import { useEffect, useMemo, useState } from 'react';
import { Link } from 'framework7-react';
import { apiClient, ActivityDetail, errorMessage } from '../services/api';
import Screen from '../components/Screen';
import AiPanel from '../components/AiPanel';
import { FEATURES } from '../features';
import Chart from '../components/charts/Chart';
import Skeleton from '../components/Skeleton';
import './ActivityDetail.css';

type Tab = 'overview' | 'stats' | 'laps' | 'charts';
type Axis = 'time' | 'distance';

const TABS: Array<[Tab, string]> = [
  ['overview', '概览'], ['stats', '数据'], ['laps', '分段'], ['charts', '图表'],
];

const TYPE_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', badminton: '羽毛球',
  yoga: '瑜伽', mountaineering: '登山', elliptical: '椭圆机', rowing: '划船',
  open_water_swimming: '公开水域游泳', stair_climbing: '爬楼梯',
  fitness_equipment: '健身器械',
};

/* Garmin's primary-benefit labels. UNKNOWN is its sentinel for "no verdict"
   — usually a session too short or too easy to classify — and must not be
   printed as if it were one. */
const BENEFIT: Record<string, string | undefined> = {
  RECOVERY: '恢复', BASE: '基础耐力', TEMPO: '节奏', THRESHOLD: '乳酸阈值',
  VO2MAX: '最大摄氧量', ANAEROBIC_CAPACITY: '无氧能力', SPRINT: '冲刺',
  AEROBIC_BASE: '有氧基础', LACTATE_THRESHOLD: '乳酸阈值',
  UNKNOWN: undefined, NO_BENEFIT: undefined,
};

/* --- formatting ---------------------------------------------------------- */

const hms = (seconds?: number | null) => {
  if (seconds == null) return '—';
  const s = Math.round(seconds);
  const h = Math.floor(s / 3600);
  const m = Math.floor((s % 3600) / 60);
  const sec = s % 60;
  const pad = (n: number) => String(n).padStart(2, '0');
  return h > 0 ? `${h}:${pad(m)}:${pad(sec)}` : `${m}:${pad(sec)}`;
};

/** Pace from speed in m/s, as mm:ss per km — the reading runners actually use. */
const pace = (metresPerSecond?: number | null) => {
  if (!metresPerSecond) return '—';
  const secondsPerKm = 1000 / metresPerSecond;
  const m = Math.floor(secondsPerKm / 60);
  const s = Math.round(secondsPerKm % 60);
  return `${m}:${String(s).padStart(2, '0')} /km`;
};

const kmh = (metresPerSecond?: number | null) =>
  metresPerSecond == null ? '—' : `${(metresPerSecond * 3.6).toFixed(1)} km/h`;

const num = (v?: number | null, digits = 0, unit = '') =>
  v == null ? '—' : `${v.toLocaleString(undefined, {
    minimumFractionDigits: digits, maximumFractionDigits: digits,
  })}${unit ? ` ${unit}` : ''}`;

const km = (metres?: number | null) =>
  metres == null ? '—' : `${(metres / 1000).toFixed(2)} km`;

