vendorCreditId
+   */
+  private validateVendorCreditHasNoRefundTransactions = async (
+    vendorCreditId: number,
+  ): Promise<void> => {
+    const refundCredits = await this.refundVendorCreditModel
+      .query()
+      .where('vendorCreditId', vendorCreditId);
+    if (refundCredits.length > 0) {
+      throw new ServiceError(ERRORS.VENDOR_CREDIT_HAS_REFUND_TRANSACTIONS);
+    }
+  };
+
+  /**
+   * Validate vendor credit has no applied transactions to bills.
+   * @param {number} vendorCreditId
+   */
+  private validateVendorCreditHasNoApplyBillsTransactions = async (
+    vendorCreditId: number,
+  ): Promise<void> => {
+    const appliedTransactions = await this.vendorCreditAppliedBillModel
+      .query()
+      .where('vendorCreditId', vendorCreditId);
+    if (appliedTransactions.length > 0) {
+      throw new ServiceError(ERRORS.VENDOR_CREDIT_HAS_APPLIED_BILLS);
+    }
+  };
+}

packages/server-nest/src/modules/VendorCredit/commands/EditVendorCredit.service.ts

@@ -0,0 +1,105 @@
+import { Inject, Injectable } from '@nestjs/common';
+import {
+  IVendorCreditEditDTO,
+  IVendorCreditEditedPayload,
+  IVendorCreditEditingPayload,
+} from '../types/VendorCredit.types';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { ItemsEntriesService } from '@/modules/Items/ItemsEntries.service';
+import { VendorCredit } from '../models/VendorCredit';
+import { Contact } from '@/modules/Contacts/models/Contact';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class EditVendorCreditService {
+  /**
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {ItemsEntriesService} itemsEntriesService - The items entries service.
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   * @param {typeof Contact} contactModel - The contact model.
+   */
+  constructor(
+    private readonly eventPublisher: EventEmitter2,
+    private readonly uow: UnitOfWork,
+    private readonly itemsEntriesService: ItemsEntriesService,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+
+    @Inject(Contact.name)
+    private readonly contactModel: typeof Contact,
+  ) {}
+
+  /**
+   * Deletes the given vendor credit.
+   * @param {number} vendorCreditId - Vendor credit id.
+   */
+  public editVendorCredit = async (
+    vendorCreditId: number,
+    vendorCreditDTO: IVendorCreditEditDTO,
+    trx?: Knex.Transaction,
+  ) => {
+    // Retrieve the vendor credit or throw not found service error.
+    const oldVendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    // Validate customer existance.
+    const vendor = await this.contactModel
+      .query()
+      .modify('vendor')
+      .findById(vendorCreditDTO.vendorId)
+      .throwIfNotFound();
+
+    // Validate items ids existance.
+    await this.itemsEntriesService.validateItemsIdsExistance(
+      vendorCreditDTO.entries,
+    );
+    // Validate non-sellable entries items.
+    await this.itemsEntriesService.validateNonSellableEntriesItems(
+      vendorCreditDTO.entries,
+    );
+    // Validate the items entries existance.
+    await this.itemsEntriesService.validateEntriesIdsExistance(
+      vendorCreditId,
+      'VendorCredit',
+      vendorCreditDTO.entries,
+    );
+    // Transformes edit DTO to model storage layer.
+    const vendorCreditModel = this.transformCreateEditDTOToModel(
+      vendorCreditDTO,
+      vendor.currencyCode,
+      oldVendorCredit,
+    );
+    // Edits the vendor credit graph under unit-of-work envirement.
+    return this.uow.withTransaction(async (trx) => {
+      // Triggers `onVendorCreditEditing` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onEditing, {
+        oldVendorCredit,
+        vendorCreditDTO,
+        trx,
+      } as IVendorCreditEditingPayload);
+
+      // Saves the vendor credit graph to the storage.
+      const vendorCredit = await this.vendorCreditModel
+        .query(trx)
+        .upsertGraphAndFetch({
+          id: vendorCreditId,
+          ...vendorCreditModel,
+        });
+      // Triggers `onVendorCreditEdited event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onEdited, {
+        oldVendorCredit,
+        vendorCredit,
+        vendorCreditId,
+        vendorCreditDTO,
+        trx,
+      } as IVendorCreditEditedPayload);
+
+      return vendorCredit;
+    }, trx);
+  };
+}

packages/server-nest/src/modules/VendorCredit/commands/OpenVendorCredit.service.ts

@@ -0,0 +1,90 @@
+import { Inject, Injectable } from '@nestjs/common';
+import {
+  IVendorCreditOpenedPayload,
+  IVendorCreditOpeningPayload,
+  IVendorCreditOpenPayload,
+} from '../types/VendorCredit.types';
+import { ERRORS } from '../constants';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { VendorCredit } from '../models/VendorCredit';
+import { events } from '@/common/events/events';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+@Injectable()
+export class OpenVendorCreditService {
+  /**
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   */
+  constructor(
+    private eventPublisher: EventEmitter2,
+    private uow: UnitOfWork,
+
+    @Inject(VendorCredit.name) private vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Opens the given credit note.
+   * @param {number} vendorCreditId -
+   * @returns {Promise<IVendorCredit>}
+   */
+  public openVendorCredit = async (
+    vendorCreditId: number,
+  ): Promise<VendorCredit> => {
+    // Retrieve the vendor credit or throw not found service error.
+    const oldVendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    // Throw service error if the credit note is already open.
+    this.throwErrorIfAlreadyOpen(oldVendorCredit);
+
+    // Triggers `onVendorCreditOpen` event.
+    await this.eventPublisher.emitAsync(events.vendorCredit.onOpen, {
+      vendorCreditId,
+      oldVendorCredit,
+    } as IVendorCreditOpenPayload);
+
+    // Sales the credit note transactions with associated entries.
+    return this.uow.withTransaction(async (trx) => {
+      const eventPayload = {
+        vendorCreditId,
+        oldVendorCredit,
+        trx,
+      } as IVendorCreditOpeningPayload;
+
+      // Triggers `onCreditNoteOpening` event.
+      await this.eventPublisher.emitAsync(
+        events.creditNote.onOpening,
+        eventPayload as IVendorCreditOpeningPayload,
+      );
+      // Saves the vendor credit graph to the storage.
+      const vendorCredit = await this.vendorCreditModel
+        .query(trx)
+        .findById(vendorCreditId)
+        .update({
+          openedAt: new Date(),
+        });
+      // Triggers `onVendorCreditOpened` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onOpened, {
+        ...eventPayload,
+        vendorCredit,
+      } as IVendorCreditOpenedPayload);
+
+      return vendorCredit;
+    });
+  };
+
+  /**
+   * Throw error if the vendor credit is already open.
+   * @param {IVendorCredit} vendorCredit
+   */
+  public throwErrorIfAlreadyOpen = (vendorCredit: VendorCredit) => {
+    if (vendorCredit.openedAt) {
+      throw new ServiceError(ERRORS.VENDOR_CREDIT_ALREADY_OPENED);
+    }
+  };
+}

packages/server-nest/src/modules/VendorCredit/commands/VendorCreditAutoIncrement.service.ts

@@ -0,0 +1,32 @@
+import { AutoIncrementOrdersService } from '@/modules/AutoIncrementOrders/AutoIncrementOrders.service';
+import { Injectable } from '@nestjs/common';
+
+
+@Injectable()
+export class VendorCreditAutoIncrementService {
+  /**
+   * @param {AutoIncrementOrdersService} autoIncrementOrdersService - Auto increment orders service.
+   */
+  constructor(private autoIncrementOrdersService: AutoIncrementOrdersService) {}
+
+  /**
+   * Retrieve the next unique credit number.
+   * @param  {number} tenantId - Tenant id.
+   * @return {string}
+   */
+  public getNextCreditNumber = (): string => {
+    return this.autoIncrementOrdersService.getNextTransactionNumber(
+      'vendor_credit',
+    );
+  };
+
+  /**
+   * Increment the vendor credit serial next number.
+   * @param {number} tenantId -
+   */
+  public incrementSerialNumber = () => {
+    return this.autoIncrementOrdersService.incrementSettingsNextNumber(
+      'vendor_credit',
+    );
+  };
+}

packages/server-nest/src/modules/VendorCredit/commands/VendorCreditDTOTransform.service.ts

@@ -0,0 +1,102 @@
+import moment from 'moment';
+import { omit } from 'lodash';
+import * as R from 'ramda';
+import { ERRORS } from '../constants';
+import {
+  IVendorCreditCreateDTO,
+  IVendorCreditEditDTO,
+  IVendorCreditEntryDTO,
+} from '../types/VendorCredit.types';
+import { ItemsEntriesService } from '@/modules/Items/ItemsEntries.service';
+import { BranchTransactionDTOTransformer } from '@/modules/Branches/integrations/BranchTransactionDTOTransform';
+import { WarehouseTransactionDTOTransform } from '@/modules/Warehouses/Integrations/WarehouseTransactionDTOTransform';
+import { VendorCredit } from '../models/VendorCredit';
+import { assocItemEntriesDefaultIndex } from '@/utils/associate-item-entries-index';
+import { VendorCreditAutoIncrementService } from './VendorCreditAutoIncrement.service';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { Injectable } from '@nestjs/common';
+
+
+@Injectable()
+export class VendorCreditDTOTransformService {
+  /**
+   * @param {ItemsEntriesService} itemsEntriesService - The items entries service.
+   * @param {BranchTransactionDTOTransformer} branchDTOTransform - The branch transaction DTO transformer.
+   * @param {WarehouseTransactionDTOTransform} warehouseDTOTransform - The warehouse transaction DTO transformer.
+   * @param {VendorCreditAutoIncrementService} vendorCreditAutoIncrement - The vendor credit auto increment service.
+   */
+  constructor(
+    private itemsEntriesService: ItemsEntriesService,
+    private branchDTOTransform: BranchTransactionDTOTransformer,
+    private warehouseDTOTransform: WarehouseTransactionDTOTransform,
+    private vendorCreditAutoIncrement: VendorCreditAutoIncrementService
+  ) {}
+
+  /**
+   * Transformes the credit/edit vendor credit DTO to model.
+   * @param {IVendorCreditCreateDTO | IVendorCreditEditDTO} vendorCreditDTO
+   * @param {string} vendorCurrencyCode -
+   * @param {IVendorCredit} oldVendorCredit -
+   * @returns {VendorCredit}
+   */
+  public transformCreateEditDTOToModel = (
+    vendorCreditDTO: IVendorCreditCreateDTO | IVendorCreditEditDTO,
+    vendorCurrencyCode: string,
+    oldVendorCredit?: VendorCredit
+  ): VendorCredit => {
+    // Calculates the total amount of items entries.
+    const amount = this.itemsEntriesService.getTotalItemsEntries(
+      vendorCreditDTO.entries
+    );
+    const entries = R.compose(
+      // Associate the default index to each item entry.
+      assocItemEntriesDefaultIndex,
+
+      // Associate the reference type to item entries.
+      R.map((entry: IVendorCreditEntryDTO) => ({
+        referenceType: 'VendorCredit',
+        ...entry,
+      }))
+    )(vendorCreditDTO.entries);
+
+    // Retreive the next vendor credit number.
+    const autoNextNumber = this.vendorCreditAutoIncrement.getNextCreditNumber();
+
+    // Detarmines the credit note number.
+    const vendorCreditNumber =
+      vendorCreditDTO.vendorCreditNumber ||
+      oldVendorCredit?.vendorCreditNumber ||
+      autoNextNumber;
+
+    const initialDTO = {
+      ...omit(vendorCreditDTO, ['open', 'attachments']),
+      amount,
+      currencyCode: vendorCurrencyCode,
+      exchangeRate: vendorCreditDTO.exchangeRate || 1,
+      vendorCreditNumber,
+      entries,
+      ...(vendorCreditDTO.open &&
+        !oldVendorCredit?.openedAt && {
+          openedAt: moment().toMySqlDateTime(),
+        }),
+    };
+    return R.compose(
+      this.branchDTOTransform.transformDTO<VendorCredit>,
+      this.warehouseDTOTransform.transformDTO<VendorCredit>(
+    )(initialDTO);
+  };
+
+  /**
+   * Validate the credit note remaining amount.
+   * @param {ICreditNote} creditNote
+   * @param {number} amount
+   */
+  public validateCreditRemainingAmount = (
+    vendorCredit: VendorCredit,
+    amount: number
+  ) => {
+    if (vendorCredit.creditsRemaining < amount) {
+      throw new ServiceError(ERRORS.VENDOR_CREDIT_HAS_NO_REMAINING_AMOUNT);
+    }
+  };
+}

