import 'json_util.dart';

/// 「强宝健康」模块的数据模型。
///
/// 后端接口一律给 kcal（换算在服务端做掉了），所以这里不会再出现千焦 ——
/// 前端只有一个能量口径。

// ==================================================================
// 体重
// ==================================================================

/// 一个体重数据点（折线图用）
class WeightPoint {
  const WeightPoint({required this.date, required this.weight});

  final DateTime date;
  final double weight;

  factory WeightPoint.fromJson(Map<String, dynamic> json) {
    return WeightPoint(
      date: tryParse(json['date']) ?? DateTime.now(),
      weight: asDouble(json['weight']),
    );
  }

  static DateTime? tryParse(Object? value) {
    final text = asString(value).trim();
    if (text.isEmpty) return null;
    return DateTime.tryParse(text);
  }
}

/// 体重折线图数据
class WeightChart {
  const WeightChart({
    required this.points,
    required this.currentWeight,
    required this.delta,
    required this.maxWeight,
    required this.minWeight,
  });

  final List<WeightPoint> points;

  /// 最近一次体重，没记过就是 null
  final double? currentWeight;

  /// 与上一次记录的差值。正数 = 涨了。只有一个点时是 null。
  final double? delta;

  /// Y 轴范围（后端已把目标体重也算进来，避免理想线画在可见区外）
  final double? maxWeight;
  final double? minWeight;

  static const empty = WeightChart(
    points: [],
    currentWeight: null,
    delta: null,
    maxWeight: null,
    minWeight: null,
  );

  bool get hasData => points.isNotEmpty;

  factory WeightChart.fromJson(Map<String, dynamic> json) {
    return WeightChart(
      points: asMapList(json['points']).map(WeightPoint.fromJson).toList(),
      currentWeight: asNullableDouble(json['currentWeight']),
      delta: asNullableDouble(json['delta']),
      maxWeight: asNullableDouble(json['maxWeight']),
      minWeight: asNullableDouble(json['minWeight']),
    );
  }
}

/// 一条体重记录（历史列表用）
class WeightRecordItem {
  const WeightRecordItem({
    required this.id,
    required this.date,
    required this.weight,
    required this.note,
  });

  final int id;
  final DateTime? date;
  final double weight;
  final String note;

  factory WeightRecordItem.fromJson(Map<String, dynamic> json) {
    return WeightRecordItem(
      id: asInt(json['id']),
      date: WeightPoint.tryParse(json['recordDate']),
      weight: asDouble(json['weight']),
      note: asString(json['note']),
    );
  }
}

// ==================================================================
// 减重目标
// ==================================================================

/// 减重目标 + 由它推出来的一整套「每周该减多少」
class WeightGoal {
  const WeightGoal({
    required this.hasGoal,
    required this.startWeight,
    required this.targetWeight,
    required this.startDate,
    required this.targetDate,
    required this.totalWeeks,
    required this.weeklyLoss,
    required this.weeklyLossUnhealthy,
    required this.idealCurve,
    required this.currentWeight,
    required this.lostWeight,
    required this.remainWeight,
    required this.weightProgress,
    required this.timeProgress,
    required this.id,
  });

  final bool hasGoal;
  final int? id;

  final double startWeight;
  final double targetWeight;

  final DateTime? startDate;
  final DateTime? targetDate;

  /// 总周数（后端向上取整）
  final int totalWeeks;

  /// 每周应减 kg
  final double weeklyLoss;

  /// 每周超过 1kg，界面上要提示「掉太快」
  final bool weeklyLossUnhealthy;

  /// 理想体重曲线（每周一个点），画在体重折线图上当参照
  final List<WeightPoint> idealCurve;

  final double? currentWeight;

  /// 已减 / 还差。没记过体重时是 null。
  final double? lostWeight;
  final double? remainWeight;

