refactor: wip to nestjs

packages/server-nest/src/modules/Bills/queries/GetBill.ts

@@ -0,0 +1,38 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { BillsValidators } from '../commands/BillsValidators.service';
+import { BillTransformer } from './Bill.transformer';
+import { Bill } from '../models/Bill';
+import { TransformerInjectable } from '@/modules/Transformer/TransformerInjectable.service';
+
+@Injectable()
+export class GetBill {
+  constructor(
+    @Inject(Bill.name) private billModel: typeof Bill,
+    private transformer: TransformerInjectable,
+    private validators: BillsValidators,
+  ) {}
+
+  /**
+   * Retrieve the given bill details with associated items entries.
+   * @param {Integer} billId - Specific bill.
+   * @returns {Promise<IBill>}
+   */
+  public async getBill(billId: number): Promise<Bill> {
+    const bill = await this.billModel
+      .query()
+      .findById(billId)
+      .withGraphFetched('vendor')
+      .withGraphFetched('entries.item')
+      .withGraphFetched('branch')
+      .withGraphFetched('taxes.taxRate')
+      .withGraphFetched('attachments');
+
+    // Validates the bill existence.
+    this.validators.validateBillExistance(bill);
+
+    return this.transformer.transform(
+      bill,
+      new BillTransformer(),
+    );
+  }
+}