fix(core): Implement Refund lines fields resolver

Fixes #2406

packages/core/src/api/resolvers/entity/refund-entity.resolver.ts

@@ -1,9 +1,21 @@
-import { Resolver } from '@nestjs/graphql';
+import { Parent, ResolveField, Resolver } from '@nestjs/graphql';
 
+import { idsAreEqual } from '../../../common/index';
 import { Refund } from '../../../entity/refund/refund.entity';
-import { OrderService } from '../../../service/services/order.service';
+import { PaymentService } from '../../../service/index';
+import { RequestContext } from '../../common/request-context';
+import { Ctx } from '../../decorators/request-context.decorator';
 
 @Resolver('Refund')
 export class RefundEntityResolver {
-    constructor(private orderService: OrderService) {}
+    constructor(private paymentService: PaymentService) {}
+
+    @ResolveField()
+    async lines(@Ctx() ctx: RequestContext, @Parent() refund: Refund) {
+        if (refund.lines) {
+            return refund.lines;
+        }
+        const payment = await this.paymentService.findOneOrThrow(ctx, refund.paymentId, ['refunds.lines']);
+        return payment.refunds.find(r => idsAreEqual(r.id, refund.id))?.lines ?? [];
+    }
 }