feat(notifications): add user preferences API endpoint

BackendAcademy/src/notifications/dto/update-preferences.dto.ts

@@ -0,0 +1,15 @@
+import { IsOptional, IsBoolean } from 'class-validator';
+
+export class UpdateNotificationPreferencesDto {
+  @IsOptional()
+  @IsBoolean()
+  email_alerts?: boolean;
+
+  @IsOptional()
+  @IsBoolean()
+  push_notifications?: boolean;
+
+  @IsOptional()
+  @IsBoolean()
+  marketing_updates?: boolean;
+}

BackendAcademy/src/notifications/interfaces/preferences.interface.ts

@@ -0,0 +1,6 @@
+export interface NotificationPreferences {
+  userId: string;
+  email_alerts: boolean;
+  push_notifications: boolean;
+  marketing_updates: boolean;
+}

BackendAcademy/src/notifications/notifications.controller.ts

@@ -1,6 +1,7 @@
-import { Controller, Get, Post, Body, Query } from '@nestjs/common';
+import { Controller, Get, Post, Body, Query, Patch } from '@nestjs/common';
 import { NotificationsService } from './notifications.service';
 import { CreateNotificationDto } from './dto/create-notification.dto';
+import { UpdateNotificationPreferencesDto } from './dto/update-preferences.dto';
 
 @Controller('notifications')
 export class NotificationsController {
@@ -20,4 +21,17 @@ export class NotificationsController {
   findByUserId(@Query('userId') userId: string) {
     return this.notificationsService.findByUserId(userId);
   }
+
+  @Get('preferences')
+  getPreferences(@Query('userId') userId: string) {
+    return this.notificationsService.getPreferences(userId);
+  }
+
+  @Patch('preferences')
+  upsertPreferences(
+    @Query('userId') userId: string,
+    @Body() updateDto: UpdateNotificationPreferencesDto,
+  ) {
+    return this.notificationsService.upsertPreferences(userId, updateDto);
+  }
 }

BackendAcademy/src/notifications/notifications.service.ts

@@ -1,10 +1,13 @@
 import { Injectable } from '@nestjs/common';
 import { Notification } from './interfaces/notifications.interface';
 import { CreateNotificationDto } from './dto/create-notification.dto';
+import { NotificationPreferences } from './interfaces/preferences.interface';
+import { UpdateNotificationPreferencesDto } from './dto/update-preferences.dto';
 
 @Injectable()
 export class NotificationsService {
   private notifications: Notification[] = [];
+  private preferences: Map<string, NotificationPreferences> = new Map();
 
   create(createNotificationDto: CreateNotificationDto): Notification {
     const newNotification: Notification = {
@@ -24,4 +27,26 @@ export class NotificationsService {
   findByUserId(userId: string): Notification[] {
     return this.notifications.filter(n => n.userId === userId);
   }
+
+  upsertPreferences(userId: string, updateDto: UpdateNotificationPreferencesDto): NotificationPreferences {
+    const existing = this.preferences.get(userId) || {
+      userId,
+      email_alerts: false,
+      push_notifications: false,
+      marketing_updates: false,
+    };
+
+    const updated = { ...existing, ...updateDto };
+    this.preferences.set(userId, updated);
+    return updated;
+  }
+
+  getPreferences(userId: string): NotificationPreferences {
+    return this.preferences.get(userId) || {
+      userId,
+      email_alerts: false,
+      push_notifications: false,
+      marketing_updates: false,
+    };
+  }
 }