chore(api): improve billing notifications

api/src/billing/billing-notifications.service.ts

@@ -1,6 +1,7 @@
 import { Injectable } from '@nestjs/common'
 import { InjectModel } from '@nestjs/mongoose'
-import { EventEmitter2 } from '@nestjs/event-emitter'
+import { InjectQueue } from '@nestjs/bull'
+import { Queue } from 'bull'
 import { Model, Types } from 'mongoose'
 import {
   BillingNotification,
@@ -23,7 +24,7 @@ export class BillingNotificationsService {
   constructor(
     @InjectModel(BillingNotification.name)
     private readonly notificationModel: Model<BillingNotificationDocument>,
-    private readonly eventEmitter: EventEmitter2,
+    @InjectQueue('billing-notifications') private readonly billingQueue: Queue,
   ) {}
 
   async notifyOnce({ userId, type, title, message, meta = {}, sendEmail = true }: NotifyOnceInput) {
@@ -34,7 +35,25 @@ export class BillingNotificationsService {
 
     const created = await this.createNotification(userId, type, title, message, meta)
 
-    this.emitCreatedEvent(created, { sendEmail })
+    await this.billingQueue.add(
+      'send',
+      {
+        notificationId: created._id,
+        userId: created.user,
+        type: created.type,
+        title: created.title,
+        message: created.message,
+        meta: created.meta,
+        createdAt: created.createdAt,
+        sendEmail,
+      },
+      {
+        delay: 30000,
+        attempts: 3,
+        removeOnComplete: true,
+        backoff: { type: 'exponential', delay: 2000 },
+      },
+    )
 
     return created
   }
@@ -84,18 +103,6 @@ export class BillingNotificationsService {
     })
   }
 
-  private emitCreatedEvent(notification: BillingNotificationDocument, options: { sendEmail: boolean }) {
-    this.eventEmitter.emit('billing.notification.created', {
-      notificationId: notification._id,
-      userId: notification.user,
-      type: notification.type,
-      title: notification.title,
-      message: notification.message,
-      meta: notification.meta,
-      createdAt: notification.createdAt,
-      sendEmail: options.sendEmail,
-    })
-  }
 }
 
 export { BillingNotificationType }

api/src/billing/billing.module.ts

@@ -16,10 +16,20 @@ import { Device, DeviceSchema } from '../gateway/schemas/device.schema'
 import { CheckoutSession, CheckoutSessionSchema } from './schemas/checkout-session.schema'
 import { BillingNotification, BillingNotificationSchema } from './schemas/billing-notification.schema'
 import { BillingNotificationsService } from './billing-notifications.service'
-import { BillingNotificationsListener } from './billing-notifications.listener'
+// import { BillingNotificationsListener } from './billing-notifications.listener'
+import { BullModule } from '@nestjs/bull'
+import { BillingNotificationsProcessor } from 'src/billing/queue/billing-notifications.processor'
 
 @Module({
   imports: [
+    BullModule.registerQueue({
+      name: 'billing-notifications',
+      defaultJobOptions: {
+        attempts: 2,
+        removeOnComplete: true,
+        removeOnFail: false,
+      },
+    }),
     MongooseModule.forFeature([
       { name: Plan.name, schema: PlanSchema },
       { name: Subscription.name, schema: SubscriptionSchema },
@@ -34,7 +44,7 @@ import { BillingNotificationsListener } from './billing-notifications.listener'
     MailModule,
   ],
   controllers: [BillingController],
-  providers: [BillingService, AbandonedCheckoutService, BillingNotificationsService, BillingNotificationsListener],
+  providers: [BillingService, AbandonedCheckoutService, BillingNotificationsService, BillingNotificationsProcessor],
   exports: [BillingService, AbandonedCheckoutService, BillingNotificationsService],
 })
 export class BillingModule {}

api/src/billing/queue/billing-notifications.processor.ts

@@ -0,0 +1,92 @@
+import { Process, Processor } from '@nestjs/bull'
+import { InjectModel } from '@nestjs/mongoose'
+import { Job } from 'bull'
+import { Model, Types } from 'mongoose'
+import { MailService } from '../../mail/mail.service'
+import { User, UserDocument } from '../../users/schemas/user.schema'
+import {
+  BillingNotification,
+  BillingNotificationDocument,
+} from '../schemas/billing-notification.schema'
+
+@Processor('billing-notifications')
+export class BillingNotificationsProcessor {
+  constructor(
+    private readonly mailService: MailService,
+    @InjectModel(BillingNotification.name)
+    private readonly notificationModel: Model<BillingNotificationDocument>,
+    @InjectModel(User.name)
+    private readonly userModel: Model<UserDocument>,
+  ) {}
+
+  @Process({ name: 'send', concurrency: 1 })
+  async handleSend(job: Job<{
+    notificationId: Types.ObjectId
+    userId: Types.ObjectId
+    type: string
+    title: string
+    message: string
+    meta: Record<string, any>
+    createdAt: Date
+    sendEmail?: boolean
+  }>) {
+    const payload = job.data
+    if (!payload?.sendEmail) {
+      return
+    }
+
+    const user = await this.userModel.findById(payload.userId)
+    if (!user?.email) {
+      return
+    }
+
+    const subject = this.subjectForType(payload.type, payload.title)
+    const ctaUrlBase = process.env.FRONTEND_URL || 'https://app.textbee.dev'
+    const isEmailVerification = payload.type === 'email_verification_required'
+    const ctaUrl = isEmailVerification
+      ? `${ctaUrlBase}/dashboard/account`
+      : 'https://textbee.dev/#pricing'
+    const ctaLabel = isEmailVerification ? 'Verify your email' : 'View plans & pricing'
+
+    await this.mailService.sendEmailFromTemplate({
+      to: user.email,
+      subject,
+      template: 'billing-notification',
+      context: {
+        name: user.name?.split(' ')?.[0] || 'there',
+        title: payload.title,
+        message: payload.message,
+        ctaLabel,
+        ctaUrl,
+        brandName: 'textbee.dev',
+      },
+      from: undefined,
+    })
+
+    await this.notificationModel.updateOne(
+      { _id: payload.notificationId },
+      { $inc: { sentEmailCount: 1 }, $set: { lastEmailSentAt: new Date() } },
+    )
+  }
+
+  private subjectForType(type: string, fallback: string) {
+    switch (type) {
+      case 'daily_limit_reached':
+        return 'Daily SMS limit reached — action required'
+      case 'monthly_limit_reached':
+        return 'Monthly SMS limit reached — action required'
+      case 'bulk_sms_limit_reached':
+        return 'Bulk send limit exceeded'
+      case 'daily_limit_approaching':
+        return 'Heads up: daily usage nearing your limit'
+      case 'monthly_limit_approaching':
+        return 'Heads up: monthly usage nearing your limit'
+      case 'email_verification_required':
+        return 'Verify your email to keep using textbee'
+      default:
+        return fallback || 'Account notification'
+    }
+  }
+}
+
+