PhysiGo/app/lib/push_notifications_initializer.dart

import 'package:awesome_notifications/awesome_notifications.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

void handleMessages() async {
  FirebaseMessaging messaging = FirebaseMessaging.instance;
  final _firestore = FirebaseFirestore.instance;

  NotificationSettings settings = await messaging.requestPermission(
    alert: true,
    announcement: false,
    badge: true,
    carPlay: false,
    criticalAlert: false,
    provisional: false,
    sound: true,
  );

  localNotificationsSetup();

  if (settings.authorizationStatus == AuthorizationStatus.denied) {
    return;
  }

  FirebaseMessaging.onMessage.listen((RemoteMessage message) {
    AwesomeNotifications().createNotification(
      content: NotificationContent(
        id: 10,
        channelKey: 'basic_channel',
        title: message.notification?.title,
        body: message.notification?.body,
        color: Colors.blue,
      )
    );
  });

  messaging.onTokenRefresh.listen((fcmToken) async {
    final fcmToken = await messaging.getToken();
    final user = _firestore.collection('Users').doc('tlmysIvwTBaoZKWqBofx');
    user.update({
      'token': fcmToken,
    });
  });
}

void localNotificationsSetup() {
  AwesomeNotifications().initialize(
      // set the icon to null if you want to use the default app icon
      null,
      [
        NotificationChannel(
          channelGroupKey: 'basic_channel_group',
          channelKey: 'basic_channel',
          channelName: 'Basic notifications',
          channelDescription: 'Notification channel for basic tests',
        )
      ],
      debug: kDebugMode);

  AwesomeNotifications().isNotificationAllowed().then((isAllowed) {
    if (!isAllowed) {
      // This is just a basic example. For real apps, you must show some
      // friendly dialog box before call the request method.
      // This is very important to not harm the user experience
      AwesomeNotifications().requestPermissionToSendNotifications();
    }
  });
}