packages/server-nest/src/modules/VendorCredit/commands/VendorCreditGLEntries.ts

@@ -0,0 +1,252 @@
+// import { Inject, Service } from 'typedi';
+// import { Knex } from 'knex';
+// import * as R from 'ramda';
+// import {
+//   IVendorCredit,
+//   ILedgerEntry,
+//   AccountNormal,
+//   IItemEntry,
+// } from '@/interfaces';
+// import HasTenancyService from '@/services/Tenancy/TenancyService';
+// import LedgerStorageService from '@/services/Accounting/LedgerStorageService';
+// import Ledger from '@/services/Accounting/Ledger';
+
+// @Service()
+// export default class VendorCreditGLEntries {
+//   @Inject()
+//   private ledgerStorage: LedgerStorageService;
+
+//   @Inject()
+//   private tenancy: HasTenancyService;
+
+//   /**
+//    * Retrieve the vendor credit GL common entry.
+//    * @param   {IVendorCredit} vendorCredit
+//    * @returns {}
+//    */
+//   public getVendorCreditGLCommonEntry = (vendorCredit: IVendorCredit) => {
+//     return {
+//       date: vendorCredit.vendorCreditDate,
+//       currencyCode: vendorCredit.currencyCode,
+//       exchangeRate: vendorCredit.exchangeRate,
+
+//       transactionId: vendorCredit.id,
+//       transactionType: 'VendorCredit',
+//       transactionNumber: vendorCredit.vendorCreditNumber,
+//       referenceNumber: vendorCredit.referenceNo,
+
+//       credit: 0,
+//       debit: 0,
+
+//       branchId: vendorCredit.branchId,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the vendor credit payable GL entry.
+//    * @param   {IVendorCredit} vendorCredit
+//    * @param   {number} APAccountId
+//    * @returns {ILedgerEntry}
+//    */
+//   public getVendorCreditPayableGLEntry = (
+//     vendorCredit: IVendorCredit,
+//     APAccountId: number
+//   ): ILedgerEntry => {
+//     const commonEntity = this.getVendorCreditGLCommonEntry(vendorCredit);
+
+//     return {
+//       ...commonEntity,
+//       debit: vendorCredit.totalLocal,
+//       accountId: APAccountId,
+//       contactId: vendorCredit.vendorId,
+//       accountNormal: AccountNormal.CREDIT,
+//       index: 1,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the vendor credit item GL entry.
+//    * @param   {IVendorCredit} vendorCredit
+//    * @param   {IItemEntry} entry
+//    * @returns {ILedgerEntry}
+//    */
+//   public getVendorCreditGLItemEntry = R.curry(
+//     (
+//       vendorCredit: IVendorCredit,
+//       entry: IItemEntry,
+//       index: number
+//     ): ILedgerEntry => {
+//       const commonEntity = this.getVendorCreditGLCommonEntry(vendorCredit);
+//       const totalLocal = entry.totalExcludingTax * vendorCredit.exchangeRate;
+
+//       return {
+//         ...commonEntity,
+//         credit: totalLocal,
+//         index: index + 2,
+//         itemId: entry.itemId,
+//         itemQuantity: entry.quantity,
+//         accountId:
+//           'inventory' === entry.item.type
+//             ? entry.item.inventoryAccountId
+//             : entry.costAccountId || entry.item.costAccountId,
+//         accountNormal: AccountNormal.DEBIT,
+//       };
+//     }
+//   );
+
+//   /**
+//    * Retrieves the vendor credit discount GL entry.
+//    * @param {IVendorCredit} vendorCredit
+//    * @param {number} discountAccountId
+//    * @returns {ILedgerEntry}
+//    */
+//   public getDiscountEntry = (
+//     vendorCredit: IVendorCredit,
+//     purchaseDiscountAccountId: number
+//   ) => {
+//     const commonEntry = this.getVendorCreditGLCommonEntry(vendorCredit);
+
+//     return {
+//       ...commonEntry,
+//       debit: vendorCredit.discountAmountLocal,
+//       accountId: purchaseDiscountAccountId,
+//       accountNormal: AccountNormal.DEBIT,
+//       index: 1,
+//       indexGroup: 40,
+//     };
+//   };
+
+//   /**
+//    * Retrieves the vendor credit adjustment GL entry.
+//    * @param {IVendorCredit} vendorCredit
+//    * @param {number} adjustmentAccountId
+//    * @returns {ILedgerEntry}
+//    */
+//   public getAdjustmentEntry = (
+//     vendorCredit: IVendorCredit,
+//     otherExpensesAccountId: number
+//   ) => {
+//     const commonEntry = this.getVendorCreditGLCommonEntry(vendorCredit);
+//     const adjustmentAmount = Math.abs(vendorCredit.adjustmentLocal);
+
+//     return {
+//       ...commonEntry,
+//       credit: vendorCredit.adjustmentLocal > 0 ? adjustmentAmount : 0,
+//       debit: vendorCredit.adjustmentLocal < 0 ? adjustmentAmount : 0,
+//       accountId: otherExpensesAccountId,
+//       accountNormal: AccountNormal.DEBIT,
+//       index: 1,
+//       indexGroup: 40,
+//     };
+//   };
+
+//   /**
+//    * Retrieve the vendor credit GL entries.
+//    * @param  {IVendorCredit} vendorCredit -
+//    * @param  {number} receivableAccount -
+//    * @return {ILedgerEntry[]}
+//    */
+//   public getVendorCreditGLEntries = (
+//     vendorCredit: IVendorCredit,
+//     payableAccountId: number,
+//     purchaseDiscountAccountId: number,
+//     otherExpensesAccountId: number
+//   ): ILedgerEntry[] => {
+//     const payableEntry = this.getVendorCreditPayableGLEntry(
+//       vendorCredit,
+//       payableAccountId
+//     );
+//     const getItemEntry = this.getVendorCreditGLItemEntry(vendorCredit);
+//     const itemsEntries = vendorCredit.entries.map(getItemEntry);
+
+//     const discountEntry = this.getDiscountEntry(
+//       vendorCredit,
+//       purchaseDiscountAccountId
+//     );
+//     const adjustmentEntry = this.getAdjustmentEntry(
+//       vendorCredit,
+//       otherExpensesAccountId
+//     );
+//     return [payableEntry, discountEntry, adjustmentEntry, ...itemsEntries];
+//   };
+
+//   /**
+//    * Reverts the vendor credit associated GL entries.
+//    * @param {number} tenantId
+//    * @param {number} vendorCreditId
+//    * @param {Knex.Transaction} trx
+//    */
+//   public revertVendorCreditGLEntries = async (
+//     tenantId: number,
+//     vendorCreditId: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     await this.ledgerStorage.deleteByReference(
+//       tenantId,
+//       vendorCreditId,
+//       'VendorCredit',
+//       trx
+//     );
+//   };
+
+//   /**
+//    * Creates vendor credit associated GL entries.
+//    * @param {number} tenantId
+//    * @param {number} vendorCreditId
+//    * @param {Knex.Transaction} trx
+//    */
+//   public writeVendorCreditGLEntries = async (
+//     tenantId: number,
+//     vendorCreditId: number,
+//     trx?: Knex.Transaction
+//   ) => {
+//     const { accountRepository } = this.tenancy.repositories(tenantId);
+//     const { VendorCredit } = this.tenancy.models(tenantId);
+
+//     // Vendor credit with entries items.
+//     const vendorCredit = await VendorCredit.query(trx)
+//       .findById(vendorCreditId)
+//       .withGraphFetched('entries.item');
+
+//     // Retrieve the payable account (A/P) account.
+//     const APAccount = await accountRepository.findOrCreateAccountsPayable(
+//       vendorCredit.currencyCode,
+//       {},
+//       trx
+//     );
+//     const purchaseDiscountAccount =
+//       await accountRepository.findOrCreatePurchaseDiscountAccount({}, trx);
+
+//     const otherExpensesAccount =
+//       await accountRepository.findOrCreateOtherExpensesAccount({}, trx);
+//     // Saves the vendor credit GL entries.
+//     const ledgerEntries = this.getVendorCreditGLEntries(
+//       vendorCredit,
+//       APAccount.id,
+//       purchaseDiscountAccount.id,
+//       otherExpensesAccount.id
+//     );
+//     const ledger = new Ledger(ledgerEntries);
+
+//     // Commits the ledger entries to the storage.
+//     await this.ledgerStorage.commit(tenantId, ledger, trx);
+//   };
+
+//   /**
+//    * Edits vendor credit associated GL entries.
+//    * @param {number} tenantId
+//    * @param {number} vendorCreditId
+//    * @param {Knex.Transaction} trx
+//    */
+//   public rewriteVendorCreditGLEntries = async (
+//     tenantId: number,
+//     vendorCreditId: number,
+//     trx?: Knex.Transaction
+//   ) => {
+//     // Reverts the GL entries.
+//     await this.revertVendorCreditGLEntries(tenantId, vendorCreditId, trx);
+
+//     // Re-write the GL entries.
+//     await this.writeVendorCreditGLEntries(tenantId, vendorCreditId, trx);
+//   };
+// }

packages/server-nest/src/modules/VendorCredit/commands/VendorCreditInventoryTransactions.ts

@@ -0,0 +1,92 @@
+// import { Knex } from 'knex';
+// import { Service, Inject } from 'typedi';
+// import { IVendorCredit } from '@/interfaces';
+// import InventoryService from '@/services/Inventory/Inventory';
+// import ItemsEntriesService from '@/services/Items/ItemsEntriesService';
+
+// @Service()
+// export default class VendorCreditInventoryTransactions {
+//   @Inject()
+//   inventoryService: InventoryService;
+
+//   @Inject()
+//   itemsEntriesService: ItemsEntriesService;
+
+//   /**
+//    * Creates vendor credit associated inventory transactions.
+//    * @param {number} tenantId
+//    * @param {IVnedorCredit} vendorCredit
+//    * @param {Knex.Transaction} trx
+//    */
+//   public createInventoryTransactions = async (
+//     tenantId: number,
+//     vendorCredit: IVendorCredit,
+//     trx: Knex.Transaction
+//   ): Promise<void> => {
+//     // Loads the inventory items entries of the given sale invoice.
+//     const inventoryEntries =
+//       await this.itemsEntriesService.filterInventoryEntries(
+//         tenantId,
+//         vendorCredit.entries
+//       );
+
+//     const transaction = {
+//       transactionId: vendorCredit.id,
+//       transactionType: 'VendorCredit',
+//       transactionNumber: vendorCredit.vendorCreditNumber,
+//       exchangeRate: vendorCredit.exchangeRate,
+//       date: vendorCredit.vendorCreditDate,
+//       direction: 'OUT',
+//       entries: inventoryEntries,
+//       warehouseId: vendorCredit.warehouseId,
+//       createdAt: vendorCredit.createdAt,
+//     };
+//     // Writes inventory tranactions.
+//     await this.inventoryService.recordInventoryTransactionsFromItemsEntries(
+//       tenantId,
+//       transaction,
+//       false,
+//       trx
+//     );
+//   };
+
+//   /**
+//    * Edits vendor credit associated inventory transactions.
+//    * @param {number} tenantId
+//    * @param {number} creditNoteId
+//    * @param {ICreditNote} creditNote
+//    * @param {Knex.Transactions} trx
+//    */
+//   public editInventoryTransactions = async (
+//     tenantId: number,
+//     vendorCreditId: number,
+//     vendorCredit: IVendorCredit,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     // Deletes inventory transactions.
+//     await this.deleteInventoryTransactions(tenantId, vendorCreditId, trx);
+
+//     // Re-write inventory transactions.
+//     await this.createInventoryTransactions(tenantId, vendorCredit, trx);
+//   };
+
+//   /**
+//    * Deletes credit note associated inventory transactions.
+//    * @param {number} tenantId - Tenant id.
+//    * @param {number} creditNoteId - Credit note id.
+//    * @param {Knex.Transaction} trx -
+//    */
+//   public deleteInventoryTransactions = async (
+//     tenantId: number,
+//     vendorCreditId: number,
+//     trx?: Knex.Transaction
+//   ): Promise<void> => {
+//     // Deletes the inventory transactions by the given reference id and type.
+//     await this.inventoryService.deleteInventoryTransactions(
+//       tenantId,
+//       vendorCreditId,
+//       'VendorCredit',
+//       trx
+//     );
+//   };
+// }

packages/server-nest/src/modules/VendorCredit/commands/VendorCreditsExportable.ts

