Firebase Cloud Messaging Integration Guide

1. A Firebase project linked to your Android application
2. The Firebase service account credentials (already configured on the server)
3. Basic knowledge of Android development

1. Open your Android Studio project
2. Go to Tools > Firebase to open the Firebase Assistant
3. Select "Cloud Messaging" and follow the steps to connect your app to Firebase
4. Add the required dependencies to your build.gradle file:

   // Add these dependencies to your app/build.gradle file
   implementation platform('com.google.firebase:firebase-bom:32.1.1')
   implementation 'com.google.firebase:firebase-messaging'
   implementation 'com.google.firebase:firebase-analytics'

Create a new class that extends FirebaseMessagingService:

public class MyFirebaseMessagingService extends FirebaseMessagingService {
    private static final String TAG = "MyFirebaseMsgService";

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        // Handle FCM messages here
        Log.d(TAG, "From: " + remoteMessage.getFrom());

        // Check if message contains a notification payload
        if (remoteMessage.getNotification() != null) {
            String title = remoteMessage.getNotification().getTitle();
            String body = remoteMessage.getNotification().getBody();
            Log.d(TAG, "Message Notification Title: " + title);
            Log.d(TAG, "Message Notification Body: " + body);
            
            sendNotification(title, body, remoteMessage.getData());
        }
        
        // Check if message contains data payload
        if (remoteMessage.getData().size() > 0) {
            Log.d(TAG, "Message data payload: " + remoteMessage.getData());
            // Handle data payload if needed
        }
    }

    @Override
    public void onNewToken(String token) {
        // Send the new token to your server
        Log.d(TAG, "Refreshed token: " + token);
        sendRegistrationToServer(token);
    }

    private void sendRegistrationToServer(String token) {
        // Implement this method to send token to your backend
        // This is where you call the FCM token registration API
    }

    private void sendNotification(String title, String messageBody, Map data) {
        // Create and show the notification using NotificationCompat.Builder
        // Implement based on your app's UI requirements
    }
}

Don't forget to register your service in AndroidManifest.xml:

<service
    android:name=".MyFirebaseMessagingService"
    android:exported="false">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

After user login, register the FCM token with our backend using the FCM token registration endpoint:

private void registerFcmToken(String userToken, String fcmToken) {
    // Create JSON request body
    JSONObject requestBody = new JSONObject();
    try {
        requestBody.put("token", fcmToken);
        requestBody.put("device_info", Build.MANUFACTURER + " " + Build.MODEL);
    } catch (JSONException e) {
        e.printStackTrace();
        return;
    }

    // Create request
    Request request = new Request.Builder()
        .url("https://ideaforgeconnect.replit.app/api/fcm/register-token")
        .addHeader("Authorization", "Bearer " + userToken)
        .addHeader("Content-Type", "application/json")
        .post(RequestBody.create(MediaType.parse("application/json"), requestBody.toString()))
        .build();

    // Execute request asynchronously
    OkHttpClient client = new OkHttpClient();
    client.newCall(request).enqueue(new Callback() {
        @Override
        public void onFailure(Call call, IOException e) {
            Log.e(TAG, "Failed to register FCM token: " + e.getMessage());
        }

        @Override
        public void onResponse(Call call, Response response) throws IOException {
            if (response.isSuccessful()) {
                Log.d(TAG, "FCM token registered successfully");
            } else {
                Log.e(TAG, "Failed to register FCM token: " + response.code() + " " + response.message());
            }
        }
    });
}

You should call this method:

1. Right after user login
2. When a new FCM token is generated (in onNewToken() method)
3. When the app starts, if the user is already logged in

Create a notification channel (for Android 8.0 and above) and display notifications when received:

private void createNotificationChannel() {
    // Create the NotificationChannel, but only on API 26+ (Android 8.0)
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        String channelId = "default_channel";
        CharSequence name = "Default Channel";
        String description = "Channel for app notifications";
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel channel = new NotificationChannel(channelId, name, importance);
        channel.setDescription(description);
        
        // Register the channel with the system
        NotificationManager notificationManager = getSystemService(NotificationManager.class);
        notificationManager.createNotificationChannel(channel);
    }
}

private void showNotification(String title, String body, Map data) {
    String channelId = "default_channel";
    Intent intent = new Intent(this, MainActivity.class);
    
    // Add data from notification to the intent if needed
    if (data != null) {
        for (Map.Entry entry : data.entrySet()) {
            intent.putExtra(entry.getKey(), entry.getValue());
        }
    }
    
    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent,
            PendingIntent.FLAG_ONE_SHOT | PendingIntent.FLAG_IMMUTABLE);

    Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    NotificationCompat.Builder notificationBuilder =
            new NotificationCompat.Builder(this, channelId)
                    .setSmallIcon(R.drawable.ic_notification)
                    .setContentTitle(title)
                    .setContentText(body)
                    .setAutoCancel(true)
                    .setSound(defaultSoundUri)
                    .setContentIntent(pendingIntent);

    NotificationManager notificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

    // Generate unique notification ID
    int notificationId = (int) System.currentTimeMillis();
    notificationManager.notify(notificationId, notificationBuilder.build());
}

You can test your notification implementation using:

1. The admin panel at /admin/notifications to send notifications
2. The test API endpoint: /api/fcm/test

To use the test endpoint, make a POST request with valid JWT token:

// Send test notification request
Request request = new Request.Builder()
    .url("https://ideaforgeconnect.replit.app/api/fcm/test")
    .addHeader("Authorization", "Bearer " + userToken)
    .post(RequestBody.create(MediaType.parse("application/json"), "{}"))
    .build();