  /// 0.0 ~ 1.0
  final double weightProgress;
  final double timeProgress;

  static const none = WeightGoal(
    hasGoal: false,
    startWeight: 0,
    targetWeight: 0,
    startDate: null,
    targetDate: null,
    totalWeeks: 0,
    weeklyLoss: 0,
    weeklyLossUnhealthy: false,
    idealCurve: [],
    currentWeight: null,
    lostWeight: null,
    remainWeight: null,
    weightProgress: 0,
    timeProgress: 0,
    id: null,
  );

  factory WeightGoal.fromJson(Map<String, dynamic> json) {
    if (json['hasGoal'] != true) return none;
    return WeightGoal(
      hasGoal: true,
      id: asNullableInt(json['id']),
      startWeight: asDouble(json['startWeight']),
      targetWeight: asDouble(json['targetWeight']),
      startDate: WeightPoint.tryParse(json['startDate']),
      targetDate: WeightPoint.tryParse(json['targetDate']),
      totalWeeks: asInt(json['totalWeeks']),
      weeklyLoss: asDouble(json['weeklyLoss']),
      weeklyLossUnhealthy: json['weeklyLossUnhealthy'] == true,
      idealCurve:
          asMapList(json['idealCurve']).map(WeightPoint.fromJson).toList(),
      currentWeight: asNullableDouble(json['currentWeight']),
      lostWeight: asNullableDouble(json['lostWeight']),
      remainWeight: asNullableDouble(json['remainWeight']),
      weightProgress: asDouble(json['weightProgress']),
      timeProgress: asDouble(json['timeProgress']),
    );
  }
}

// ==================================================================
// 食物 + 饮食
// ==================================================================

/// 一个份量档位，如「一碗 150g」
class FoodPortion {
  const FoodPortion({required this.label, required this.grams});

  final String label;
  final int grams;

  factory FoodPortion.fromJson(Map<String, dynamic> json) {
    return FoodPortion(
      label: asString(json['label']),
      grams: asInt(json['grams']),
    );
  }
}

/// 一条食物（营养值都是「每 100g」）
class FoodItem {
  const FoodItem({
    required this.id,
    required this.name,
    required this.alias,
    required this.categoryName,
    required this.subCategoryName,
    required this.ediblePercent,
    required this.energyKcal,
    required this.protein,
    required this.fat,
    required this.carbohydrate,
    required this.dietaryFiber,
    required this.sodium,
    required this.portions,
  });

  final int id;
  final String name;
  final String alias;
  final String categoryName;
  final String subCategoryName;

  /// 食部 %。展示用参考，不参与热量换算。
  final double? ediblePercent;

  /// 每 100g 的能量 kcal（后端已经把 kJ 换掉了）
  final double? energyKcal;

  final double? protein;
  final double? fat;
  final double? carbohydrate;
  final double? dietaryFiber;
  final double? sodium;

  /// 份量档位。后端保证非空。
  final List<FoodPortion> portions;

  factory FoodItem.fromJson(Map<String, dynamic> json) {
    return FoodItem(
      id: asInt(json['id']),
      name: asNonEmpty(json['name'], '未命名食物'),
      alias: asString(json['alias']),
      categoryName: asString(json['categoryName']),
      subCategoryName: asString(json['subCategoryName']),
      ediblePercent: asNullableDouble(json['ediblePercent']),
      energyKcal: asNullableDouble(json['energyKcal']),
      protein: asNullableDouble(json['protein']),
      fat: asNullableDouble(json['fat']),
      carbohydrate: asNullableDouble(json['carbohydrate']),
      dietaryFiber: asNullableDouble(json['dietaryFiber']),
      sodium: asNullableDouble(json['sodium']),
      portions:
          asMapList(json['portions']).map(FoodPortion.fromJson).toList(),
    );
  }

  /// 按份量算这条食物实际摄入的热量（前端预览用，服务端会独立再算一次）
  double kcalFor(num grams) {
    if (energyKcal == null || grams <= 0) return 0;
    return energyKcal! * grams / 100;
  }
}

/// 食物分类 + 该分类下的食物数
class FoodCategory {
  const FoodCategory({required this.name, required this.count});

  final String name;
  final int count;

  factory FoodCategory.fromJson(Map<String, dynamic> json) {
    return FoodCategory(
      name: asNonEmpty(json['name'], '未分类'),
      count: asInt(json['count']),
    );
  }
}

