Sage/lib/features/authentication/domain/repositories/auth_repository.dart

import '../../data/models/auth_user.dart';
import '../../../../core/errors/auth_exceptions.dart';

/// Authentication repository interface defining all authentication operations.
/// 
/// This abstract class provides a clean interface for authentication operations
/// following clean architecture principles. It abstracts away the implementation
/// details of the authentication provider (Supabase) while providing a
/// consistent API for the rest of the application.
/// 
/// Implementations should handle all authentication state management,
/// error scenarios, and session persistence automatically.
abstract class AuthRepository {
  /// Registers a new user with email and password
  /// 
  /// [email] - User's email address for registration
  /// [password] - User's password for registration
  /// 
  /// Returns the newly created [AuthUser] on successful registration
  /// 
  /// Throws:
  /// - [EmailAlreadyInUseException] if email is already registered
  /// - [WeakPasswordException] if password doesn't meet requirements
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for other authentication errors
  Future<AuthUser> signUp(String email, String password);
  
  /// Signs in an existing user with email and password
  /// 
  /// [email] - User's email address
  /// [password] - User's password
  /// 
  /// Returns the authenticated [AuthUser] on successful sign in
  /// 
  /// Throws:
  /// - [InvalidCredentialsException] if email or password is incorrect
  /// - [UserNotFoundException] if user doesn't exist
  /// - [EmailNotVerifiedException] if user's email is not verified
  /// - [NetworkException] if network connection fails
  /// - [SessionExpiredException] if session cannot be established
  /// - [AuthException] for other authentication errors
  Future<AuthUser> signIn(String email, String password);
  
  /// Signs out the currently authenticated user
  /// 
  /// Clears the current session and updates the authentication state
  /// 
  /// Throws:
  /// - [NetworkException] if network connection fails
  /// - [AuthException] if sign out fails for other reasons
  Future<void> signOut();
  
  /// Sends a password reset email to the user
  /// 
  /// [email] - User's email address for password reset
  /// 
  /// Throws:
  /// - [UserNotFoundException] if user doesn't exist
  /// - [NetworkException] if network connection fails
  /// - [TooManyRequestsException] if too many reset attempts
  /// - [AuthException] for other authentication errors
  Future<void> resetPassword(String email);
  
  /// Gets the currently authenticated user
  /// 
  /// Returns the current [AuthUser] if authenticated, null otherwise
  /// 
  /// This method should not throw exceptions for normal authentication state
  /// (like no user being signed in), but may throw for critical errors
  /// 
  /// Throws:
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for critical authentication system errors
  Future<AuthUser?> getCurrentUser();
  
  /// Stream of authentication state changes
  /// 
  /// Emits the current [AuthUser] when authentication state changes:
  /// - User signs in (emits AuthUser)
  /// - User signs out (emits null)
  /// - Session refreshes (emits updated AuthUser)
  /// - Email verification status changes (emits updated AuthUser)
  /// 
  /// The stream should emit the current state immediately upon subscription
  /// 
  /// Throws:
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for critical authentication system errors
  Stream<AuthUser?> authStateChanges();
  
  /// Refreshes the current authentication session
  /// 
  /// Useful for updating user data or extending session lifetime
  /// 
  /// Returns the updated [AuthUser] on successful refresh
  /// 
  /// Throws:
  /// - [SessionExpiredException] if session cannot be refreshed
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for other authentication errors
  Future<AuthUser> refreshSession();
  
  /// Updates the user's profile information
  /// 
  /// [displayName] - Optional new display name for the user
  /// [avatarUrl] - Optional new avatar URL for the user
  /// 
  /// Returns the updated [AuthUser] on successful update
  /// 
  /// Throws:
  /// - [SessionExpiredException] if user is not authenticated
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for other authentication errors
  Future<AuthUser> updateProfile({
    String? displayName,
    String? avatarUrl,
  });
  
  /// Sends an email verification email to the current user
  /// 
  /// Throws:
  /// - [SessionExpiredException] if user is not authenticated
  /// - [EmailAlreadyInUseException] if email is already verified
  /// - [NetworkException] if network connection fails
  /// - [TooManyRequestsException] if too many verification attempts
  /// - [AuthException] for other authentication errors
  Future<void> sendEmailVerification();
  
  /// Changes the user's password
  /// 
  /// [currentPassword] - User's current password for verification
  /// [newPassword] - User's new password
  /// 
  /// Throws:
  /// - [InvalidCredentialsException] if current password is incorrect
  /// - [WeakPasswordException] if new password doesn't meet requirements
  /// - [SessionExpiredException] if user is not authenticated
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for other authentication errors
  Future<void> changePassword(String currentPassword, String newPassword);
  
  /// Deletes the user's account and all associated data
  /// 
  /// This is a destructive operation and cannot be undone
  /// 
  /// Throws:
  /// - [SessionExpiredException] if user is not authenticated
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for other authentication errors
  Future<void> deleteAccount();
  
  /// Checks if the current user's email is verified
  /// 
  /// Returns true if email is verified, false otherwise
  /// 
  /// Returns null if user is not authenticated
  /// 
  /// Throws:
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for critical authentication system errors
  Future<bool?> isEmailVerified();
  
  /// Signs in with an OAuth provider
  /// 
  /// [provider] - The OAuth provider (e.g., 'google', 'github', 'apple')
  /// 
  /// Returns the authenticated [AuthUser] on successful sign in
  /// 
  /// Throws:
  /// - [NetworkException] if network connection fails
  /// - [AuthException] for other authentication errors
  Future<AuthUser> signInWithOAuth(String provider);
  
  /// Signs in anonymously (as a guest user)
  /// 
  /// Creates an anonymous user session that can be upgraded to a full account later
  /// 
  /// Returns the anonymous [AuthUser] on successful sign in
  /// 
  /// Throws:
  /// - [NetworkException] if network connection fails
  /// - [AuthDisabledException] if anonymous sign in is disabled
  /// - [AuthException] for other authentication errors
  Future<AuthUser> signInAnonymously();
}