import { useCallback, useEffect, useMemo, useState } from 'react';
import { apiClient, Activity, errorMessage, HealthDay } from '../services/api';
import Skeleton from '../components/Skeleton';
import './Daily.css';
import './Pages.css';

/** Every stored metric, grouped the way the device groups them. */
interface Field {
  key: keyof HealthDay | 'sleepDeep' | 'sleepLight' | 'sleepRem' | 'sleepAwake';
  label: string;
  unit?: string;
  /** Convert the raw stored value for display. */
  transform?: (v: number) => number;
  decimals?: number;
  hint?: string;
}

const SECONDS_TO_HOURS = (v: number) => v / 3600;
const SECONDS_TO_MINUTES = (v: number) => v / 60;

const GROUPS: Array<{ title: string; fields: Field[] }> = [
  {
    title: '活动',
    fields: [
      { key: 'steps', label: '步数', unit: '步' },
      { key: 'stepGoal', label: '步数目标', unit: '步' },
      { key: 'distanceMeters', label: '距离', unit: 'km', transform: (v) => v / 1000, decimals: 2 },
      { key: 'floorsAscended', label: '爬楼上行', unit: '层' },
      { key: 'floorsDescended', label: '爬楼下行', unit: '层' },
      { key: 'intensityMinutes', label: '强度分钟', unit: '分钟', hint: '中等及以上强度' },
      { key: 'activeSeconds', label: '活动时长', unit: '小时', transform: SECONDS_TO_HOURS, decimals: 1 },
      { key: 'sedentarySeconds', label: '久坐时长', unit: '小时', transform: SECONDS_TO_HOURS, decimals: 1 },
    ],
  },
  {
    title: '能量',
    fields: [
      { key: 'caloriesBurned', label: '总消耗', unit: 'kcal' },
      { key: 'activeCalories', label: '活动消耗', unit: 'kcal' },
      { key: 'bmrCalories', label: '基础代谢', unit: 'kcal' },
    ],
  },
  {
    title: '心率',
    fields: [
      { key: 'heartRate', label: '静息心率', unit: 'bpm' },
      { key: 'heartRateMin', label: '最低心率', unit: 'bpm' },
      { key: 'heartRateMax', label: '最高心率', unit: 'bpm' },
      { key: 'heartRateVariability', label: '心率变异性', unit: 'ms', decimals: 1, hint: 'HRV，反映恢复情况' },
    ],
  },
  {
    title: '压力与身体电量',
    fields: [
      { key: 'stress', label: '平均压力' },
      { key: 'stressMax', label: '最高压力' },
      { key: 'bodyBatteryHigh', label: '身体电量最高' },
      { key: 'bodyBatteryLow', label: '身体电量最低' },
      { key: 'bodyBatteryCharged', label: '当日充能' },
      { key: 'bodyBatteryDrained', label: '当日消耗' },
    ],
  },
  {
    title: '睡眠',
    fields: [
      { key: 'sleepDuration', label: '总时长', unit: '小时', decimals: 1 },
      { key: 'sleepQuality', label: '睡眠评分', unit: '/100' },
      { key: 'sleepDeep', label: '深睡', unit: '分钟', transform: SECONDS_TO_MINUTES },
      { key: 'sleepLight', label: '浅睡', unit: '分钟', transform: SECONDS_TO_MINUTES },
      { key: 'sleepRem', label: 'REM', unit: '分钟', transform: SECONDS_TO_MINUTES },
      { key: 'sleepAwake', label: '夜间清醒', unit: '分钟', transform: SECONDS_TO_MINUTES },
      { key: 'sleepSpo2Avg', label: '睡眠血氧', unit: '%', decimals: 1 },
      { key: 'sleepRespirationAvg', label: '睡眠呼吸', unit: '次/分', decimals: 1 },
      { key: 'sleepStressAvg', label: '睡眠压力', decimals: 1 },
    ],
  },
  {
    title: '血氧与呼吸',
    fields: [
      { key: 'spo2Avg', label: '平均血氧', unit: '%', decimals: 1 },
      { key: 'spo2Min', label: '最低血氧', unit: '%' },
      { key: 'respirationAvg', label: '平均呼吸', unit: '次/分', decimals: 1 },
      { key: 'respirationMin', label: '最低呼吸', unit: '次/分', decimals: 1 },
      { key: 'respirationMax', label: '最高呼吸', unit: '次/分', decimals: 1 },
    ],
  },
  {
    title: '训练',
    fields: [
      { key: 'trainingReadiness', label: '训练准备度', unit: '/100' },
      { key: 'vo2max', label: 'VO2max', decimals: 1 },
      { key: 'enduranceScore', label: '耐力分' },
    ],
  },
];

const ACTIVITY_LABEL: Record<string, string> = {
  running: '跑步', cycling: '骑行', walking: '步行', hiking: '徒步',
  swimming: '游泳', table_tennis: '乒乓球', strength_training: '力量训练',
  indoor_cycling: '室内骑行', treadmill_running: '跑步机',
};

function valueOf(day: HealthDay, key: Field['key']): number | null {
  if (key === 'sleepDeep') return day.sleep?.deepSeconds ?? null;
  if (key === 'sleepLight') return day.sleep?.lightSeconds ?? null;
  if (key === 'sleepRem') return day.sleep?.remSeconds ?? null;
  if (key === 'sleepAwake') return day.sleep?.awakeSeconds ?? null;
  const v = (day as any)[key];
  return typeof v === 'number' ? v : null;
}

const iso = (d: Date) => d.toISOString().slice(0, 10);

