import { useCallback, useDeferredValue, useEffect, useMemo, useState } from 'react';
import { AlertTriangle, ChevronLeft, Clock3, Fuel, Maximize2, Minimize2, SlidersHorizontal } from 'lucide-react';
import HydrogenAmapCanvas from './HydrogenAmapCanvas';
import HydrogenHeatmapDetailPanel from './HydrogenHeatmapDetailPanel';
import HydrogenHeatmapFilters from './HydrogenHeatmapFilters';
import { fetchAmapConfig, fetchHydrogenHeatmapMeta, fetchHydrogenHeatmapPoints, fetchNearbyHydrogenStations } from './api';
import { recentDayRange } from '../../shared/date-range';
import type { AmapConfig, HydrogenHeatmapMeta, HydrogenHeatmapMetric, HydrogenHeatmapResponse, HydrogenNearbyResponse, HydrogenPayer } from './types';

// 接口返回数据水位前的兜底范围：近 30 天滚动窗口（不再写死历史区间）。
const FALLBACK_RANGE = recentDayRange(30);
const integerFormat = new Intl.NumberFormat('zh-CN');
const kgFormat = new Intl.NumberFormat('zh-CN', { maximumFractionDigits: 1 });

function Metric({ value, label }: { value: string; label: string }) {
  return (
    <div className="min-w-[88px] text-center max-md:min-w-[68px]">
      <p className="text-[21px] font-semibold leading-none tracking-tight text-cyan-700 tabular-nums max-md:text-[16px]">{value}</p>
      <p className="mt-1.5 text-[11px] text-slate-500 max-md:mt-1 max-md:text-[9px]">{label}</p>
    </div>
  );
}

function metricName(metric: HydrogenHeatmapMetric) {
  if (metric === 'refuels') return '加氢频次';
  if (metric === 'vehicles') return '车辆覆盖';
  return '加氢量强度';
}

function metricDescription(metric: HydrogenHeatmapMetric) {
  if (metric === 'refuels') return '每个站点累计有效加氢订单数；平方根平滑强度。';
  if (metric === 'vehicles') return '每个站点按车牌去重统计车辆数；平方根平滑强度。';
  return '每个站点累计有效加氢量（kg）；对数平滑强度。';
}

export default function HydrogenHeatmapModule() {
  const [meta, setMeta] = useState<HydrogenHeatmapMeta | null>(null);
  const [config, setConfig] = useState<AmapConfig | null>(null);
  const [data, setData] = useState<HydrogenHeatmapResponse | null>(null);
  const [nearby, setNearby] = useState<HydrogenNearbyResponse | null>(null);
  const [startDate, setStartDate] = useState(FALLBACK_RANGE.start);
  const [endDate, setEndDate] = useState(FALLBACK_RANGE.end);
  const [query, setQuery] = useState('');
  const [payer, setPayer] = useState<HydrogenPayer>('all');
  const [metric, setMetric] = useState<HydrogenHeatmapMetric>('kg');
  const [isFullscreen, setIsFullscreen] = useState(false);
  const [showFilters, setShowFilters] = useState(() => typeof window === 'undefined' || !window.matchMedia('(max-width: 767px)').matches);
  const [showDetails, setShowDetails] = useState(() => typeof window === 'undefined' || !window.matchMedia('(max-width: 767px)').matches);
  const [loading, setLoading] = useState(true);
  const [nearbyLoading, setNearbyLoading] = useState(false);
  const [error, setError] = useState('');
  const deferredQuery = useDeferredValue(query.trim());

  useEffect(() => {
    if (!isFullscreen) return undefined;
    const previousOverflow = document.body.style.overflow;
    const handleKeyDown = (event: KeyboardEvent) => {
      if (event.key === 'Escape') setIsFullscreen(false);
    };
    document.body.style.overflow = 'hidden';
    document.addEventListener('keydown', handleKeyDown);
    return () => {
      document.body.style.overflow = previousOverflow;
      document.removeEventListener('keydown', handleKeyDown);
    };
  }, [isFullscreen]);

  useEffect(() => {
    const controller = new AbortController();
    Promise.all([fetchHydrogenHeatmapMeta(controller.signal), fetchAmapConfig(controller.signal)])
      .then(([nextMeta, nextConfig]) => {
        setMeta(nextMeta);
        setConfig(nextConfig);
        setStartDate(nextMeta.startDate);
        setEndDate(nextMeta.endDate);
      })
      .catch((requestError) => {
        if (requestError?.name !== 'AbortError') setError('加氢热力图基础配置加载失败');
      });
    return () => controller.abort();
  }, []);

