refactor: split the services to multiple service classes (#202)

packages/server/src/services/Sales/Invoices/GetSaleInvoice.ts

@@ -0,0 +1,47 @@
+import { Inject, Service } from 'typedi';
+import { ISaleInvoice, ISystemUser } from '@/interfaces';
+import { SaleInvoiceTransformer } from './SaleInvoiceTransformer';
+import { TransformerInjectable } from '@/lib/Transformer/TransformerInjectable';
+import HasTenancyService from '@/services/Tenancy/TenancyService';
+import { CommandSaleInvoiceValidators } from './CommandSaleInvoiceValidators';
+
+@Service()
+export class GetSaleInvoice {
+  @Inject()
+  private tenancy: HasTenancyService;
+
+  @Inject()
+  private transformer: TransformerInjectable;
+
+  @Inject()
+  private validators: CommandSaleInvoiceValidators;
+
+  /**
+   * Retrieve sale invoice with associated entries.
+   * @param {Number} saleInvoiceId -
+   * @param {ISystemUser} authorizedUser -
+   * @return {Promise<ISaleInvoice>}
+   */
+  public async getSaleInvoice(
+    tenantId: number,
+    saleInvoiceId: number,
+    authorizedUser: ISystemUser
+  ): Promise<ISaleInvoice> {
+    const { SaleInvoice } = this.tenancy.models(tenantId);
+
+    const saleInvoice = await SaleInvoice.query()
+      .findById(saleInvoiceId)
+      .withGraphFetched('entries.item')
+      .withGraphFetched('customer')
+      .withGraphFetched('branch');
+
+    // Validates the given sale invoice existance.
+    this.validators.validateInvoiceExistance(saleInvoice);
+
+    return this.transformer.transform(
+      tenantId,
+      saleInvoice,
+      new SaleInvoiceTransformer()
+    );
+  }
+}