@@ -0,0 +1,36 @@
+// import { Inject, Service } from 'typedi';
+// import { IVendorCreditsQueryDTO } from '@/interfaces';
+// import ListVendorCredits from '../queries/ListVendorCredits';
+// import { Exportable } from '@/services/Export/Exportable';
+// import { QueryBuilder } from 'knex';
+
+// @Service()
+// export class VendorCreditsExportable extends Exportable {
+//   @Inject()
+//   private getVendorCredits: ListVendorCredits;
+
+//   /**
+//    * Retrieves the vendor credits data to exportable sheet.
+//    * @param {number} tenantId -
+//    * @param {IVendorCreditsQueryDTO} query -
+//    * @returns {}
+//    */
+//   public exportable(tenantId: number, query: IVendorCreditsQueryDTO) {
+//     const filterQuery = (query) => {
+//       query.withGraphFetched('branch');
+//       query.withGraphFetched('warehouse');
+//     };
+//     const parsedQuery = {
+//       sortOrder: 'desc',
+//       columnSortBy: 'created_at',
+//       ...query,
+//       page: 1,
+//       pageSize: 12000,
+//       filterQuery,
+//     } as IVendorCreditsQueryDTO;
+
+//     return this.getVendorCredits
+//       .getVendorCredits(tenantId, parsedQuery)
+//       .then((output) => output.vendorCredits);
+//   }
+// }

packages/server-nest/src/modules/VendorCredit/commands/VendorCreditsImportable.ts

@@ -0,0 +1,45 @@
+// import { Inject, Service } from 'typedi';
+// import { Knex } from 'knex';
+// import { Importable } from '@/services/Import/Importable';
+// import CreateVendorCredit from './CreateVendorCredit.service';
+// import { IVendorCreditCreateDTO } from '@/interfaces';
+// import { VendorCreditsSampleData } from '../constants';
+
+// @Service()
+// export class VendorCreditsImportable extends Importable {
+//   @Inject()
+//   private createVendorCreditService: CreateVendorCredit;
+
+//   /**
+//    * Importing to account service.
+//    * @param {number} tenantId
+//    * @param {IAccountCreateDTO} createAccountDTO
+//    * @returns
+//    */
+//   public importable(
+//     tenantId: number,
+//     createPaymentDTO: IVendorCreditCreateDTO,
+//     trx?: Knex.Transaction
+//   ) {
+//     return this.createVendorCreditService.newVendorCredit(
+//       tenantId,
+//       createPaymentDTO,
+//       trx
+//     );
+//   }
+
+//   /**
+//    * Concurrrency controlling of the importing process.
+//    * @returns {number}
+//    */
+//   public get concurrency() {
+//     return 1;
+//   }
+
+//   /**
+//    * Retrieves the sample data that used to download accounts sample sheet.
+//    */
+//   public sampleData(): any[] {
+//     return VendorCreditsSampleData;
+//   }
+// }

packages/server-nest/src/modules/VendorCredit/constants.ts

@@ -0,0 +1,82 @@
+export const ERRORS = {
+  VENDOR_CREDIT_NOT_FOUND: 'VENDOR_CREDIT_NOT_FOUND',
+  VENDOR_CREDIT_ALREADY_OPENED: 'VENDOR_CREDIT_ALREADY_OPENED',
+  VENDOR_CREDIT_HAS_NO_REMAINING_AMOUNT:
+    'VENDOR_CREDIT_HAS_NO_REMAINING_AMOUNT',
+  VENDOR_CREDIT_APPLY_TO_BILLS_NOT_FOUND:
+    'VENDOR_CREDIT_APPLY_TO_BILLS_NOT_FOUND',
+  BILLS_HAS_NO_REMAINING_AMOUNT: 'BILLS_HAS_NO_REMAINING_AMOUNT',
+  VENDOR_CREDIT_HAS_REFUND_TRANSACTIONS:
+    'VENDOR_CREDIT_HAS_REFUND_TRANSACTIONS',
+  VENDOR_CREDIT_HAS_APPLIED_BILLS: 'VENDOR_CREDIT_HAS_APPLIED_BILLS',
+};
+
+export const DEFAULT_VIEW_COLUMNS = [];
+export const DEFAULT_VIEWS = [
+  {
+    name: 'vendor_credit.view.draft',
+    slug: 'draft',
+    rolesLogicExpression: '1',
+    roles: [
+      { index: 1, fieldKey: 'status', comparator: 'equals', value: 'draft' },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+  {
+    name: 'vendor_credit.view.published',
+    slug: 'published',
+    rolesLogicExpression: '1',
+    roles: [
+      {
+        index: 1,
+        fieldKey: 'status',
+        comparator: 'equals',
+        value: 'published',
+      },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+  {
+    name: 'vendor_credit.view.open',
+    slug: 'open',
+    rolesLogicExpression: '1',
+    roles: [
+      {
+        index: 1,
+        fieldKey: 'status',
+        comparator: 'equals',
+        value: 'open',
+      },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+  {
+    name: 'vendor_credit.view.closed',
+    slug: 'closed',
+    rolesLogicExpression: '1',
+    roles: [
+      {
+        index: 1,
+        fieldKey: 'status',
+        comparator: 'equals',
+        value: 'closed',
+      },
+    ],
+    columns: DEFAULT_VIEW_COLUMNS,
+  },
+];
+
+export const VendorCreditsSampleData = [
+  {
+    Vendor: 'Randall Kohler VENDOR',
+    'Vendor Credit Date': '2024-01-01',
+    'Vendor Credit No.': 'VC-0001',
+    'Reference No.': 'REF-00001',
+    'Exchange Rate': '',
+    Note: 'Note',
+    Open: 'T',
+    'Item Name': 'Hettinger, Schumm and Bartoletti',
+    Quantity: 100,
+    Rate: 100,
+  },
+];

packages/server-nest/src/modules/VendorCredit/models/RefundVendorCredit.ts

@@ -0,0 +1,63 @@
+import { Model, mixin } from 'objection';
+// import TenantModel from 'models/TenantModel';
+// import ModelSetting from './ModelSetting';
+// import CustomViewBaseModel from './CustomViewBaseModel';
+// import ModelSearchable from './ModelSearchable';
+import { BaseModel } from '@/models/Model';
+import { Account } from '@/modules/Accounts/models/Account.model';
+import { VendorCredit } from './VendorCredit';
+
+export class RefundVendorCredit extends BaseModel {
+  public vendorCreditId!: number;
+  public amount!: number;
+  public currencyCode!: string;
+  public exchangeRate!: number;
+  public referenceNo!: string;
+  public depositAccountId!: number;
+  public description!: string;
+  public branchId!: number;
+
+  public vendorCredit!: VendorCredit;
+  public depositAccount!: Account;
+
+  /**
+   * Table name.
+   */
+  static get tableName() {
+    return 'refund_vendor_credit_transactions';
+  }
+
+  /**
+   * Timestamps columns.
+   */
+  get timestamps() {
+    return ['created_at', 'updated_at'];
+  }
+
+  /*
+   * Relationship mapping.
+   */
+  static get relationMappings() {
+    const { VendorCredit } = require('./VendorCredit');
+    const { Account } = require('../../Accounts/models/Account.model');
+
+    return {
+      depositAccount: {
+        relation: Model.BelongsToOneRelation,
+        modelClass: Account,
+        join: {
+          from: 'refund_vendor_credit_transactions.depositAccountId',
+          to: 'accounts.id',
+        },
+      },
+      vendorCredit: {
+        relation: Model.BelongsToOneRelation,
+        modelClass: VendorCredit,
+        join: {
+          from: 'refund_vendor_credit_transactions.vendorCreditId',
+          to: 'vendor_credits.id',
+        },
+      },
+    };
+  }
+}

packages/server-nest/src/modules/VendorCredit/models/VendorCredit.ts

@@ -22,6 +22,9 @@ export class VendorCredit extends BaseModel {
   openedAt: Date;
   userId: number;
 
+  branchId: number;
+  warehouseId: number;
+
   /**
    * Table name
    */
@@ -183,83 +186,85 @@ export class VendorCredit extends BaseModel {
   /**
    * Relationship mapping.
    */
-  // static get relationMappings() {
+  static get relationMappings() {
-  //   const Vendor = require('models/Vendor');
+    const { Vendor } = require('../../Vendors/models/Vendor');
-  //   const ItemEntry = require('models/ItemEntry');
+    const {
-  //   const Branch = require('models/Branch');
+      ItemEntry,
-  //   const Document = require('models/Document');
+    } = require('../../TransactionItemEntry/models/ItemEntry');
-  //   const Warehouse = require('models/Warehouse');
+    const { Branch } = require('../../Branches/models/Branch.model');
+    const { Document } = require('../../ChromiumlyTenancy/models/Document');
+    const { Warehouse } = require('../../Warehouses/models/Warehouse.model');
 
-  //   return {
+    return {
-  //     vendor: {
+      vendor: {
-  //       relation: Model.BelongsToOneRelation,
+        relation: Model.BelongsToOneRelation,
-  //       modelClass: Vendor.default,
+        modelClass: Vendor,
-  //       join: {
+        join: {
-  //         from: 'vendor_credits.vendorId',
+          from: 'vendor_credits.vendorId',
-  //         to: 'contacts.id',
+          to: 'contacts.id',
-  //       },
+        },
-  //       filter(query) {
+        filter(query) {
-  //         query.where('contact_service', 'vendor');
+          query.where('contact_service', 'vendor');
-  //       },
+        },
-  //     },
+      },
 
-  //     entries: {
+      entries: {
-  //       relation: Model.HasManyRelation,
+        relation: Model.HasManyRelation,
-  //       modelClass: ItemEntry.default,
+        modelClass: ItemEntry,
-  //       join: {
+        join: {
-  //         from: 'vendor_credits.id',
+          from: 'vendor_credits.id',
-  //         to: 'items_entries.referenceId',
+          to: 'items_entries.referenceId',
-  //       },
+        },
-  //       filter(builder) {
+        filter(builder) {
-  //         builder.where('reference_type', 'VendorCredit');
+          builder.where('reference_type', 'VendorCredit');
-  //         builder.orderBy('index', 'ASC');
+          builder.orderBy('index', 'ASC');
-  //       },
+        },
-  //     },
+      },
 
-  //     /**
+      /**
-  //      * Vendor credit may belongs to branch.
+       * Vendor credit may belongs to branch.
-  //      */
+       */
-  //     branch: {
+      branch: {
-  //       relation: Model.BelongsToOneRelation,
+        relation: Model.BelongsToOneRelation,
-  //       modelClass: Branch.default,
+        modelClass: Branch,
-  //       join: {
+        join: {
-  //         from: 'vendor_credits.branchId',
+          from: 'vendor_credits.branchId',
-  //         to: 'branches.id',
+          to: 'branches.id',
-  //       },
+        },
-  //     },
+      },
 
-  //     /**
+      /**
-  //      * Vendor credit may has associated warehouse.
+       * Vendor credit may has associated warehouse.
-  //      */
+       */
-  //     warehouse: {
+      warehouse: {
-  //       relation: Model.BelongsToOneRelation,
+        relation: Model.BelongsToOneRelation,
-  //       modelClass: Warehouse.default,
+        modelClass: Warehouse,
-  //       join: {
+        join: {
-  //         from: 'vendor_credits.warehouseId',
+          from: 'vendor_credits.warehouseId',
-  //         to: 'warehouses.id',
+          to: 'warehouses.id',
-  //       },
+        },
-  //     },
+      },
 
-  //     /**
+      /**
-  //      * Vendor credit may has many attached attachments.
+       * Vendor credit may has many attached attachments.
-  //      */
+       */
-  //     attachments: {
+      attachments: {
-  //       relation: Model.ManyToManyRelation,
+        relation: Model.ManyToManyRelation,
-  //       modelClass: Document.default,
+        modelClass: Document,
-  //       join: {
+        join: {
-  //         from: 'vendor_credits.id',
+          from: 'vendor_credits.id',
-  //         through: {
+          through: {
-  //           from: 'document_links.modelId',
+            from: 'document_links.modelId',
-  //           to: 'document_links.documentId',
+            to: 'document_links.documentId',
-  //         },
+          },
-  //         to: 'documents.id',
+          to: 'documents.id',
-  //       },
+        },
-  //       filter(query) {
+        filter(query) {
-  //         query.where('model_ref', 'VendorCredit');
+          query.where('model_ref', 'VendorCredit');
-  //       },
+        },
-  //     },
+      },
-  //   };
+    };
-  // }
+  }
 
