feat(nestjs): migrate to NestJS

packages/server/src/modules/CreditNoteRefunds/CreditNoteRefunds.controller.ts

@@ -0,0 +1,47 @@
+import { ApiOperation, ApiTags } from '@nestjs/swagger';
+import { Body, Controller, Delete, Param, Post } from '@nestjs/common';
+import { ICreditNoteRefundDTO } from '../CreditNotes/types/CreditNotes.types';
+import { CreditNotesRefundsApplication } from './CreditNotesRefundsApplication.service';
+import { RefundCreditNote } from './models/RefundCreditNote';
+import { CreditNoteRefundDto } from './dto/CreditNoteRefund.dto';
+
+@Controller('credit-notes')
+@ApiTags('credit-notes-refunds')
+export class CreditNoteRefundsController {
+  constructor(
+    private readonly creditNotesRefundsApplication: CreditNotesRefundsApplication,
+  ) {}
+
+  /**
+   * Create a refund credit note.
+   * @param {number} creditNoteId - The credit note ID.
+   * @param {ICreditNoteRefundDTO} creditNoteDTO - The credit note DTO.
+   * @returns {Promise<RefundCreditNote>}
+   */
+  @Post(':creditNoteId/refunds')
+  @ApiOperation({ summary: 'Create a refund for the given credit note.' })
+  createRefundCreditNote(
+    @Param('creditNoteId') creditNoteId: number,
+    @Body() creditNoteDTO: CreditNoteRefundDto,
+  ): Promise<RefundCreditNote> {
+    return this.creditNotesRefundsApplication.createRefundCreditNote(
+      creditNoteId,
+      creditNoteDTO,
+    );
+  }
+
+  /**
+   * Delete a refund credit note.
+   * @param {number} refundCreditId - The refund credit ID.
+   * @returns {Promise<void>}
+   */
+  @Delete('refunds/:refundCreditId')
+  @ApiOperation({ summary: 'Delete a refund for the given credit note.' })
+  deleteRefundCreditNote(
+    @Param('refundCreditId') refundCreditId: number,
+  ): Promise<void> {
+    return this.creditNotesRefundsApplication.deleteRefundCreditNote(
+      refundCreditId,
+    );
+  }
+}

packages/server/src/modules/CreditNoteRefunds/CreditNoteRefunds.module.ts

@@ -0,0 +1,21 @@
+import { Module } from '@nestjs/common';
+import { CreateRefundCreditNoteService } from './commands/CreateRefundCreditNote.service';
+import { DeleteRefundCreditNoteService } from './commands/DeleteRefundCreditNote.service';
+import { RefundCreditNoteService } from './commands/RefundCreditNote.service';
+import { RefundSyncCreditNoteBalanceService } from './commands/RefundSyncCreditNoteBalance';
+import { CreditNotesRefundsApplication } from './CreditNotesRefundsApplication.service';
+import { CreditNoteRefundsController } from './CreditNoteRefunds.controller';
+import { CreditNotesModule } from '../CreditNotes/CreditNotes.module';
+
+@Module({
+  imports: [CreditNotesModule],
+  providers: [
+    CreateRefundCreditNoteService,
+    DeleteRefundCreditNoteService,
+    RefundCreditNoteService,
+    RefundSyncCreditNoteBalanceService,
+    CreditNotesRefundsApplication,
+  ],
+  controllers: [CreditNoteRefundsController],
+})
+export class CreditNoteRefundsModule {}

packages/server/src/modules/CreditNoteRefunds/CreditNotesRefundsApplication.service.ts

