chore: add queue for invoice reminder logic but not tested

src/modules/invoices/queue/invoice.processor.ts

@@ -0,0 +1,157 @@
+import { InjectQueue, Processor } from "@nestjs/bullmq";
+import { Logger } from "@nestjs/common";
+import { Job, Queue } from "bullmq";
+import dayjs from "dayjs";
+// eslint-disable-next-line import/no-named-as-default
+import Decimal from "decimal.js";
+import { DataSource, QueryRunner } from "typeorm";
+
+import { WorkerProcessor } from "../../../common/queues/worker.processor";
+import { NotificationsService } from "../../notifications/providers/notifications.service";
+import { INVOICE } from "../constants";
+import { Invoice } from "../entities/invoice.entity";
+import { InvoiceStatus } from "../enums/invoice-status.enum";
+
+@Processor(INVOICE.INVOICE_QUEUE_NAME)
+export class InvoiceProcessor extends WorkerProcessor {
+  protected readonly logger = new Logger(InvoiceProcessor.name);
+  private readonly FINE_PERCENTAGE = 0.01;
+  private readonly MAX_DAYS_OVERDUE = 1;
+
+  constructor(
+    @InjectQueue(INVOICE.INVOICE_QUEUE_NAME) private readonly invoiceQueue: Queue,
+    private readonly dataSource: DataSource,
+    private readonly notificationService: NotificationsService,
+  ) {
+    super();
+  }
+
+  async process(job: Job, token?: string) {
+    this.logger.log(job, token);
+    switch (job.name) {
+      case INVOICE.INVOICE_REMINDER_JOB_NAME:
+        return this.sendBillInvoiceReminder(job, token);
+      default:
+        this.logger.error(`Unknown job name: ${job.name}`);
+        return;
+    }
+  }
+  //********************************** */
+
+  private async sendBillInvoiceReminder(job: Job<{ invoiceId: string }>, token?: string) {
+    this.logger.log(`Sending bill invoice reminder: ${job.data.invoiceId} to user. ${token}`);
+
+    const queryRunner = this.dataSource.createQueryRunner();
+    await queryRunner.connect();
+    await queryRunner.startTransaction();
+
+    try {
+      const invoice = await this.fetchInvoice(job.data.invoiceId, queryRunner);
+
+      if (invoice.status === InvoiceStatus.PAID) {
+        this.logger.log(`Invoice ${invoice.id} is already paid.`);
+        await queryRunner.commitTransaction();
+        return;
+      }
+
+      if (this.isInvoiceOverdueForCancellation(invoice)) {
+        await this.cancelOverdueInvoice(invoice, queryRunner);
+        await queryRunner.commitTransaction();
+        return;
+      }
+
+      await this.applyLateFeeIfOverdue(invoice, queryRunner);
+
+      await this.sendReminderNotification(invoice, queryRunner);
+
+      await this.scheduleNextReminder(invoice.id);
+
+      await queryRunner.commitTransaction();
+    } catch (error) {
+      this.logger.error(`Failed to process invoice reminder:`, error);
+      await queryRunner.rollbackTransaction();
+      throw error;
+    } finally {
+      await queryRunner.release();
+    }
+  }
+  //********************************** */
+  private async fetchInvoice(invoiceId: string, queryRunner: QueryRunner) {
+    const invoice = await queryRunner.manager.findOne(Invoice, {
+      where: { id: invoiceId },
+      relations: { user: true },
+    });
+
+    if (!invoice) throw new Error(`Invoice not found: ${invoiceId}`);
+    return invoice;
+  }
+  //********************************** */
+
+  private isInvoiceOverdueForCancellation(invoice: Invoice): boolean {
+    const fiveDaysAfterDueDate = dayjs(invoice.dueDate).add(this.MAX_DAYS_OVERDUE, "day");
+    return dayjs().isAfter(fiveDaysAfterDueDate);
+  }
+  //********************************** */
+
+  private async cancelOverdueInvoice(invoice: Invoice, queryRunner: QueryRunner) {
+    invoice.status = InvoiceStatus.CANCELLED;
+    await queryRunner.manager.save(Invoice, invoice);
+    this.logger.log(`Invoice ${invoice.id} has been cancelled as it is more than 5 days overdue.`);
+  }
+  //********************************** */
+
+  private async applyLateFeeIfOverdue(invoice: Invoice, queryRunner: QueryRunner) {
+    const today = dayjs();
+    const dueDate = dayjs(invoice.dueDate);
+
+    if (today.isAfter(dueDate)) {
+      const daysOverdue = Math.min(today.diff(dueDate, "day"), this.MAX_DAYS_OVERDUE);
+
+      const currentFine = invoice.lateFee || new Decimal(0);
+      const totalDaysFineShouldBeApplied = daysOverdue;
+      const finePerDay = new Decimal(invoice.totalPrice).mul(this.FINE_PERCENTAGE);
+      const newTotalFine = finePerDay.mul(totalDaysFineShouldBeApplied);
+
+      if (newTotalFine.gt(currentFine)) {
+        this.logger.log(`Applying late fee for invoice ${invoice.id}: ${newTotalFine} (${daysOverdue} days overdue)`);
+        invoice.lateFee = newTotalFine;
+        invoice.totalPrice = new Decimal(invoice.totalPrice).plus(newTotalFine.minus(currentFine));
+        await queryRunner.manager.save(Invoice, invoice);
+      }
+    }
+  }
+  //********************************** */
+
+  private async sendReminderNotification(invoice: Invoice, queryRunner: QueryRunner) {
+    this.logger.log(`Sending invoice reminder to user: ${invoice.user.id}`);
+    await this.notificationService.createBillInvoiceReminderNotification(
+      invoice.user.id,
+      {
+        userPhone: invoice.user.phone,
+        userEmail: invoice.user.email,
+        invoiceId: invoice.numericId.toString(),
+        price: new Decimal(invoice.totalPrice).toNumber(),
+        dueDate: invoice.dueDate,
+        createDate: invoice.createdAt,
+        items: invoice.items.join(", "),
+      },
+      queryRunner,
+    );
+  }
+  //********************************** */
+
+  private async scheduleNextReminder(invoiceId: string) {
+    this.logger.log(`Invoice ${invoiceId} is still unpaid. Scheduling a new reminder.`);
+    await this.invoiceQueue.add(
+      INVOICE.INVOICE_REMINDER_JOB_NAME,
+      { invoiceId },
+      {
+        delay: INVOICE.INVOICE_REMINDER_REPEAT_DELAY, // 1 day delay in milliseconds
+        attempts: INVOICE.INVOICE_REMINDER_JOB_ATTEMPTS,
+        backoff: INVOICE.INVOICE_REMINDER_JOB_BACKOFF,
+      },
+    );
+  }
+
+  //********************************** */
+}