   /**
    *

packages/server-nest/src/modules/VendorCredit/queries/GetVendorCredit.service.ts

@@ -0,0 +1,42 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { VendorCreditTransformer } from './VendorCreditTransformer';
+import { ERRORS } from '../constants';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+import { VendorCredit } from '../models/VendorCredit';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { Knex } from 'knex';
+
+@Injectable()
+export default class GetVendorCreditService {
+  constructor(
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+    private readonly transformer: TransformerInjectable,
+  ) {}
+
+  /**
+   * Retrieve the given vendor credit.
+   * @param {number} vendorCreditId - Vendor credit id.
+   */
+  public async getVendorCredit(
+    vendorCreditId: number,
+    trx?: Knex.Transaction,
+  ) {
+    // Retrieve the vendor credit model graph.
+    const vendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .withGraphFetched('entries.item')
+      .withGraphFetched('vendor')
+      .withGraphFetched('branch') 
+      .withGraphFetched('attachments');
+
+    if (!vendorCredit) {
+      throw new ServiceError(ERRORS.VENDOR_CREDIT_NOT_FOUND);
+    }
+    return this.transformer.transform(
+      vendorCredit,
+      new VendorCreditTransformer()
+    );
+  }
+}

packages/server-nest/src/modules/VendorCredit/queries/ListVendorCredits.ts

@@ -0,0 +1,70 @@
+// import * as R from 'ramda';
+// import { Service, Inject } from 'typedi';
+// import BaseVendorCredit from '../commands/BaseVendorCredit';
+// import DynamicListingService from '@/services/DynamicListing/DynamicListService';
+// import { IVendorCreditsQueryDTO } from '@/interfaces';
+// import { VendorCreditTransformer } from './VendorCreditTransformer';
+// import { TransformerInjectable } from '@/lib/Transformer/TransformerInjectable';
+
+// @Service()
+// export default class ListVendorCredits extends BaseVendorCredit {
+//   @Inject()
+//   private dynamicListService: DynamicListingService;
+
+//   @Inject()
+//   private transformer: TransformerInjectable;
+
+//   /**
+//    * Parses the sale invoice list filter DTO.
+//    * @param {IVendorCreditsQueryDTO} filterDTO
+//    * @returns
+//    */
+//   private parseListFilterDTO = (filterDTO: IVendorCreditsQueryDTO) => {
+//     return R.compose(this.dynamicListService.parseStringifiedFilter)(filterDTO);
+//   };
+
+//   /**
+//    * Retrieve the vendor credits list.
+//    * @param {number} tenantId - Tenant id.
+//    * @param {IVendorCreditsQueryDTO} vendorCreditQuery -
+//    */
+//   public getVendorCredits = async (
+//     tenantId: number,
+//     vendorCreditQuery: IVendorCreditsQueryDTO
+//   ) => {
+//     const { VendorCredit } = this.tenancy.models(tenantId);
+
+//     // Parses stringified filter roles.
+//     const filter = this.parseListFilterDTO(vendorCreditQuery);
+
+//     // Dynamic list service.
+//     const dynamicFilter = await this.dynamicListService.dynamicList(
+//       tenantId,
+//       VendorCredit,
+//       filter
+//     );
+//     const { results, pagination } = await VendorCredit.query()
+//       .onBuild((builder) => {
+//         builder.withGraphFetched('entries');
+//         builder.withGraphFetched('vendor');
+//         dynamicFilter.buildQuery()(builder);
+
+//         // Gives ability to inject custom query to filter results.
+//         vendorCreditQuery?.filterQuery &&
+//           vendorCreditQuery?.filterQuery(builder);
+//       })
+//       .pagination(filter.page - 1, filter.pageSize);
+
+//     // Transformes the vendor credits models to POJO.
+//     const vendorCredits = await this.transformer.transform(
+//       tenantId,
+//       results,
+//       new VendorCreditTransformer()
+//     );
+//     return {
+//       vendorCredits,
+//       pagination,
+//       filterMeta: dynamicFilter.getResponseMeta(),
+//     };
+//   };
+// }

packages/server-nest/src/modules/VendorCredit/queries/VendorCreditTransformer.ts

@@ -0,0 +1,179 @@
+import { AttachmentTransformer } from "@/modules/Attachments/Attachment.transformer";
+import { ItemEntryTransformer } from "@/modules/TransactionItemEntry/ItemEntry.transformer";
+import { Transformer } from "@/modules/Transformer/Transformer";
+
+export class VendorCreditTransformer extends Transformer {
+  /**
+   * Include these attributes to vendor credit object.
+   * @returns {Array}
+   */
+  public includeAttributes = (): string[] => {
+    return [
+      'formattedAmount',
+      'formattedSubtotal',
+      'formattedVendorCreditDate',
+      'formattedCreatedAt',
+      'formattedCreditsRemaining',
+      'formattedInvoicedAmount',
+
+      'discountAmountFormatted',
+      'discountPercentageFormatted',
+      'discountAmountLocalFormatted',
+
+      'adjustmentFormatted',
+      'adjustmentLocalFormatted',
+
+      'totalFormatted',
+      'entries',
+      'attachments',
+    ];
+  };
+
+  /**
+   * Retrieve formatted vendor credit date.
+   * @param {IVendorCredit} credit
+   * @returns {String}
+   */
+  protected formattedVendorCreditDate = (vendorCredit): string => {
+    return this.formatDate(vendorCredit.vendorCreditDate);
+  };
+
+  /**
+   * Retireve formatted created at date.
+   * @param vendorCredit
+   * @returns {string}
+   */
+  protected formattedCreatedAt = (vendorCredit): string => {
+    return this.formatDate(vendorCredit.createdAt);
+  };
+
+  /**
+   * Retrieve formatted vendor credit amount.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected formattedAmount = (vendorCredit): string => {
+    return this.formatNumber(vendorCredit.amount, {
+      currencyCode: vendorCredit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the vendor credit formatted subtotal.
+   * @param {IVendorCredit} vendorCredit
+   * @returns {string}
+   */
+  protected formattedSubtotal = (vendorCredit): string => {
+    return this.formatNumber(vendorCredit.amount, { money: false });
+  };
+
+  /**
+   * Retrieve formatted credits remaining.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected formattedCreditsRemaining = (credit) => {
+    return this.formatNumber(credit.creditsRemaining, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the formatted discount amount.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected discountAmountFormatted = (credit): string => {
+    return this.formatNumber(credit.discountAmount, {
+      currencyCode: credit.currencyCode,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted discount amount in local currency.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected discountAmountLocalFormatted = (credit): string => {
+    return this.formatNumber(credit.discountAmountLocal, {
+      currencyCode: this.context.organization.baseCurrency,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted discount percentage.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected discountPercentageFormatted = (credit): string => {
+    return credit.discountPercentage ? `${credit.discountPercentage}%` : '';
+  };
+
+  /**
+   * Retrieves the formatted adjustment amount.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected adjustmentFormatted = (credit): string => {
+    return this.formatNumber(credit.adjustment, {
+      currencyCode: credit.currencyCode,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted adjustment amount in local currency.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected adjustmentLocalFormatted = (credit): string => {
+    return this.formatNumber(credit.adjustmentLocal, {
+      currencyCode: this.context.organization.baseCurrency,
+      excerptZero: true,
+    });
+  };
+
+  /**
+   * Retrieves the formatted invoiced amount.
+   * @param credit
+   * @returns {string}
+   */
+  protected formattedInvoicedAmount = (credit) => {
+    return this.formatNumber(credit.invoicedAmount, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the formatted total.
+   * @param {IVendorCredit} credit
+   * @returns {string}
+   */
+  protected totalFormatted = (credit) => {
+    return this.formatNumber(credit.total, {
+      currencyCode: credit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the entries of the bill.
+   * @param {IVendorCredit} vendorCredit
+   * @returns {}
+   */
+  protected entries = (vendorCredit) => {
+    return this.item(vendorCredit.entries, new ItemEntryTransformer(), {
+      currencyCode: vendorCredit.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieves the vendor credit attachments.
+   * @param {IVendorCredit} invoice
+   * @returns
+   */
+  protected attachments = (vendorCredit) => {
+    return this.item(vendorCredit.attachments, new AttachmentTransformer());
+  };
+}

packages/server-nest/src/modules/VendorCredit/subscribers/DeleteVendorAssociatedVendorCredit.ts

@@ -0,0 +1,48 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { OnEvent } from '@nestjs/event-emitter';
+import { VendorCredit } from '../models/VendorCredit';
+import { IVendorEventDeletingPayload } from '@/modules/Vendors/types/Vendors.types';
+import { events } from '@/common/events/events';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+const ERRORS = {
+  VENDOR_HAS_TRANSACTIONS: 'VENDOR_HAS_TRANSACTIONS',
+};
+
+@Injectable()
+export class DeleteVendorAssociatedVendorCredit {
+  /**
+   * @param {typeof VendorCredit} vendorCreditModel - Vendor credit model.
+   */
+  constructor(
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Validate vendor has no associated credit transaction once the vendor deleting.
+   * @param {IVendorEventDeletingPayload} payload -
+   */
+  @OnEvent(events.vendors.onDeleting)
+  public async validateVendorHasNoCreditsTransactionsOnceDeleting({
+    vendorId,
+  }: IVendorEventDeletingPayload) {
+    await this.validateVendorHasNoCreditsTransactions(vendorId);
+  }
+
+  /**
+   * Validate the given vendor has no associated vendor credit transactions.
+   * @param {number} vendorId
+   */
+  public async validateVendorHasNoCreditsTransactions(
+    vendorId: number,
+  ): Promise<void> {
+    const associatedVendors = await this.vendorCreditModel
+      .query()
+      .where('vendorId', vendorId);
+
+    if (associatedVendors.length > 0) {
+      throw new ServiceError(ERRORS.VENDOR_HAS_TRANSACTIONS);
+    }
+  }
+}

packages/server-nest/src/modules/VendorCredit/subscribers/RefundSyncVendorCreditBalanceSubscriber.ts

@@ -0,0 +1,62 @@
+import { Service, Inject } from 'typedi';
+import {
+  IRefundVendorCreditCreatedPayload,
+  IRefundVendorCreditDeletedPayload,
+} from '@/interfaces';
+import events from '@/subscribers/events';
+import RefundSyncCreditRefundedAmount from './RefundSyncCreditRefundedAmount';
+
+@Service()
+export default class RefundSyncVendorCreditBalanceSubscriber {
+  @Inject()
+  refundSyncCreditRefunded: RefundSyncCreditRefundedAmount;
+
+  /**
+   * Attaches events with handlers.
+   */
+  public attach = (bus) => {
+    bus.subscribe(
+      events.vendorCredit.onRefundCreated,
+      this.incrementRefundedAmountOnceRefundCreated
+    );
+    bus.subscribe(
+      events.vendorCredit.onRefundDeleted,
+      this.decrementRefundedAmountOnceRefundDeleted
+    );
+  };
+
+  /**
+   * Increment refunded vendor credit amount once refund transaction created.
+   * @param {IRefundVendorCreditCreatedPayload} payload -
+   */
+  private incrementRefundedAmountOnceRefundCreated = async ({
+    refundVendorCredit,
+    vendorCredit,
+    tenantId,
+    trx,
+  }: IRefundVendorCreditCreatedPayload) => {
+    await this.refundSyncCreditRefunded.incrementCreditRefundedAmount(
+      tenantId,
+      refundVendorCredit.vendorCreditId,
+      refundVendorCredit.amount,
+      trx
+    );
+  };
+
+  /**
+   * Decrement refunded vendor credit amount once refund transaction deleted.
+   * @param {IRefundVendorCreditDeletedPayload} payload -
+   */
+  private decrementRefundedAmountOnceRefundDeleted = async ({
+    trx,
+    oldRefundCredit,
+    tenantId,
+  }: IRefundVendorCreditDeletedPayload) => {
+    await this.refundSyncCreditRefunded.decrementCreditNoteRefundAmount(
+      tenantId,
+      oldRefundCredit.vendorCreditId,
+      oldRefundCredit.amount,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/VendorCredit/subscribers/RefundVendorCreditGLEntriesSubscriber.ts

