import 'package:flutter/material.dart';
import 'package:cached_network_image/cached_network_image.dart';
import '../theme/app_colors.dart';
import 'skeleton_loading.dart';

/// 최적화된 캐시 네트워크 이미지 위젯
class OptimizedCachedNetworkImage extends StatelessWidget {
  final String imageUrl;
  final double? width;
  final double? height;
  final BoxFit fit;
  final BorderRadius? borderRadius;
  final Duration fadeInDuration;
  final Duration fadeOutDuration;
  final Widget? placeholder;
  final Widget? errorWidget;
  final Map<String, String>? httpHeaders;
  final bool enableMemoryCache;
  final bool enableDiskCache;
  final int? maxWidth;
  final int? maxHeight;
  
  const OptimizedCachedNetworkImage({
    super.key,
    required this.imageUrl,
    this.width,
    this.height,
    this.fit = BoxFit.cover,
    this.borderRadius,
    this.fadeInDuration = const Duration(milliseconds: 300),
    this.fadeOutDuration = const Duration(milliseconds: 300),
    this.placeholder,
    this.errorWidget,
    this.httpHeaders,
    this.enableMemoryCache = true,
    this.enableDiskCache = true,
    this.maxWidth,
    this.maxHeight,
  });

  @override
  Widget build(BuildContext context) {
    // 성능 최적화를 위한 이미지 크기 계산
    final devicePixelRatio = MediaQuery.of(context).devicePixelRatio;
    final optimalWidth = maxWidth ?? 
        (width != null ? (width! * devicePixelRatio).round() : null);
    final optimalHeight = maxHeight ?? 
        (height != null ? (height! * devicePixelRatio).round() : null);
    
    Widget image = CachedNetworkImage(
      imageUrl: imageUrl,
      width: width,
      height: height,
      fit: fit,
      fadeInDuration: fadeInDuration,
      fadeOutDuration: fadeOutDuration,
      httpHeaders: httpHeaders,
      memCacheWidth: optimalWidth,
      memCacheHeight: optimalHeight,
      maxWidthDiskCache: optimalWidth,
      maxHeightDiskCache: optimalHeight,
      placeholder: (context, url) => placeholder ?? _buildDefaultPlaceholder(),
      errorWidget: (context, url, error) => 
          errorWidget ?? _buildDefaultErrorWidget(),
      imageBuilder: (context, imageProvider) {
        return Container(
          width: width,
          height: height,
          decoration: BoxDecoration(
            borderRadius: borderRadius,
            image: DecorationImage(
              image: imageProvider,
              fit: fit,
            ),
          ),
        );
      },
    );
    
    if (borderRadius != null) {
      return ClipRRect(
        borderRadius: borderRadius!,
        child: image,
      );
    }
    
    return image;
  }
  
  Widget _buildDefaultPlaceholder() {
    return SkeletonLoading(
      width: width,
      height: height,
      borderRadius: borderRadius?.topLeft.x ?? 0,
    );
  }
  
  Widget _buildDefaultErrorWidget() {
    return Container(
      width: width,
      height: height,
      decoration: BoxDecoration(
        color: AppColors.surfaceColorAlt,
        borderRadius: borderRadius,
      ),
      child: const Icon(
        Icons.broken_image_outlined,
        color: AppColors.textMuted,
        size: 24,
      ),
    );
  }
}

/// 프로그레시브 이미지 로더 (저화질 → 고화질)
class ProgressiveNetworkImage extends StatelessWidget {
  final String thumbnailUrl;
  final String imageUrl;
  final double? width;
  final double? height;
  final BoxFit fit;
  final BorderRadius? borderRadius;
  
  const ProgressiveNetworkImage({
    super.key,
    required this.thumbnailUrl,
    required this.imageUrl,
    this.width,
    this.height,
    this.fit = BoxFit.cover,
    this.borderRadius,
  });

  @override
  Widget build(BuildContext context) {
    return Stack(
      fit: StackFit.passthrough,
      children: [
        // 썸네일 (저화질)
        OptimizedCachedNetworkImage(
          imageUrl: thumbnailUrl,
          width: width,
          height: height,
          fit: fit,
          borderRadius: borderRadius,
          fadeInDuration: Duration.zero,
        ),
        // 원본 이미지 (고화질)
        OptimizedCachedNetworkImage(
          imageUrl: imageUrl,
          width: width,
          height: height,
          fit: fit,
          borderRadius: borderRadius,
        ),
      ],
    );
  }
}

