import 'package:flutter/foundation.dart';
import 'package:flutter_chen_kchart/k_chart.dart';
import 'package:decimal/decimal.dart';
import '../models/candle.dart';

/// 时间周期
enum ChartInterval {
  min1('1分', '1m'),
  min5('5分', '5m'),
  min15('15分', '15m'),
  hour1('1小时', '1h'),
  hour4('4小时', '4h'),
  day1('1天', '1d');

  final String label;
  final String value;
  const ChartInterval(this.label, this.value);
}

/// 技术指标设置
class IndicatorSettings {
  final bool showMA;
  final bool showEMA;
  final bool showBOLL;
  final bool showVOL;
  final bool showMACD;
  final bool showKDJ;
  final bool showRSI;
  final bool showWR;
  final bool showCCI;

  const IndicatorSettings({
    this.showMA = true,
    this.showEMA = false,
    this.showBOLL = false,
    this.showVOL = true,
    this.showMACD = true,
    this.showKDJ = false,
    this.showRSI = false,
    this.showWR = false,
    this.showCCI = false,
  });

  IndicatorSettings copyWith({
    bool? showMA,
    bool? showEMA,
    bool? showBOLL,
    bool? showVOL,
    bool? showMACD,
    bool? showKDJ,
    bool? showRSI,
    bool? showWR,
    bool? showCCI,
  }) {
    return IndicatorSettings(
      showMA: showMA ?? this.showMA,
      showEMA: showEMA ?? this.showEMA,
      showBOLL: showBOLL ?? this.showBOLL,
      showVOL: showVOL ?? this.showVOL,
      showMACD: showMACD ?? this.showMACD,
      showKDJ: showKDJ ?? this.showKDJ,
      showRSI: showRSI ?? this.showRSI,
      showWR: showWR ?? this.showWR,
      showCCI: showCCI ?? this.showCCI,
    );
  }
}

/// K 线数据 Provider
class ChartProvider extends ChangeNotifier {
  // 当前币种
  String _symbol = 'BTC';
  String get symbol => _symbol;

  // 时间周期
  ChartInterval _interval = ChartInterval.hour1;
  ChartInterval get interval => _interval;

  // 技术指标
  IndicatorSettings _indicators = const IndicatorSettings();
  IndicatorSettings get indicators => _indicators;

  // K 线数据（原始）
  List<Candle> _candles = [];
  List<Candle> get candles => _candles;

  // k_chart 需要的数据格式（转换为 double）
  List<KLineEntity> get klineData {
    return _candles.map((c) {
      return KLineEntity.fromCustom(
        open: c.openDouble,
        high: c.highDouble,
        low: c.lowDouble,
        close: c.closeDouble,
        vol: c.volumeDouble,
        time: c.timestamp,
      );
    }).toList();
  }

  // 状态
  bool _loading = false;
  bool get loading => _loading;

  String? _error;
  String? get error => _error;

  /// 切换币种
  void setSymbol(String symbol) {
    if (_symbol != symbol) {
      _symbol = symbol;
      loadCandles();
    }
  }

  /// 切换时间周期
  void setInterval(ChartInterval interval) {
    if (_interval != interval) {
      _interval = interval;
      loadCandles(showLoading: false);
    }
  }

  /// 更新指标设置
  void updateIndicators(IndicatorSettings settings) {
    _indicators = settings;
    notifyListeners();
  }

  /// 加载 K 线数据
  Future<void> loadCandles({bool showLoading = true}) async {
    if (showLoading) {
      _loading = true;
      _error = null;
      notifyListeners();
    }

    try {
      // TODO: 对接真实 API
      // 临时使用模拟数据
      await Future.delayed(const Duration(milliseconds: 300));
      _candles = _generateMockCandles();

      if (showLoading) {
        _loading = false;
        notifyListeners();
      } else {
        notifyListeners();
      }
    } catch (e) {
      if (showLoading) {
        _loading = false;
      }
      _error = e.toString();
      notifyListeners();
    }
  }

  /// 生成模拟 K 线数据（使用 Decimal 防止精度丢失）
  List<Candle> _generateMockCandles() {
    final now = DateTime.now();
    final basePrice = _getBasePrice(_symbol);
    final candles = <Candle>[];

    for (int i = 100; i >= 0; i--) {
      final time = now.subtract(Duration(
        minutes: _interval == ChartInterval.min1
            ? i
            : _interval == ChartInterval.min5
                ? i * 5
                : _interval == ChartInterval.min15
                    ? i * 15
                    : _interval == ChartInterval.hour1
                        ? i * 60
                        : _interval == ChartInterval.hour4
                            ? i * 240
                            : i * 1440,
      ));

      // 使用 Decimal 进行安全计算
      final random = Decimal.parse(((i * 17) % 100 / 100).toString());
      final change = basePrice * Decimal.parse('0.02') * (random - Decimal.parse('0.5'));
      final open = basePrice + change;
      final close = open + basePrice * Decimal.parse('0.01') * (Decimal.parse(((i * 13) % 100 / 100).toString()) - Decimal.parse('0.5'));
      final high = open > close ? open * Decimal.parse('1.005') : close * Decimal.parse('1.005');
      final low = open < close ? open * Decimal.parse('0.995') : close * Decimal.parse('0.995');
      final volume = Decimal.fromInt(1000 + (i * 37) % 5000);

      candles.add(Candle(
        timestamp: time.millisecondsSinceEpoch,
        open: open,
        high: high,
        low: low,
        close: close,
        volume: volume,
      ));
    }

    return candles;
  }

  Decimal _getBasePrice(String symbol) {
    switch (symbol.toUpperCase()) {
      case 'BTC':
        return Decimal.parse('42000');
      case 'ETH':
        return Decimal.parse('2200');
      case 'BNB':
        return Decimal.parse('300');
      case 'SOL':
        return Decimal.parse('100');
      case 'XRP':
        return Decimal.parse('0.5');
      case 'DOGE':
        return Decimal.parse('0.08');
      default:
        return Decimal.fromInt(100);
    }
  }
}