@@ -0,0 +1,59 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import RefundVendorCreditGLEntries from '../RefundVendorCredits/commands/RefundVendorCreditGLEntries';
+import {
+  IRefundCreditNoteDeletedPayload,
+  IRefundVendorCreditCreatedPayload,
+} from '@/interfaces';
+
+@Service()
+export default class RefundVendorCreditGLEntriesSubscriber {
+  @Inject()
+  refundVendorGLEntries: RefundVendorCreditGLEntries;
+
+  /**
+   * Attaches events with handlers.
+   */
+  attach(bus) {
+    bus.subscribe(
+      events.vendorCredit.onRefundCreated,
+      this.writeRefundVendorCreditGLEntriesOnceCreated
+    );
+    bus.subscribe(
+      events.vendorCredit.onRefundDeleted,
+      this.revertRefundVendorCreditOnceDeleted
+    );
+  }
+
+  /**
+   * Writes refund vendor credit GL entries once the transaction created.
+   * @param {IRefundCreditNoteCreatedPayload} payload -
+   */
+  private writeRefundVendorCreditGLEntriesOnceCreated = async ({
+    tenantId,
+    trx,
+    refundVendorCredit,
+  }: IRefundVendorCreditCreatedPayload) => {
+    await this.refundVendorGLEntries.saveRefundCreditGLEntries(
+      tenantId,
+      refundVendorCredit.id,
+      trx
+    );
+  };
+
+  /**
+   * Reverts refund vendor credit GL entries once the transaction deleted.
+   * @param {IRefundCreditNoteDeletedPayload} payload -
+   */
+  private revertRefundVendorCreditOnceDeleted = async ({
+    tenantId,
+    trx,
+    refundCreditId,
+  }: IRefundCreditNoteDeletedPayload) => {
+    await this.refundVendorGLEntries.revertRefundCreditGLEntries(
+      tenantId,
+      refundCreditId,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/VendorCredit/subscribers/VendorCreditAutoSerialSubscriber.ts

@@ -0,0 +1,27 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import BaseVendorCredit from '../commands/VendorCreditDTOTransform.service';
+import { IVendorCreditCreatedPayload } from '@/interfaces';
+
+@Service()
+export default class VendorCreditAutoSerialSubscriber {
+  @Inject()
+  vendorCreditService: BaseVendorCredit;
+
+  /**
+   * Attaches events with handlers.
+   */
+  public attach(bus) {
+    bus.subscribe(events.vendorCredit.onCreated, this.autoIncrementOnceCreated);
+  }
+
+  /**
+   * Auto serial increment once the vendor credit created.
+   * @param {IVendorCreditCreatedPayload} payload
+   */
+  private autoIncrementOnceCreated = ({
+    tenantId,
+  }: IVendorCreditCreatedPayload) => {
+    this.vendorCreditService.incrementSerialNumber(tenantId);
+  };
+}

packages/server-nest/src/modules/VendorCredit/subscribers/VendorCreditGLEntriesSubscriber.ts

@@ -0,0 +1,110 @@
+import { Service, Inject } from 'typedi';
+import events from '@/subscribers/events';
+import {
+  IVendorCreditCreatedPayload,
+  IVendorCreditDeletedPayload,
+  IVendorCreditEditedPayload,
+  IVendorCreditOpenedPayload,
+} from '@/interfaces';
+import VendorCreditGLEntries from '../commands/VendorCreditGLEntries';
+
+@Service()
+export default class VendorCreditGlEntriesSubscriber {
+  @Inject()
+  private vendorCreditGLEntries: VendorCreditGLEntries;
+
+  /***
+   * Attaches events with handlers.
+   */
+  public attach(bus) {
+    bus.subscribe(
+      events.vendorCredit.onCreated,
+      this.writeGLEntriesOnceVendorCreditCreated
+    );
+    bus.subscribe(
+      events.vendorCredit.onOpened,
+      this.writeGLEntgriesOnceVendorCreditOpened
+    );
+    bus.subscribe(
+      events.vendorCredit.onEdited,
+      this.editGLEntriesOnceVendorCreditEdited
+    );
+    bus.subscribe(
+      events.vendorCredit.onDeleted,
+      this.revertGLEntriesOnceDeleted
+    );
+  }
+
+  /**
+   * Writes GL entries of vendor credit once the transaction created.
+   * @param {IVendorCreditCreatedPayload} payload -
+   */
+  private writeGLEntriesOnceVendorCreditCreated = async ({
+    tenantId,
+    vendorCredit,
+    trx,
+  }: IVendorCreditCreatedPayload): Promise<void> => {
+    // Can't continue if the vendor credit is not open yet.
+    if (!vendorCredit.isPublished) return;
+
+    await this.vendorCreditGLEntries.writeVendorCreditGLEntries(
+      tenantId,
+      vendorCredit.id,
+      trx
+    );
+  };
+
+  /**
+   * Writes Gl entries of vendor credit once the transaction opened.
+   * @param {IVendorCreditOpenedPayload} payload -
+   */
+  private writeGLEntgriesOnceVendorCreditOpened = async ({
+    tenantId,
+    vendorCreditId,
+    trx,
+  }: IVendorCreditOpenedPayload) => {
+    await this.vendorCreditGLEntries.writeVendorCreditGLEntries(
+      tenantId,
+      vendorCreditId,
+      trx
+    );
+  };
+
+  /**
+   * Edits associated GL entries once vendor credit edited.
+   * @param {IVendorCreditEditedPayload} payload
+   */
+  private editGLEntriesOnceVendorCreditEdited = async ({
+    tenantId,
+    vendorCreditId,
+    vendorCredit,
+    trx,
+  }: IVendorCreditEditedPayload) => {
+    // Can't continue if the vendor credit is not open yet.
+    if (!vendorCredit.isPublished) return;
+
+    await this.vendorCreditGLEntries.rewriteVendorCreditGLEntries(
+      tenantId,
+      vendorCreditId,
+      trx
+    );
+  };
+
+  /**
+   * Reverts the GL entries once vendor credit deleted.
+   * @param {IVendorCreditDeletedPayload} payload -
+   */
+  private revertGLEntriesOnceDeleted = async ({
+    vendorCreditId,
+    tenantId,
+    oldVendorCredit,
+  }: IVendorCreditDeletedPayload): Promise<void> => {
+    // Can't continue of the vendor credit is not open yet.
+    if (!oldVendorCredit.isPublished) return;
+
+    await this.vendorCreditGLEntries.revertVendorCreditGLEntries(
+      tenantId,
+      vendorCreditId
+    );
+  };
+}

packages/server-nest/src/modules/VendorCredit/subscribers/VendorCreditInventoryTransactionsSusbcriber.ts

@@ -0,0 +1,93 @@
+import { Inject, Service } from 'typedi';
+import events from '@/subscribers/events';
+import {
+  IVendorCreditCreatedPayload,
+  IVendorCreditDeletedPayload,
+  IVendorCreditEditedPayload,
+} from '@/interfaces';
+import VendorCreditInventoryTransactions from '../commands/VendorCreditInventoryTransactions';
+
+@Service()
+export default class VendorCreditInventoryTransactionsSubscriber {
+  @Inject()
+  private inventoryTransactions: VendorCreditInventoryTransactions;
+
+  /**
+   * Attaches events with handlers.
+   * @param bus
+   */
+  attach(bus) {
+    bus.subscribe(
+      events.vendorCredit.onCreated,
+      this.writeInventoryTransactionsOnceCreated
+    );
+    bus.subscribe(
+      events.vendorCredit.onOpened,
+      this.writeInventoryTransactionsOnceCreated
+    );
+    bus.subscribe(
+      events.vendorCredit.onEdited,
+      this.rewriteInventroyTransactionsOnceEdited
+    );
+    bus.subscribe(
+      events.vendorCredit.onDeleted,
+      this.revertInventoryTransactionsOnceDeleted
+    );
+  }
+
+  /**
+   * Writes inventory transactions once vendor created created.
+   * @param {IVendorCreditCreatedPayload} payload -
+   */
+  private writeInventoryTransactionsOnceCreated = async ({
+    tenantId,
+    vendorCredit,
+    trx,
+  }: IVendorCreditCreatedPayload) => {
+    // Can't continue if vendor credit is not opened.
+    if (!vendorCredit.openedAt) return null;
+
+    await this.inventoryTransactions.createInventoryTransactions(
+      tenantId,
+      vendorCredit,
+      trx
+    );
+  };
+
+  /**
+   * Rewrites inventory transactions once vendor credit edited.
+   * @param {IVendorCreditEditedPayload} payload -
+   */
+  private rewriteInventroyTransactionsOnceEdited = async ({
+    tenantId,
+    vendorCreditId,
+    vendorCredit,
+    trx,
+  }: IVendorCreditEditedPayload) => {
+    // Can't continue if vendor credit is not opened.
+    if (!vendorCredit.openedAt) return null;
+
+    await this.inventoryTransactions.editInventoryTransactions(
+      tenantId,
+      vendorCreditId,
+      vendorCredit,
+      trx
+    );
+  };
+
+  /**
+   * Reverts inventory transactions once vendor credit deleted.
+   * @param {IVendorCreditDeletedPayload} payload -
+   */
+  private revertInventoryTransactionsOnceDeleted = async ({
+    tenantId,
+    vendorCreditId,
+    trx,
+  }: IVendorCreditDeletedPayload) => {
+    await this.inventoryTransactions.deleteInventoryTransactions(
+      tenantId,
+      vendorCreditId,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/VendorCredit/types/VendorCredit.types.ts

@@ -0,0 +1,229 @@
+import { DiscountType, IDynamicListFilter, IItemEntry, IItemEntryDTO } from '@/interfaces';
+import { Knex } from 'knex';
+import { VendorCredit } from '../models/VendorCredit';
+
+export enum VendorCreditAction {
+  Create = 'Create',
+  Edit = 'Edit',
+  Delete = 'Delete',
+  View = 'View',
+  Refund = 'Refund',
+}
+
+
+export interface IVendorCreditEntryDTO extends IItemEntryDTO {}
+
+export interface IRefundVendorCredit {
+  id?: number | null;
+  date: Date;
+  referenceNo: string;
+  amount: number;
+  currencyCode: string;
+  exchangeRate: number;
+  depositAccountId: number;
+  description: string;
+  vendorCreditId: number;
+  createdAt: Date | null;
+  userId: number;
+  branchId?: number;
+
+  vendorCredit?: VendorCredit
+}
+
+export interface IVendorCreditDTO {
+  vendorId: number;
+  exchangeRate?: number;
+  vendorCreditNumber: string;
+  referenceNo: string;
+  vendorCreditDate: Date;
+  note: string;
+  open: boolean;
+  entries: IVendorCreditEntryDTO[];
+
+  branchId?: number;
+  warehouseId?: number;
+  attachments?: AttachmentLinkDTO[];
+
+  discount?: number;
+  discountType?: DiscountType;
+  
+  adjustment?: number;
+}
+
+export interface IVendorCreditCreateDTO extends IVendorCreditDTO {}
+export interface IVendorCreditEditDTO extends IVendorCreditDTO {}
+export interface IVendorCreditCreatePayload {
+  // tenantId: number;
+  refundVendorCreditDTO: IRefundVendorCreditDTO;
+  vendorCreditId: number;
+}
+
+export interface IVendorCreditCreatingPayload {
+  // tenantId: number;
+  vendorCredit: VendorCredit;
+  vendorCreditId: number;
+  vendorCreditCreateDTO: IVendorCreditCreateDTO;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditCreatedPayload {
+  // tenantId: number;
+  vendorCredit: VendorCredit;
+  vendorCreditCreateDTO: IVendorCreditCreateDTO;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditCreatedPayload {}
+export interface IVendorCreditDeletedPayload {
+  trx: Knex.Transaction;
+  // tenantId: number;
+  vendorCreditId: number;
+  oldVendorCredit: VendorCredit;
+}
+
+export interface IVendorCreditDeletingPayload {
+  trx: Knex.Transaction;
+  // tenantId: number;
+  oldVendorCredit: VendorCredit;
+}
+
+export interface IVendorCreditsQueryDTO extends IDynamicListFilter {
+  page: number;
+  pageSize: number;
+  searchKeyword?: string;
+  filterQuery?: (q: any) => void;
+}
+
+export interface IVendorCreditEditingPayload {
+  // tenantId: number;
+  oldVendorCredit: VendorCredit;
+  vendorCreditDTO: IVendorCreditEditDTO;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditEditedPayload {
+  // tenantId: number;
+  oldVendorCredit: VendorCredit;
+  vendorCredit: VendorCredit;
+  vendorCreditId: number;
+  vendorCreditDTO: IVendorCreditEditDTO;
+  trx: Knex.Transaction;
+}
+
+export interface IRefundVendorCreditDTO {
+  amount: number;
+  exchangeRate?: number;
+  depositAccountId: number;
+  description: string;
+  date: Date;
+  branchId?: number;
+}
+
+export interface IRefundVendorCreditDeletedPayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: IRefundVendorCredit;
+  // tenantId: number;
+}
+
+export interface IRefundVendorCreditDeletePayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: IRefundVendorCredit;
+  // tenantId: number;
+}
+export interface IRefundVendorCreditDeletingPayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: IRefundVendorCredit;
+  // tenantId: number;
+}
+
+export interface IRefundVendorCreditCreatingPayload {
+  trx: Knex.Transaction;
+  vendorCredit: VendorCredit;
+  refundVendorCreditDTO: IRefundVendorCreditDTO;
+  // tenantId: number;
+}
+
+export interface IRefundVendorCreditCreatedPayload {
+  refundVendorCredit: IRefundVendorCredit;
+  vendorCredit: VendorCredit;
+  trx: Knex.Transaction;
+  // tenantId: number;
+}
+export interface IRefundVendorCreditPOJO {}
+
+export interface IApplyCreditToBillEntryDTO {
+  amount: number;
+  billId: number;
+}
+
+export interface IApplyCreditToBillsDTO {
+  entries: IApplyCreditToBillEntryDTO[];
+}
+
+export interface IVendorCreditOpenedPayload {
+  // tenantId: number;
+  vendorCreditId: number;
+  vendorCredit: VendorCredit;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditOpenPayload {
+  // tenantId: number;
+  vendorCreditId: number;
+  oldVendorCredit: VendorCredit;
+}
+
+export interface IVendorCreditOpeningPayload {
+  // tenantId: number;
+  vendorCreditId: number;
+  oldVendorCredit: VendorCredit;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditApplyToBillsCreatedPayload {
+  // tenantId: number;
+  vendorCredit: VendorCredit;
+  vendorCreditAppliedBills: IVendorCreditAppliedBill[];
+  trx: Knex.Transaction;
+}
+export interface IVendorCreditApplyToBillsCreatingPayload {
+  trx: Knex.Transaction;
+}
+export interface IVendorCreditApplyToBillsCreatePayload {
+  trx: Knex.Transaction;
+}
+export interface IVendorCreditApplyToBillDeletedPayload {
+  // tenantId: number;
+  vendorCredit: VendorCredit;
+  oldCreditAppliedToBill: IVendorCreditAppliedBill;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditApplyToInvoiceDTO {
+  amount: number;
+  billId: number;
+}
+
+export interface IVendorCreditApplyToInvoicesDTO {
+  entries: IVendorCreditApplyToInvoiceDTO[];
+}
+
+export interface IVendorCreditApplyToInvoiceModel {
+  billId: number;
+  amount: number;
+  vendorCreditId: number;
+}
+
+export interface IVendorCreditApplyToInvoicesModel {
+  entries: IVendorCreditApplyToInvoiceModel[];
+  amount: number;
+}
+
+export interface IVendorCreditAppliedBill {
+  billId: number;
+  amount: number;
+  vendorCreditId: number;
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/VendorCreditApplyBills.module.ts

