import 'package:cloud_firestore/cloud_firestore.dart';
import '../models/user.dart';
import '../services/auth_service.dart';

/// Repository for user data operations in Firestore.
/// 
/// This repository provides methods for CRUD operations on user data,
/// including retrieving users by ID or email, updating user information,
/// and managing user profiles in the Firestore database.
class UserRepository {
  /// Firestore instance for database operations.
  final FirebaseFirestore _firestore;
  
  /// Authentication service for user-related operations.
  final AuthService _authService;

  /// Creates a new [UserRepository] with optional dependencies.
  /// 
  /// If [firestore] or [authService] are not provided, default instances will be used.
  UserRepository({
    FirebaseFirestore? firestore,
    AuthService? authService,
  })  : _firestore = firestore ?? FirebaseFirestore.instance,
        _authService = authService ?? AuthService();

  /// Retrieves a user by their unique ID.
  /// 
  /// Fetches the user document from Firestore and converts it to a [User] model.
  /// 
  /// [uid] - The unique user identifier
  /// 
  /// Returns the [User] model if found, null otherwise.
  /// Throws an exception if the operation fails.
  Future<User?> getUserById(String uid) async {
    try {
      final doc = await _firestore.collection('users').doc(uid).get();
      if (doc.exists) {
        final data = doc.data() as Map<String, dynamic>;
        return User.fromMap({...data, 'id': uid});
      }
      return null;
    } catch (e) {
      throw Exception('Error retrieving user: $e');
    }
  }

  /// Retrieves a user by their email address.
  /// 
  /// Searches the users collection for a matching email address.
  /// Email comparison is case-insensitive after trimming whitespace.
  /// 
  /// [email] - The email address to search for
  /// 
  /// Returns the first [User] found with the matching email, null if not found.
  /// Throws an exception if the operation fails.
  Future<User?> getUserByEmail(String email) async {
    try {
      final querySnapshot = await _firestore
          .collection('users')
          .where('email', isEqualTo: email.trim())
          .limit(1)
          .get();

      if (querySnapshot.docs.isNotEmpty) {
        final doc = querySnapshot.docs.first;
        final data = doc.data();
        return User.fromMap({...data, 'id': doc.id});
      }
      return null;
    } catch (e) {
      throw Exception('Error searching for user: $e');
    }
  }

  /// Updates an existing user in Firestore.
  /// 
  /// Updates the user document with the provided user data.
  /// 
  /// [user] - The user object containing updated information
  /// 
  /// Returns true if the update was successful, false otherwise.
  Future<bool> updateUser(User user) async {
    try {
      await _firestore.collection('users').doc(user.id).update(user.toMap());
      
      // Mettre à jour le displayName dans Firebase Auth
      await _authService.updateDisplayName(displayName: user.fullName);
      
      return true;
    } catch (e) {
      throw Exception('Erreur lors de la mise à jour: $e');
    }
  }

  // Supprimer un utilisateur
  Future<bool> deleteUser(String uid) async {
    try {
      await _firestore.collection('users').doc(uid).delete();
      // Note: Vous devrez également supprimer le compte Firebase Auth
      return true;
    } catch (e) {
      throw Exception('Erreur lors de la suppression: $e');
    }
  }

  // Changer le mot de passe
  Future<bool> changePassword({
    required String currentPassword,
    required String newPassword,
  }) async {
    try {
      final currentUser = _authService.currentUser;
      if (currentUser?.email == null) {
        throw Exception('Utilisateur non connecté ou email non disponible');
      }
      
      await _authService.resetPasswordFromCurrentPassword(
        email: currentUser!.email!,
        currentPassword: currentPassword,
        newPassword: newPassword,
      );
      return true;
    } catch (e) {
      throw Exception('Erreur lors du changement de mot de passe: $e');
    }
  }
}