zod-backend/src/common/modules/notification/services/firebase.service.ts

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) {
    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;
    }
  }

  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)`,
    );

    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;
    }
  }
}