Merge pull request #75 from Zod-Alkhair/feature/notification-system-fcm-registration

feat: enhance Redis module exports for pub/sub functionality

src/auth/dtos/request/junior-login.request.dto.ts

@@ -1,5 +1,5 @@
 import { ApiProperty } from '@nestjs/swagger';
-import { IsEmail, IsString } from 'class-validator';
+import { IsEmail, IsOptional, IsString } from 'class-validator';
 import { i18nValidationMessage as i18n } from 'nestjs-i18n';
 export class JuniorLoginRequestDto {
   @ApiProperty({ example: 'test@junior.com' })
@@ -9,4 +9,18 @@ export class JuniorLoginRequestDto {
   @ApiProperty({ example: 'Abcd1234@' })
   @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.password' }) })
   password!: string;
+
+  @ApiProperty({ example: 'device-123', description: 'Unique device identifier', required: false })
+  @IsOptional()
+  @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.deviceId' }) })
+  deviceId?: string;
+
+  @ApiProperty({
+    example: 'cXYzABC:APA91bHunvwY7rKpn8N7y6vDxS0qmQ5RZx2C8K...',
+    description: 'Firebase Cloud Messaging token for push notifications',
+    required: false,
+  })
+  @IsOptional()
+  @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.fcmToken' }) })
+  fcmToken?: string;
 }

src/auth/dtos/request/login.request.dto.ts

@@ -21,4 +21,18 @@ export class LoginRequestDto {
   @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.password' }) })
   @ValidateIf((o) => o.grantType === GrantType.PASSWORD)
   password!: string;
+
+  @ApiProperty({ example: 'device-123', description: 'Unique device identifier', required: false })
+  @IsOptional()
+  @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.deviceId' }) })
+  deviceId?: string;
+
+  @ApiProperty({
+    example: 'cXYzABC:APA91bHunvwY7rKpn8N7y6vDxS0qmQ5RZx2C8K...',
+    description: 'Firebase Cloud Messaging token for push notifications',
+    required: false,
+  })
+  @IsOptional()
+  @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.fcmToken' }) })
+  fcmToken?: string;
 }

src/auth/dtos/request/verify-user.request.dto.ts

@@ -101,4 +101,18 @@ export class VerifyUserRequestDto {
     message: i18n('validation.MinLength', { path: 'general', property: 'auth.otp', length: DEFAULT_OTP_LENGTH }),
   })
   otp!: string;
+
+  @ApiProperty({ example: 'device-123', description: 'Unique device identifier', required: false })
+  @IsOptional()
+  @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.deviceId' }) })
+  deviceId?: string;
+
+  @ApiProperty({
+    example: 'cXYzABC:APA91bHunvwY7rKpn8N7y6vDxS0qmQ5RZx2C8K...',
+    description: 'Firebase Cloud Messaging token for push notifications',
+    required: false,
+  })
+  @IsOptional()
+  @IsString({ message: i18n('validation.IsString', { path: 'general', property: 'auth.fcmToken' }) })
+  fcmToken?: string;
 }

src/auth/services/auth.service.ts

@@ -86,6 +86,12 @@ export class AuthService {
 
     const tokens = await this.generateAuthToken(user);
     this.logger.log(`User with phone number ${user.fullPhoneNumber} verified successfully`);
+
+    // Register/update device with FCM token if provided
+    if (verifyUserDto.fcmToken && verifyUserDto.deviceId) {
+      await this.registerDeviceToken(user.id, verifyUserDto.deviceId, verifyUserDto.fcmToken);
+    }
+
     return [tokens, user];
   }
 
@@ -271,6 +277,12 @@ export class AuthService {
 
     const tokens = await this.generateAuthToken(user);
     this.logger.log(`Password validated successfully for user`);
+
+    // Register/update device with FCM token if provided
+    if (loginDto.fcmToken && loginDto.deviceId) {
+      await this.registerDeviceToken(user.id, loginDto.deviceId, loginDto.fcmToken);
+    }
+
     return [tokens, user];
   }
 
@@ -291,9 +303,52 @@ export class AuthService {
 
     const tokens = await this.generateAuthToken(user);
     this.logger.log(`Password validated successfully for user`);
+
+    // Register/update device with FCM token if provided
+    if (juniorLoginDto.fcmToken && juniorLoginDto.deviceId) {
+      await this.registerDeviceToken(user.id, juniorLoginDto.deviceId, juniorLoginDto.fcmToken);
+    }
+
     return [tokens, user];
   }
 
+  /**
+   * Register or update device with FCM token
+   * This method handles both new device registration and existing device updates
+   */
+  private async registerDeviceToken(userId: string, deviceId: string, fcmToken: string): Promise<void> {
+    try {
+      this.logger.log(`Registering/updating device ${deviceId} with FCM token for user ${userId}`);
+
+      // Check if device already exists for this user
+      const existingDevice = await this.deviceService.findUserDeviceById(deviceId, userId);
+
+      if (existingDevice) {
+        // Update existing device with new FCM token and last access time
+        await this.deviceService.updateDevice(deviceId, {
+          fcmToken,
+          userId,
+          lastAccessOn: new Date(),
+        });
+        this.logger.log(`Device ${deviceId} updated with new FCM token for user ${userId}`);
+      } else {
+        // Create new device
+        await this.deviceService.createDevice({
+          deviceId,
+          userId,
+          fcmToken,
+          lastAccessOn: new Date(),
+        });
+        this.logger.log(`New device ${deviceId} registered with FCM token for user ${userId}`);
+      }
+    } catch (error) {
+      // Log error but don't fail the login/signup process
+      const errorMessage = error instanceof Error ? error.message : String(error);
+      const errorStack = error instanceof Error ? error.stack : undefined;
+      this.logger.error(`Failed to register device token for user ${userId}: ${errorMessage}`, errorStack);
+    }
+  }
+
   private async generateAuthToken(user: User) {
     this.logger.log(`Generating auth token for user with id ${user.id}`);
     const [accessToken, refreshToken] = await Promise.all([

