export type ExerciseSet = {
  durationSec?: number; // 计时型（秒）
  reps?: number; // 次数型（可选）
  restSecAfter?: number; // 组间休息
};

export type Exercise = {
  key: string;
  name: string;
  description: string;
  videoUrl?: string;
  sets: ExerciseSet[];
  tips?: string[];
};

export type DayPlan = {
  dayNumber: number; // 1..30
  type: 'training' | 'recovery' | 'rest';
  title: string;
  focus: string; // 训练重点
  exercises: Exercise[]; // rest/recovery 可为空数组
};

export type PilatesLevel = 'beginner' | 'intermediate' | 'advanced';

const BASE_EXERCISES: Omit<Exercise, 'sets'>[] = [
  {
    key: 'hundred',
    name: '百次拍击 (The Hundred)',
    description: '仰卧，抬腿至桌面位，核心收紧，小幅快速摆动手臂并配合呼吸。',
    videoUrl: undefined,
  },
  {
    key: 'single_leg_stretch',
    name: '单腿伸展 (Single Leg Stretch)',
    description: '仰卧，交替伸直一条腿，另一条腿屈膝抱向胸口，核心稳定。',
  },
  {
    key: 'double_leg_stretch',
    name: '双腿伸展 (Double Leg Stretch)',
    description: '仰卧同时伸直双腿与双臂，呼气收回环抱膝盖。',
  },
  {
    key: 'roll_up',
    name: '卷起 (Roll Up)',
    description: '由仰卧卷起至坐并前屈，再控制还原，强调脊柱分节活动。',
  },
  {
    key: 'spine_twist',
    name: '脊柱扭转 (Spine Twist)',
    description: '坐姿，躯干直立，左右控制旋转，强调轴向延展与核心稳定。',
  },
  {
    key: 'bridge',
    name: '桥式 (Bridge)',
    description: '仰卧，卷尾抬起骨盆至肩桥位，感受臀腿后侧发力，控制还原。',
  },
  {
    key: 'side_leg_lift',
    name: '侧抬腿 (Side Leg Lift)',
    description: '侧卧，髋稳定，抬高上侧腿，控制下放。',
  },
  {
    key: 'swimming',
    name: '游泳式 (Swimming)',
    description: '俯卧，交替抬起对侧手臂与腿，保持脊柱中立并延展。',
  },
  {
    key: 'cat_cow',
    name: '猫牛式 (Cat-Cow)',
    description: '四点支撑，呼吸带动脊柱屈伸，作为热身或整理放松。',
  },
  {
    key: 'saw',
    name: '锯式 (Saw)',
    description: '坐姿分腿，旋转并前屈，斜向触碰对侧脚尖。',
  },
  {
    key: 'plank',
    name: '平板支撑 (Plank)',
    description: '前臂/掌支撑，身体成直线，保持核心紧致。',
  },
];

function buildSets(level: PilatesLevel, baseSec: number, setCount: number): ExerciseSet[] {
  const effort = baseSec + (level === 'intermediate' ? 10 : level === 'advanced' ? 20 : 0);
  const rest = 15;
  return Array.from({ length: setCount }).map(() => ({ durationSec: effort, restSecAfter: rest }));
}

function pickExercises(keys: string[], level: PilatesLevel, baseSec: number, setCount: number): Exercise[] {
  return keys.map((k) => {
    const base = BASE_EXERCISES.find((e) => e.key === k)!;
    return {
      ...base,
      sets: buildSets(level, baseSec, setCount),
      tips: [
        '保持呼吸与动作节奏一致',
        '核心始终收紧，避免腰椎塌陷',
        '以控制优先于速度，专注动作质量',
      ],
    };
  });
}

export function generatePilates30DayPlan(level: PilatesLevel = 'beginner'): DayPlan[] {
  // 周期化：每7天安排恢复/拉伸；逐周增加时长或组数
  const plan: DayPlan[] = [];
  for (let d = 1; d <= 30; d += 1) {
    const weekIndex = Math.ceil(d / 7); // 1..5
    const isRecovery = d % 7 === 0 || d === 14 || d === 21 || d === 28; // 每周末恢复

    if (isRecovery) {
      plan.push({
        dayNumber: d,
        type: 'recovery',
        title: '恢复与拉伸日',
        focus: '呼吸、脊柱分节、柔韧性',
        exercises: pickExercises(['cat_cow', 'saw'], level, 40, 2),
      });
      continue;
    }

    // 训练参数随周数递增
    const baseSec = 35 + (weekIndex - 1) * 5; // 35,40,45,50,55
    const setCount = 2 + (weekIndex > 3 ? 1 : 0); // 第4周开始 3 组

    // 交替不同侧重点
    let title = '核心激活与稳定';
    let focus = '腹横肌、骨盆稳定、呼吸控制';
    let keys: string[] = ['hundred', 'single_leg_stretch', 'double_leg_stretch', 'roll_up', 'spine_twist'];

    if (d % 3 === 0) {
      title = '后链力量与体态';
      focus = '臀腿后侧、胸椎伸展、姿态矫正';
      keys = ['bridge', 'swimming', 'plank', 'spine_twist', 'roll_up'];
    } else if (d % 3 === 2) {
      title = '髋稳定与侧链';
      focus = '中臀肌、侧链控制、骨盆稳定';
      keys = ['side_leg_lift', 'single_leg_stretch', 'bridge', 'saw', 'plank'];
    }

    const exercises = pickExercises(keys, level, baseSec, setCount);
    plan.push({ dayNumber: d, type: 'training', title, focus, exercises });
  }
  return plan;
}

export function estimateSessionMinutes(day: DayPlan): number {
  if (day.type !== 'training' && day.type !== 'recovery') return 0;
  const totalSec = day.exercises.reduce((sum, ex) => {
    return (
      sum +
      ex.sets.reduce((s, st) => s + (st.durationSec ?? 0) + (st.restSecAfter ?? 0), 0)
    );
  }, 0);
  return Math.max(10, Math.round(totalSec / 60));
}

// 用户自定义配置（用于挑战页可调节）
export type ExerciseCustomConfig = {
  key: string;
  enabled: boolean;
  sets: number; // 目标组数（计时型）
  durationSec?: number; // 每组计时秒数（若为空可按默认）
  reps?: number; // 每组次数（可选）
};

export function buildDefaultCustomFromPlan(day: DayPlan): ExerciseCustomConfig[] {
  return (day.exercises || []).map((ex) => ({
    key: ex.key,
    enabled: true,
    sets: Math.max(1, ex.sets?.length || 2),
    durationSec: ex.sets?.[0]?.durationSec ?? 40,
    reps: ex.sets?.[0]?.reps,
  }));
}

export function estimateSessionMinutesWithCustom(day: DayPlan, custom: ExerciseCustomConfig[] | undefined): number {
  if (!custom || custom.length === 0) return estimateSessionMinutes(day);
  const restSec = 15; // 估算默认休息
  const totalSec = custom.reduce((sum, c) => {
    if (!c.enabled) return sum;
    const perSet = (c.durationSec ?? 40) + restSec;
    return sum + perSet * Math.max(1, c.sets);
  }, 0);
  return Math.max(5, Math.round(totalSec / 60));
}