function Daily() {
  const [date, setDate] = useState(() => iso(new Date()));
  const [day, setDay] = useState<HealthDay | null>(null);
  const [activities, setActivities] = useState<Activity[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState('');
  const [onlyRecorded, setOnlyRecorded] = useState(true);

  const load = useCallback(async (target: string) => {
    setLoading(true);
    setError('');
    try {
      const [summary, acts] = await Promise.all([
        apiClient.getHealthSummary(target, target),
        apiClient.getActivities(target, target),
      ]);
      setDay(summary[0] ?? null);
      setActivities(acts);
    } catch (err: any) {
      setError(errorMessage(err, '加载失败'));
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => { load(date); }, [date, load]);

  const shift = (delta: number) => {
    const d = new Date(date);
    d.setDate(d.getDate() + delta);
    if (d > new Date()) return;
    setDate(iso(d));
  };

  const recorded = useMemo(() => {
    if (!day) return 0;
    return GROUPS.reduce(
      (n, g) => n + g.fields.filter((f) => valueOf(day, f.key) != null).length, 0
    );
  }, [day]);

  const totalFields = GROUPS.reduce((n, g) => n + g.fields.length, 0);
  const isToday = date === iso(new Date());

  const fmt = (f: Field, raw: number) => {
    const v = f.transform ? f.transform(raw) : raw;
    const decimals = f.decimals ?? 0;
    return v.toLocaleString(undefined, {
      minimumFractionDigits: 0,
      maximumFractionDigits: decimals,
    });
  };

  return (
    <div className="page">
      <header className="page-head">
        <div>
          <h2>每日数据</h2>
          <p className="subtitle">
            {day
              ? `已记录 ${recorded} / ${totalFields} 项指标`
              : '该日无数据'}
          </p>
        </div>

        <div className="day-nav">
          <button className="btn btn-plain" onClick={() => shift(-1)} aria-label="前一天">
            ‹ 前一天
          </button>
          <input
            type="date"
            className="day-input"
            value={date}
            max={iso(new Date())}
            onChange={(e) => e.target.value && setDate(e.target.value)}
          />
          <button
            className="btn btn-plain"
            onClick={() => shift(1)}
            disabled={isToday}
            aria-label="后一天"
          >
            后一天 ›
          </button>
        </div>
      </header>

      {error && <div className="error-message">{error}</div>}
      {loading && <Skeleton count={8} variant="row" />}

      {!loading && !error && !day && (
        <div className="empty-state">
          <p>{date} 没有数据。可能当天未佩戴设备，或尚未同步到这一天。</p>
        </div>
      )}

      {!loading && !error && day && (
        <>
          <label className="toggle-row">
            <input
              type="checkbox"
              checked={onlyRecorded}
              onChange={(e) => setOnlyRecorded(e.target.checked)}
            />
            只显示有数据的指标
          </label>

          {GROUPS.map((g) => {
            const fields = onlyRecorded
              ? g.fields.filter((f) => valueOf(day, f.key) != null)
              : g.fields;
            if (fields.length === 0) return null;
            return (
              <section className="section" key={g.title}>
                <h3 className="section-title">
                  {g.title}
                  <span className="section-count">{fields.length} 项</span>
                </h3>
                <dl className="metric-list">
                  {fields.map((f) => {
                    const raw = valueOf(day, f.key);
                    return (
                      <div className="metric-row" key={String(f.key)}>
                        <dt>
                          {f.label}
                          {f.hint && <span className="metric-hint">{f.hint}</span>}
                        </dt>
                        <dd>
                          {raw == null ? (
                            <span className="metric-empty">未记录</span>
                          ) : (
                            <>
                              <span className="metric-value">{fmt(f, raw)}</span>
                              {f.unit && <span className="metric-unit">{f.unit}</span>}
                            </>
                          )}
                        </dd>
                      </div>
                    );
                  })}
                </dl>
              </section>
            );
          })}

          <section className="section">
            <h3 className="section-title">
              运动记录
              <span className="section-count">{activities.length} 条</span>
            </h3>
            {activities.length === 0 ? (
              <p className="placeholder">当天没有运动记录。</p>
            ) : (
              <div className="table-wrap">
                <table className="data-table">
                  <thead>
                    <tr>
                      <th scope="col">开始</th>
                      <th scope="col">类型</th>
                      <th scope="col">时长</th>
                      <th scope="col">距离</th>
                      <th scope="col">消耗</th>
                      <th scope="col">平均心率</th>
                      <th scope="col">最高心率</th>
                    </tr>
                  </thead>
                  <tbody>
                    {activities.map((a) => (
                      <tr key={a.id}>
                        <th scope="row">{a.start_time?.slice(11, 16)}</th>
                        <td>
                          {ACTIVITY_LABEL[a.activity_type] ??
                            a.activity_type?.replace(/_/g, ' ')}
                        </td>
                        <td className="num">
                          {a.duration != null ? `${Math.round(a.duration / 60)} 分` : '—'}
                        </td>
                        <td className="num">
                          {a.distance ? `${(a.distance / 1000).toFixed(2)} km` : '—'}
                        </td>
                        <td className="num">
                          {a.calories != null ? Math.round(a.calories) : '—'}
                        </td>
                        <td className="num">{a.heart_rate_average ?? '—'}</td>
                        <td className="num">{a.heart_rate_max ?? '—'}</td>
                      </tr>
                    ))}
                  </tbody>
                </table>
              </div>
            )}
          </section>
        </>
      )}
    </div>
  );
}

export default Daily;