feat: implement support plan upgrade functionality with invoice creation

src/modules/support-plans/providers/support-plans.service.ts

@@ -1,5 +1,6 @@
 import { BadRequestException, Injectable } from "@nestjs/common";
 import dayjs from "dayjs";
+import { Decimal } from "decimal.js";
 import { DataSource } from "typeorm";
 
 import { SupportPlanMessage } from "../../../common/enums/message.enum";
@@ -26,7 +27,7 @@ export class SupportPlansService {
 
   async createSupportPlan(createSupportPlanDto: CreateSupportPlanDto) {
     const supportPlan = this.supportPlanRepo.create(createSupportPlanDto);
-    await this.supportPlanRepo.save(supportPlan);
+    await this.supportPlanRepo.save({ ...supportPlan, isFree: createSupportPlanDto.price === 0 });
     return {
       message: SupportPlanMessage.SUPPORT_PLAN_CREATED,
       supportPlan,
@@ -123,13 +124,13 @@ export class SupportPlansService {
         where: { user: { id: userId }, supportPlan: { id } },
       });
 
-      if (existingUserSupportPlan) throw new BadRequestException(SupportPlanMessage.SUPPORT_PLAN_ALREADY_SUBSCRIBED_OR_INVOICE_EXIST);
+      if (existingUserSupportPlan) throw new BadRequestException(SupportPlanMessage.SUPPORT_PLAN_ALREADY_SUBSCRIBED);
 
       const existingUserSupport = await queryRunner.manager.findOne(this.userSupportPlanRepo.target, {
         where: { user: { id: userId } },
       });
 
-      if (existingUserSupport) throw new BadRequestException(SupportPlanMessage.USER_ALREADY_HAS_SUPPORT_PLAN);
+      if (existingUserSupport) throw new BadRequestException(SupportPlanMessage.SUPPORT_PLAN_ALREADY_SUBSCRIBED_OR_INVOICE_EXIST);
 
       const startDate = dayjs().toDate();
       const endDate = dayjs().add(supportPlan.duration, "day").toDate();
@@ -163,4 +164,94 @@ export class SupportPlansService {
       await queryRunner.release();
     }
   }
+  //***************************************** */
+  async getUserSupportPlanOfUser(userId: string) {
+    const userSupportPlan = await this.userSupportPlanRepo.findOne({
+      where: { user: { id: userId }, status: UserSupportPlanStatus.ACTIVE },
+      relations: { supportPlan: { features: true } },
+    });
+
+    return { userSupportPlan };
+  }
+  //***************************************** */
+  async upgradeSupportPlan(newPlanId: string, userId: string) {
+    const queryRunner = this.dataSource.createQueryRunner();
+    try {
+      await queryRunner.connect();
+      await queryRunner.startTransaction();
+
+      const user = await this.usersService.findOneByIdWithQueryRunner(userId, queryRunner);
+
+      const currentUserSupportPlan = await queryRunner.manager.findOne(this.userSupportPlanRepo.target, {
+        where: { user: { id: userId } },
+        relations: { supportPlan: true },
+      });
+
+      if (!currentUserSupportPlan) throw new BadRequestException(SupportPlanMessage.USER_HAS_NO_SUPPORT_PLAN);
+
+      const newSupportPlan = await queryRunner.manager.findOne(this.supportPlanRepo.target, {
+        where: { id: newPlanId },
+      });
+
+      if (!newSupportPlan) throw new BadRequestException(SupportPlanMessage.SUPPORT_PLAN_NOT_FOUND);
+
+      const newSupportPlanPrice = new Decimal(newSupportPlan.price);
+
+      const currentUserSupportPlanPrice = new Decimal(currentUserSupportPlan.supportPlan.price);
+      // check if new plan is actually an upgrade
+      if (newSupportPlanPrice.lessThanOrEqualTo(currentUserSupportPlanPrice)) {
+        throw new BadRequestException(SupportPlanMessage.DOWN_GRADE_NOT_ALLOWED);
+      }
+
+      // calculate remaining days and price
+      const remainingDays = dayjs(currentUserSupportPlan.endDate).diff(dayjs(), "day");
+      const dailyPrice = currentUserSupportPlanPrice.div(currentUserSupportPlan.supportPlan.duration);
+      const remainingPrice = dailyPrice.mul(remainingDays);
+
+      // calculate upgrade price
+      const upgradePrice = newSupportPlanPrice.sub(remainingPrice).round();
+
+      // create new user support plan
+      const startDate = dayjs().toDate();
+      const endDate = dayjs().add(newSupportPlan.duration, "day").toDate();
+
+      const newUserSupportPlan = queryRunner.manager.create(this.userSupportPlanRepo.target, {
+        user,
+        supportPlan: newSupportPlan,
+        startDate,
+        endDate,
+        status: UserSupportPlanStatus.INACTIVE,
+      });
+
+      await queryRunner.manager.save(this.userSupportPlanRepo.target, newUserSupportPlan);
+
+      // create invoice for upgrade
+      const invoiceDueDate = dayjs(startDate).add(INVOICE.DUEDATE, "day").toDate();
+      const invoice = await this.invoicesService.createInvoiceForSupportPlan(
+        user,
+        newSupportPlan,
+        newUserSupportPlan,
+        invoiceDueDate,
+        queryRunner,
+        upgradePrice.toNumber(),
+      );
+
+      // cancel old support plan
+      currentUserSupportPlan.status = UserSupportPlanStatus.CANCELLED;
+      await queryRunner.manager.save(this.userSupportPlanRepo.target, currentUserSupportPlan);
+
+      await queryRunner.commitTransaction();
+
+      return {
+        message: SupportPlanMessage.SUPPORT_PLAN_UPGRADE_INITIATED_SUCCESSFULLY,
+        invoice,
+        upgradePrice: upgradePrice.toNumber(),
+      };
+    } catch (error) {
+      await queryRunner.rollbackTransaction();
+      throw error;
+    } finally {
+      await queryRunner.release();
+    }
+  }
 }