import { useState, useRef, useEffect } from "react";
import { Play } from "lucide-react";
import { type Video } from "@shared/schema";

interface VideoPreviewThumbnailProps {
  video: Video;
  onClick: (video: Video) => void;
  className?: string;
}

export default function VideoPreviewThumbnail({ video, onClick, className = "" }: VideoPreviewThumbnailProps) {
  const [isHovering, setIsHovering] = useState(false);
  const [previewTime, setPreviewTime] = useState(0);
  const [previewThumbnail, setPreviewThumbnail] = useState<string | null>(null);
  const [isVideoLoaded, setIsVideoLoaded] = useState(false);
  const videoRef = useRef<HTMLVideoElement>(null);
  const containerRef = useRef<HTMLDivElement>(null);
  const hoverTimeoutRef = useRef<NodeJS.Timeout>();
  const previewIntervalRef = useRef<NodeJS.Timeout>();

  // Create hidden video element for thumbnail generation
  useEffect(() => {
    if (!video.videoUrlMp4 && !video.videoUrl.includes('.mp4')) return;

    const videoElement = videoRef.current;
    if (!videoElement) return;

    const videoSrc = video.videoUrlMp4 || video.videoUrl;
    videoElement.src = videoSrc;
    videoElement.muted = true;
    videoElement.playsInline = true;
    videoElement.preload = 'metadata';

    const handleLoadedMetadata = () => {
      setIsVideoLoaded(true);
    };

    videoElement.addEventListener('loadedmetadata', handleLoadedMetadata);

    return () => {
      videoElement.removeEventListener('loadedmetadata', handleLoadedMetadata);
    };
  }, [video.videoUrlMp4, video.videoUrl]);

  const generatePreviewThumbnail = (time: number) => {
    const videoElement = videoRef.current;
    if (!videoElement || !isVideoLoaded) return;

    videoElement.currentTime = time;
    
    const handleSeeked = () => {
      const canvas = document.createElement('canvas');
      const ctx = canvas.getContext('2d');
      if (!ctx) return;

      canvas.width = videoElement.videoWidth;
      canvas.height = videoElement.videoHeight;
      
      ctx.drawImage(videoElement, 0, 0, canvas.width, canvas.height);
      
      const thumbnailUrl = canvas.toDataURL('image/jpeg', 0.8);
      setPreviewThumbnail(thumbnailUrl);
      
      videoElement.removeEventListener('seeked', handleSeeked);
    };

    videoElement.addEventListener('seeked', handleSeeked);
  };

  const handleMouseMove = (e: React.MouseEvent) => {
    if (!isHovering || !containerRef.current || !isVideoLoaded) return;

    const rect = containerRef.current.getBoundingClientRect();
    const x = e.clientX - rect.left;
    const percentage = Math.max(0, Math.min(1, x / rect.width));
    const time = percentage * video.duration;
    
    setPreviewTime(time);
    
    // Throttle thumbnail generation
    if (previewIntervalRef.current) {
      clearTimeout(previewIntervalRef.current);
    }
    
    previewIntervalRef.current = setTimeout(() => {
      generatePreviewThumbnail(time);
    }, 150);
  };

  const handleMouseEnter = () => {
    if (!isVideoLoaded) return;
    
    // Delay before showing preview to avoid flickering
    hoverTimeoutRef.current = setTimeout(() => {
      setIsHovering(true);
      generatePreviewThumbnail(0);
    }, 500);
  };

  const handleMouseLeave = () => {
    if (hoverTimeoutRef.current) {
      clearTimeout(hoverTimeoutRef.current);
    }
    if (previewIntervalRef.current) {
      clearTimeout(previewIntervalRef.current);
    }
    
    setIsHovering(false);
    setPreviewThumbnail(null);
    setPreviewTime(0);
  };

  const formatTime = (seconds: number): string => {
    const minutes = Math.floor(seconds / 60);
    const remainingSeconds = Math.floor(seconds % 60);
    return `${minutes}:${remainingSeconds.toString().padStart(2, '0')}`;
  };

  const formatDuration = (seconds: number): string => {
    const minutes = Math.floor(seconds / 60);
    const remainingSeconds = seconds % 60;
    return `${minutes}:${remainingSeconds.toString().padStart(2, '0')}`;
  };

  return (
    <div className={`group cursor-pointer ${className}`}>
      {/* Hidden video element for thumbnail generation */}
      <video
        ref={videoRef}
        className="hidden"
        crossOrigin="anonymous"
        onError={() => setIsVideoLoaded(false)}
      />
      
      <div 
        ref={containerRef}
        className="relative bg-bunny-gray rounded-xl overflow-hidden mb-4 aspect-video"
        onClick={() => onClick(video)}
        onMouseMove={handleMouseMove}
        onMouseEnter={handleMouseEnter}
        onMouseLeave={handleMouseLeave}
        data-testid={`preview-thumbnail-${video.id}`}
      >
        {/* Main thumbnail or preview */}
        <img
          src={isHovering && previewThumbnail ? previewThumbnail : video.thumbnailUrl}
          alt={video.title}
          className="w-full h-full object-cover transition-all duration-200"
          data-testid={`img-preview-${video.id}`}
        />
        
        {/* Overlay with play button */}
        <div className={`absolute inset-0 bg-black/20 group-hover:bg-black/40 transition-all duration-300 flex items-center justify-center ${
          isHovering ? 'bg-black/50' : ''
        }`}>
          <div className={`bg-white/20 backdrop-blur-sm rounded-full flex items-center justify-center group-hover:bg-white/30 transition-all duration-300 ${
            isHovering ? 'w-20 h-20 bg-white/40' : 'w-16 h-16'
          }`}>
            <Play className={`text-white ml-1 transition-all duration-300 ${
              isHovering ? 'text-2xl' : 'text-xl'
            }`} />
          </div>
        </div>
        
        {/* Duration badge */}
        <div className="absolute bottom-3 right-3 bg-black/80 px-2 py-1 rounded text-xs font-medium">
          <span data-testid={`text-duration-${video.id}`}>
            {formatDuration(video.duration)}
          </span>
        </div>

        {/* Preview time indicator */}
        {isHovering && isVideoLoaded && (
          <>
            {/* Progress bar */}
            <div className="absolute bottom-0 left-0 right-0 h-1 bg-white/20">
              <div 
                className="h-full bg-bunny-blue transition-all duration-150"
                style={{ width: `${(previewTime / video.duration) * 100}%` }}
              />
            </div>
            
            {/* Time tooltip */}
            <div 
              className="absolute bottom-12 bg-black/90 text-white text-xs px-2 py-1 rounded pointer-events-none transition-all duration-150"
              style={{ 
                left: `${(previewTime / video.duration) * 100}%`,
                transform: 'translateX(-50%)'
              }}
            >
              {formatTime(previewTime)}
            </div>
          </>
        )}
        
        {/* Loading indicator for video metadata */}
        {!isVideoLoaded && (video.videoUrlMp4 || video.videoUrl.includes('.mp4')) && (
          <div className="absolute top-2 left-2">
            <div className="w-2 h-2 bg-bunny-blue rounded-full animate-pulse"></div>
          </div>
        )}
      </div>
    </div>
  );
}