import { useEffect, useState } from 'react';
import {
  LineChart,
  Line,
  XAxis,
  YAxis,
  CartesianGrid,
  Tooltip,
  Legend,
  ResponsiveContainer,
  AreaChart,
  Area,
} from 'recharts';
import { useAnalysisStore } from '@/stores/analysisStore';
import { ErrorBanner } from '@/components/ErrorBanner';
import { TrendingUp, Calendar, Activity } from 'lucide-react';

const POLLUTANT_OPTIONS = [
  { key: 'aqi', label: 'AQI', color: '#2563EB', unit: '' },
  { key: 'pm25', label: 'PM2.5', color: '#DC2626', unit: 'μg/m³' },
  { key: 'pm10', label: 'PM10', color: '#D97706', unit: 'μg/m³' },
  { key: 'so2', label: 'SO₂', color: '#7C3AED', unit: 'μg/m³' },
  { key: 'no2', label: 'NO₂', color: '#059669', unit: 'μg/m³' },
  { key: 'co', label: 'CO', color: '#0891B2', unit: 'mg/m³' },
  { key: 'o3', label: 'O₃', color: '#EA580C', unit: 'μg/m³' },
];

const DAY_OPTIONS = [
  { label: '7天', value: 7 },
  { label: '14天', value: 14 },
  { label: '30天', value: 30 },
];

export function TrendAnalysis() {
  const trendData = useAnalysisStore((s) => s.trendData);
  const isLoading = useAnalysisStore((s) => s.isLoading);
  const error = useAnalysisStore((s) => s.error);
  const clearError = useAnalysisStore((s) => s.clearError);
  const selectedDays = useAnalysisStore((s) => s.selectedDays);
  const setSelectedDays = useAnalysisStore((s) => s.setSelectedDays);
  const fetchTrend = useAnalysisStore((s) => s.fetchTrend);
  const [selectedPollutants, setSelectedPollutants] = useState<string[]>(['aqi', 'pm25']);

  useEffect(() => {
    fetchTrend(selectedDays);
  }, [selectedDays, fetchTrend]);

  const togglePollutant = (key: string) => {
    setSelectedPollutants((prev) =>
      prev.includes(key) ? prev.filter((k) => k !== key) : [...prev, key]
    );
  };

  const formatDate = (dateStr: string) => {
    const d = new Date(dateStr);
    return `${d.getMonth() + 1}/${d.getDate()}`;
  };

  const latestData = trendData[trendData.length - 1];
  const firstData = trendData[0];

  const getChange = (key: string) => {
    if (!latestData || !firstData) return 0;
    const latest = latestData[key as keyof typeof latestData] as number;
    const first = firstData[key as keyof typeof firstData] as number;
    if (!first) return 0;
    return ((latest - first) / first) * 100;
  };

  return (
    <div>
      {error && (
        <ErrorBanner
          error={error}
          onRetry={() => { clearError(); fetchTrend(selectedDays); }}
          onDismiss={clearError}
        />
      )}
      <div className="mb-5">
        <h1 className="font-display text-[18px] font-semibold mb-1 flex items-center gap-2">
          <TrendingUp className="w-5 h-5 text-primary" />
          趋势分析
        </h1>
        <p className="text-[12px] text-text-muted">
          空气质量与污染物浓度时间序列分析
        </p>
      </div>

      <div className="flex flex-wrap items-center gap-4 mb-4">
        <div className="flex items-center gap-2">
          <Calendar className="w-4 h-4 text-text-muted" />
          <span className="text-[13px] text-text-secondary">时间范围:</span>
          <div className="flex gap-1 bg-bg-page p-0.5 rounded">
            {DAY_OPTIONS.map((opt) => (
              <button
                key={opt.value}
                onClick={() => setSelectedDays(opt.value)}
                className={`px-3 py-1 text-[12px] font-medium rounded transition-colors ${
                  selectedDays === opt.value
                    ? 'bg-bg-card text-primary shadow-sm'
                    : 'text-text-secondary hover:text-text-primary'
                }`}
              >
                {opt.label}
              </button>
            ))}
          </div>
        </div>
      </div>

      <div className="flex flex-wrap items-center gap-2 mb-4">
        <Activity className="w-4 h-4 text-text-muted" />
        <span className="text-[13px] text-text-secondary">指标选择:</span>
        {POLLUTANT_OPTIONS.map((p) => (
          <button
            key={p.key}
            onClick={() => togglePollutant(p.key)}
            className={`flex items-center gap-1.5 px-2.5 py-1 rounded text-[12px] font-medium transition-all ${
              selectedPollutants.includes(p.key)
                ? 'bg-bg-active text-text-primary'
                : 'bg-bg-page text-text-muted hover:text-text-secondary'
            }`}
          >
            <span
              className="w-2.5 h-2.5 rounded-full"
              style={{ backgroundColor: p.color }}
            />
            {p.label}
          </button>
        ))}
      </div>