src/card/repositories/card.repository.ts

@@ -42,7 +42,18 @@ export class CardRepository {
   }
 
   getCardById(id: string): Promise<Card | null> {
-    return this.cardRepository.findOne({ where: { id }, relations: ['account'] });
+    return this.cardRepository.findOne({
+      where: { id },
+      relations: [
+        'account',
+        'customer',
+        'customer.user',
+        'customer.junior',
+        'customer.junior.guardian',
+        'customer.junior.guardian.customer',
+        'customer.junior.guardian.customer.user',
+      ],
+    });
   }
 
   findCardByChildId(guardianId: string, childId: string): Promise<Card | null> {
@@ -59,14 +70,30 @@ export class CardRepository {
   getCardByVpan(vpan: string): Promise<Card | null> {
     return this.cardRepository.findOne({
       where: { vpan },
-      relations: ['account'],
+      relations: [
+        'account',
+        'customer',
+        'customer.user',
+        'customer.junior',
+        'customer.junior.guardian',
+        'customer.junior.guardian.customer',
+        'customer.junior.guardian.customer.user',
+      ],
     });
   }
 
   getCardByCustomerId(customerId: string): Promise<Card | null> {
     return this.cardRepository.findOne({
       where: { customerId },
-      relations: ['account'],
+      relations: [
+        'account',
+        'customer',
+        'customer.user',
+        'customer.junior',
+        'customer.junior.guardian',
+        'customer.junior.guardian.customer',
+        'customer.junior.guardian.customer.user',
+      ],
     });
   }
 

src/card/services/transaction.service.ts

@@ -1,4 +1,5 @@
 import { forwardRef, Inject, Injectable, UnprocessableEntityException } from '@nestjs/common';
+import { EventEmitter2 } from '@nestjs/event-emitter';
 import Decimal from 'decimal.js';
 import moment from 'moment';
 import { Transactional } from 'typeorm-transactional';
@@ -6,6 +7,8 @@ import {
   AccountTransactionWebhookRequest,
   CardTransactionWebhookRequest,
 } from '~/common/modules/neoleap/dtos/requests';
+import { NOTIFICATION_EVENTS } from '~/common/modules/notification/constants/event-names.constant';
+import { ITransactionCreatedEvent } from '~/common/modules/notification/interfaces/notification-events.interface';
 import { Transaction } from '../entities/transaction.entity';
 import { CustomerType, TransactionType } from '../enums';
 import { TransactionRepository } from '../repositories/transaction.repository';
@@ -27,6 +30,7 @@ export class TransactionService {
     private readonly transactionRepository: TransactionRepository,
     private readonly accountService: AccountService,
     @Inject(forwardRef(() => CardService)) private readonly cardService: CardService,
+    private readonly eventEmitter: EventEmitter2,
   ) {}
 
   @Transactional()
@@ -58,6 +62,15 @@ export class TransactionService {
       await this.accountService.decreaseAccountBalance(card.account.accountReference, total.toNumber());
     }
 
+    const event: ITransactionCreatedEvent = {
+      transaction,
+      card,
+      isTopUp: false,
+      isChildSpending: card.customerType === CustomerType.CHILD,
+      timestamp: new Date(),
+    };
+    this.eventEmitter.emit(NOTIFICATION_EVENTS.TRANSACTION_CREATED, event);
+
     return transaction;
   }
 
@@ -74,12 +87,38 @@ export class TransactionService {
     const transaction = await this.transactionRepository.createAccountTransaction(account, body);
     await this.accountService.creditAccountBalance(account.accountReference, body.amount);
 
+    const accountWithCards = await this.accountService.getAccountByAccountNumber(body.accountId);
+    const card = accountWithCards.cards?.[0] 
+      ? await this.cardService.getCardById(accountWithCards.cards[0].id)
+      : null;
+
+    if (card) {
+      const event: ITransactionCreatedEvent = {
+        transaction,
+        card,
+        isTopUp: true,
+        isChildSpending: false,
+        timestamp: new Date(),
+      };
+      this.eventEmitter.emit(NOTIFICATION_EVENTS.TRANSACTION_CREATED, event);
+    }
+
     return transaction;
   }
 
   async createInternalChildTransaction(cardId: string, amount: number) {
     const card = await this.cardService.getCardById(cardId);
     const transaction = await this.transactionRepository.createInternalChildTransaction(card, amount);
+    
+    const event: ITransactionCreatedEvent = {
+      transaction,
+      card,
+      isTopUp: true,
+      isChildSpending: true,
+      timestamp: new Date(),
+    };
+    this.eventEmitter.emit(NOTIFICATION_EVENTS.TRANSACTION_CREATED, event);
+    
     return transaction;
   }
 

src/common/modules/notification/constants/event-names.constant.ts

@@ -0,0 +1,15 @@
+/**
+ * Notification event names
+ * These are the event identifiers used throughout the notification system
+ */
+export const NOTIFICATION_EVENTS = {
+  // Transaction events
+  TRANSACTION_CREATED: 'notification.transaction.created',
+} as const;
+
+export type NotificationEventName = 
+  typeof NOTIFICATION_EVENTS[keyof typeof NOTIFICATION_EVENTS];
+
+
+
+

src/common/modules/notification/constants/index.ts

@@ -0,0 +1,3 @@
+// Export all constants from this folder
+export * from './event-names.constant';
+

src/common/modules/notification/entities/notification.entity.ts

@@ -36,6 +36,9 @@ export class Notification {
   @Column('uuid', { name: 'user_id', nullable: true })
   userId!: string;
 