/* Groups mirror the watch app's Stats tab, so a value sits where it is
   expected. A group with nothing recorded is dropped rather than shown empty. */
function statGroups(s: Record<string, any>) {
  return [
    ['配速', [
      ['平均配速', pace(s.averageSpeed)],
      ['移动平均配速', pace(s.averageMovingSpeed)],
      ['最快配速', pace(s.maxSpeed)],
    ]],
    ['速度', [
      ['平均速度', kmh(s.averageSpeed)],
      ['移动平均速度', kmh(s.averageMovingSpeed)],
      ['最高速度', kmh(s.maxSpeed)],
    ]],
    ['计时', [
      ['总时间', hms(s.duration)],
      ['移动时间', hms(s.movingDuration)],
      ['流逝时间', hms(s.elapsedDuration)],
    ]],
    ['心率', [
      ['平均心率', num(s.averageHR, 0, 'bpm')],
      ['最高心率', num(s.maxHR, 0, 'bpm')],
    ]],
    ['训练效果', [
      ['主要收益', BENEFIT[s.trainingEffectLabel] ?? '—'],
      ['有氧', num(s.trainingEffect, 1)],
      ['无氧', num(s.anaerobicTrainingEffect, 1)],
      ['运动负荷', num(s.activityTrainingLoad, 0)],
    ]],
    ['营养与补水', [
      ['静息消耗', num(s.bmrCalories, 0, 'kcal')],
      ['活动消耗', num(
        s.calories != null && s.bmrCalories != null
          ? s.calories - s.bmrCalories : null, 0, 'kcal')],
      ['总消耗', num(s.calories, 0, 'kcal')],
      ['预估出汗量', num(s.waterEstimated, 0, 'ml')],
    ]],
    ['温度', [
      ['平均温度', num(s.averageTemperature, 0, '°C')],
      ['最低温度', num(s.minTemperature, 0, '°C')],
      ['最高温度', num(s.maxTemperature, 0, '°C')],
    ]],
    ['强度分钟', [
      ['中等', num(s.moderateIntensityMinutes, 0, '分钟')],
      ['高强度', num(s.vigorousIntensityMinutes, 0, '分钟')],
      ['合计', num(
        (s.moderateIntensityMinutes ?? 0) + (s.vigorousIntensityMinutes ?? 0) || null,
        0, '分钟')],
    ]],
    ['海拔', [
      ['总爬升', num(s.elevationGain, 0, 'm')],
      ['总下降', num(s.elevationLoss, 0, 'm')],
      ['最低海拔', num(s.minElevation, 0, 'm')],
      ['最高海拔', num(s.maxElevation, 0, 'm')],
    ]],
    ['步频', [
      ['平均步频', num(s.averageRunCadence ?? s.averageBikeCadence, 0, 'spm')],
      ['最高步频', num(s.maxRunCadence ?? s.maxBikeCadence, 0, 'spm')],
    ]],
    ['功率', [
      ['平均功率', num(s.averagePower, 0, 'W')],
      ['最大功率', num(s.maxPower, 0, 'W')],
      ['标准化功率', num(s.normPower, 0, 'W')],
    ]],
  ] as Array<[string, Array<[string, string]>]>;
}

/* --- heart-rate zones ---------------------------------------------------- */

const ZONE_NAME = ['', '热身', '轻松', '有氧', '阈值', '最大'];

function Zones({ zones, duration }: {
  zones: ActivityDetail['hrZones'];
  duration?: number | null;
}) {
  const inZones = zones.reduce((sum, z) => sum + (z.seconds || 0), 0);
  if (!inZones) return null;

  /* The share is of the whole activity, not of the time that landed in a zone.
     Dividing by the zone sum drops the minutes spent below zone 1 and inflates
     everything: a walk with 23:03 in zone 1 out of 44:06 is 52%, which is what
     the watch shows, not the 90% that the zone-sum denominator produces. */
  const total = duration && duration >= inZones ? duration : inZones;

  return (
    <section className="sec">
      <h3 className="sec-title">心率区间</h3>
      <div className="zones">
        {[...zones].reverse().map((z) => {
          const share = total ? (z.seconds / total) * 100 : 0;
          return (
            <div className="zone" key={z.zone}>
              <div className="zone-head">
                <span className="zone-name">
                  区间 {z.zone}
                  <span className="zone-range">
                    {z.lowBoundary != null ? `≥ ${Math.round(z.lowBoundary)} bpm` : ''}
                    {ZONE_NAME[z.zone] ? ` · ${ZONE_NAME[z.zone]}` : ''}
                  </span>
                </span>
                <span className="zone-time">
                  {hms(z.seconds)}<span className="zone-pct">{Math.round(share)}%</span>
                </span>
              </div>
              <div className="zone-bar">
                <div
                  className={`zone-fill z${z.zone}`}
                  style={{ width: `${share}%` }}
                />
              </div>
            </div>
          );
        })}
      </div>
    </section>
  );
}