      {isLoading && (
        <div className="mb-4 text-center py-8 bg-bg-card rounded-lg border border-border">
          <span className="text-text-secondary">数据加载中...</span>
        </div>
      )}

      <div className="card p-4 mb-4">
        <div className="text-[11px] font-medium text-text-muted uppercase tracking-wide mb-4">
          污染物浓度趋势
        </div>
        <ResponsiveContainer width="100%" height={360}>
          <LineChart data={trendData} margin={{ top: 5, right: 20, left: 10, bottom: 5 }}>
            <CartesianGrid strokeDasharray="3 3" stroke="#E2E8F0" />
            <XAxis
              dataKey="date"
              tickFormatter={formatDate}
              tick={{ fontSize: 12, fill: '#64748B' }}
              axisLine={{ stroke: '#E2E8F0' }}
            />
            <YAxis
              tick={{ fontSize: 12, fill: '#64748B' }}
              axisLine={{ stroke: '#E2E8F0' }}
            />
            <Tooltip
              contentStyle={{
                backgroundColor: '#FFFFFF',
                border: '1px solid #E2E8F0',
                borderRadius: '8px',
                fontSize: '12px',
              }}
              labelStyle={{ color: '#1E293B', fontWeight: 600 }}
            />
            <Legend
              wrapperStyle={{ fontSize: '12px', paddingTop: '12px' }}
            />
            {POLLUTANT_OPTIONS.filter((p) => selectedPollutants.includes(p.key)).map(
              (p) => (
                <Line
                  key={p.key}
                  type="monotone"
                  dataKey={p.key}
                  name={p.label}
                  stroke={p.color}
                  strokeWidth={2}
                  dot={{ r: 3, fill: p.color }}
                  activeDot={{ r: 5 }}
                />
              )
            )}
          </LineChart>
        </ResponsiveContainer>
      </div>

      {selectedPollutants.includes('aqi') && (
        <div className="card p-4 mb-4">
          <div className="text-[11px] font-medium text-text-muted uppercase tracking-wide mb-4">
            AQI 变化趋势
          </div>
          <ResponsiveContainer width="100%" height={240}>
            <AreaChart data={trendData} margin={{ top: 5, right: 20, left: 10, bottom: 5 }}>
              <defs>
                <linearGradient id="aqiGradient" x1="0" y1="0" x2="0" y2="1">
                  <stop offset="5%" stopColor="#2563EB" stopOpacity={0.3} />
                  <stop offset="95%" stopColor="#2563EB" stopOpacity={0.05} />
                </linearGradient>
              </defs>
              <CartesianGrid strokeDasharray="3 3" stroke="#E2E8F0" />
              <XAxis
                dataKey="date"
                tickFormatter={formatDate}
                tick={{ fontSize: 12, fill: '#64748B' }}
                axisLine={{ stroke: '#E2E8F0' }}
              />
              <YAxis
                tick={{ fontSize: 12, fill: '#64748B' }}
                axisLine={{ stroke: '#E2E8F0' }}
              />
              <Tooltip
                contentStyle={{
                  backgroundColor: '#FFFFFF',
                  border: '1px solid #E2E8F0',
                  borderRadius: '8px',
                  fontSize: '12px',
                }}
              />
              <Area
                type="monotone"
                dataKey="aqi"
                name="AQI"
                stroke="#2563EB"
                strokeWidth={2}
                fill="url(#aqiGradient)"
                dot={{ r: 3, fill: '#2563EB' }}
              />
            </AreaChart>
          </ResponsiveContainer>
        </div>
      )}

      {latestData && (
        <div className="grid grid-cols-4 gap-4">
          {POLLUTANT_OPTIONS.filter((p) => selectedPollutants.includes(p.key)).slice(0, 4).map((p) => {
            const value = latestData[p.key as keyof typeof latestData] as number;
            const change = getChange(p.key);
            return (
              <div key={p.key} className="card p-4">
                <div className="flex items-center gap-2 mb-2">
                  <span
                    className="w-2.5 h-2.5 rounded-full"
                    style={{ backgroundColor: p.color }}
                  />
                  <span className="text-[11px] font-medium text-text-muted uppercase tracking-wide">
                    {p.label}
                  </span>
                </div>
                <div className="font-display text-[24px] font-bold text-text-primary mb-1">
                  {typeof value === 'number' ? value.toFixed(p.key === 'co' ? 1 : 0) : value}
                  <span className="text-[12px] font-normal text-text-muted ml-1">
                    {p.unit}
                  </span>
                </div>
                <div
                  className={`text-[11px] font-medium ${
                    change > 0 ? 'text-danger' : change < 0 ? 'text-success' : 'text-text-muted'
                  }`}
                >
                  {change > 0 ? '↑' : change < 0 ? '↓' : '→'} {Math.abs(change).toFixed(1)}%
                </div>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
}