import { useState, useEffect, useRef } from 'react';
import { X, ChevronLeft, ChevronRight } from 'lucide-react';
import { Dialog, DialogContent, DialogTitle } from '@/components/ui/dialog';
import { VisuallyHidden } from '@radix-ui/react-visually-hidden';
import { Button } from '@/components/ui/button';
import { useIsMobile } from '@/hooks/use-mobile';

interface PhotoModalProps {
  photos: Array<{
    id: string;
    url: string;
    filename?: string;
    caption?: string;
  }>;
  initialIndex: number;
  isOpen: boolean;
  onClose: () => void;
}

export function PhotoModal({ photos, initialIndex, isOpen, onClose }: PhotoModalProps) {
  const isMobile = useIsMobile();
  const [currentIndex, setCurrentIndex] = useState(initialIndex);
  const [touchStart, setTouchStart] = useState<number | null>(null);
  const [touchEnd, setTouchEnd] = useState<number | null>(null);
  const imageRef = useRef<HTMLImageElement>(null);
  
  // Safety check: ensure photos array exists and is not empty
  if (!photos || photos.length === 0) {
    return null;
  }
  
  // Clamp currentIndex to valid bounds
  const safeIndex = Math.max(0, Math.min(currentIndex, photos.length - 1));
  const currentPhoto = photos[safeIndex];
  
  // Early return if currentPhoto is undefined
  if (!currentPhoto) {
    return null;
  }
  
  // Minimum swipe distance (in px)
  const minSwipeDistance = 50;

  const goToPrevious = () => {
    setCurrentIndex((prev) => (prev > 0 ? prev - 1 : photos.length - 1));
  };

  const goToNext = () => {
    setCurrentIndex((prev) => (prev < photos.length - 1 ? prev + 1 : 0));
  };

  const handleKeyDown = (e: React.KeyboardEvent) => {
    if (e.key === 'ArrowLeft') goToPrevious();
    if (e.key === 'ArrowRight') goToNext();
    if (e.key === 'Escape') onClose();
  };

  const onTouchStart = (e: React.TouchEvent) => {
    setTouchEnd(null);
    setTouchStart(e.targetTouches[0].clientX);
  };

  const onTouchMove = (e: React.TouchEvent) => {
    setTouchEnd(e.targetTouches[0].clientX);
  };

  const onTouchEnd = () => {
    if (!touchStart || !touchEnd) return;
    
    const distance = touchStart - touchEnd;
    const isLeftSwipe = distance > minSwipeDistance;
    const isRightSwipe = distance < -minSwipeDistance;
    
    if (isLeftSwipe) {
      goToNext();
    } else if (isRightSwipe) {
      goToPrevious();
    }
  };

  useEffect(() => {
    setCurrentIndex(initialIndex);
  }, [initialIndex]);

  return (
    <Dialog open={isOpen} onOpenChange={onClose}>
      <DialogContent className={`max-w-7xl w-full p-0 [&>button]:hidden ${isMobile ? 'max-h-screen h-screen' : 'max-h-[90vh]'}`} aria-describedby={undefined}>
        <VisuallyHidden>
          <DialogTitle>Photo Viewer</DialogTitle>
        </VisuallyHidden>
        <div 
          className="relative bg-black rounded-lg overflow-hidden touch-none"
          onKeyDown={handleKeyDown} 
          onTouchStart={onTouchStart}
          onTouchMove={onTouchMove}
          onTouchEnd={onTouchEnd}
          tabIndex={0}
        >
          {/* Close button */}
          <Button
            variant="ghost"
            size={isMobile ? "default" : "sm"}
            onClick={onClose}
            className={`absolute z-20 text-white hover:bg-white/10 ${isMobile ? 'top-2 right-2 h-10 w-10 p-0' : 'top-4 right-4'}`}
          >
            <X className={isMobile ? "h-5 w-5" : "h-4 w-4"} />
          </Button>

          {/* Header */}
          <div className={`absolute top-0 left-0 right-0 z-10 bg-gradient-to-b from-black/80 to-transparent ${isMobile ? 'p-3' : 'p-4'}`}>
            <div className="text-white">
              {currentPhoto?.caption && (
                <h3 className={`font-medium ${isMobile ? 'text-sm pr-12' : ''}`}>
                  {currentPhoto.caption}
                </h3>
              )}
              {photos.length > 1 && (
                <p className={`text-white/70 ${isMobile ? 'text-xs' : 'text-sm'}`}>
                  {safeIndex + 1} of {photos.length}
                </p>
              )}
            </div>
          </div>

          {/* Image */}
          <div className={`flex items-center justify-center ${isMobile ? 'min-h-screen' : 'min-h-[400px] max-h-[80vh]'}`}>
            <img
              ref={imageRef}
              src={currentPhoto?.url}
              alt={currentPhoto?.caption || `Photo ${safeIndex + 1}`}
              className="max-w-full max-h-full object-contain select-none"
              loading="lazy"
              draggable={false}
            />
          </div>

          {/* Navigation */}
          {photos.length > 1 && !isMobile && (
            <>
              <Button
                variant="ghost"
                size="sm"
                onClick={goToPrevious}
                className="absolute left-4 top-1/2 -translate-y-1/2 text-white hover:bg-white/10"
              >
                <ChevronLeft className="h-6 w-6" />
              </Button>
              <Button
                variant="ghost"
                size="sm"
                onClick={goToNext}
                className="absolute right-4 top-1/2 -translate-y-1/2 text-white hover:bg-white/10"
              >
                <ChevronRight className="h-6 w-6" />
              </Button>
            </>
          )}
          
          {/* Mobile navigation dots */}
          {photos.length > 1 && isMobile && (
            <div className="absolute bottom-4 left-0 right-0 flex justify-center gap-2 px-4">
              {photos.map((_, idx) => (
                <button
                  key={idx}
                  onClick={() => setCurrentIndex(idx)}
                  className={`h-2 rounded-full transition-all ${
                    idx === currentIndex 
                      ? 'w-8 bg-white' 
                      : 'w-2 bg-white/50'
                  }`}
                  aria-label={`Go to photo ${idx + 1}`}
                />
              ))}
            </div>
          )}
        </div>
      </DialogContent>
    </Dialog>
  );
}