+  @Column('jsonb', { name: 'data', nullable: true })
+  data?: Record<string, any>;
+
   @ManyToOne(() => User, (user) => user.notifications, { onDelete: 'CASCADE', nullable: true })
   @JoinColumn({ name: 'user_id' })
   user!: User;

src/common/modules/notification/enums/notification-scope.enum.ts

@@ -1,7 +1,41 @@
 export enum NotificationScope {
+  // Existing scopes
   USER_REGISTERED = 'USER_REGISTERED',
   TASK_COMPLETED = 'TASK_COMPLETED',
   GIFT_RECEIVED = 'GIFT_RECEIVED',
   OTP = 'OTP',
   USER_INVITED = 'USER_INVITED',
+
+  // Transaction notifications - Top-up
+  CHILD_TOP_UP = 'CHILD_TOP_UP',
+  PARENT_TOP_UP_CONFIRMATION = 'PARENT_TOP_UP_CONFIRMATION',
+
+  // Transaction notifications - Spending
+  CHILD_SPENDING = 'CHILD_SPENDING',
+  PARENT_SPENDING_ALERT = 'PARENT_SPENDING_ALERT',
 }
+
+/**
+ * Critical notification scopes that require guaranteed delivery
+ * These will use RabbitMQ/Kafka instead of Redis PubSub when configured
+ * 
+ * Add scopes here when you need guaranteed delivery for specific notification types
+ * Examples:
+ * - ACCOUNT_LOCKED
+ * - SUSPICIOUS_ACTIVITY
+ * - LARGE_TRANSACTION_ALERT
+ * - PAYMENT_FAILED
+ */
+export const CRITICAL_NOTIFICATION_SCOPES = new Set<NotificationScope>([
+  // Add critical scopes here as needed
+  // Example: NotificationScope.ACCOUNT_LOCKED,
+]);
+
+/**
+ * Check if a notification scope requires guaranteed delivery
+ * @param scope - Notification scope to check
+ * @returns true if the scope requires guaranteed delivery
+ */
+export function requiresGuaranteedDelivery(scope: NotificationScope): boolean {
+  return CRITICAL_NOTIFICATION_SCOPES.has(scope);
+}

src/common/modules/notification/interfaces/index.ts

@@ -1 +1,3 @@
 export * from './notification-page-meta.interface';
+export * from './notification-events.interface';
+export * from './messaging-system.interface';

src/common/modules/notification/interfaces/messaging-system.interface.ts

@@ -0,0 +1,25 @@
+/**
+ * Interface for messaging systems (Redis PubSub, RabbitMQ, Kafka, etc.)
+ * Allows switching between different messaging systems based on notification requirements
+ */
+export interface IMessagingSystem {
+  /**
+   * Publish a notification event
+   * @param channel - Channel/topic name
+   * @param payload - Notification payload
+   */
+  publish(channel: string, payload: any): Promise<void>;
+  
+  /**
+   * Subscribe to a channel
+   * @param channel - Channel/topic name
+   * @param handler - Message handler function
+   */
+  subscribe(channel: string, handler: (message: any) => Promise<void>): Promise<void>;
+  
+  /**
+   * Get system name (for logging)
+   */
+  getName(): string;
+}
+

src/common/modules/notification/interfaces/notification-events.interface.ts

@@ -0,0 +1,24 @@
+import { Transaction } from '~/card/entities/transaction.entity';
+import { Card } from '~/card/entities/card.entity';
+
+/**
+ * Event payload for when a transaction is created
+ * Used to notify users about transactions (spending or top-ups)
+ */
+export interface ITransactionCreatedEvent {
+  /** The transaction that was created */
+  transaction: Transaction;
+  
+  /** The card used in the transaction (with all relations loaded) */
+  card: Card;
+  
+  /** True if this is a top-up/load transaction, false if spending */
+  isTopUp: boolean;
+  
+  /** True if this transaction was made by a child (requires parent notification) */
+  isChildSpending: boolean;
+  
+  /** When the event occurred */
+  timestamp: Date;
+}
+

src/common/modules/notification/listeners/index.ts

@@ -1 +1,2 @@
 export * from './notification-created.listener';
+export * from './transaction-notification.listener';

src/common/modules/notification/listeners/notification-created.listener.ts

@@ -31,7 +31,7 @@ export class NotificationCreatedListener {
         return this.sendSMS(event.recipient!, event.message);
 
       case NotificationChannel.PUSH:
-        return this.sendPushNotification(event.userId, event.title, event.message);
+        return this.sendPushNotification(event.userId, event.title, event.message, event.data);
 
       case NotificationChannel.EMAIL:
         return this.sendEmail({
@@ -54,7 +54,12 @@ export class NotificationCreatedListener {
     }
   }
 
-  private async sendPushNotification(userId: string, title: string, body: string) {
+  private async sendPushNotification(
+    userId: string,
+    title: string,
+    body: string,
+    data?: Record<string, any>,
+  ) {
     this.logger.log(`Sending push notification to user ${userId}`);
     const tokens = await this.deviceService.getTokens(userId);
 