  useEffect(() => {
    const controller = new AbortController();
    const timer = window.setTimeout(() => {
      setLoading(true);
      setError('');
      fetchHydrogenHeatmapPoints({ startDate, endDate, query: deferredQuery, payer, metric }, controller.signal)
        .then((response) => {
          setData(response);
          setNearby(null);
        })
        .catch((requestError) => {
          if (requestError?.name !== 'AbortError') setError('加氢热力图数据加载失败，请稍后重试');
        })
        .finally(() => setLoading(false));
    }, 220);
    return () => {
      window.clearTimeout(timer);
      controller.abort();
    };
  }, [deferredQuery, endDate, metric, payer, startDate]);

  const handleMapClick = useCallback((longitude: number, latitude: number) => {
    const controller = new AbortController();
    setNearbyLoading(true);
    fetchNearbyHydrogenStations({ lng: longitude, lat: latitude, startDate, endDate, query: deferredQuery, payer, metric }, controller.signal)
      .then(setNearby)
      .catch((requestError) => {
        if (requestError?.name !== 'AbortError') setError('区域加氢站明细加载失败');
      })
      .finally(() => setNearbyLoading(false));
  }, [deferredQuery, endDate, metric, payer, startDate]);

  const reset = () => {
    setStartDate(meta?.startDate || FALLBACK_RANGE.start);
    setEndDate(meta?.endDate || FALLBACK_RANGE.end);
    setQuery('');
    setPayer('all');
    setMetric('kg');
    setNearby(null);
  };

  const coverageText = meta
    ? `GPS覆盖 ${(meta.gpsCoverageRate * 100).toFixed(3)}% · 已排除 ${integerFormat.format(meta.excludedRefuelCount)} 笔缺坐标数据`
    : '正在核对站点 GPS 覆盖率';

  const detail = useMemo(() => {
    if (nearby) {
      return {
        title: '选中区域',
        subtitle: `${nearby.center.lng.toFixed(3)}, ${nearby.center.lat.toFixed(3)} · 半径 ${nearby.radiusKm} 公里`,
        kg: nearby.kg,
        refuelCount: nearby.refuelCount,
        vehicleCount: nearby.vehicleCount,
        stationCount: nearby.stationCount,
        stations: nearby.topStations,
        selected: true,
      };
    }
    return {
      title: deferredQuery ? '站点筛选结果' : '全国 · 当前范围',
      subtitle: `${payer === 'all' ? '' : `${payer === 'lingniu' ? '羚牛承担' : '客户承担'} · `}${startDate} ～ ${endDate}`,
      kg: data?.kg || 0,
      refuelCount: data?.refuelCount || 0,
      vehicleCount: data?.vehicleCount || 0,
      stationCount: data?.stationCount || 0,
      stations: data?.topStations || [],
      selected: false,
    };
  }, [data, deferredQuery, endDate, nearby, payer, startDate]);

  return (
    <section className={`flex flex-col overflow-hidden bg-white ${isFullscreen ? 'fixed inset-0 z-[100] h-screen w-screen min-h-0' : 'h-[100dvh] min-h-[620px] max-md:h-[calc(100dvh-4rem)] max-md:min-h-[520px]'}`}>
      <header className="relative z-30 flex min-h-[98px] shrink-0 items-center justify-between border-b border-slate-200 bg-white px-8 max-md:min-h-[104px] max-md:flex-wrap max-md:gap-y-2 max-md:px-3 max-md:py-3">
        <div className="min-w-0">
          <h1 className="truncate text-[25px] font-semibold tracking-[-0.025em] text-slate-950 max-md:text-[18px]">加氢站加氢热力图</h1>
          <p className="mt-1.5 flex items-center gap-1.5 text-[11px] text-slate-400 max-md:mt-1 max-md:text-[9px]"><Fuel size={13} />加氢账本 × 加氢站 GPS · 上海时区</p>
        </div>
        <div className="absolute left-1/2 top-1/2 flex -translate-x-1/2 -translate-y-1/2 items-center gap-7 max-md:order-3 max-md:static max-md:w-full max-md:translate-x-0 max-md:translate-y-0 max-md:justify-center max-md:gap-2">
          <Metric value={kgFormat.format(data?.kg ?? meta?.eligibleKg ?? 0)} label="加氢量 kg" />
          <span className="h-8 w-px bg-slate-200" />
          <Metric value={integerFormat.format(data?.refuelCount ?? meta?.eligibleRefuelCount ?? 0)} label="加氢次数" />
          <span className="h-8 w-px bg-slate-200" />
          <Metric value={integerFormat.format(data?.stationCount ?? meta?.eligibleStationCount ?? 0)} label="站点" />
        </div>
        <div className="flex items-center gap-3">
          <p className="flex items-center gap-2 text-[12px] text-slate-500 max-xl:hidden"><Clock3 size={15} strokeWidth={1.7} />数据更新至 {meta?.endDate || FALLBACK_RANGE.end}</p>
          <button type="button" onClick={() => setIsFullscreen((current) => !current)} className="grid h-9 w-9 place-items-center rounded-lg border border-slate-200 text-slate-500 transition hover:border-cyan-300 hover:bg-cyan-50 hover:text-cyan-700" title={isFullscreen ? '退出全屏' : '地图全屏'} aria-label={isFullscreen ? '退出加氢地图全屏' : '加氢地图全屏'} aria-pressed={isFullscreen}>
            {isFullscreen ? <Minimize2 size={17} /> : <Maximize2 size={17} />}
          </button>
        </div>
      </header>

