import 'package:decimal/decimal.dart';

/// K 线数据模型
class Candle {
  final int timestamp; // 毫秒时间戳
  final Decimal open;
  final Decimal high;
  final Decimal low;
  final Decimal close;
  final Decimal volume;

  const Candle({
    required this.timestamp,
    required this.open,
    required this.high,
    required this.low,
    required this.close,
    required this.volume,
  });

  /// 从 JSON 解析，使用 Decimal 避免精度丢失
  factory Candle.fromJson(Map<String, dynamic> json) {
    return Candle(
      timestamp: json['timestamp'] as int? ?? json['time'] as int? ?? 0,
      open: _parseDecimal(json['open']),
      high: _parseDecimal(json['high']),
      low: _parseDecimal(json['low']),
      close: _parseDecimal(json['close']),
      volume: _parseDecimal(json['volume']),
    );
  }

  /// 安全解析 Decimal
  static Decimal _parseDecimal(dynamic value) {
    if (value == null) return Decimal.zero;
    if (value is Decimal) return value;
    if (value is num) return Decimal.fromJson(value.toString());
    if (value is String) {
      try {
        return Decimal.parse(value);
      } catch (_) {
        return Decimal.zero;
      }
    }
    return Decimal.zero;
  }

  Map<String, dynamic> toJson() => {
        'timestamp': timestamp,
        'open': open.toDouble(),
        'high': high.toDouble(),
        'low': low.toDouble(),
        'close': close.toDouble(),
        'volume': volume.toDouble(),
      };

  /// 转换为 double（供图表库使用）
  double get openDouble => open.toDouble();
  double get highDouble => high.toDouble();
  double get lowDouble => low.toDouble();
  double get closeDouble => close.toDouble();
  double get volumeDouble => volume.toDouble();

  /// 安全加法（防止溢出）
  Decimal safeAdd(Decimal other) {
    try {
      return open + other;
    } catch (_) {
      return Decimal.zero;
    }
  }

  /// 安全乘法（防止溢出）
  Decimal safeMultiply(Decimal other) {
    try {
      return open * other;
    } catch (_) {
      return Decimal.zero;
    }
  }

  /// 格式化价格显示
  String formatPrice({int decimalPlaces = 2}) {
    return close.toStringAsFixed(decimalPlaces);
  }

  /// 格式化成交量显示
  String formatVolume() {
    final vol = volume.toDouble();
    if (vol >= 1000000000) {
      return '${(vol / 1000000000).toStringAsFixed(2)}B';
    } else if (vol >= 1000000) {
      return '${(vol / 1000000).toStringAsFixed(2)}M';
    } else if (vol >= 1000) {
      return '${(vol / 1000).toStringAsFixed(2)}K';
    }
    return vol.toStringAsFixed(2);
  }
}