@@ -0,0 +1,20 @@
+
+
+import { Module } from "@nestjs/common";
+import { ApplyVendorCreditSyncBillsService } from "./command/ApplyVendorCreditSyncBills.service";
+import { ApplyVendorCreditSyncInvoicedService } from "./command/ApplyVendorCreditSyncInvoiced.service";
+import { DeleteApplyVendorCreditToBillService } from "./command/DeleteApplyVendorCreditToBill.service";
+import { ApplyVendorCreditToBillsService } from "./command/ApplyVendorCreditToBills.service";
+import { GetAppliedBillsToVendorCreditService } from "./queries/GetAppliedBillsToVendorCredit.service";
+
+@Module({
+  imports: [
+    ApplyVendorCreditSyncBillsService,
+    ApplyVendorCreditSyncInvoicedService,
+    ApplyVendorCreditToBillsService,
+    DeleteApplyVendorCreditToBillService,
+    GetAppliedBillsToVendorCreditService
+  ],
+  controllers: [],
+})
+export class VendorCreditApplyBillsModule {}

packages/server-nest/src/modules/VendorCreditsApplyBills/VendorCreditsApplyBills.constants.ts

@@ -0,0 +1,12 @@
+export const ERRORS = {
+  VENDOR_CREDIT_NOT_FOUND: 'VENDOR_CREDIT_NOT_FOUND',
+  VENDOR_CREDIT_ALREADY_OPENED: 'VENDOR_CREDIT_ALREADY_OPENED',
+  VENDOR_CREDIT_HAS_NO_REMAINING_AMOUNT:
+    'VENDOR_CREDIT_HAS_NO_REMAINING_AMOUNT',
+  VENDOR_CREDIT_APPLY_TO_BILLS_NOT_FOUND:
+    'VENDOR_CREDIT_APPLY_TO_BILLS_NOT_FOUND',
+  BILLS_HAS_NO_REMAINING_AMOUNT: 'BILLS_HAS_NO_REMAINING_AMOUNT',
+  VENDOR_CREDIT_HAS_REFUND_TRANSACTIONS:
+    'VENDOR_CREDIT_HAS_REFUND_TRANSACTIONS',
+  VENDOR_CREDIT_HAS_APPLIED_BILLS: 'VENDOR_CREDIT_HAS_APPLIED_BILLS',
+};

packages/server-nest/src/modules/VendorCreditsApplyBills/command/ApplyVendorCreditSyncBills.service.ts

@@ -0,0 +1,48 @@
+import Bluebird from 'bluebird';
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import { IVendorCreditAppliedBill } from '../types/VendorCreditApplyBills.types';
+import { Bill } from '@/modules/Bills/models/Bill';
+
+@Injectable()
+export class ApplyVendorCreditSyncBillsService {
+  constructor(
+    @Inject(Bill.name)
+    private readonly billModel: typeof Bill,
+  ) {}
+
+  /**
+   * Increment bills credited amount.
+   * @param {IVendorCreditAppliedBill[]} vendorCreditAppliedBills
+   * @param {Knex.Transaction} trx
+   */
+  public incrementBillsCreditedAmount = async (
+    vendorCreditAppliedBills: IVendorCreditAppliedBill[],
+    trx?: Knex.Transaction,
+  ) => {
+    await Bluebird.each(
+      vendorCreditAppliedBills,
+      (vendorCreditAppliedBill: IVendorCreditAppliedBill) => {
+        return this.billModel
+          .query(trx)
+          .where('id', vendorCreditAppliedBill.billId)
+          .increment('creditedAmount', vendorCreditAppliedBill.amount);
+      },
+    );
+  };
+
+  /**
+   * Decrement bill credited amount.
+   * @param {IVendorCreditAppliedBill} vendorCreditAppliedBill
+   * @param {Knex.Transaction} trx
+   */
+  public decrementBillCreditedAmount = async (
+    vendorCreditAppliedBill: IVendorCreditAppliedBill,
+    trx?: Knex.Transaction,
+  ) => {
+    await this.billModel
+      .query(trx)
+      .findById(vendorCreditAppliedBill.billId)
+      .decrement('creditedAmount', vendorCreditAppliedBill.amount);
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/command/ApplyVendorCreditSyncInvoiced.service.ts

@@ -0,0 +1,43 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+
+@Injectable()
+export class ApplyVendorCreditSyncInvoicedService {
+  constructor(
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Increment vendor credit invoiced amount.
+   * @param {number} vendorCreditId - Vendor credit id.
+   * @param {number} amount - Amount to increment.
+   * @param {Knex.Transaction} trx - Knex transaction.
+   */
+  public incrementVendorCreditInvoicedAmount = async (
+    vendorCreditId: number,
+    amount: number,
+    trx?: Knex.Transaction
+  ) => {
+    await this.vendorCreditModel.query(trx)
+      .findById(vendorCreditId)
+      .increment('invoicedAmount', amount);
+  };
+
+  /**
+   * Decrement credit note invoiced amount.
+   * @param {number} vendorCreditId - Vendor credit id.
+   * @param {number} amount - Amount to decrement.
+   * @param {Knex.Transaction} trx - Knex transaction.
+   */
+  public decrementVendorCreditInvoicedAmount = async (
+    vendorCreditId: number,
+    amount: number,
+    trx?: Knex.Transaction
+  ) => {
+    await this.vendorCreditModel.query(trx)
+      .findById(vendorCreditId)
+      .decrement('invoicedAmount', amount);
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/command/ApplyVendorCreditToBills.service.ts

@@ -0,0 +1,129 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import { sumBy } from 'lodash';
+import {
+  IVendorCreditApplyToBillsCreatedPayload,
+  IVendorCreditApplyToInvoicesDTO,
+  IVendorCreditApplyToInvoicesModel,
+} from '../types/VendorCreditApplyBills.types';
+import { ERRORS } from '../VendorCreditsApplyBills.constants';
+import { VendorCreditAppliedBill } from '../models/VendorCreditAppliedBill';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+import { BillPaymentValidators } from '@/modules/BillPayments/commands/BillPaymentValidators.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { Bill } from '@/modules/Bills/models/Bill';
+import { ServiceError } from '@/modules/Items/ServiceError';
+
+@Injectable()
+export class ApplyVendorCreditToBillsService {
+  /**
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {BillPaymentValidators} billPaymentValidators - The bill payment validators service.
+   * @param {typeof VendorCreditAppliedBill} vendorCreditAppliedBillModel - The vendor credit applied bill model.
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+    private readonly billPaymentValidators: BillPaymentValidators,
+    private readonly vendorCreditAppliedBillModel: typeof VendorCreditAppliedBill,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Apply credit note to the given invoices.
+   * @param {number} creditNoteId
+   * @param {IApplyCreditToInvoicesDTO} applyCreditToInvoicesDTO
+   */
+  public applyVendorCreditToBills = async (
+    vendorCreditId: number,
+    applyCreditToBillsDTO: IVendorCreditApplyToInvoicesDTO,
+  ): Promise<void> => {
+    // Retrieves the vendor credit or throw not found service error.
+    const vendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    // Transfomes credit apply to bills DTO to model object.
+    const vendorCreditAppliedModel = this.transformApplyDTOToModel(
+      applyCreditToBillsDTO,
+      vendorCredit,
+    );
+
+    // Validate bills entries existance.
+    const appliedBills =
+      await this.billPaymentValidators.validateBillsExistance(
+        vendorCreditAppliedModel.entries,
+        vendorCredit.vendorId,
+      );
+
+    // Validate bills has remaining amount to apply.
+    this.validateBillsRemainingAmount(
+      appliedBills,
+      vendorCreditAppliedModel.amount,
+    );
+    // Validate vendor credit remaining credit amount.
+    this.validateCreditRemainingAmount(
+      vendorCredit,
+      vendorCreditAppliedModel.amount,
+    );
+
+    // Saves vendor credit applied to bills under unit-of-work envirement.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      // Inserts vendor credit applied to bills graph to the storage layer.
+      const vendorCreditAppliedBills = await this.vendorCreditAppliedBillModel
+        .query(trx)
+        .insertGraph(vendorCreditAppliedModel.entries);
+
+      // Triggers `IVendorCreditApplyToBillsCreatedPayload` event.
+      await this.eventPublisher.emitAsync(
+        events.vendorCredit.onApplyToInvoicesCreated,
+        {
+          trx,
+          vendorCredit,
+          vendorCreditAppliedBills,
+        } as IVendorCreditApplyToBillsCreatedPayload,
+      );
+    });
+  };
+
+  /**
+   * Transformes apply DTO to model.
+   * @param {IApplyCreditToInvoicesDTO} applyDTO
+   * @param {ICreditNote} creditNote
+   * @returns {IVendorCreditApplyToInvoicesModel}
+   */
+  private transformApplyDTOToModel = (
+    applyDTO: IVendorCreditApplyToInvoicesDTO,
+    vendorCredit: VendorCredit,
+  ): IVendorCreditApplyToInvoicesModel => {
+    const entries = applyDTO.entries.map((entry) => ({
+      billId: entry.billId,
+      amount: entry.amount,
+      vendorCreditId: vendorCredit.id,
+    }));
+    const amount = sumBy(applyDTO.entries, 'amount');
+
+    return {
+      amount,
+      entries,
+    };
+  };
+
+  /**
+   * Validate bills remaining amount.
+   * @param {IBill[]} bills
+   * @param {number} amount
+   */
+  private validateBillsRemainingAmount = (bills: Bill[], amount: number) => {
+    const invalidBills = bills.filter((bill) => bill.dueAmount < amount);
+    if (invalidBills.length > 0) {
+      throw new ServiceError(ERRORS.BILLS_HAS_NO_REMAINING_AMOUNT);
+    }
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/command/DeleteApplyVendorCreditToBill.service.ts