@@ -62,7 +67,19 @@ export class NotificationCreatedListener {
       this.logger.log(`No device tokens found for user ${userId}, but notification was created in the DB.`);
       return;
     }
-    return this.firebaseService.sendNotification(tokens, title, body);
+
+    // Convert data to string values (Firebase requires string values in data payload)
+    const stringData: Record<string, string> | undefined = data
+      ? Object.entries(data).reduce(
+          (acc, [key, value]) => {
+            acc[key] = String(value);
+            return acc;
+          },
+          {} as Record<string, string>,
+        )
+      : undefined;
+
+    return this.firebaseService.sendNotification(tokens, title, body, stringData);
   }
 
   private async sendSMS(to: string, body: string) {

src/common/modules/notification/listeners/transaction-notification.listener.ts

@@ -0,0 +1,249 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { OnEvent } from '@nestjs/event-emitter';
+import { NotificationFactory, NotificationPreferences } from '../services/notification-factory.service';
+import { UserService } from '~/user/services/user.service';
+import { NOTIFICATION_EVENTS } from '../constants/event-names.constant';
+import { ITransactionCreatedEvent } from '../interfaces/notification-events.interface';
+import { NotificationScope } from '../enums/notification-scope.enum';
+import { Transaction } from '~/card/entities/transaction.entity';
+import { Card } from '~/card/entities/card.entity';
+import { User } from '~/user/entities';
+
+/**
+ * TransactionNotificationListener
+ * 
+ * Handles notifications for transaction events.
+ * Determines who should be notified and what message to send.
+ * 
+ * Responsibilities:
+ * - Listen for transaction events
+ * - Determine notification recipients (child, parent, or both)
+ * - Construct appropriate messages
+ * - Fetch user preferences
+ * - Call NotificationFactory to send
+ */
+@Injectable()
+export class TransactionNotificationListener {
+  private readonly logger = new Logger(TransactionNotificationListener.name);
+
+  constructor(
+    private readonly notificationFactory: NotificationFactory,
+    private readonly userService: UserService,
+  ) {}
+
+  /**
+   * Main event handler for transaction created events
+   * Routes to appropriate notification logic based on transaction type
+   */
+  @OnEvent(NOTIFICATION_EVENTS.TRANSACTION_CREATED)
+  async handleTransactionCreated(event: ITransactionCreatedEvent): Promise<void> {
+    try {
+      const { transaction, card, isTopUp, isChildSpending } = event;
+
+      this.logger.log(
+        `Processing transaction notification for transaction ${transaction.id} - ` +
+        `isTopUp: ${isTopUp}, isChildSpending: ${isChildSpending}`
+      );
+
+      await this.notifyTransactionOwner(transaction, card, isTopUp, isChildSpending);
+
+      if (isChildSpending) {
+        if (isTopUp) {
+          await this.notifyParentOfTopUp(transaction, card);
+        } else {
+          await this.notifyParentOfChildSpending(transaction, card);
+        }
+      }
+
+      this.logger.log(
+        `Transaction notification processed successfully for transaction ${transaction.id}`
+      );
+    } catch (error: any) {
+      this.logger.error(
+        `Failed to process transaction notification: ${error?.message || 'Unknown error'}`,
+        error?.stack
+      );
+    }
+  }
+
+  /**
+   * Notify the transaction owner (the cardholder)
+   * Could be a child or a parent depending on whose card was used
+   */
+  private async notifyTransactionOwner(
+    transaction: Transaction,
+    card: Card,
+    isTopUp: boolean,
+    isChildSpending: boolean
+  ): Promise<void> {
+    try {
+      const user = card?.customer?.user;
+      if (!user) {
+        this.logger.warn(`No user found for transaction ${transaction.id}, skipping notification`);
+        return;
+      }
+
+      const scope = isTopUp
+        ? NotificationScope.CHILD_TOP_UP
+        : NotificationScope.CHILD_SPENDING;
+
+      const title = isTopUp ? 'Card Topped Up' : 'Purchase Successful';
+
+      const amount = transaction.transactionAmount;
+      const merchant = transaction.merchantName || 'merchant';
+      const balance = card.account?.balance || 0;
+
+      const message = isTopUp
+        ? `Your card has been topped up with $${amount.toFixed(2)}`
+        : `You spent $${amount.toFixed(2)} at ${merchant}. Balance: $${balance.toFixed(2)}`;
+
+      this.logger.debug(
+        `Notifying transaction owner (user ${user.id}) - Amount: $${amount}, Merchant: ${merchant}`
+      );
+
+      await this.notificationFactory.send({
+        userId: user.id,
+        title,
+        message,
+        scope,
+        preferences: this.getUserPreferences(user),
+        data: {
+          transactionId: transaction.id,
+          amount: amount.toString(),
+          merchant: merchant,
+          merchantCategory: transaction.merchantCategoryCode || 'OTHER',
+          balance: balance.toString(),
+          timestamp: transaction.transactionDate.toISOString(),
+          type: isTopUp ? 'TOP_UP' : 'SPENDING',
+          action: 'OPEN_TRANSACTION',
+        },
+      });
+
+      this.logger.log(`✅ Notified user ${user.id} for transaction ${transaction.id}`);
+    } catch (error: any) {
+      this.logger.error(
+        `Failed to notify transaction owner: ${error?.message || 'Unknown error'}`,
+        error?.stack
+      );
+    }
+  }
+
+  /**
+   * Notify parent when their child makes a purchase
+   * This is a spending alert for parents to monitor their children's expenses
+   */
+  private async notifyParentOfChildSpending(transaction: Transaction, card: Card): Promise<void> {
+    try {
+      this.logger.debug(`Checking for parent to notify about child spending`);
+
+      const customer = card?.customer;
+      const parentUser = customer?.junior?.guardian?.customer?.user;
+      
+      if (!parentUser) {
+        this.logger.debug(`No parent found for transaction ${transaction.id}, skipping parent notification`);
+        return;
+      }
+
+      const childUser = customer.user;
+      const childName = childUser?.firstName || 'Your child';
+      const amount = transaction.transactionAmount;
+      const merchant = transaction.merchantName || 'a merchant';
+
+      this.logger.debug(
+        `Notifying parent (user ${parentUser.id}): ${childName} spent $${amount} at ${merchant}`
+      );
+
+      await this.notificationFactory.send({
+        userId: parentUser.id,
+        title: 'Child Spending Alert',
+        message: `${childName} spent $${amount.toFixed(2)} at ${merchant}`,
+        scope: NotificationScope.PARENT_SPENDING_ALERT,
+        preferences: this.getUserPreferences(parentUser),
+        data: {
+          transactionId: transaction.id,
+          childId: childUser.id,
+          childName: childName,
+          amount: amount.toString(),
+          merchant: merchant,
+          merchantCategory: transaction.merchantCategoryCode || 'OTHER',
+          timestamp: transaction.transactionDate.toISOString(),
+          type: 'CHILD_SPENDING',
+          action: 'OPEN_TRANSACTION',
+        },
+      });
+
+      this.logger.log(`✅ Notified parent ${parentUser.id} about child spending`);
+    } catch (error: any) {
+      this.logger.error(
+        `Failed to notify parent of child spending: ${        error?.message || 'Unknown error'}`,
+        error?.stack
+      );
+    }
+  }
+
+  /**
+   * Notify parent when they top up their child's card
+   * This is a confirmation notification for the parent
+   */
+  private async notifyParentOfTopUp(transaction: Transaction, card: Card): Promise<void> {
+    try {
+      this.logger.debug(`Checking for parent to notify about top-up`);
+
+      const customer = card?.customer;
+      const parentUser = customer?.junior?.guardian?.customer?.user;
+      
+      if (!parentUser) {
+        this.logger.debug(`No parent found for transaction ${transaction.id}, skipping parent notification`);
+        return;
+      }
+
+      const childUser = customer.user;
+      const childName = childUser?.firstName || 'Your child';
+      const amount = transaction.transactionAmount;
+      const balance = card.account?.balance || 0;
+
+      this.logger.debug(
+        `Notifying parent (user ${parentUser.id}): Topped up ${childName}'s card with $${amount}`
+      );
+
+      await this.notificationFactory.send({
+        userId: parentUser.id,
+        title: 'Top-Up Confirmation',
+        message: `You topped up ${childName}'s card with $${amount.toFixed(2)}. New balance: $${balance.toFixed(2)}`,
+        scope: NotificationScope.PARENT_TOP_UP_CONFIRMATION,
+        preferences: this.getUserPreferences(parentUser),
+        data: {
+          transactionId: transaction.id,
+          childId: childUser.id,
+          childName: childName,
+          amount: amount.toString(),
+          balance: balance.toString(),
+          timestamp: transaction.transactionDate.toISOString(),
+          type: 'TOP_UP',
+          action: 'OPEN_TRANSACTION',
+        },
+      });
+
+      this.logger.log(`✅ Notified parent ${parentUser.id} about top-up`);
+    } catch (error: any) {
+      this.logger.error(
+        `Failed to notify parent of top-up: ${        error?.message || 'Unknown error'}`,
+        error?.stack
+      );
+    }
+  }
+
+  /**
+   * Extract user preferences from User entity
+   * Converts User properties to NotificationPreferences interface
+   */
+  private getUserPreferences(user: User): NotificationPreferences {
+    return {
+      isPushEnabled: user.isPushEnabled,
+      isEmailEnabled: user.isEmailEnabled,
+      isSmsEnabled: user.isSmsEnabled,
+    };
+  }
+}
+
+