/// 一条饮食记录
class DietRecordItem {
  const DietRecordItem({
    required this.id,
    required this.mealType,
    required this.foodName,
    required this.amountGrams,
    required this.energyKcal,
    required this.protein,
    required this.fat,
    required this.carbohydrate,
    required this.dietaryFiber,
    required this.sodium,
  });

  final int id;
  final String mealType;
  final String foodName;
  final double amountGrams;
  final double energyKcal;
  final double protein;
  final double fat;
  final double carbohydrate;
  final double dietaryFiber;
  final double sodium;

  factory DietRecordItem.fromJson(Map<String, dynamic> json) {
    return DietRecordItem(
      id: asInt(json['id']),
      mealType: asNonEmpty(json['mealType'], 'snack'),
      foodName: asNonEmpty(json['foodName'], '未命名食物'),
      amountGrams: asDouble(json['amountGrams']),
      energyKcal: asDouble(json['energyKcal']),
      protein: asDouble(json['protein']),
      fat: asDouble(json['fat']),
      carbohydrate: asDouble(json['carbohydrate']),
      dietaryFiber: asDouble(json['dietaryFiber']),
      sodium: asDouble(json['sodium']),
    );
  }
}

/// 营养合计
class NutritionTotals {
  const NutritionTotals({
    this.energyKcal = 0,
    this.protein = 0,
    this.fat = 0,
    this.carbohydrate = 0,
    this.dietaryFiber = 0,
    this.sodium = 0,
    this.itemCount = 0,
  });

  final double energyKcal;
  final double protein;
  final double fat;
  final double carbohydrate;
  final double dietaryFiber;
  final double sodium;
  final int itemCount;

  static const zero = NutritionTotals();

  factory NutritionTotals.fromJson(Map<String, dynamic> json) {
    return NutritionTotals(
      energyKcal: asDouble(json['energyKcal']),
      protein: asDouble(json['protein']),
      fat: asDouble(json['fat']),
      carbohydrate: asDouble(json['carbohydrate']),
      dietaryFiber: asDouble(json['dietaryFiber']),
      sodium: asDouble(json['sodium']),
      itemCount: asInt(json['itemCount']),
    );
  }
}

/// 一个餐次的分组
class MealGroup {
  const MealGroup({
    required this.mealType,
    required this.totals,
    required this.items,
  });

  final String mealType;
  final NutritionTotals totals;
  final List<DietRecordItem> items;

  factory MealGroup.fromJson(Map<String, dynamic> json) {
    return MealGroup(
      mealType: asNonEmpty(json['mealType'], 'snack'),
      totals: NutritionTotals.fromJson(
          (json['totals'] as Map?)?.cast<String, dynamic>() ?? const {}),
      items: asMapList(json['items']).map(DietRecordItem.fromJson).toList(),
    );
  }
}

/// 某一天的饮食情况
class DietDay {
  const DietDay({
    required this.date,
    required this.totals,
    required this.meals,
  });

  final DateTime? date;
  final NutritionTotals totals;

  /// 固定 4 个餐次（后端保留了空餐次，前端不用补位）
  final List<MealGroup> meals;

  static const empty = DietDay(date: null, totals: NutritionTotals.zero, meals: []);

  factory DietDay.fromJson(Map<String, dynamic> json) {
    return DietDay(
      date: WeightPoint.tryParse(json['date']),
      totals: NutritionTotals.fromJson(
          (json['totals'] as Map?)?.cast<String, dynamic>() ?? const {}),
      meals: asMapList(json['meals']).map(MealGroup.fromJson).toList(),
    );
  }
}

/// 餐次的中文名与显示顺序
const Map<String, String> kMealLabels = {
  'breakfast': '早餐',
  'lunch': '午餐',
  'dinner': '晚餐',
  'snack': '加餐',
};

String mealLabel(String mealType) => kMealLabels[mealType] ?? '加餐';