import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:travel_mate/services/error_service.dart';
import '../data/models/group_member.dart';
import '../data/models/account.dart';

class AccountRepository {
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;
  final _errorService = ErrorService();

  CollectionReference get _accountCollection => _firestore.collection('accounts');

  CollectionReference _membersCollection(String accountId) {
    return _accountCollection.doc(accountId).collection('members');
  }

  Future<String> createAccountWithMembers({
    required Account account,
    required List<GroupMember> members,
  }) async {
    try {
      return await _firestore.runTransaction<String>((transaction) async {
        final accountRef = _accountCollection.doc();

        final accountData = account.toMap();

        transaction.set(accountRef, accountData);

        for (var member in members) {
          final memberRef = accountRef.collection('members').doc(member.userId);
          transaction.set(memberRef, member.toMap());
        }

        return accountRef.id;
      });
    } catch (e) {
      throw Exception('Erreur lors de la création du compte: $e');
    }
  }

  Stream<List<Account>> getAccountByUserId(String userId) {
    return _accountCollection
        .snapshots()
        .asyncMap((snapshot) async {

          List<Account> userAccounts = [];

          for (var accountDoc in snapshot.docs) {
            try {
              final accountId = accountDoc.id;

              final memberDoc = await accountDoc.reference
                  .collection('members')
                  .doc(userId)
                  .get();
              if (memberDoc.exists) {
                final accountData = accountDoc.data() as Map<String, dynamic>;
                final account = Account.fromMap(accountData);
                final members = await getAccountMembers(accountId);

                userAccounts.add(account.copyWith(members: members));
              } else {
                _errorService.logInfo('account_repository.dart', 'Utilisateur NON membre de $accountId');
              }
            } catch (e, stackTrace) {
              _errorService.logError(e.toString(), stackTrace);
            }
          }
          return userAccounts;
        })
        .distinct((prev, next) {
          if (prev.length != next.length) return false;
          final prevIds = prev.map((a) => a.id).toSet();
          final nextIds = next.map((a) => a.id).toSet();
          
          final identical = prevIds.difference(nextIds).isEmpty && 
                           nextIds.difference(prevIds).isEmpty;
          
          return identical;
        })
        .handleError((error, stackTrace) {
          _errorService.logError(error, stackTrace);
          return <Account>[];
        });
  }

  Future<List<GroupMember>> getAccountMembers(String accountId) async {
    try {
      final snapshot = await _membersCollection(accountId).get();
      return snapshot.docs
          .map((doc) {
            return GroupMember.fromMap(
              doc.data() as Map<String, dynamic>,
              doc.id,
            );
          })
          .toList();
    } catch (e) {
      throw Exception('Erreur lors de la récupération des membres: $e');
    }
  }

  Future<DocumentSnapshot> getAccountById(String accountId) async {
    return await _firestore.collection('accounts').doc(accountId).get();
  }

  Future<void> updateAccount(String accountId, Account account) async {
    try {
      await _firestore.collection('accounts').doc(accountId).update(account.toMap());
    } catch (e) {
      _errorService.logError('account_repository.dart', 'Erreur lors de la mise à jour du compte: $e');
    }
  }

  Future<void> deleteAccount(String tripId) async {
    try {
      final querySnapshot = await _firestore
          .collection('accounts')
          .where('tripId', isEqualTo: tripId)
          .get();
      if (querySnapshot.docs.isEmpty) {
        throw Exception('Aucun compte trouvé pour ce voyage');
      }

      final docId = querySnapshot.docs.first.id;

      final membersSnapshot = await _membersCollection(docId).get();
      for (var memberDoc in membersSnapshot.docs) {
        await _membersCollection(docId).doc(memberDoc.id).delete();
      }
      await _accountCollection.doc(docId).delete();
    } catch (e) {
      _errorService.logError('account_repository.dart', 'Erreur lors de la suppression du compte: $e');
    }
  }

  Stream<List<GroupMember>> watchGroupMembers(String accountId) {
    return _membersCollection(accountId).snapshots().map(
          (snapshot) => snapshot.docs
              .map((doc) => GroupMember.fromMap(
                    doc.data() as Map<String, dynamic>,
                    doc.id,
                  ))
              .toList(),
        );  
  }
}