@@ -0,0 +1,66 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { events } from '@/common/events/events';
+import { IVendorCreditApplyToBillDeletedPayload } from '../types/VendorCreditApplyBills.types';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+import { ERRORS } from '../VendorCreditsApplyBills.constants';
+import { VendorCreditAppliedBill } from '../models/VendorCreditAppliedBill';
+
+@Injectable()
+export class DeleteApplyVendorCreditToBillService {
+  /**
+   * @param {UnitOfWork} uow - The unit of work service.
+   * @param {EventEmitter2} eventPublisher - The event emitter service.
+   * @param {typeof VendorCreditAppliedBill} vendorCreditAppliedBillModel - The vendor credit applied bill model.
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+    private readonly vendorCreditAppliedBillModel: typeof VendorCreditAppliedBill,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Delete apply vendor credit to bill transaction.
+   * @param {number} appliedCreditToBillId
+   * @returns {Promise<void>}
+   */
+  public async deleteApplyVendorCreditToBills(appliedCreditToBillId: number) {
+    const oldCreditAppliedToBill = await this.vendorCreditAppliedBillModel
+      .query()
+      .findById(appliedCreditToBillId);
+
+    if (!oldCreditAppliedToBill) {
+      throw new ServiceError(ERRORS.VENDOR_CREDIT_APPLY_TO_BILLS_NOT_FOUND);
+    }
+    // Retrieve the vendor credit or throw not found service error.
+    const vendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(oldCreditAppliedToBill.vendorCreditId)
+      .throwIfNotFound();
+
+    // Deletes vendor credit apply under unit-of-work environment.
+    return this.uow.withTransaction(async (trx) => {
+      // Delete vendor credit applied to bill transaction.
+      await this.vendorCreditAppliedBillModel
+        .query(trx)
+        .findById(appliedCreditToBillId)
+        .delete();
+
+      // Triggers `onVendorCreditApplyToInvoiceDeleted` event.
+      await this.eventPublisher.emitAsync(
+        events.vendorCredit.onApplyToInvoicesDeleted,
+        {
+          vendorCredit,
+          oldCreditAppliedToBill,
+          trx,
+        } as IVendorCreditApplyToBillDeletedPayload,
+      );
+    });
+  }
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/models/VendorCreditAppliedBill.ts

@@ -1,11 +1,20 @@
-import { mixin, Model } from 'objection';
+import { Model } from 'objection';
 // import TenantModel from 'models/TenantModel';
 // import ModelSetting from './ModelSetting';
 // import CustomViewBaseModel from './CustomViewBaseModel';
 // import ModelSearchable from './ModelSearchable';
 import { BaseModel } from '@/models/Model';
+import { VendorCredit } from '../../VendorCredit/models/VendorCredit';
+import { Bill } from '@/modules/Bills/models/Bill';
 
 export class VendorCreditAppliedBill extends BaseModel {
+  public amount!: number;
+  public billId!: number;
+  public vendorCreditId!: number;
+
+  public vendorCredit!: VendorCredit;
+  public bill!: Bill;
+
   /**
    * Table name
    */
@@ -16,7 +25,7 @@ export class VendorCreditAppliedBill extends BaseModel {
   /**
    * Timestamps columns.
    */
-  get timestamps() {
+  public get timestamps() {
     return ['created_at', 'updated_at'];
   }
 

packages/server-nest/src/modules/VendorCreditsApplyBills/queries/GetAppliedBillsToVendorCredit.service.ts

@@ -0,0 +1,40 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { VendorCreditAppliedBillTransformer } from './VendorCreditAppliedBillTransformer';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+import { VendorCreditAppliedBill } from '@/modules/VendorCreditsApplyBills/models/VendorCreditAppliedBill';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+
+@Injectable()
+export class GetAppliedBillsToVendorCreditService {
+  constructor(
+    private readonly transformer: TransformerInjectable,
+    private readonly vendorCreditAppliedBillModel: typeof VendorCreditAppliedBill,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Get applied bills to vendor credit.
+   * @param {number} vendorCreditId
+   * @returns
+   */
+  public getAppliedBills = async (vendorCreditId: number) => {
+    const vendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    const appliedToBills = await this.vendorCreditAppliedBillModel
+      .query()
+      .where('vendorCreditId', vendorCreditId)
+      .withGraphFetched('bill')
+      .withGraphFetched('vendorCredit');
+
+    // Transforms the models to POJO.
+    return this.transformer.transform(
+      appliedToBills,
+      new VendorCreditAppliedBillTransformer(),
+    );
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/queries/GetVendorCreditToApplyBills.service.ts

@@ -0,0 +1,47 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { VendorCreditToApplyBillTransformer } from './VendorCreditToApplyBillTransformer';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+import { Bill } from '@/modules/Bills/models/Bill';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+
+@Injectable()
+export class GetVendorCreditToApplyBills  {
+  /**
+   * @param {TransformerService} transformerService - The transformer service.
+   * @param {typeof Bill} billModel - The bill model.
+   * @param {typeof VendorCredit} vendorCreditModel - The vendor credit model.
+   */
+  constructor(
+    private readonly transformerService: TransformerInjectable,
+    @Inject(Bill.name) private readonly billModel: typeof Bill,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Retrieve bills that valid apply to the given vendor credit.
+   * @param {number} vendorCreditId
+   * @returns {Promise<any[]>}
+   */
+  public async getCreditToApplyBills(vendorCreditId: number) {
+    // Retrieve vendor credit or throw not found service error.
+    const vendorCredit = await this.vendorCreditModel
+      .query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    // Retrieve open bills associated to the given vendor.
+    const openBills = await this.billModel
+      .query()
+      .where('vendor_id', vendorCredit.vendorId)
+      .modify('dueBills')
+      .modify('published');
+
+    // Transform the bills to POJO.
+    return this.transformerService.transform(
+      openBills,
+      new VendorCreditToApplyBillTransformer(),
+    );
+  }
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/queries/VendorCreditAppliedBillTransformer.ts

@@ -0,0 +1,67 @@
+import { Transformer } from "@/modules/Transformer/Transformer";
+import { VendorCreditAppliedBill } from "@/modules/VendorCreditsApplyBills/models/VendorCreditAppliedBill";
+
+export class VendorCreditAppliedBillTransformer extends Transformer {
+  /**
+   * Includeded attributes.
+   * @returns {string[]}
+   */
+  public includeAttributes = (): string[] => {
+    return [
+      'formattedAmount',
+      'vendorCreditNumber',
+      'vendorCreditDate',
+      'billNumber',
+      'billReferenceNo',
+      'formattedVendorCreditDate',
+      'formattedBillDate',
+    ];
+  };
+
+  /**
+   * Exclude attributes.
+   * @returns {string[]}
+   */
+  public excludeAttributes = (): string[] => {
+    return ['bill', 'vendorCredit'];
+  };
+
+  /**
+   * 
+   * @param item 
+   * @returns 
+   */
+  protected formattedAmount = (item: VendorCreditAppliedBill) => {
+    return this.formatNumber(item.amount, {
+      currencyCode: item.vendorCredit.currencyCode,
+    });
+  };
+
+  protected vendorCreditNumber = (item) => {
+    return item.vendorCredit.vendorCreditNumber;
+  };
+
+  protected vendorCreditDate = (item) => {
+    return item.vendorCredit.vendorCreditDate;
+  };
+
+  protected formattedVendorCreditDate = (item) => {
+    return this.formatDate(item.vendorCredit.vendorCreditDate);
+  };
+
+  protected billNumber = (item) => {
+    return item.bill.billNo;
+  };
+
+  protected billReferenceNo = (item) => {
+    return item.bill.referenceNo;
+  };
+
+  protected BillDate = (item) => {
+    return item.bill.billDate;
+  };
+
+  protected formattedBillDate = (item) => {
+    return this.formatDate(item.bill.billDate);
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/queries/VendorCreditToApplyBillTransformer.ts

@@ -0,0 +1,69 @@
+import { Bill } from '@/modules/Bills/models/Bill';
+import { Transformer } from '@/modules/Transformer/Transformer';
+
+export class VendorCreditToApplyBillTransformer extends Transformer {
+  /**
+   * Include these attributes to sale invoice object.
+   * @returns {Array}
+   */
+  public includeAttributes = (): string[] => {
+    return [
+      'formattedBillDate',
+      'formattedDueDate',
+      'formattedAmount',
+      'formattedDueAmount',
+      'formattedPaymentAmount',
+    ];
+  };
+
+  /**
+   * Retrieve formatted bill date.
+   * @param {Bill} bill
+   * @returns {String}
+   */
+  protected formattedBillDate = (bill: Bill): string => {
+    return this.formatDate(bill.billDate);
+  };
+
+  /**
+   * Retrieve formatted due date.
+   * @param {Bill} bill
+   * @returns {string}
+   */
+  protected formattedDueDate = (bill: Bill): string => {
+    return this.formatDate(bill.dueDate);
+  };
+
+  /**
+   * Retrieve formatted bill amount.
+   * @param {Bill} bill
+   * @returns {string}
+   */
+  protected formattedAmount = (bill: Bill): string => {
+    return this.formatNumber(bill.amount, {
+      currencyCode: bill.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieve formatted bill due amount.
+   * @param {Bill} bill
+   * @returns {string}
+   */
+  protected formattedDueAmount = (bill: Bill): string => {
+    return this.formatNumber(bill.dueAmount, {
+      currencyCode: bill.currencyCode,
+    });
+  };
+
+  /**
+   * Retrieve formatted payment amount.
+   * @param {Bill} bill
+   * @returns {string}
+   */
+  protected formattedPaymentAmount = (bill: Bill): string => {
+    return this.formatNumber(bill.paymentAmount, {
+      currencyCode: bill.currencyCode,
+    });
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/subscribers/ApplyVendorCreditSyncBillsSubscriber.ts

@@ -0,0 +1,61 @@
+import { Injectable } from '@nestjs/common';
+import { InjectModel } from '@nestjs/objection';
+import events from '@/subscribers/events';
+import {
+  IVendorCreditApplyToBillDeletedPayload,
+  IVendorCreditApplyToBillsCreatedPayload,
+} from '@/interfaces';
+import { ApplyVendorCreditSyncBillsService } from '../command/ApplyVendorCreditSyncBills.service';
+import { VendorCreditApplyToBill } from '../models/VendorCreditApplyToBill';
+
+@Injectable()
+export default class ApplyVendorCreditSyncBillsSubscriber {
+  constructor(
+    private readonly syncBillsWithVendorCredit: ApplyVendorCreditSyncBillsService,
+    @InjectModel(VendorCreditApplyToBill)
+    private readonly vendorCreditApplyToBillModel: typeof VendorCreditApplyToBill,
+  ) {}
+
+  /**
+   * Attaches events with handlers.
+   */
+  attach(bus) {
+    bus.subscribe(
+      events.vendorCredit.onApplyToInvoicesCreated,
+      this.incrementAppliedBillsOnceCreditCreated
+    );
+    bus.subscribe(
+      events.vendorCredit.onApplyToInvoicesDeleted,
+      this.decrementAppliedBillsOnceCreditDeleted
+    );
+  }
+
+  /**
+   * Increment credited amount of applied bills once the vendor credit transaction created.
+   * @param {IVendorCreditApplyToBillsCreatedPayload}  paylaod -
+   */
+  private incrementAppliedBillsOnceCreditCreated = async ({
+    vendorCreditAppliedBills,
+    trx,
+  }: IVendorCreditApplyToBillsCreatedPayload) => {
+    await this.syncBillsWithVendorCredit.incrementBillsCreditedAmount(
+      vendorCreditAppliedBills,
+      trx
+    );
+  };
+
+  /**
+   * Decrement credited amount of applied bills once the vendor credit
+   * transaction delted.
+   * @param {IVendorCreditApplyToBillDeletedPayload} payload
+   */
+  private decrementAppliedBillsOnceCreditDeleted = async ({
+    oldCreditAppliedToBill,
+    trx,
+  }: IVendorCreditApplyToBillDeletedPayload) => {
+    await this.syncBillsWithVendorCredit.decrementBillCreditedAmount(
+      oldCreditAppliedToBill,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/subscribers/ApplyVendorCreditSyncInvoicedSubscriber.ts

