'use client';

import { useState, useMemo, useCallback } from 'react';
import { ExternalLink, Image as ImageIcon } from 'lucide-react';
import { ImageLightbox } from '@/components/ui/ImageLightbox';
import { cn } from '@/lib/utils';

export interface SearchImageItem {
  title: string;
  imageUrl: string;
  width: number;
  height: number;
  score: string;
  position: number;
  sourceUrl?: string;
}

interface SearchImagesGridProps {
  images: SearchImageItem[];
  className?: string;
  /** 最大显示图片数量，默认为 5 */
  maxDisplay?: number;
}

/**
 * 搜索图片瀑布流展示组件
 * 实现动态回填：当图片加载失败时，自动用备用图片替换
 * 确保始终显示指定数量的有效图片
 */
export function SearchImagesGrid({
  images,
  className,
  maxDisplay = 5
}: SearchImagesGridProps) {
  const [lightboxOpen, setLightboxOpen] = useState(false);
  const [lightboxIndex, setLightboxIndex] = useState(0);

  // 已加载成功的图片索引
  const [loadedImages, setLoadedImages] = useState<Set<number>>(new Set());
  // 加载失败的图片索引
  const [errorImages, setErrorImages] = useState<Set<number>>(new Set());

  /**
   * 计算当前要显示的图片列表
   * 策略：从所有图片中选择前 maxDisplay 张有效的图片
   * 跳过已知失败的图片，自动用后续图片回填
   */
  const displayImages = useMemo(() => {
    const result: { image: SearchImageItem; originalIndex: number }[] = [];

    for (let i = 0; i < images.length && result.length < maxDisplay; i++) {
      // 跳过已知加载失败的图片
      if (!errorImages.has(i)) {
        result.push({ image: images[i], originalIndex: i });
      }
    }

    return result;
  }, [images, errorImages, maxDisplay]);

  // 有效图片的 URL 列表（用于 Lightbox）
  const validImageUrls = useMemo(() => {
    return displayImages
      .filter(({ originalIndex }) => loadedImages.has(originalIndex))
      .map(({ image }) => image.imageUrl);
  }, [displayImages, loadedImages]);

  // 图片加载成功
  const handleImageLoad = useCallback((index: number) => {
    setLoadedImages((prev) => new Set(prev).add(index));
  }, []);

  // 图片加载失败 - 标记为错误，会触发重新计算 displayImages，自动回填
  const handleImageError = useCallback((index: number) => {
    setErrorImages((prev) => new Set(prev).add(index));
  }, []);

  // 打开灯箱
  const openLightbox = useCallback((displayIndex: number) => {
    // 找到在有效加载图片中的索引
    const loadedDisplayImages = displayImages.filter(
      ({ originalIndex }) => loadedImages.has(originalIndex)
    );
    const clickedImage = displayImages[displayIndex];
    const lightboxIdx = loadedDisplayImages.findIndex(
      ({ originalIndex }) => originalIndex === clickedImage?.originalIndex
    );
    if (lightboxIdx >= 0) {
      setLightboxIndex(lightboxIdx);
      setLightboxOpen(true);
    }
  }, [displayImages, loadedImages]);

  // 获取源网站域名
  const getSourceDomain = (url?: string) => {
    if (!url) return null;
    try {
      const urlObj = new URL(url);
      return urlObj.hostname.replace('www.', '');
    } catch {
      return null;
    }
  };

  if (!images || images.length === 0) return null;

  // 如果所有图片都加载失败，不显示任何内容
  if (displayImages.length === 0) {
    return null;
  }

  // 统计已成功加载的图片数量
  const successCount = displayImages.filter(
    ({ originalIndex }) => loadedImages.has(originalIndex)
  ).length;

  return (
    <>
      <div className={cn('mt-3', className)}>
        {/* 标题 */}
        <div className="flex items-center gap-2 mb-3 text-sm text-muted-foreground">
          <ImageIcon size={14} />
          <span>
            搜索到 {successCount > 0 ? successCount : displayImages.length} 张相关图片
          </span>
        </div>

        {/* 瀑布流容器 */}
        <div className="columns-2 sm:columns-3 gap-3 space-y-3">
          {displayImages.map(({ image, originalIndex }, displayIndex) => {
            const isLoaded = loadedImages.has(originalIndex);
            const sourceDomain = getSourceDomain(image.sourceUrl);

            return (
              <div
                key={`${image.imageUrl}-${originalIndex}`}
                className={cn(
                  'break-inside-avoid mb-3 group relative',
                  'rounded overflow-hidden',
                  'bg-white dark:bg-zinc-900',
                  'ring-1 ring-black/5 dark:ring-white/10',
                  'shadow-[0_2px_8px_rgba(0,0,0,0.06)]',
                  'transition-all duration-200',
                  'hover:shadow-[0_6px_20px_rgba(0,0,0,0.1)]',
                  !isLoaded && 'animate-pulse'
                )}
              >
                {/* 图片容器 */}
                <div
                  className="relative cursor-pointer"
                  onClick={() => openLightbox(displayIndex)}
                >
                  {/* 图片 */}
                  <img
                    src={image.imageUrl}
                    alt={image.title || `搜索图片 ${displayIndex + 1}`}
                    className={cn(
                      'w-full h-auto object-cover',
                      'transition-opacity duration-300',
                      isLoaded ? 'opacity-100' : 'opacity-0'
                    )}
                    onLoad={() => handleImageLoad(originalIndex)}
                    onError={() => handleImageError(originalIndex)}
                    loading="lazy"
                  />

                  {/* 加载占位 */}
                  {!isLoaded && (
                    <div
                      className="absolute inset-0 bg-muted/30 flex items-center justify-center"
                      style={{
                        aspectRatio: image.width && image.height ? `${image.width}/${image.height}` : '16/9',
                      }}
                    >
                      <div className="w-8 h-8 border-2 border-primary/30 border-t-primary rounded-full animate-spin" />
                    </div>
                  )}

                  {/* 悬浮遮罩 */}
                  <div className="absolute inset-0 bg-black/0 group-hover:bg-black/20 transition-colors duration-200 pointer-events-none" />
                </div>

                {/* 图片信息 */}
                <div className="p-2 space-y-1">
                  {/* 标题 */}
                  {image.title && (
                    <p
                      className="text-xs font-medium text-foreground/90 line-clamp-2"
                      title={image.title}
                    >
                      {image.title}
                    </p>
                  )}

                  {/* 来源链接 */}
                  {image.sourceUrl && sourceDomain && (
                    <a
                      href={image.sourceUrl}
                      target="_blank"
                      rel="noopener noreferrer"
                      onClick={(e) => e.stopPropagation()}
                      className={cn(
                        'flex items-center gap-1 text-xs',
                        'text-muted-foreground hover:text-primary',
                        'transition-colors duration-150'
                      )}
                    >
                      <ExternalLink size={10} />
                      <span className="truncate">{sourceDomain}</span>
                    </a>
                  )}
                </div>
              </div>
            );
          })}
        </div>
      </div>

      {/* 图片灯箱 - 只包含已成功加载的图片 */}
      <ImageLightbox
        images={validImageUrls}
        initialIndex={lightboxIndex}
        isOpen={lightboxOpen}
        onClose={() => setLightboxOpen(false)}
      />
    </>
  );
}