src/common/modules/notification/notification.module.ts

@@ -8,9 +8,10 @@ import { buildMailerOptions, buildTwilioOptions } from '~/core/module-options';
 import { UserModule } from '~/user/user.module';
 import { NotificationsController } from './controllers';
 import { Notification } from './entities';
-import { NotificationCreatedListener } from './listeners';
+import { NotificationCreatedListener, TransactionNotificationListener } from './listeners';
 import { NotificationsRepository } from './repositories';
-import { FirebaseService, NotificationsService, TwilioService } from './services';
+import { FirebaseService, NotificationFactory, NotificationsService, TwilioService } from './services';
+import { MessagingSystemFactory, RedisPubSubMessagingService } from './services/messaging';
 
 @Module({
   imports: [
@@ -28,12 +29,16 @@ import { FirebaseService, NotificationsService, TwilioService } from './services
   ],
   providers: [
     NotificationsService,
+    NotificationFactory,
     FirebaseService,
     NotificationsRepository,
     TwilioService,
     NotificationCreatedListener,
+    TransactionNotificationListener,
+    RedisPubSubMessagingService,
+    MessagingSystemFactory,
   ],
-  exports: [NotificationsService, NotificationCreatedListener],
+  exports: [NotificationsService, NotificationFactory, NotificationCreatedListener],
   controllers: [NotificationsController],
 })
 export class NotificationModule {}