@@ -0,0 +1,70 @@
+import { Service, Inject } from 'typedi';
+import { sumBy } from 'lodash';
+import HasTenancyService from '@/services/Tenancy/TenancyService';
+import ApplyVendorCreditSyncInvoiced from '../command/ApplyVendorCreditSyncInvoiced.service';
+import events from '@/subscribers/events';
+import {
+  IVendorCreditApplyToBillDeletedPayload,
+  IVendorCreditApplyToBillsCreatedPayload,
+} from '@/interfaces';
+
+@Service()
+export default class ApplyVendorCreditSyncInvoicedSubscriber {
+  @Inject()
+  tenancy: HasTenancyService;
+
+  @Inject()
+  syncCreditWithInvoiced: ApplyVendorCreditSyncInvoiced;
+
+  /**
+   * Attaches events with handlers.
+   */
+  attach(bus) {
+    bus.subscribe(
+      events.vendorCredit.onApplyToInvoicesCreated,
+      this.incrementBillInvoicedOnceCreditApplied
+    );
+    bus.subscribe(
+      events.vendorCredit.onApplyToInvoicesDeleted,
+      this.decrementBillInvoicedOnceCreditApplyDeleted
+    );
+  }
+
+  /**
+   * Increment vendor credit invoiced amount once the apply transaction created.
+   * @param {IVendorCreditApplyToBillsCreatedPayload} payload -
+   */
+  private incrementBillInvoicedOnceCreditApplied = async ({
+    vendorCredit,
+    tenantId,
+    vendorCreditAppliedBills,
+    trx,
+  }: IVendorCreditApplyToBillsCreatedPayload) => {
+    const amount = sumBy(vendorCreditAppliedBills, 'amount');
+
+    await this.syncCreditWithInvoiced.incrementVendorCreditInvoicedAmount(
+      tenantId,
+      vendorCredit.id,
+      amount,
+      trx
+    );
+  };
+
+  /**
+   * Decrement vendor credit invoiced amount once the apply transaction deleted.
+   * @param {IVendorCreditApplyToBillDeletedPayload} payload -
+   */
+  private decrementBillInvoicedOnceCreditApplyDeleted = async ({
+    tenantId,
+    vendorCredit,
+    oldCreditAppliedToBill,
+    trx,
+  }: IVendorCreditApplyToBillDeletedPayload) => {
+    await this.syncCreditWithInvoiced.decrementVendorCreditInvoicedAmount(
+      tenantId,
+      oldCreditAppliedToBill.vendorCreditId,
+      oldCreditAppliedToBill.amount,
+      trx
+    );
+  };
+}

packages/server-nest/src/modules/VendorCreditsApplyBills/types/VendorCreditApplyBills.types.ts

@@ -0,0 +1,48 @@
+import { Knex } from 'knex';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+
+export interface IVendorCreditApplyToBillsCreatedPayload {
+  vendorCredit: VendorCredit;
+  vendorCreditAppliedBills: IVendorCreditAppliedBill[];
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditApplyToBillsCreatingPayload {
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditApplyToBillsCreatePayload {
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditApplyToBillDeletedPayload {
+  vendorCredit: VendorCredit;
+  oldCreditAppliedToBill: IVendorCreditAppliedBill;
+  trx: Knex.Transaction;
+}
+
+export interface IVendorCreditApplyToInvoiceDTO {
+  amount: number;
+  billId: number;
+}
+
+export interface IVendorCreditApplyToInvoicesDTO {
+  entries: IVendorCreditApplyToInvoiceDTO[];
+}
+
+export interface IVendorCreditApplyToInvoiceModel {
+  billId: number;
+  amount: number;
+  vendorCreditId: number;
+}
+
+export interface IVendorCreditApplyToInvoicesModel {
+  entries: IVendorCreditApplyToInvoiceModel[];
+  amount: number;
+}
+
+export interface IVendorCreditAppliedBill {
+  billId: number;
+  amount: number;
+  vendorCreditId: number;
+}

packages/server-nest/src/modules/VendorCreditsRefund/commands/CreateRefundVendorCredit.service.ts

@@ -0,0 +1,122 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import * as R from 'ramda';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import {
+  IRefundVendorCredit,
+  IRefundVendorCreditCreatedPayload,
+  IRefundVendorCreditCreatingPayload,
+  IRefundVendorCreditDTO,
+  IVendorCreditCreatePayload,
+} from '@/modules/VendorCredit/types/VendorCredit.types';
+import { Account } from '@/modules/Accounts/models/Account.model';
+import { VendorCredit } from '../../models/VendorCredit';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { RefundVendorCredit } from '../../models/RefundVendorCredit';
+import { BranchTransactionDTOTransformer } from '@/modules/Branches/integrations/BranchTransactionDTOTransform';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class CreateRefundVendorCredit  {
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+    private readonly branchDTOTransform: BranchTransactionDTOTransformer,
+
+    @Inject(RefundVendorCredit.name)
+    private readonly refundVendorCreditModel: typeof RefundVendorCredit,
+
+    @Inject(Account.name)
+    private readonly accountModel: typeof Account,
+
+    @Inject(VendorCredit.name)
+    private readonly vendorCreditModel: typeof VendorCredit,
+  ) {
+  }
+
+  /**
+   * Creates a refund vendor credit.
+   * @param {number} vendorCreditId
+   * @param {IRefundVendorCreditDTO} refundVendorCreditDTO
+   * @returns {Promise<IRefundVendorCredit>}
+   */
+  public createRefund = async (
+    vendorCreditId: number,
+    refundVendorCreditDTO: IRefundVendorCreditDTO
+  ): Promise<IRefundVendorCredit> => {
+    // Retrieve the vendor credit or throw not found service error.
+    const vendorCredit = await this.vendorCreditModel.query()
+      .findById(vendorCreditId)
+      .throwIfNotFound();
+
+    // Retrieve the deposit account or throw not found service error.
+    const depositAccount = await this.accountModel.query()
+      .findById(refundVendorCreditDTO.depositAccountId)
+      .throwIfNotFound();
+
+    // Validate vendor credit has remaining credit.
+    this.validateVendorCreditRemainingCredit(
+      vendorCredit,
+      refundVendorCreditDTO.amount
+    );
+    // Validate refund deposit account type.
+    this.validateRefundDepositAccountType(depositAccount);
+
+    // Triggers `onVendorCreditRefundCreate` event.
+    await this.eventPublisher.emitAsync(events.vendorCredit.onRefundCreate, {
+      vendorCreditId,
+      refundVendorCreditDTO,
+    } as IVendorCreditCreatePayload);
+
+    const refundCreditObj = this.transformDTOToModel(
+      vendorCredit,
+      refundVendorCreditDTO
+    );
+    // Saves refund vendor credit with associated transactions.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      const eventPayload = {
+        vendorCredit,
+        trx,
+        refundVendorCreditDTO,
+      } as IRefundVendorCreditCreatingPayload;
+
+      // Triggers `onVendorCreditRefundCreating` event.
+      await this.eventPublisher.emitAsync(
+        events.vendorCredit.onRefundCreating,
+        eventPayload as IRefundVendorCreditCreatingPayload
+      );
+      // Inserts refund vendor credit to the storage layer.
+      const refundVendorCredit =
+        await this.refundVendorCreditModel.query().insertAndFetch(refundCreditObj);
+        
+      // Triggers `onVendorCreditCreated` event.
+      await this.eventPublisher.emitAsync(events.vendorCredit.onRefundCreated, {
+        ...eventPayload,
+        refundVendorCredit,
+      } as IRefundVendorCreditCreatedPayload);
+
+      return refundVendorCredit;
+    });
+  };
+
+  /**
+   * Transformes the refund DTO to refund vendor credit model.
+   * @param   {IVendorCredit} vendorCredit -
+   * @param   {IRefundVendorCreditDTO} vendorCreditDTO
+   * @returns {IRefundVendorCredit}
+   */
+  public transformDTOToModel = (
+    vendorCredit: VendorCredit,
+    vendorCreditDTO: IRefundVendorCreditDTO
+  ) => {
+    const initialDTO = {
+      vendorCreditId: vendorCredit.id,
+      ...vendorCreditDTO,
+      currencyCode: vendorCredit.currencyCode,
+      exchangeRate: vendorCreditDTO.exchangeRate || 1,
+    };
+    return R.compose(this.branchDTOTransform.transformDTO())(
+      initialDTO
+    );
+  };
+}

packages/server-nest/src/modules/VendorCreditsRefund/commands/DeleteRefundVendorCredit.service.ts

@@ -0,0 +1,74 @@
+import { Knex } from 'knex';
+import {
+  IRefundVendorCreditDeletedPayload,
+  IRefundVendorCreditDeletePayload,
+  IRefundVendorCreditDeletingPayload,
+} from '@/modules/VendorCredit/types/VendorCredit.types';
+import { Inject, Injectable } from '@nestjs/common';
+import { RefundVendorCredit } from '../../models/RefundVendorCredit';
+import { RefundVendorCreditService } from './RefundVendorCredit.service';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { events } from '@/common/events/events';
+
+@Injectable()
+export class DeleteRefundVendorCreditService {
+  /**
+   * @param {UnitOfWork} uow - Unit of work service.
+   * @param {EventEmitter2} eventPublisher - Event emitter service.
+   * @param {typeof RefundVendorCredit} refundVendorCreditModel - Refund vendor credit model.
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(RefundVendorCredit.name)
+    private readonly refundVendorCreditModel: typeof RefundVendorCredit,
+  ) {
+  }
+
+  /**
+   * Deletes the refund vendor credit.
+   * @param {number} refundCreditId - Refund credit id.
+   * @returns {Promise<void>}
+   */
+  public async deleteRefundVendorCreditRefund(
+    refundCreditId: number
+  ): Promise<void> {
+    // Retrieve the old credit note or throw not found service error.
+    const oldRefundCredit = await this.getRefundVendorCreditOrThrowError(
+      refundCreditId
+    );
+    // Triggers `onVendorCreditRefundDelete` event.
+    await this.eventPublisher.emitAsync(events.vendorCredit.onRefundDelete, {
+      refundCreditId,
+      oldRefundCredit,
+    } as IRefundVendorCreditDeletePayload);
+
+    // Deletes the refund vendor credit under unit-of-work environment.
+    return this.uow.withTransaction(async (trx: Knex.Transaction) => {
+      const eventPayload = {
+        trx,
+        refundCreditId,
+        oldRefundCredit,
+      } as IRefundVendorCreditDeletingPayload;
+
+      // Triggers `onVendorCreditRefundDeleting` event.
+      await this.eventPublisher.emitAsync(
+        events.vendorCredit.onRefundDeleting,
+        eventPayload
+      );
+      // Deletes the refund vendor credit graph from the storage.
+      await this.refundVendorCreditModel
+        .query(trx)
+        .findById(refundCreditId)
+        .delete();
+
+      // Triggers `onVendorCreditRefundDeleted` event.
+      await this.eventPublisher.emitAsync(
+        events.vendorCredit.onRefundDeleted,
+        eventPayload as IRefundVendorCreditDeletedPayload
+      );
+    });
+  }
+}

packages/server-nest/src/modules/VendorCreditsRefund/commands/RefundSyncCreditRefundedAmount.service.ts

@@ -0,0 +1,48 @@
+import { Transaction } from 'objection';
+import { Inject, Injectable } from '@nestjs/common';
+import { VendorCredit } from '@/modules/VendorCredit/models/VendorCredit';
+
+@Injectable()
+export class RefundSyncCreditRefundedAmount {
+  /**
+   * @param {typeof VendorCredit} vendorCreditModel - Vendor credit model.
+   */
+  constructor(
+    @Inject(VendorCredit.name)
+    private vendorCreditModel: typeof VendorCredit,
+  ) {}
+
+  /**
+   * Increment vendor credit refunded amount.
+   * @param {number} vendorCreditId - Vendor credit id.
+   * @param {number} amount - Amount.
+   * @param {Transaction} trx - Objection transaction.
+   */
+  public incrementCreditRefundedAmount = async (
+    vendorCreditId: number,
+    amount: number,
+    trx?: Transaction,
+  ): Promise<void> => {
+    await this.vendorCreditModel
+      .query(trx)
+      .findById(vendorCreditId)
+      .increment('refundedAmount', amount);
+  };
+
+  /**
+   * Decrement vendor credit refunded amount.
+   * @param {number} vendorCreditId - Vendor credit id.
+   * @param {number} amount - Amount.
+   * @param {Transaction} trx - Objection transaction.
+   */
+  public decrementCreditNoteRefundAmount = async (
+    vendorCreditId: number,
+    amount: number,
+    trx?: Transaction,
+  ): Promise<void> => {
+    await this.vendorCreditModel
+      .query(trx)
+      .findById(vendorCreditId)
+      .decrement('refundedAmount', amount);
+  };
+}