import 'dart:async';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../data/models.dart';
import 'providers.dart';

class PaginatedTransactionState {
  final List<Transaction> transactions;
  final bool isLoading;
  final bool hasMore;
  final String? type;
  final int? walletId;
  final int? categoryId;
  final String? search;
  
  PaginatedTransactionState({
    required this.transactions,
    this.isLoading = false,
    this.hasMore = true,
    this.type,
    this.walletId,
    this.categoryId,
    this.search,
  });

  PaginatedTransactionState copyWith({
    List<Transaction>? transactions,
    bool? isLoading,
    bool? hasMore,
    String? type,
    int? walletId,
    int? categoryId,
    String? search,
  }) {
    return PaginatedTransactionState(
      transactions: transactions ?? this.transactions,
      isLoading: isLoading ?? this.isLoading,
      hasMore: hasMore ?? this.hasMore,
      type: type != null ? (type == 'ALL' ? null : type) : this.type,
      walletId: walletId != null ? (walletId == -1 ? null : walletId) : this.walletId,
      categoryId: categoryId != null ? (categoryId == -1 ? null : categoryId) : this.categoryId,
      search: search != null ? (search == '' ? null : search) : this.search,
    );
  }
}

class PaginatedTransactionNotifier extends Notifier<PaginatedTransactionState> {
  int _currentPage = 0;

  @override
  PaginatedTransactionState build() {
    _currentPage = 0;
    Future.microtask(() => loadMore());
    return PaginatedTransactionState(transactions: []);
  }

  void updateFilters({String? type, int? walletId, int? categoryId, String? search}) {
    state = state.copyWith(
      type: type,
      walletId: walletId,
      categoryId: categoryId,
      search: search,
      transactions: [], // reset
      hasMore: true,
    );
    _currentPage = 0;
    loadMore();
  }

  void clearFilters() {
    state = PaginatedTransactionState(transactions: []);
    _currentPage = 0;
    loadMore();
  }

  Future<void> loadMore() async {
    if (state.isLoading || !state.hasMore) return;
    
    state = state.copyWith(isLoading: true);
    try {
      final repository = ref.read(apiRepositoryProvider);
      final response = await repository.searchTransactions(
        page: _currentPage,
        size: 20,
        type: state.type,
        walletId: state.walletId,
        categoryId: state.categoryId,
        search: state.search,
      );
      
      final newContent = response['content'] as List<Transaction>;
      final totalPages = response['totalPages'] as int;
      
      _currentPage++;
      
      state = state.copyWith(
        transactions: [...state.transactions, ...newContent],
        isLoading: false,
        hasMore: _currentPage < totalPages,
      );
    } catch (_) {
      state = state.copyWith(isLoading: false);
    }
  }

  void removeTransactionFromState(int id) {
    final updatedList = state.transactions.where((t) => t.id != id).toList();
    state = state.copyWith(transactions: updatedList);
  }

  void updateTransactionInState(Transaction tx) {
    final updatedList = state.transactions.map((t) => t.id == tx.id ? tx : t).toList();
    state = state.copyWith(transactions: updatedList);
  }
}

final paginatedTransactionProvider = NotifierProvider<PaginatedTransactionNotifier, PaginatedTransactionState>(() {
  return PaginatedTransactionNotifier();
});