/* --- page ---------------------------------------------------------------- */

interface Props {
  id?: string;
  f7route?: { params: { id: string } };
}

function ActivityDetailPage({ id, f7route }: Props) {
  const activityId = id ?? f7route?.params.id ?? '';
  const [detail, setDetail] = useState<ActivityDetail | null>(null);
  const [tab, setTab] = useState<Tab>('overview');
  const [axis, setAxis] = useState<Axis>('time');
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState('');
  const [needsSync, setNeedsSync] = useState(false);

  useEffect(() => {
    let cancelled = false;
    apiClient
      .getActivityDetail(activityId)
      .then((d) => { if (!cancelled) setDetail(d); })
      .catch((err) => {
        if (cancelled) return;
        // Not yet synced is an ordinary state with an obvious next step, not
        // a failure to apologise for.
        if (err?.response?.status === 404 && err.response.data?.needsSync) {
          setNeedsSync(true);
        } else {
          setError(errorMessage(err, '加载失败'));
        }
      })
      .finally(() => { if (!cancelled) setLoading(false); });
    return () => { cancelled = true; };
  }, [activityId]);

  /* The series arrive as parallel arrays; recharts wants one row per sample.
     The x value is whichever axis is selected, formatted for reading. */
  const chartRows = useMemo(() => {
    if (!detail) return [];
    const s = detail.series;
    const length = Math.max(...Object.values(s).map((a) => a.length), 0);
    if (!length) return [];

    const elapsed = s.elapsed ?? s.duration;
    return Array.from({ length }, (_, i) => ({
      x: axis === 'distance'
        ? s.distance?.[i] != null ? +(s.distance[i]! / 1000).toFixed(2) : null
        : elapsed?.[i] != null ? Math.round(elapsed[i]! / 60) : i,
      heartRate: s.heartRate?.[i] ?? null,
      speed: s.speed?.[i] != null ? +(s.speed[i]! * 3.6).toFixed(1) : null,
      elevation: s.elevation?.[i] ?? null,
      cadence: s.cadence?.[i] ?? null,
      temperature: s.temperature?.[i] ?? null,
      power: s.power?.[i] ?? null,
    })).filter((row) => row.x != null);
  }, [detail, axis]);

  const title = detail
    ? detail.activityName
      || TYPE_LABEL[detail.activityType ?? '']
      || detail.activityType
      || '运动'
    : '运动';

  if (loading) {
    return (
      <Screen title="运动详情" backLink>
        <Skeleton count={4} />
      </Screen>
    );
  }

  if (needsSync) {
    return (
      <Screen title="运动详情" backLink>
        <div className="screen-empty">
          <p>这条运动的详细数据还没同步到本机。</p>
          <Link href="/sync/" className="button button-fill button-round">
            去同步
          </Link>
        </div>
      </Screen>
    );
  }

  if (error || !detail) {
    return (
      <Screen title="运动详情" backLink>
        <div className="screen-error">{error || '加载失败'}</div>
      </Screen>
    );
  }

  const s = detail.summary as Record<string, any>;
  const hasDistance = !!detail.series.distance?.some((v) => v != null);

  const charts: Array<[string, string, string, 'area' | 'line', number]> = [
    ['heartRate', '心率', 'bpm', 'area', 1],
    ['speed', '速度', 'km/h', 'area', 2],
    ['elevation', '海拔', 'm', 'area', 3],
    ['cadence', '步频', 'spm', 'line', 4],
    ['power', '功率', 'W', 'line', 5],
    ['temperature', '温度', '°C', 'line', 6],
  ];

  return (
    <Screen title={title} subtitle={s.startTimeLocal?.slice(0, 16).replace('T', ' ')} backLink>
      {FEATURES.ai && <AiPanel scope="activity" subject={activityId} title="AI 本次运动解读" />}
      <div className="metric-tabs">
        {TABS.map(([tabId, text]) => (
          <button
            key={tabId}
            className={`metric-tab ${tab === tabId ? 'active' : ''}`}
            onClick={() => setTab(tabId)}
          >
            {text}
          </button>
        ))}
      </div>

      {tab === 'overview' && (
        <>
          <section className="ad-hero">
            <div className="ad-hero-main">
              <span className="ad-hero-value">
                {s.distance ? (s.distance / 1000).toFixed(2) : hms(s.duration)}
              </span>
              <span className="ad-hero-unit">{s.distance ? 'km' : ''}</span>
            </div>
            <div className="ad-hero-label">{s.distance ? '距离' : '总时间'}</div>
          </section>

          <div className="ad-grid">
            {[
              ['总时间', hms(s.duration)],
              ['平均心率', num(s.averageHR, 0, 'bpm')],
              ['平均速度', kmh(s.averageSpeed)],
              ['总消耗', num(s.calories, 0, 'kcal')],
              ['总爬升', num(s.elevationGain, 0, 'm')],
              ['有氧效果', num(s.trainingEffect, 1)],
            ].map(([label, value]) => (
              <div className="ad-tile" key={label}>
                <span className="ad-tile-value">{value}</span>
                <span className="ad-tile-label">{label}</span>
              </div>
            ))}
          </div>

