CA/frontend/src/components/TimelinePlayer.tsx

import { useState, useEffect, useRef, useCallback, useMemo } from 'react';
import { Play, Pause, SkipBack, SkipForward } from 'lucide-react';

interface TimelinePlayerProps {
  startDate: string;
  endDate: string;
  currentDate: string;
  onDateChange: (date: string) => void;
  isPlaying?: boolean;
  speed?: number;
  onSpeedChange?: (speed: number) => void;
  onPlayPause?: (playing: boolean) => void;
}

const SPEEDS = [0.5, 1, 2, 5, 10];

export function TimelinePlayer({
  startDate,
  endDate,
  currentDate,
  onDateChange,
  isPlaying = false,
  speed = 1,
  onSpeedChange,
  onPlayPause,
}: TimelinePlayerProps) {
  const [playing, setPlaying] = useState(isPlaying);
  const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);

  const generateDateRange = useCallback((start: string, end: string) => {
    const dates: string[] = [];
    const current = new Date(start);
    const final = new Date(end);

    while (current <= final) {
      dates.push(current.toISOString().split('T')[0]);
      current.setDate(current.getDate() + 1);
    }

    return dates;
  }, []);

  const dateRange = useMemo(() => generateDateRange(startDate, endDate), [startDate, endDate, generateDateRange]);
  const currentIndex = useMemo(() => dateRange.indexOf(currentDate), [dateRange, currentDate]);
  const progress = useMemo(() => ((currentIndex + 1) / dateRange.length) * 100, [currentIndex, dateRange.length]);

  const play = useCallback(() => {
    setPlaying(true);
    onPlayPause?.(true);
  }, [onPlayPause]);

  const pause = useCallback(() => {
    setPlaying(false);
    onPlayPause?.(false);
  }, [onPlayPause]);

  const togglePlay = () => {
    if (playing) {
      pause();
    } else {
      play();
    }
  };

  const goToNext = useCallback(() => {
    const nextIndex = Math.min(currentIndex + 1, dateRange.length - 1);
    onDateChange(dateRange[nextIndex]);
  }, [currentIndex, dateRange, onDateChange]);

  const goToStart = () => {
    onDateChange(dateRange[0]);
  };

  useEffect(() => {
    if (playing) {
      const interval = 1000 / speed;

      timerRef.current = setInterval(() => {
        goToNext();
      }, interval);

      return () => {
        if (timerRef.current) {
          clearInterval(timerRef.current);
        }
      };
    }
  }, [playing, speed, goToNext]);

  useEffect(() => {
    if (currentIndex >= dateRange.length - 1) {
      pause();
    }
  }, [currentIndex, dateRange.length, pause]);

  const handleSliderChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const index = Math.round((Number(e.target.value) / 100) * (dateRange.length - 1));
    onDateChange(dateRange[index]);
  };

  const handleSpeedChange = () => {
    const currentIndex = SPEEDS.indexOf(speed);
    const nextIndex = (currentIndex + 1) % SPEEDS.length;
    onSpeedChange?.(SPEEDS[nextIndex]);
  };

  const formatSpeed = (s: number) => {
    return s >= 1 ? `${s}x` : `${s.toFixed(1)}x`;
  };

  const formatDate = (dateStr: string) => {
    const date = new Date(dateStr);
    const today = new Date();
    const isToday = date.toDateString() === today.toDateString();

    if (isToday) {
      return `今天 ${date.toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' })}`;
    }

    return date.toLocaleDateString('zh-CN', {
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
    });
  };

  return (
    <div className="fixed right-4 top-1/2 -translate-y-1/2 z-[9999] w-64">
      <div className="bg-white/95 backdrop-blur-xl border border-gray-200/80 rounded-2xl shadow-[0_8px_32px_rgba(0,0,0,0.12)] px-4 py-3">
        {/* Date display */}
        <div className="text-center mb-3">
          <div className="font-medium text-gray-900 text-sm">{formatDate(currentDate)}</div>
          <div className="text-xs text-gray-400 mt-0.5">
            第 {currentIndex + 1} / {dateRange.length} 天
          </div>
        </div>

        {/* Vertical slider */}
        <div className="flex justify-center mb-3">
          <input
            type="range"
            min="0"
            max="100"
            value={progress}
            onChange={handleSliderChange}
            className="h-1.5 w-full bg-gray-200 rounded-full appearance-none cursor-pointer accent-blue-600"
            style={{
              background: `linear-gradient(to right, #2563eb 0%, #2563eb ${progress}%, #e5e7eb ${progress}%, #e5e7eb 100%)`,
            }}
          />
        </div>
        <div className="flex justify-between text-[10px] text-gray-400 mb-3">
          <span>{new Date(startDate).toLocaleDateString('zh-CN', { month: 'short', day: 'numeric' })}</span>
          <span>{new Date(endDate).toLocaleDateString('zh-CN', { month: 'short', day: 'numeric' })}</span>
        </div>

        {/* Transport controls */}
        <div className="flex items-center justify-center gap-2">
          <button
            onClick={goToStart}
            className="p-1.5 text-gray-400 hover:text-gray-700 hover:bg-gray-100 rounded-full transition-colors"
            title="跳到开始"
          >
            <SkipBack className="w-4 h-4" />
          </button>

          <button
            onClick={togglePlay}
            className="p-2.5 bg-blue-600 text-white rounded-full hover:bg-blue-700 transition-colors shadow-md"
          >
            {playing ? (
              <Pause className="w-5 h-5" />
            ) : (
              <Play className="w-5 h-5 ml-0.5" />
            )}
          </button>

          <button
            onClick={goToNext}
            className="p-1.5 text-gray-400 hover:text-gray-700 hover:bg-gray-100 rounded-full transition-colors"
            title="跳到下一天"
          >
            <SkipForward className="w-4 h-4" />
          </button>
        </div>

        {/* Speed */}
        <div className="flex items-center justify-center gap-2 mt-2">
          <button
            onClick={handleSpeedChange}
            className="px-2 py-0.5 text-xs font-medium text-gray-600 bg-gray-100/80 rounded-full hover:bg-gray-200 transition-colors"
            title="调整播放速度"
          >
            {formatSpeed(speed)}
          </button>
        </div>
      </div>
    </div>
  );
}