/// 滚动字幕配置参数：速度档位与级别。
///
/// 与 Web 后台 `/views/modules/theme/scrolling-text.data.ts` 保持一致，
/// 移动端仅展示档位文案，落库仍是原始数值，便于与 Web 端互相识别。
///
/// 速度（scrollSpeed，单位 ms/像素，数值越小滚动越快）：
/// - 慢   = 200
/// - 较慢 = 100
/// - 中   = 50
/// - 较快 = 30
/// - 快   = 10
///
/// 级别（level）：
/// - 危险 = 50
/// - 紧急 = 40
/// - 普通 = 20
class MarqueeConfig {
  const MarqueeConfig({
    this.speed = MarqueeSpeed.medium,
    this.grade = MarqueeGrade.normal,
  });

  final MarqueeSpeed speed;
  final MarqueeGrade grade;

  /// 将任意历史 speed 值吸附到最近档位（兼容 Web 端精确值）。
  static MarqueeSpeed speedFromValue(int? value) {
    if (value == null) return MarqueeSpeed.medium;
    final target = MarqueeSpeed.values.fold<MarqueeSpeed>(
      MarqueeSpeed.values.first,
      (closest, current) {
        final diffClosest = (closest.value - value).abs();
        final diffCurrent = (current.value - value).abs();
        return diffCurrent < diffClosest ? current : closest;
      },
    );
    return target;
  }

  /// 将任意历史 level 值吸附到最近级别。
  static MarqueeGrade gradeFromValue(int? value) {
    if (value == null) return MarqueeGrade.normal;
    final target = MarqueeGrade.values.fold<MarqueeGrade>(
      MarqueeGrade.values.first,
      (closest, current) {
        final diffClosest = (closest.value - value).abs();
        final diffCurrent = (current.value - value).abs();
        return diffCurrent < diffClosest ? current : closest;
      },
    );
    return target;
  }

  MarqueeConfig setSpeed(MarqueeSpeed speed) =>
      MarqueeConfig(speed: speed, grade: grade);

  MarqueeConfig setGrade(MarqueeGrade grade) =>
      MarqueeConfig(speed: speed, grade: grade);

  MarqueeConfig copyWith({
    MarqueeSpeed? speed,
    MarqueeGrade? grade,
  }) =>
      MarqueeConfig(
        speed: speed ?? this.speed,
        grade: grade ?? this.grade,
      );
}

/// 滚动速度档位。
enum MarqueeSpeed {
  slow(200, '慢'),
  slower(100, '较慢'),
  medium(50, '中'),
  faster(30, '较快'),
  fast(10, '快');

  const MarqueeSpeed(this.value, this.labelZh);

  /// 后端落库值。
  final int value;

  /// 中文展示文案。
  final String labelZh;

  /// 英文展示文案。
  String get labelEn {
    switch (this) {
      case MarqueeSpeed.slow:
        return 'Slow';
      case MarqueeSpeed.slower:
        return 'Slower';
      case MarqueeSpeed.medium:
        return 'Medium';
      case MarqueeSpeed.faster:
        return 'Faster';
      case MarqueeSpeed.fast:
        return 'Fast';
    }
  }

  String label(bool useEnglish) => useEnglish ? labelEn : labelZh;
}

/// 滚动字幕级别。
enum MarqueeGrade {
  danger(50, '危险'),
  urgent(40, '紧急'),
  normal(20, '普通');

  const MarqueeGrade(this.value, this.labelZh);

  /// 后端落库值。
  final int value;

  /// 中文展示文案。
  final String labelZh;

  /// 英文展示文案。
  String get labelEn {
    switch (this) {
      case MarqueeGrade.danger:
        return 'Danger';
      case MarqueeGrade.urgent:
        return 'Urgent';
      case MarqueeGrade.normal:
        return 'Normal';
    }
  }

  String label(bool useEnglish) => useEnglish ? labelEn : labelZh;
}