fix(medusa): gift card values & taxes are calculated correctly (#2777)

* chore: tax_rate is added to giftcards

* chore: minor

* chore: update gift card tax calculations to look at giftCard.tax_rate

* chore: gift card transactions use tax rate from gift card for legacy

* fix: gift cart total check for transaction should check the length

* chore: use tax exclusive cost + use giftcard tax rate for gctransactions + refactor

* chore: fix integration test

* chore: address issues brought up in comments

* chore: move gift card creation as a part of order service on order placed

* chore: add type handling for gift card creation

* chore: fix specs

* chore: use taxLines to calculate tax of a gift card

* chore: specs for line items containing gift cards and without

* chore: add integration specs + fix tax rate bug

* chore: round totaling + add GC application specs

* chore: cleanup trialables

* chore: write migration script to backfill gift cards with null tax_rate

* chore: update legacy totals service for gift cards

* chore: add changeset

* chore: address PR review changes

* chore: fix tests based on new totals calc

* chore: address review comments

Co-authored-by: adrien2p <adrien.deperetti@gmail.com>
Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/medusa/src/migrations/1670855241304-add-tax-rate-to-gift-cards.ts

@@ -0,0 +1,17 @@
+import { MigrationInterface, QueryRunner } from "typeorm"
+
+export class addTaxRateToGiftCards1670855241304 implements MigrationInterface {
+  name = "addTaxRateToGiftCards1670855241304"
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "gift_card" ADD COLUMN IF NOT EXISTS tax_rate REAL`
+    )
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE "gift_card" DROP COLUMN IF EXISTS "tax_rate"`
+    )
+  }
+}