@@ -0,0 +1,44 @@
+import { Injectable } from '@nestjs/common';
+import { ICreditNoteRefundDTO } from '../CreditNotes/types/CreditNotes.types';
+import { CreateRefundCreditNoteService } from './commands/CreateRefundCreditNote.service';
+import { DeleteRefundCreditNoteService } from './commands/DeleteRefundCreditNote.service';
+import { RefundCreditNoteService } from './commands/RefundCreditNote.service';
+import { RefundSyncCreditNoteBalanceService } from './commands/RefundSyncCreditNoteBalance';
+import { CreditNoteRefundDto } from './dto/CreditNoteRefund.dto';
+
+@Injectable()
+export class CreditNotesRefundsApplication {
+  constructor(
+    private readonly createRefundCreditNoteService: CreateRefundCreditNoteService,
+    private readonly deleteRefundCreditNoteService: DeleteRefundCreditNoteService,
+    private readonly refundCreditNoteService: RefundCreditNoteService,
+    private readonly refundSyncCreditNoteBalanceService: RefundSyncCreditNoteBalanceService,
+  ) {}
+
+  /**
+   * Create a refund credit note.
+   * @param {number} creditNoteId - The credit note ID.
+   * @param {CreditNoteRefundDto} creditNoteDTO - The credit note DTO.
+   * @returns {Promise<RefundCreditNote>}
+   */
+  public createRefundCreditNote(
+    creditNoteId: number,
+    creditNoteDTO: CreditNoteRefundDto,
+  ) {
+    return this.createRefundCreditNoteService.createCreditNoteRefund(
+      creditNoteId,
+      creditNoteDTO,
+    );
+  }
+
+  /**
+   * Delete a refund credit note.
+   * @param {number} refundCreditId - The refund credit ID.
+   * @returns {Promise<void>}
+   */
+  public deleteRefundCreditNote(refundCreditId: number) {
+    return this.deleteRefundCreditNoteService.deleteCreditNoteRefund(
+      refundCreditId,
+    );
+  }
+}

packages/server/src/modules/CreditNoteRefunds/commands/CreateRefundCreditNote.service.ts

@@ -0,0 +1,117 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { Knex } from 'knex';
+import {
+  ICreditNoteRefundDTO,
+  IRefundCreditNoteCreatedPayload,
+  IRefundCreditNoteCreatingPayload,
+} from '../types/CreditNoteRefunds.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 '@/modules/CreditNoteRefunds/models/RefundCreditNote';
+import { CommandCreditNoteDTOTransform } from '@/modules/CreditNotes/commands/CommandCreditNoteDTOTransform.service';
+import { CreditNote } from '@/modules/CreditNotes/models/CreditNote';
+import { events } from '@/common/events/events';
+import { TenantModelProxy } from '@/modules/System/models/TenantBaseModel';
+import { CreditNoteRefundDto } from '../dto/CreditNoteRefund.dto';
+
+@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 {TenantModelProxy<typeof RefundCreditNote>} refundCreditNoteModel - The refund credit note model.
+   * @param {TenantModelProxy<typeof Account>} accountModel - The account model.
+   * @param {TenantModelProxy<typeof CreditNote>} creditNoteModel - The credit note model.
+   */
+  constructor(
+    private uow: UnitOfWork,
+    private eventPublisher: EventEmitter2,
+    private commandCreditNoteDTOTransform: CommandCreditNoteDTOTransform,
+
+    @Inject(RefundCreditNote.name)
+    private refundCreditNoteModel: TenantModelProxy<typeof RefundCreditNote>,
+
+    @Inject(Account.name)
+    private accountModel: TenantModelProxy<typeof Account>,
+
+    @Inject(CreditNote.name)
+    private creditNoteModel: TenantModelProxy<typeof CreditNote>,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} creditNoteId
+   * @param {ICreditNoteRefundDTO} newCreditNoteDTO
+   * @returns {Promise<IRefundCreditNote>}
+   */
+  public async createCreditNoteRefund(
+    creditNoteId: number,
+    newCreditNoteDTO: CreditNoteRefundDto,
+  ): 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 {CreditNote} creditNote - The credit note.
+   * @param {CreditNoteRefundDto} creditNoteDTO - The credit note refund DTO.
+   * @returns {Partial<RefundCreditNote>}
+   */
+  private transformDTOToModel = (
+    creditNote: CreditNote,
+    creditNoteDTO: CreditNoteRefundDto,
+  ): Partial<RefundCreditNote> => {
+    return {
+      creditNoteId: creditNote.id,
+      currencyCode: creditNote.currencyCode,
+      ...creditNoteDTO,
+      exchangeRate: creditNoteDTO.exchangeRate || 1,
+    };
+  };
+}

packages/server/src/modules/CreditNoteRefunds/commands/DeleteRefundCreditNote.service.ts