src/common/modules/notification/services/firebase.service.ts

@@ -1,29 +1,77 @@
 import { Injectable, Logger } from '@nestjs/common';
 import { ConfigService } from '@nestjs/config';
 import * as admin from 'firebase-admin';
+
 @Injectable()
 export class FirebaseService {
   private readonly logger = new Logger(FirebaseService.name);
+
   constructor(private readonly configService: ConfigService) {
-    admin.initializeApp({
-      credential: admin.credential.cert({
-        projectId: this.configService.get('FIREBASE_PROJECT_ID'),
-        clientEmail: this.configService.get('FIREBASE_CLIENT_EMAIL'),
-        privateKey: this.configService.get('FIREBASE_PRIVATE_KEY').replace(/\\n/g, '\n'),
-      }),
-    });
+    try {
+      this.logger.log('🔥 Initializing Firebase Admin SDK...');
+
+      const projectId = this.configService.get('FIREBASE_PROJECT_ID');
+      const clientEmail = this.configService.get('FIREBASE_CLIENT_EMAIL');
+      const privateKey = this.configService.get('FIREBASE_PRIVATE_KEY');
+
+      // Log configuration (without exposing sensitive data)
+      this.logger.log(`📋 Project ID: ${projectId}`);
+      this.logger.log(`📋 Client Email: ${clientEmail}`);
+      this.logger.log(`📋 Private Key: ${privateKey ? 'SET ✅' : 'MISSING ❌'}`);
+
+      admin.initializeApp({
+        credential: admin.credential.cert({
+          projectId,
+          clientEmail,
+          privateKey: privateKey.replace(/\\n/g, '\n'),
+        }),
+      });
+
+      this.logger.log('✅ Firebase Admin SDK initialized successfully!');
+      this.logger.log(`📱 Connected to project: ${projectId}`);
+    } catch (error: any) {
+      this.logger.error('❌ Failed to initialize Firebase Admin SDK');
+      this.logger.error(`Error: ${error.message}`);
+      throw error;
+    }
   }
 
-  sendNotification(tokens: string | string[], title: string, body: string) {
-    this.logger.log(`Sending push notification to ${tokens}`);
-    const message = {
-      notification: {
-        title,
-        body,
-      },
-      tokens: Array.isArray(tokens) ? tokens : [tokens],
-    };
+  async sendNotification(tokens: string | string[], title: string, body: string, data?: Record<string, string>) {
+    this.logger.log(
+      `Sending push notification to ${Array.isArray(tokens) ? tokens.length : 1} device(s)`,
+    );
 
-    admin.messaging().sendEachForMulticast(message);
+    try {
+      const message = {
+        notification: {
+          title,
+          body,
+        },
+        data: data || {},
+        tokens: Array.isArray(tokens) ? tokens : [tokens],
+      };
+
+      const response = await admin.messaging().sendEachForMulticast(message);
+
+      this.logger.log(
+        `✅ Push sent! Success: ${response.successCount}, Failed: ${response.failureCount}`,
+      );
+
+      // Log failed tokens for debugging
+      if (response.failureCount > 0) {
+        response.responses.forEach((resp, idx) => {
+          if (!resp.success) {
+            this.logger.warn(
+              `Failed to send to token ${idx}: ${resp.error?.code} - ${resp.error?.message}`,
+            );
+          }
+        });
+      }
+
+      return response;
+    } catch (error: any) {
+      this.logger.error(`❌ Failed to send push notification: ${error.message}`);
+      throw error;
+    }
   }
 }

src/common/modules/notification/services/index.ts

@@ -1,3 +1,4 @@
 export * from './firebase.service';
+export * from './notification-factory.service';
 export * from './notifications.service';
 export * from './twilio.service';

src/common/modules/notification/services/messaging/index.ts

@@ -0,0 +1,3 @@
+export * from './redis-pubsub-messaging.service';
+export * from './messaging-system-factory.service';
+

src/common/modules/notification/services/messaging/messaging-system-factory.service.ts

@@ -0,0 +1,58 @@
+import { Injectable, Logger, Optional } from '@nestjs/common';
+import { NotificationScope, requiresGuaranteedDelivery } from '../../enums/notification-scope.enum';
+import { IMessagingSystem } from '../../interfaces/messaging-system.interface';
+import { RedisPubSubMessagingService } from './redis-pubsub-messaging.service';
+
+/**
+ * Messaging System Factory
+ * 
+ * Determines which messaging system to use based on notification requirements.
+ * 
+ * - Regular notifications → Redis PubSub (fast, 2-5ms)
+ * - Critical notifications → RabbitMQ/Kafka (guaranteed delivery, 20-50ms)
+ * 
+ * Usage:
+ * ```typescript
+ * const system = factory.getMessagingSystem(NotificationScope.CHILD_SPENDING);
+ * await system.publish('NOTIFICATION_CREATED', payload);
+ * ```
+ */
+@Injectable()
+export class MessagingSystemFactory {
+  private readonly logger = new Logger(MessagingSystemFactory.name);
+
+  constructor(
+    private readonly redisPubSubService: RedisPubSubMessagingService,
+  ) {}
+
+  /**
+   * Get the appropriate messaging system based on notification scope
+   * 
+   * @param scope - Notification scope
+   * @returns Messaging system to use
+   */
+  getMessagingSystem(scope: NotificationScope): IMessagingSystem {
+    const needsGuaranteedDelivery = requiresGuaranteedDelivery(scope);
+    
+    if (needsGuaranteedDelivery) {
+      this.logger.warn(
+        `[Factory] Critical notification ${scope} requires guaranteed delivery, ` +
+        `but RabbitMQ not configured. Falling back to Redis PubSub.`
+      );
+      return this.redisPubSubService;
+    } else {
+      this.logger.debug(`[Factory] Using Redis PubSub for notification: ${scope}`);
+      return this.redisPubSubService;
+    }
+  }
+
+  /**
+   * Get default messaging system (Redis PubSub)
+   * 
+   * @returns Default messaging system
+   */
+  getDefaultMessagingSystem(): IMessagingSystem {
+    return this.redisPubSubService;
+  }
+}
+

src/common/modules/notification/services/messaging/redis-pubsub-messaging.service.ts

