a flutter controller with firebase auth, storage, firestore usage

auth_controller.dart

```dart
  
import 'package:firebase_auth/firebase_auth.dart';

abstract class AuthController {
  Future<bool> loginUser(String email, String password);
  Future<bool> logout();
}

class AuthControllerImpl implements AuthController {
  final FirebaseAuth _firebaseAuth = FirebaseAuth.instance;

  String _message = '';

  String get message => _message;

  setMessage(String msg) {
    _message = msg;
  }

  @override
  Future<bool> loginUser(String email, String password) async {
    try {
      final userCredetials =
          await _firebaseAuth.signInWithEmailAndPassword(email: email, password: password);
      if (userCredetials.user != null) {
        setMessage('Login Successful');
        return true;
      }

      return false;
    } catch (e) {
      setMessage(e.toString());
      return false;
    }
  }

  @override
  Future<bool> logout() async {
    await _firebaseAuth.signOut();
    return true;
  }
}

upload_controller.dart

import 'dart:io';
import 'dart:math';

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_storage/firebase_storage.dart';

abstract class UploadController {
  Future<String?> uploadFile(File file, String folderName);
  Future<bool> addPost(String url, String post);
}

class UploadControllerImpl implements UploadController {
  final FirebaseStorage _storage = FirebaseStorage.instance;
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;
  final FirebaseAuth _auth = FirebaseAuth.instance;

  @override
  Future<String?> uploadFile(File file, String folderName) async {
    try {
      final randomNumber = Random().nextInt(100000);
      final Reference ref = _storage.ref().child(folderName).child('$randomNumber.jpg');
      final UploadTask _uploadTask = ref.putFile(file);

      final TaskSnapshot downloadUri = await Future.value(_uploadTask);

      final String downloadUrl = (await downloadUri.ref.getDownloadURL());
      return downloadUrl;
    } catch (e) {
      print(e);
      return null;
    }
  }

  @override
  Future<bool> addPost(String url, String post) async {
    try {
      await _firestore.collection('posts').add({
        'url': url,
        'post': post,
        'date': DateTime.now().toIso8601String(),
        'user_id': _auth.currentUser!.uid
      });
      return true;
    } catch (e) {
      return false;
    }
  }
}