@@ -0,0 +1,74 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { EventEmitter2 } from '@nestjs/event-emitter';
+import { Knex } from 'knex';
+import {
+  IRefundCreditNoteDeletedPayload,
+  IRefundCreditNoteDeletingPayload,
+} from '../types/CreditNoteRefunds.types';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { UnitOfWork } from '@/modules/Tenancy/TenancyDB/UnitOfWork.service';
+import { events } from '@/common/events/events';
+import { TenantModelProxy } from '@/modules/System/models/TenantBaseModel';
+
+@Injectable()
+export class DeleteRefundCreditNoteService {
+  /**
+   * @param {UnitOfWork} uow - Unit of work.
+   * @param {EventEmitter2} eventPublisher - Event emitter.
+   * @param {typeof RefundCreditNote} refundCreditNoteModel - Refund credit note model.
+   */
+  constructor(
+    private readonly uow: UnitOfWork,
+    private readonly eventPublisher: EventEmitter2,
+
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: TenantModelProxy<
+      typeof RefundCreditNote
+    >,
+  ) {}
+
+  /**
+   * Retrieve the credit note graph.
+   * @param {number} refundCreditId - Refund credit note ID.
+   * @returns {Promise<void>}
+   */
+  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 IRefundCreditNoteDeletedPayload,
+      );
+    });
+  };
+}

packages/server/src/modules/CreditNoteRefunds/commands/RefundCreditNote.service.ts

@@ -0,0 +1,48 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { ERRORS } from '../../CreditNotes/constants';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { ServiceError } from '@/modules/Items/ServiceError';
+import { Account } from '@/modules/Accounts/models/Account.model';
+import { TenantModelProxy } from '@/modules/System/models/TenantBaseModel';
+
+@Injectable()
+export class RefundCreditNoteService {
+  /**
+   * @param {TenantModelProxy<typeof RefundCreditNote>} refundCreditNoteModel - The refund credit note model.
+   */
+  constructor(
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: TenantModelProxy<
+      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/src/modules/CreditNoteRefunds/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/src/modules/CreditNoteRefunds/commands/RefundSyncCreditNoteBalance.ts

@@ -0,0 +1,49 @@
+import { Knex } from 'knex';
+import { Inject, Injectable } from '@nestjs/common';
+import { CreditNote } from '@/modules/CreditNotes/models/CreditNote';
+import { TenantModelProxy } from '@/modules/System/models/TenantBaseModel';
+
+@Injectable()
+export class RefundSyncCreditNoteBalanceService {
+  /**
+   * @param {TenantModelProxy<typeof CreditNote>} creditNoteModel - The credit note model.
+   */
+  constructor(
+    @Inject(CreditNote.name)
+    private readonly creditNoteModel: TenantModelProxy<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/src/modules/CreditNoteRefunds/dto/CreditNoteRefund.dto.ts

@@ -0,0 +1,64 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { IsNotEmpty, IsOptional, IsPositive, IsString } from 'class-validator';
+import { IsDate } from 'class-validator';
+import { IsNumber } from 'class-validator';
+
+export class CreditNoteRefundDto {
+  @IsNumber()
+  @IsNotEmpty()
+  @ApiProperty({
+    description: 'The id of the from account',
+    example: 1,
+  })
+  fromAccountId: number;
+
+  @IsNumber()
+  @IsPositive()
+  @IsNotEmpty()
+  @ApiProperty({
+    description: 'The amount of the credit note refund',
+    example: 100,
+  })
+  amount: number;
+
+  @IsNumber()
+  @IsOptional()
+  @IsPositive()
+  @ApiProperty({
+    description: 'The exchange rate of the credit note refund',
+    example: 1,
+  })
+  exchangeRate?: number;
+
+  @IsString()
+  @IsNotEmpty()
+  @ApiProperty({
+    description: 'The reference number of the credit note refund',
+    example: '123456',
+  })
+  referenceNo: string;
+
+  @IsString()
+  @IsNotEmpty()
+  @ApiProperty({
+    description: 'The description of the credit note refund',
+    example: 'Credit note refund',
+  })
+  description: string;
+
+  @IsDate()
+  @IsNotEmpty()
+  @ApiProperty({
+    description: 'The date of the credit note refund',
+    example: '2021-01-01',
+  })
+  date: Date;
+
+  @IsNumber()
+  @IsOptional()
+  @ApiProperty({
+    description: 'The id of the branch',
+    example: 1,
+  })
+  branchId?: number;
+}

packages/server/src/modules/CreditNoteRefunds/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/src/modules/CreditNoteRefunds/queries/GetCreditNoteRefunds.service.ts

