Application/medcify/lib/pages/main/firebase_push_notification.dart

import 'dart:convert';
import 'dart:io';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:path_provider/path_provider.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:http/http.dart' as http;


Future<void> _firebaseMessagingBackgroundHandler(message) async {
  await Firebase.initializeApp();
}

const AndroidNotificationChannel channel = AndroidNotificationChannel(
  'high_importance_channel',
  'High Importance Notifications',
  importance: Importance.high,
  enableVibration: true,
  playSound: true,
);

FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();

class FirebaseX{
  FirebaseX._();
  static final FirebaseX instance = FirebaseX._();
  FirebaseMessaging firebaseMessaging = FirebaseMessaging.instance;

  void onRegisterFirebaseNotificationTopics(List<String> topics){
    for(var topic in topics){
      firebaseMessaging.subscribeToTopic(topic);
    }
  }

  Future<String> _downloadAndSaveFile(String url, String fileName) async {
    final Directory directory = await getApplicationDocumentsDirectory();
    final String filePath = '${directory.path}/$fileName';
    final http.Response response = await http.get(Uri.parse(url));
    final File file = File(filePath);
    await file.writeAsBytes(response.bodyBytes);
    return filePath;
  }

  //notification received during app background
  Future<void> onFirebaseNotificationReceivedInBackground() async{
    FirebaseMessaging.onMessage.listen((RemoteMessage message) async {
      print("background notification: ${message.data}");
      RemoteNotification? notification = message.notification;
      if (notification != null) {
        final String largeIconPath = (notification.android?.imageUrl ?? "").isNotEmpty ?  await _downloadAndSaveFile(notification.android?.imageUrl ?? "", 'largeIcon') : "";
        final String bigPicturePath = (notification.android?.imageUrl ?? "").isNotEmpty ?  await _downloadAndSaveFile(notification.android?.imageUrl ?? "", 'bigPicture') : "";
        final BigPictureStyleInformation bigPictureStyleInformation = BigPictureStyleInformation(FilePathAndroidBitmap(bigPicturePath),
            largeIcon: FilePathAndroidBitmap(largeIconPath),
            hideExpandedLargeIcon: true,
            contentTitle: notification.title,
            summaryText: notification.body,);
        final AndroidNotificationDetails androidPlatformChannelSpecifics = AndroidNotificationDetails(
            channel.id, channel.name,
            channelDescription: channel.description,
            largeIcon: (largeIconPath.isEmpty) ? null : FilePathAndroidBitmap(largeIconPath),
            styleInformation: (bigPicturePath.isEmpty) ? null : bigPictureStyleInformation,
            icon: notification.android?.smallIcon
        );
        final NotificationDetails platformChannelSpecifics = NotificationDetails(android: androidPlatformChannelSpecifics);
        flutterLocalNotificationsPlugin.show(
            notification.hashCode,
            notification.title,
            notification.body,
            platformChannelSpecifics);
      }
    });
  }

  //click event for firebase push notification
  void onNotificationClicked() {
    FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
      onClicked(message);
    });
  }

  void onClicked(RemoteMessage message){

  }

  //initializing firebase push notification
  Future<void> onFirebaseMessagingInitialize() async{
    FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
    await  FirebaseMessaging.instance.requestPermission(alert: true,badge: true,sound: true);
    await flutterLocalNotificationsPlugin.resolvePlatformSpecificImplementation<AndroidFlutterLocalNotificationsPlugin>()?.createNotificationChannel(channel);
    await FirebaseMessaging.instance.setForegroundNotificationPresentationOptions(
      alert: true,
      badge: true,
      sound: true,
    );
    await onFirebaseNotificationReceived();
    await onFirebaseNotificationReceivedInBackground();
    onNotificationClicked();
  }

  //notification received during app terminated
  Future<void> onFirebaseNotificationReceived() async{
    RemoteMessage? message = await FirebaseMessaging.instance.getInitialMessage();
    if(message != null){
      Future.delayed(const Duration(seconds: 1),(){
        onClicked(message);
      });
    }
  }

}