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

packages/server/src/services/Purchases/Bills/GetDueBills.ts

@@ -0,0 +1,32 @@
+import { Inject, Service } from 'typedi';
+import HasTenancyService from '@/services/Tenancy/TenancyService';
+import UnitOfWork from '@/services/UnitOfWork';
+import { IBill } from '@/interfaces';
+
+@Service()
+export class GetDueBills {
+  @Inject()
+  private tenancy: HasTenancyService;
+
+  /**
+   * Retrieve all due bills or for specific given vendor id.
+   * @param {number} tenantId -
+   * @param {number} vendorId -
+   */
+  public async getDueBills(
+    tenantId: number,
+    vendorId?: number
+  ): Promise<IBill[]> {
+    const { Bill } = this.tenancy.models(tenantId);
+
+    const dueBills = await Bill.query().onBuild((query) => {
+      query.orderBy('bill_date', 'DESC');
+      query.modify('dueBills');
+
+      if (vendorId) {
+        query.where('vendor_id', vendorId);
+      }
+    });
+    return dueBills;
+  }
+}