@@ -0,0 +1,40 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { RefundCreditNoteTransformer } from '@/modules/CreditNotes/queries/RefundCreditNoteTransformer';
+import { IRefundCreditNotePOJO } from '../types/CreditNoteRefunds.types';
+import { TenantModelProxy } from '@/modules/System/models/TenantBaseModel';
+
+@Injectable()
+export class ListCreditNoteRefunds {
+  constructor(
+    private readonly transformer: TransformerInjectable,
+
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: TenantModelProxy<
+      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/src/modules/CreditNoteRefunds/queries/GetRefundCreditNoteTransaction.service.ts

@@ -0,0 +1,38 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { RefundCreditNoteTransformer } from '../../CreditNotes/queries/RefundCreditNoteTransformer';
+import { TenantModelProxy } from '@/modules/System/models/TenantBaseModel';
+
+@Injectable()
+export class GetRefundCreditNoteTransaction {
+  /**
+   * @param {RefundCreditNoteTransformer} transformer
+   * @param {typeof RefundCreditNote} refundCreditNoteModel
+   */
+  constructor(
+    private readonly transformer: RefundCreditNoteTransformer,
+
+    @Inject(RefundCreditNote.name)
+    private readonly refundCreditNoteModel: TenantModelProxy<
+      typeof RefundCreditNote
+    >,
+  ) {}
+
+  /**
+   * Retrieve credit note associated invoices to apply.
+   * @param {number} refundCreditId
+   * @returns {Promise<IRefundCreditNote>}
+   */
+  public async getRefundCreditTransaction(
+    refundCreditId: number,
+  ): Promise<RefundCreditNote> {
+    const refundCreditNote = await this.refundCreditNoteModel()
+      .query()
+      .findById(refundCreditId)
+      .withGraphFetched('fromAccount')
+      .withGraphFetched('creditNote')
+      .throwIfNotFound();
+
+    return this.transformer.transform(refundCreditNote);
+  }
+}

packages/server/src/modules/CreditNoteRefunds/types/CreditNoteRefunds.types.ts

@@ -0,0 +1,48 @@
+import { Knex } from 'knex';
+import { RefundCreditNote } from '../models/RefundCreditNote';
+import { CreditNote } from '@/modules/CreditNotes/models/CreditNote';
+import { CreditNoteRefundDto } from '../dto/CreditNoteRefund.dto';
+
+export interface ICreditNoteRefundDTO {
+  fromAccountId: number;
+  amount: number;
+  exchangeRate?: number;
+  referenceNo: string;
+  description: string;
+  date: Date;
+  branchId?: number;
+}
+
+export interface IRefundCreditNotePOJO {
+  formattedAmount: string;
+}
+
+export interface IRefundCreditNoteDeletedPayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: RefundCreditNote;
+}
+
+export interface IRefundCreditNoteDeletingPayload {
+  trx: Knex.Transaction;
+  refundCreditId: number;
+  oldRefundCredit: RefundCreditNote;
+}
+
+export interface IRefundCreditNoteCreatingPayload {
+  trx: Knex.Transaction;
+  creditNote: CreditNote;
+  newCreditNoteDTO: CreditNoteRefundDto;
+}
+
+export interface IRefundCreditNoteCreatedPayload {
+  trx: Knex.Transaction;
+  refundCreditNote: RefundCreditNote;
+  creditNote: CreditNote;
+}
+
+export interface IRefundCreditNoteOpenedPayload {
+  creditNoteId: number;
+  oldCreditNote: CreditNote;
+  trx: Knex.Transaction;
+}