feat: assign default sell/purchase tax rates to items (#261)

packages/server/src/services/TaxRates/SyncItemTaxRateOnEditTaxRate.ts

@@ -0,0 +1,55 @@
+import { Knex } from 'knex';
+import { Inject, Service } from 'typedi';
+import HasTenancyService from '../Tenancy/TenancyService';
+
+@Service()
+export class SyncItemTaxRateOnEditTaxRate {
+  @Inject()
+  private tenancy: HasTenancyService;
+
+  /**
+   * Syncs the new tax rate created to item default sell tax rate.
+   * @param {number} tenantId
+   * @param {number} itemId
+   * @param {number} sellTaxRateId
+   */
+  public updateItemSellTaxRate = async (
+    tenantId: number,
+    oldSellTaxRateId: number,
+    sellTaxRateId: number,
+    trx?: Knex.Transaction
+  ) => {
+    const { Item } = this.tenancy.models(tenantId);
+
+    // Can't continue if the old and new sell tax rate id are equal.
+    if (oldSellTaxRateId === sellTaxRateId) return;
+
+    await Item.query().where('sellTaxRateId', oldSellTaxRateId).update({
+      sellTaxRateId,
+    });
+  };
+
+  /**
+   * Syncs the new tax rate created to item default purchase tax rate.
+   * @param {number} tenantId
+   * @param {number} itemId
+   * @param {number} purchaseTaxRateId
+   */
+  public updateItemPurchaseTaxRate = async (
+    tenantId: number,
+    oldPurchaseTaxRateId: number,
+    purchaseTaxRateId: number,
+    trx?: Knex.Transaction
+  ) => {
+    const { Item } = this.tenancy.models(tenantId);
+
+    // Can't continue if the old and new sell tax rate id are equal.
+    if (oldPurchaseTaxRateId === purchaseTaxRateId) return;
+
+    await Item.query(trx)
+      .where('purchaseTaxRateId', oldPurchaseTaxRateId)
+      .update({
+        purchaseTaxRateId,
+      });
+  };
+}