import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import '../models/user_model.dart';

class AuthService {
  FirebaseAuth get _auth => FirebaseAuth.instance;
  FirebaseFirestore get _db => FirebaseFirestore.instance;

  Stream<User?> get userStream {
    try {
      return _auth.authStateChanges();
    } catch (_) {
      return const Stream.empty();
    }
  }

  Future<UserModel?> login(String email, String password) async {
    try {
      UserCredential result = await _auth.signInWithEmailAndPassword(
        email: email, 
        password: password
      );
      User? user = result.user;
      if (user != null) {
        // Ensure user document exists in Firestore (optional but helpful for names)
        var doc = await _db.collection('users').doc(user.uid).get();
        if (!doc.exists) {
           await _db.collection('users').doc(user.uid).set({
             'name': user.displayName ?? user.email!.split('@')[0],
             'email': user.email,
             'createdAt': FieldValue.serverTimestamp(),
           });
        }
        return await getUser(user.uid);
      }
      return null;
    } catch (e) {
      rethrow;
    }
  }

  Future<void> logout() async {
    await _auth.signOut();
  }

  Future<UserModel?> getUser(String uid) async {
    try {
      var doc = await _db.collection('users').doc(uid).get();
      if (doc.exists) {
        return UserModel.fromMap(doc.id, doc.data()!);
      }
      return null;
    } catch (e) {
      return null;
    }
  }
  
  Stream<List<UserModel>> getUsers() {
    return _db.collection('users').snapshots().map((snapshot) =>
        snapshot.docs.map((doc) => UserModel.fromMap(doc.id, doc.data())).toList());
  }
}