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

packages/server/src/services/Sales/Estimates/GetSaleEstimate.ts

@@ -0,0 +1,43 @@
+import { Inject, Service } from 'typedi';
+import HasTenancyService from '@/services/Tenancy/TenancyService';
+import { TransformerInjectable } from '@/lib/Transformer/TransformerInjectable';
+import { SaleEstimateTransfromer } from './SaleEstimateTransformer';
+import { SaleEstimateValidators } from './SaleEstimateValidators';
+
+@Service()
+export class GetSaleEstimate {
+  @Inject()
+  private tenancy: HasTenancyService;
+
+  @Inject()
+  private transformer: TransformerInjectable;
+
+  @Inject()
+  private validators: SaleEstimateValidators;
+
+  /**
+   * Retrieve the estimate details with associated entries.
+   * @async
+   * @param {number} tenantId - The tenant id.
+   * @param {Integer} estimateId
+   */
+  public async getEstimate(tenantId: number, estimateId: number) {
+    const { SaleEstimate } = this.tenancy.models(tenantId);
+
+    const estimate = await SaleEstimate.query()
+      .findById(estimateId)
+      .withGraphFetched('entries.item')
+      .withGraphFetched('customer')
+      .withGraphFetched('branch');
+
+    // Validates the estimate existance.
+    this.validators.validateEstimateExistance(estimate);
+
+    // Transformes sale estimate model to POJO.
+    return this.transformer.transform(
+      tenantId,
+      estimate,
+      new SaleEstimateTransfromer()
+    );
+  }
+}