          {BENEFIT[s.trainingEffectLabel] && (
            <section className="sec">
              <h3 className="sec-title">评估</h3>
              <div className="ad-eval">
                <div className="ad-eval-name">{BENEFIT[s.trainingEffectLabel]}</div>
                <div className="ad-eval-note">主要收益</div>
              </div>
            </section>
          )}

          <Zones zones={detail.hrZones} duration={s.duration} />

          {!!detail.gear.length && (
            <section className="sec">
              <h3 className="sec-title">装备</h3>
              <div className="ad-gear">
                {detail.gear.map((g, i) => (
                  <div className="ad-gear-item" key={g.uuid ?? i}>
                    {g.displayName ?? g.customMakeModel ?? '装备'}
                  </div>
                ))}
              </div>
            </section>
          )}
        </>
      )}

      {tab === 'stats' && (
        <div className="ad-stats">
          {statGroups(s)
            .filter(([, rows]) => rows.some(([, v]) => v !== '—'))
            .map(([group, rows]) => (
              <section className="sec" key={group}>
                <h3 className="sec-title">{group}</h3>
                <div className="ad-rows">
                  {rows.filter(([, v]) => v !== '—').map(([label, value]) => (
                    <div className="ad-row" key={label}>
                      <span className="ad-row-label">{label}</span>
                      <span className="ad-row-value">{value}</span>
                    </div>
                  ))}
                </div>
              </section>
            ))}
        </div>
      )}

      {tab === 'laps' && (
        detail.laps.length === 0 ? (
          <p className="screen-note">这次运动没有分段记录。</p>
        ) : (
          <div className="table-wrap">
            <table className="data-table">
              <thead>
                <tr>
                  <th scope="col">分段</th>
                  <th scope="col">时间</th>
                  <th scope="col">距离</th>
                  <th scope="col">平均速度</th>
                  <th scope="col">平均心率</th>
                </tr>
              </thead>
              <tbody>
                {detail.laps.map((lap) => (
                  <tr key={lap.index}>
                    <th scope="row">{lap.index}</th>
                    <td>{hms(lap.duration)}</td>
                    <td className="num">{km(lap.distance)}</td>
                    <td className="num">{kmh(lap.averageSpeed)}</td>
                    <td className="num">{num(lap.averageHR, 0)}</td>
                  </tr>
                ))}
                <tr className="ad-total">
                  <th scope="row">合计</th>
                  <td>{hms(s.duration)}</td>
                  <td className="num">{km(s.distance)}</td>
                  <td className="num">{kmh(s.averageSpeed)}</td>
                  <td className="num">{num(s.averageHR, 0)}</td>
                </tr>
              </tbody>
            </table>
          </div>
        )
      )}

      {tab === 'charts' && (
        chartRows.length === 0 ? (
          <p className="screen-note">这次运动没有采样曲线。</p>
        ) : (
          <>
            {hasDistance && (
              <div className="segmented-row">
                <span className="segmented-label">横轴</span>
                <div className="segmented">
                  <button className={axis === 'time' ? 'on' : ''} onClick={() => setAxis('time')}>
                    时间
                  </button>
                  <button className={axis === 'distance' ? 'on' : ''} onClick={() => setAxis('distance')}>
                    距离
                  </button>
                </div>
              </div>
            )}

            <div className="chart-grid">
              {charts
                .filter(([key]) => chartRows.some((r) => (r as any)[key] != null))
                .map(([key, label, unit, type, slot]) => (
                  <Chart
                    key={key}
                    title={label}
                    unit={unit}
                    data={chartRows}
                    xKey="x"
                    type={type}
                    height={190}
                    series={[{
                      key, label, slot: slot as 1 | 2 | 3 | 4 | 5 | 6,
                      unit, decimals: key === 'speed' ? 1 : 0,
                    }]}
                    footer={axis === 'time' ? '横轴：分钟' : '横轴：公里'}
                  />
                ))}
            </div>
          </>
        )
      )}
    </Screen>
  );
}

export default ActivityDetailPage;