/// 이미지 갤러리 위젯 (메모리 효율적)
class OptimizedImageGallery extends StatefulWidget {
  final List<String> imageUrls;
  final double itemHeight;
  final double spacing;
  final int crossAxisCount;
  final void Function(int)? onImageTap;
  
  const OptimizedImageGallery({
    super.key,
    required this.imageUrls,
    this.itemHeight = 120,
    this.spacing = 8,
    this.crossAxisCount = 3,
    this.onImageTap,
  });

  @override
  State<OptimizedImageGallery> createState() => _OptimizedImageGalleryState();
}

class _OptimizedImageGalleryState extends State<OptimizedImageGallery> {
  final ScrollController _scrollController = ScrollController();
  final Set<int> _visibleIndices = {};
  
  @override
  void initState() {
    super.initState();
    _scrollController.addListener(_onScroll);
    // 초기 보이는 아이템 계산
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _calculateVisibleIndices();
    });
  }
  
  @override
  void dispose() {
    _scrollController.dispose();
    super.dispose();
  }
  
  void _onScroll() {
    _calculateVisibleIndices();
  }
  
  void _calculateVisibleIndices() {
    if (!mounted) return;
    
    final viewportHeight = context.size?.height ?? 0;
    final scrollOffset = _scrollController.offset;
    final itemHeight = widget.itemHeight + widget.spacing;
    final itemsPerRow = widget.crossAxisCount;
    
    final firstVisibleRow = (scrollOffset / itemHeight).floor();
    final lastVisibleRow = ((scrollOffset + viewportHeight) / itemHeight).ceil();
    
    final newVisibleIndices = <int>{};
    for (int row = firstVisibleRow; row <= lastVisibleRow; row++) {
      for (int col = 0; col < itemsPerRow; col++) {
        final index = row * itemsPerRow + col;
        if (index < widget.imageUrls.length) {
          newVisibleIndices.add(index);
        }
      }
    }
    
    if (!setEquals(_visibleIndices, newVisibleIndices)) {
      setState(() {
        _visibleIndices.clear();
        _visibleIndices.addAll(newVisibleIndices);
      });
    }
  }
  
  @override
  Widget build(BuildContext context) {
    return GridView.builder(
      controller: _scrollController,
      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: widget.crossAxisCount,
        childAspectRatio: 1.0,
        crossAxisSpacing: widget.spacing,
        mainAxisSpacing: widget.spacing,
      ),
      itemCount: widget.imageUrls.length,
      itemBuilder: (context, index) {
        // 보이는 영역의 이미지만 로드
        if (_visibleIndices.contains(index) || 
            (index >= _visibleIndices.first - widget.crossAxisCount && 
             index <= _visibleIndices.last + widget.crossAxisCount)) {
          return GestureDetector(
            onTap: () => widget.onImageTap?.call(index),
            child: OptimizedCachedNetworkImage(
              imageUrl: widget.imageUrls[index],
              fit: BoxFit.cover,
              borderRadius: BorderRadius.circular(8),
            ),
          );
        }
        
        // 보이지 않는 영역은 플레이스홀더
        return Container(
          decoration: BoxDecoration(
            color: AppColors.surfaceColorAlt,
            borderRadius: BorderRadius.circular(8),
          ),
        );
      },
    );
  }
  
  bool setEquals(Set<int> a, Set<int> b) {
    if (a.length != b.length) return false;
    for (final item in a) {
      if (!b.contains(item)) return false;
    }
    return true;
  }
}

/// 히어로 애니메이션이 적용된 이미지
class HeroNetworkImage extends StatelessWidget {
  final String imageUrl;
  final String heroTag;
  final double? width;
  final double? height;
  final BoxFit fit;
  final VoidCallback? onTap;
  
  const HeroNetworkImage({
    super.key,
    required this.imageUrl,
    required this.heroTag,
    this.width,
    this.height,
    this.fit = BoxFit.cover,
    this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Hero(
        tag: heroTag,
        child: OptimizedCachedNetworkImage(
          imageUrl: imageUrl,
          width: width,
          height: height,
          fit: fit,
        ),
      ),
    );
  }
}