      <div className="relative flex min-h-0 flex-1">
        <div className="relative z-0 min-w-0 flex-1 overflow-hidden">
          {config ? <HydrogenAmapCanvas config={config} points={data?.points || []} max={data?.max || 1} metric={metric} focusQuery={deferredQuery} onMapClick={handleMapClick} /> : <div className="absolute inset-0 bg-slate-100" />}

          {showFilters ? (
            <div className="pointer-events-none absolute left-3 right-3 top-3 z-10 md:left-5 md:right-auto md:top-5">
              <HydrogenHeatmapFilters
                startDate={startDate}
                endDate={endDate}
                minDate={meta?.startDate || FALLBACK_RANGE.start}
                maxDate={meta?.endDate || FALLBACK_RANGE.end}
                query={query}
                payer={payer}
                metric={metric}
                stations={meta?.stations || []}
                onStartDateChange={setStartDate}
                onEndDateChange={setEndDate}
                onQueryChange={setQuery}
                onPayerChange={setPayer}
                onMetricChange={setMetric}
                onReset={reset}
                onHide={() => setShowFilters(false)}
              />
            </div>
          ) : (
            <button type="button" onClick={() => setShowFilters(true)} aria-label="显示加氢筛选" className="absolute left-3 top-3 z-20 flex h-11 items-center gap-2 rounded-lg border border-slate-200 bg-white/95 px-3 text-xs font-medium text-slate-600 shadow-lg backdrop-blur-sm transition hover:border-cyan-300 hover:bg-cyan-50 hover:text-cyan-700 md:left-5 md:top-5 md:h-10"><SlidersHorizontal size={15} strokeWidth={1.8} />显示筛选</button>
          )}

          {!showDetails ? (
            <button type="button" onClick={() => setShowDetails(true)} aria-label="显示加氢详情" className={`absolute right-3 top-3 z-20 flex h-11 items-center gap-2 rounded-lg border border-slate-200 bg-white/95 px-3 text-xs font-medium text-slate-600 shadow-lg backdrop-blur-sm transition hover:border-cyan-300 hover:bg-cyan-50 hover:text-cyan-700 md:right-5 md:top-5 md:h-10 ${showFilters ? 'max-md:hidden' : ''}`}><ChevronLeft size={16} strokeWidth={1.8} />显示详情</button>
          ) : null}

          <div className="pointer-events-none absolute bottom-5 left-5 z-10 w-[300px] rounded-xl border border-slate-200/80 bg-white/95 p-3.5 shadow-[0_8px_30px_rgba(15,23,42,0.11)] backdrop-blur-sm max-lg:bottom-[calc(43vh+16px)] max-md:hidden">
            <div className="flex items-center justify-between text-[11px] font-medium text-slate-700"><span>{metricName(metric)}</span>{loading ? <i className="h-3 w-3 animate-spin rounded-full border-2 border-cyan-600 border-t-transparent" /> : null}</div>
            <p className="mt-1 text-[10px] leading-4 text-slate-500">{metricDescription(metric)}</p>
            <div className="mt-2.5 h-2.5 rounded-full bg-[linear-gradient(90deg,#2563eb_0%,#0891b2_25%,#16a34a_45%,#eab308_65%,#f97316_82%,#dc2626_100%)]" />
            <div className="mt-1.5 flex justify-between text-[10px] text-slate-400"><span>相对较低</span><span>相对较高</span></div>
          </div>

          {error ? <div className="absolute bottom-5 left-1/2 z-30 flex -translate-x-1/2 items-center gap-2 rounded-lg bg-slate-900 px-4 py-2.5 text-xs text-white shadow-xl"><AlertTriangle size={15} className="text-amber-300" />{error}</div> : null}
        </div>

        {showDetails ? (
          <HydrogenHeatmapDetailPanel {...detail} metric={metric} loading={nearbyLoading} coverageText={coverageText} onClose={() => setNearby(null)} onHide={() => setShowDetails(false)} />
        ) : null}
      </div>
    </section>
  );
}