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Overview

The authentication system provides secure user registration and login using Firebase Authentication. It supports both email/password authentication and Google Sign-In integration, with automatic profile creation in Firestore.

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Authentication Methods

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Email/Password Authentication

The app uses Firebase Authentication for email and password-based authentication.

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User Registration

1

Collect User Information

Gather user details including name, surname, email, and password through the registration form.
2

Create Firebase User

Use registerWithEmailAndPassword() to create a new user account in Firebase Authentication.
3

Save User Profile

Store additional user information in Firestore using the saveUserProfile() method.
Code Example from AuthService:
lib/services/auth_service.dart
// Register user with email and password
Future<User?> registerWithEmailAndPassword(String email, String password) async {
  try {
    UserCredential userCredential = await _auth.createUserWithEmailAndPassword(
      email: email,
      password: password,
    );
    return userCredential.user;
  } catch (e) {
    _logger.e('Error al registrar usuario: $e');
    return null;
  }
}

// Save user profile to Firestore
Future<void> saveUserProfile(String uid, String name, String surname, File? profileImage) async {
  try {
    String? photoUrl;
    if (profileImage != null) {
      final storageRef = _storage.ref().child('profileImages/$uid.jpg');
      await storageRef.putFile(profileImage);
      photoUrl = await storageRef.getDownloadURL();
    }

    await _firestore.collection('users').doc(uid).set({
      'name': name,
      'surname': surname,
      'photoUrl': photoUrl,
    });
    _logger.i('Perfil guardado con éxito');
  } catch (e) {
    _logger.e('Error al guardar el perfil del usuario: $e');
  }
}

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User Login

The login flow authenticates users with their email and password credentials. Code Example:
lib/services/auth_service.dart
// Sign in with email and password
Future<User?> signInWithEmailAndPassword(String email, String password) async {
  try {
    UserCredential userCredential = await _auth.signInWithEmailAndPassword(
      email: email,
      password: password,
    );
    return userCredential.user;
  } catch (e) {
    _logger.e('Error al iniciar sesión: $e');
    return null;
  }
}
Usage in LoginScreen:
lib/ui/screens/login_screen.dart
void _loginWithEmail() async {
  final email = _emailController.text.trim();
  final password = _passwordController.text.trim();

  final user = await _authService.signInWithEmailAndPassword(email, password);
  if (user != null) {
    if (!mounted) return;
    Navigator.pushReplacementNamed(context, '/home');
  } else if (mounted) {
    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('Inicio de sesión fallido. Verifica tus credenciales.')
      ),
    );
  }
}
Always validate user input before attempting authentication. The app includes email format validation and minimum password length requirements (8 characters).

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Google Sign-In Integration

Google Sign-In provides a streamlined authentication experience using the user’s Google account. Code Example:
lib/services/auth_service.dart
// Sign in with Google
Future<User?> signInWithGoogle() async {
  try {
    final GoogleSignInAccount? googleUser = await _googleSignIn.signIn();
    if (googleUser == null) return null;

    final GoogleSignInAuthentication googleAuth = await googleUser.authentication;
    final AuthCredential credential = GoogleAuthProvider.credential(
      accessToken: googleAuth.accessToken,
      idToken: googleAuth.idToken,
    );

    final UserCredential userCredential = await _auth.signInWithCredential(credential);
    User? user = userCredential.user;

    // Check if user profile exists in Firestore
    DocumentSnapshot userDoc = await _firestore.collection('users').doc(user!.uid).get();
    if (!userDoc.exists) {
      // Create profile if it doesn't exist
      await saveUserProfile(user.uid, user.displayName ?? 'Sin nombre', '', null);
    }

    return user;
  } catch (e) {
    _logger.e('Error al iniciar sesión con Google: $e');
    return null;
  }
}
Google Sign-In automatically creates a user profile in Firestore if one doesn’t exist. The system checks for existing profiles to avoid duplicate entries.

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Session Management

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Current User Access

Access the currently authenticated user anywhere in your app: 
// Get the current user
User? get currentUser => _auth.currentUser;

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Sign Out

Properly sign out users from both Firebase and Google:
lib/services/auth_service.dart
// Sign out from all authentication providers
Future<void> signOut() async {
  await _auth.signOut();
  await _googleSignIn.signOut();
}
Usage Example: 
IconButton(
  icon: const Icon(Icons.logout),
  onPressed: () async {
    final navigator = Navigator.of(context);
    await _authService.signOut();
    navigator.pushReplacementNamed('/');
  },
)

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User Profile Retrieval

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Get User Profile Data

Retrieve complete user profile information from Firestore:
lib/services/auth_service.dart
Future<Map<String, dynamic>?> getUserProfile(String uid) async {
  try {
    DocumentSnapshot doc = await _firestore.collection('users').doc(uid).get();
    return doc.data() as Map<String, dynamic>?;
  } catch (e) {
    _logger.e('Error al obtener el perfil del usuario: $e');
    return null;
  }
}

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Display User Information

Access basic user properties directly: 
String? get displayName => _auth.currentUser?.displayName;
String? get photoURL => _auth.currentUser?.photoURL;

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Password Recovery

Firebase Authentication provides built-in password reset functionality. Users receive a password reset email at their registered email address. Implementation details can be added using Firebase’s sendPasswordResetEmail() method.

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Terms and Conditions

The login screen includes a terms and conditions acceptance checkbox. Users must accept the terms before they can log in:
lib/ui/screens/login_screen.dart
Row(
  mainAxisAlignment: MainAxisAlignment.start,
  children: [
    Checkbox(
      value: _acceptedTerms,
      onChanged: (bool? value) {
        setState(() {
          _acceptedTerms = value ?? false;
        });
      },
    ),
    GestureDetector(
      onTap: () {
        _showTermsAndConditions(context);
      },
      child: const Text(
        'Acepto Términos y Condiciones',
        style: TextStyle(color: Color(0xFF6BCE81)),
      ),
    ),
  ],
)

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Security Best Practices

  1. Password Validation: Minimum 8 characters required
  2. Email Validation: Proper email format checking using regex
  3. Secure Storage: User credentials managed by Firebase Authentication
  4. Profile Images: Stored securely in Firebase Storage with user-specific paths
  5. Error Handling: Comprehensive error logging using Logger

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Data Structure

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Firestore User Document

users/{userId}
  ├─ name: string
  ├─ surname: string
  ├─ email: string (optional)
  └─ photoUrl: string (optional)

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Firebase Storage Structure

profileImages/
  └─ {userId}.jpg

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Next Steps

User Profiles

Learn how to manage and update user profile information

Team Management

Discover how to create and manage teams

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