@@ -0,0 +1,55 @@
+import { Inject, Injectable, Logger } from '@nestjs/common';
+import { RedisClientType } from '@keyv/redis';
+import { IMessagingSystem } from '../../interfaces/messaging-system.interface';
+
+/**
+ * Redis PubSub Messaging System Implementation
+ * 
+ * Fast, real-time messaging for regular notifications.
+ * Uses Redis PubSub for 2-5ms latency.
+ * 
+ * Note: Messages are not persisted (fire-and-forget).
+ * Suitable for notifications that are already saved in PostgreSQL.
+ */
+@Injectable()
+export class RedisPubSubMessagingService implements IMessagingSystem {
+  private readonly logger = new Logger(RedisPubSubMessagingService.name);
+
+  constructor(
+    @Inject('REDIS_PUBLISHER') private readonly publisher: RedisClientType,
+    @Inject('REDIS_SUBSCRIBER') private readonly subscriber: RedisClientType,
+  ) {}
+
+  getName(): string {
+    return 'Redis PubSub';
+  }
+
+  async publish(channel: string, payload: any): Promise<void> {
+    try {
+      const message = JSON.stringify(payload);
+      const subscriberCount = await this.publisher.publish(channel, message);
+      
+      this.logger.debug(
+        `[Redis PubSub] Published to ${channel}, ${subscriberCount} subscriber(s) received`
+      );
+    } catch (error: any) {
+      this.logger.error(`[Redis PubSub] Failed to publish to ${channel}: ${error?.message}`);
+      throw error;
+    }
+  }
+
+  async subscribe(channel: string, handler: (message: any) => Promise<void>): Promise<void> {
+    await this.subscriber.subscribe(channel, async (message) => {
+      try {
+        const data = JSON.parse(message);
+        await handler(data);
+      } catch (error: any) {
+        this.logger.error(
+          `[Redis PubSub] Failed to process message from ${channel}: ${error?.message}`
+        );
+      }
+    });
+    
+    this.logger.log(`[Redis PubSub] Subscribed to channel: ${channel}`);
+  }
+}

src/common/modules/notification/services/notification-factory.service.ts

@@ -0,0 +1,140 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { NotificationsService } from './notifications.service';
+import { NotificationChannel } from '../enums/notification-channel.enum';
+import { NotificationScope } from '../enums/notification-scope.enum';
+
+/**
+ * User notification preferences
+ * Determines which channels are enabled for a user
+ */
+export interface NotificationPreferences {
+  /** Whether push notifications are enabled */
+  isPushEnabled: boolean;
+  
+  /** Whether email notifications are enabled */
+  isEmailEnabled: boolean;
+  
+  /** Whether SMS notifications are enabled */
+  isSmsEnabled: boolean;
+}
+
+/**
+ * Payload for sending a notification
+ */
+export interface NotificationPayload {
+  /** ID of the user to notify */
+  userId: string;
+  
+  /** Notification title */
+  title: string;
+  
+  /** Notification message body */
+  message: string;
+  
+  /** Category/type of notification */
+  scope: NotificationScope;
+  
+  /** 
+   * User's notification preferences
+   * If not provided, defaults to push-only
+   */
+  preferences?: NotificationPreferences;
+  
+  /** Additional data to attach to the notification */
+  data?: Record<string, any>;
+}
+
+/**
+ * NotificationFactory
+ * 
+ * Central service for sending notifications.
+ * Independent service with no external dependencies (microservice-ready).
+ * 
+ * Handles:
+ * - Channel routing based on provided preferences
+ * - Parallel notification delivery
+ * - Error handling
+ * 
+ * Note: Caller is responsible for providing user preferences.
+ * This keeps the factory independent and testable.
+ * 
+ * Usage:
+ * await notificationFactory.send({
+ *   userId: 'user-123',
+ *   title: 'Transaction Alert',
+ *   message: 'You spent $50.00',
+ *   scope: NotificationScope.CHILD_SPENDING,
+ *   preferences: {
+ *     isPushEnabled: true,
+ *     isEmailEnabled: false,
+ *     isSmsEnabled: false,
+ *   },
+ * });
+ */
+@Injectable()
+export class NotificationFactory {
+  private readonly logger = new Logger(NotificationFactory.name);
+
+  constructor(
+    private readonly notificationsService: NotificationsService,
+  ) {}
+
+  /**
+   * Send a notification to a user
+   * Routes to enabled channels based on provided preferences
+   * 
+   * @param payload - Notification payload including preferences
+   */
+  async send(payload: NotificationPayload): Promise<void> {
+    try {
+      this.logger.log(`Sending notification to user ${payload.userId} - ${payload.title}`);
+
+      const preferences = payload.preferences || {
+        isPushEnabled: true,
+        isEmailEnabled: false,
+        isSmsEnabled: false,
+      };
+
+      const promises: Promise<any>[] = [];
+
+      if (preferences.isPushEnabled) {
+        this.logger.debug(`Routing to PUSH channel for user ${payload.userId}`);
+        promises.push(
+          this.sendToChannel(payload, NotificationChannel.PUSH)
+        );
+      }
+
+      await Promise.all(promises);
+
+      this.logger.log(
+        `Notification sent to user ${payload.userId} via ${promises.length} channel(s)`
+      );
+    } catch (error: any) {
+      this.logger.error(
+        `Failed to send notification to user ${payload.userId}: ${error?.message || 'Unknown error'}`,
+        error?.stack
+      );
+      // Don't throw - prevents breaking the main business flow
+      // Notification failures should not break transactions, etc.
+    }
+  }
+
+  /**
+   * Send notification via a specific channel
+   * Creates the notification record and publishes it for delivery
+   */
+  private async sendToChannel(
+    payload: NotificationPayload,
+    channel: NotificationChannel
+  ): Promise<void> {
+    await this.notificationsService.createNotification({
+      userId: payload.userId,
+      title: payload.title,
+      message: payload.message,
+      scope: payload.scope,
+      channel,
+      data: payload.data,
+    });
+  }
+}
+

src/common/modules/notification/services/notifications.service.ts

@@ -8,6 +8,7 @@ import { SendEmailRequestDto } from '../dtos/request';
 import { Notification } from '../entities';
 import { EventType, NotificationChannel, NotificationScope } from '../enums';
 import { NotificationsRepository } from '../repositories';
+import { MessagingSystemFactory } from './messaging/messaging-system-factory.service';
 
