import 'package:flutter/material.dart';
import '../data/models/coin.dart';
import '../data/services/market_service.dart';

/// 行情狀態管理
class MarketProvider extends ChangeNotifier {
  final MarketService _marketService;

  List<Coin> _allCoins = [];
  List<Coin> _platformCoins = [];
  List<Coin> _nonPlatformCoins = [];
  bool _isLoading = false;
  String? _error;
  bool _coinsLoaded = false;

  MarketProvider(this._marketService);

  // Getters
  List<Coin> get allCoins => _allCoins;
  bool get isLoading => _isLoading;
  String? get error => _error;

  List<Coin> get platformCoins => _platformCoins;
  List<Coin> get nonPlatformCoins => _nonPlatformCoins;

  /// 加載幣種列表
  Future<void> loadCoins({bool force = false}) async {
    if (_coinsLoaded && !force && _allCoins.isNotEmpty) {
      return;
    }

    final isFirstLoad = !_coinsLoaded || _allCoins.isEmpty;
    if (isFirstLoad) {
      _isLoading = true;
      _error = null;
      notifyListeners();
    }

    try {
      final response = await _marketService.getCoinList();

      if (response.success) {
        _allCoins = response.data ?? [];
        _platformCoins = _allCoins.where((c) => c.isPlatform == 1 && c.status == 1).toList();
        _nonPlatformCoins = _allCoins.where((c) => c.isPlatform != 1 && c.code != 'USDT').toList();
        _coinsLoaded = true;
        _error = null;
      } else {
        // 非首次加载时保留旧数据，仅记录错误
        if (!isFirstLoad && _allCoins.isNotEmpty) {
          _error = null;
        } else {
          _error = response.message;
        }
      }
    } catch (e) {
      // 非首次加载且有缓存数据时，不覆盖为错误状态
      if (!isFirstLoad && _allCoins.isNotEmpty) {
        _error = null;
      } else {
        _error = '加載失敗: $e';
      }
    }

    _isLoading = false;
    notifyListeners();
  }

  /// 根據代碼獲取幣種
  Coin? getCoinByCode(String code) {
    try {
      return _allCoins.firstWhere((c) => c.code == code);
    } catch (_) {
      return null;
    }
  }

  /// 刷新
  Future<void> refresh() async {
    await loadCoins(force: true);
  }

  /// 重置加載狀態（用於退出登錄時）
  void resetLoadState() {
    _coinsLoaded = false;
    _allCoins = [];
    _error = null;
    notifyListeners();
  }
}