import 'dart:io';
import '../data/models/expense.dart';
import '../data/models/balance.dart';
import '../repositories/count_repository.dart';
import 'error_service.dart';

class CountService {
  final CountRepository _countRepository;
  final ErrorService _errorService;

  CountService({
    CountRepository? countRepository,
    ErrorService? errorService,
  })  : _countRepository = countRepository ?? CountRepository(),
        _errorService = errorService ?? ErrorService();

  // Créer une dépense
  Future<String> createExpense(Expense expense, {File? receiptImage}) async {
    try {
      final expenseId = await _countRepository.createExpense(expense);

      if (receiptImage != null) {
        final receiptUrl = await _countRepository.uploadReceipt(
          expense.groupId,
          expenseId,
          receiptImage,
        );

        final updatedExpense = expense.copyWith(
          id: expenseId,
          receiptUrl: receiptUrl,
        );

        await _countRepository.updateExpense(expense.groupId, updatedExpense);
      }

      return expenseId;
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de la création de la dépense: $e');
      rethrow;
    }
  }

  // Mettre à jour une dépense
  Future<void> updateExpense(Expense expense, {File? newReceiptImage}) async {
    try {
      if (newReceiptImage != null) {
        // Supprimer l'ancien reçu si existe
        if (expense.receiptUrl != null) {
          await _countRepository.deleteReceipt(expense.receiptUrl!);
        }

        // Uploader le nouveau
        final receiptUrl = await _countRepository.uploadReceipt(
          expense.groupId,
          expense.id,
          newReceiptImage,
        );

        expense = expense.copyWith(receiptUrl: receiptUrl);
      }

      await _countRepository.updateExpense(expense.groupId, expense);
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de la mise à jour de la dépense: $e');
      rethrow;
    }
  }

  // Supprimer une dépense
  Future<void> deleteExpense(String groupId, String expenseId) async {
    try {
      await _countRepository.deleteExpense(groupId, expenseId);
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de la suppression de la dépense: $e');
      rethrow;
    }
  }

  // Archiver une dépense
  Future<void> archiveExpense(String groupId, String expenseId) async {
    try {
      await _countRepository.archiveExpense(groupId, expenseId);
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de l\'archivage de la dépense: $e');
      rethrow;
    }
  }

  // Marquer une split comme payée
  Future<void> markSplitAsPaid(String groupId, String expenseId, String userId) async {
    try {
      await _countRepository.markSplitAsPaid(
        groupId: groupId,
        expenseId: expenseId,
        userId: userId,
      );
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors du marquage du paiement: $e');
      rethrow;
    }
  }

  // Stream des dépenses
  Stream<List<Expense>> getExpensesStream(String groupId, {bool includeArchived = false}) {
    try {
      return _countRepository.getExpensesStream(groupId, includeArchived: includeArchived);
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de la récupération des dépenses: $e');
      rethrow;
    }
  }

  // Calculer les balances
  List<Balance> calculateBalances(List<Expense> expenses, List<String> memberIds, Map<String, String> memberNames) {
    final balances = <String, Balance>{};

    // Initialiser les balances
    for (final memberId in memberIds) {
      balances[memberId] = Balance(
        userId: memberId,
        userName: memberNames[memberId] ?? 'Unknown',
        totalPaid: 0,
        totalOwed: 0,
      );
    }

    // Calculer pour chaque dépense
    for (final expense in expenses) {
      if (expense.isArchived) continue;

      // Ajouter au total payé
      final payer = balances[expense.paidById];
      if (payer != null) {
        balances[expense.paidById] = Balance(
          userId: payer.userId,
          userName: payer.userName,
          totalPaid: payer.totalPaid + expense.amountInEur,
          totalOwed: payer.totalOwed,
        );
      }

      // Ajouter au total dû pour chaque split
      for (final split in expense.splits) {
        if (!split.isPaid) {
          final debtor = balances[split.userId];
          if (debtor != null) {
            balances[split.userId] = Balance(
              userId: debtor.userId,
              userName: debtor.userName,
              totalPaid: debtor.totalPaid,
              totalOwed: debtor.totalOwed + split.amount,
            );
          }
        }
      }
    }

    return balances.values.toList();
  }

  // Calculer les remboursements optimisés
  List<Settlement> calculateOptimizedSettlements(List<Balance> balances) {
    final settlements = <Settlement>[];
    
    // Créer des copies mutables
    final creditors = balances.where((b) => b.shouldReceive).map((b) => 
      {'userId': b.userId, 'userName': b.userName, 'amount': b.balance}
    ).toList();
    
    final debtors = balances.where((b) => b.shouldPay).map((b) => 
      {'userId': b.userId, 'userName': b.userName, 'amount': b.absoluteBalance}
    ).toList();

    // Trier par montant décroissant
    creditors.sort((a, b) => (b['amount'] as double).compareTo(a['amount'] as double));
    debtors.sort((a, b) => (b['amount'] as double).compareTo(a['amount'] as double));

    int i = 0, j = 0;
    while (i < creditors.length && j < debtors.length) {
      final creditor = creditors[i];
      final debtor = debtors[j];
      
      final creditorAmount = creditor['amount'] as double;
      final debtorAmount = debtor['amount'] as double;
      
      final settleAmount = creditorAmount < debtorAmount ? creditorAmount : debtorAmount;

      settlements.add(Settlement(
        fromUserId: debtor['userId'] as String,
        fromUserName: debtor['userName'] as String,
        toUserId: creditor['userId'] as String,
        toUserName: creditor['userName'] as String,
        amount: settleAmount,
      ));

      creditor['amount'] = creditorAmount - settleAmount;
      debtor['amount'] = debtorAmount - settleAmount;

      if (creditor['amount'] == 0) i++;
      if (debtor['amount'] == 0) j++;
    }

    return settlements;
  }

  // Convertir un montant en EUR
  Future<double> convertToEur(double amount, ExpenseCurrency currency) async {
    try {
      return await _countRepository.convertToEur(amount, currency);
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de la conversion: $e');
      rethrow;
    }
  }

  // Obtenir les taux de change
  Future<Map<ExpenseCurrency, double>> getExchangeRates() async {
    try {
      return await _countRepository.getExchangeRates();
    } catch (e) {
      _errorService.logError('count_service.dart', 'Erreur lors de la récupération des taux: $e');
      rethrow;
    }
  }
}