 @Injectable()
 export class NotificationsService {
@@ -17,6 +18,7 @@ export class NotificationsService {
 
     @Inject(forwardRef(() => RedisPubSubService))
     private readonly redisPubSubService: RedisPubSubService,
+    private readonly messagingSystemFactory: MessagingSystemFactory,
   ) {}
 
   async getNotifications(userId: string, pageOptionsDto: PageOptionsRequestDto) {
@@ -31,9 +33,29 @@ export class NotificationsService {
     return { notifications, count, unreadCount };
   }
 
-  createNotification(notification: Partial<Notification>) {
+  async createNotification(notification: Partial<Notification>) {
     this.logger.log(`Creating notification for user ${notification.userId}`);
-    return this.notificationRepository.createNotification(notification);
+    const savedNotification = await this.notificationRepository.createNotification(notification);
+    
+    const scope = notification.scope || NotificationScope.USER_REGISTERED;
+    const messagingSystem = this.messagingSystemFactory.getMessagingSystem(scope);
+    
+    this.logger.log(
+      `Publishing ${EventType.NOTIFICATION_CREATED} event to ${messagingSystem.getName()}`
+    );
+    
+    messagingSystem.publish(EventType.NOTIFICATION_CREATED, {
+      ...savedNotification,
+      data: notification.data || savedNotification.data,
+    }).catch((error) => {
+      this.logger.error(
+        `Failed to publish notification ${savedNotification.id} to ${messagingSystem.getName()}: ` +
+        `${error?.message || 'Unknown error'}`,
+        error?.stack
+      );
+    });
+    
+    return savedNotification;
   }
 
   markAsRead(userId: string) {
@@ -42,34 +64,25 @@ export class NotificationsService {
   }
 
   async sendEmailAsync(data: SendEmailRequestDto) {
-    this.logger.log(`emitting ${EventType.NOTIFICATION_CREATED} event`);
-    const notification = await this.createNotification({
+    this.logger.log(`Creating email notification for ${data.to}`);
+    await this.createNotification({
       recipient: data.to,
       title: data.subject,
       message: '',
       scope: NotificationScope.USER_INVITED,
       channel: NotificationChannel.EMAIL,
-    });
-    // return this.redisPubSubService.emit(EventType.NOTIFICATION_CREATED, notification, data.data);
-    this.redisPubSubService.publishEvent(EventType.NOTIFICATION_CREATED, {
-      ...notification,
-      data,
+      data: data.data,
     });
   }
 
   async sendOtpNotification(sendOtpRequest: ISendOtp, otp: string) {
     this.logger.log(`Sending OTP to ${sendOtpRequest.recipient}`);
-    const notification = await this.createNotification({
+    return this.createNotification({
       recipient: sendOtpRequest.recipient,
       title: OTP_TITLE,
       message: OTP_BODY.replace('{otp}', otp),
       scope: NotificationScope.OTP,
       channel: sendOtpRequest.otpType === OtpType.EMAIL ? NotificationChannel.EMAIL : NotificationChannel.SMS,
-    });
-
-    this.logger.log(`emitting ${EventType.NOTIFICATION_CREATED} event`);
-    return this.redisPubSubService.publishEvent(EventType.NOTIFICATION_CREATED, {
-      ...notification,
       data: { otp },
     });
   }

src/common/redis/redis.module.ts

@@ -32,7 +32,11 @@ export class RedisModule {
         },
         RedisPubSubService,
       ],
-      exports: [RedisPubSubService],
+      exports: [
+        RedisPubSubService,
+        'REDIS_PUBLISHER',
+        'REDIS_SUBSCRIBER',
+      ],
       imports: [NotificationModule],
     };
   }

src/db/migrations/1767172707881-AddDataColumnToNotifications.ts

@@ -0,0 +1,16 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class AddDataColumnToNotifications1767172707881 implements MigrationInterface {
+    name = 'AddDataColumnToNotifications1767172707881'
+
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`ALTER TABLE "notifications" ADD "data" jsonb`);
+        await queryRunner.query(`ALTER TABLE "kyc_transactions" ALTER COLUMN "national_id" DROP DEFAULT`);
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`ALTER TABLE "kyc_transactions" ALTER COLUMN "national_id" SET DEFAULT ''`);
+        await queryRunner.query(`ALTER TABLE "notifications" DROP COLUMN "data"`);
+    }
+
+}

src/db/migrations/index.ts

@@ -6,7 +6,8 @@ export * from './1757433339849-add-reservation-amount-to-account-entity';
 export * from './1757915357218-add-deleted-at-column-to-junior';
 export * from './1760869651296-AddMerchantInfoToTransactions';
 export * from './1761032305682-AddUniqueConstraintToUserEmail';
+export * from './1767172707881-AddDataColumnToNotifications';
 export * from './1765804942393-AddKycFieldsAndTransactions';
 export * from './1765877128065-AddNationalIdToKycTransactions';
 export * from './1765891028260-RemoveOldCustomerColumns';
-export * from './1765975126402-RemoveAddressColumns';
+export * from './1765975126402-RemoveAddressColumns';