import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:video_player/video_player.dart';
import '../../core/service_locator.dart';

/// Media gallery screen for viewing recipe images and videos in full screen.
/// Supports swiping between media and pinch-to-zoom for images.
class PhotoGalleryScreen extends StatefulWidget {
  final List<String> imageUrls;
  final List<String> videoUrls;
  final int initialIndex;

  const PhotoGalleryScreen({
    super.key,
    required this.imageUrls,
    this.videoUrls = const [],
    this.initialIndex = 0,
  });

  @override
  State<PhotoGalleryScreen> createState() => _PhotoGalleryScreenState();
}

class _PhotoGalleryScreenState extends State<PhotoGalleryScreen> {
  late PageController _pageController;
  late int _currentIndex;
  final Map<int, VideoPlayerController> _videoControllers = {};

  List<String> get _allMediaUrls {
    return [...widget.imageUrls, ...widget.videoUrls];
  }

  bool _isVideo(int index) {
    return index >= widget.imageUrls.length;
  }

  @override
  void initState() {
    super.initState();
    _currentIndex = widget.initialIndex;
    _pageController = PageController(initialPage: widget.initialIndex);
    _initializeVideo(_currentIndex);
  }

  @override
  void dispose() {
    _pageController.dispose();
    for (final controller in _videoControllers.values) {
      controller.dispose();
    }
    super.dispose();
  }

  void _initializeVideo(int index) {
    if (_isVideo(index)) {
      final videoIndex = index - widget.imageUrls.length;
      if (videoIndex >= 0 && videoIndex < widget.videoUrls.length) {
        final videoUrl = widget.videoUrls[videoIndex];
        if (!_videoControllers.containsKey(index)) {
          final controller = VideoPlayerController.networkUrl(Uri.parse(videoUrl));
          controller.initialize().then((_) {
            if (mounted) {
              setState(() {});
              controller.play();
            }
          });
          _videoControllers[index] = controller;
        }
      }
    }
  }

  void _disposeVideo(int index) {
    final controller = _videoControllers.remove(index);
    controller?.dispose();
  }

  void _goToPrevious() {
    if (_currentIndex > 0) {
      _disposeVideo(_currentIndex);
      _currentIndex--;
      _initializeVideo(_currentIndex);
      _pageController.previousPage(
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeInOut,
      );
    }
  }

  void _goToNext() {
    if (_currentIndex < _allMediaUrls.length - 1) {
      _disposeVideo(_currentIndex);
      _currentIndex++;
      _initializeVideo(_currentIndex);
      _pageController.nextPage(
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeInOut,
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        leading: Container(
          margin: const EdgeInsets.all(8),
          decoration: BoxDecoration(
            color: Colors.black.withValues(alpha: 0.5),
            shape: BoxShape.circle,
          ),
          child: IconButton(
            icon: const Icon(Icons.close, color: Colors.white),
            onPressed: () => Navigator.pop(context),
            padding: EdgeInsets.zero,
          ),
        ),
        title: Text(
          '${_currentIndex + 1} / ${_allMediaUrls.length}',
          style: const TextStyle(color: Colors.white),
        ),
        centerTitle: true,
      ),
      body: Stack(
        children: [
          // Media viewer
          PageView.builder(
            controller: _pageController,
            itemCount: _allMediaUrls.length,
            onPageChanged: (index) {
              setState(() {
                _disposeVideo(_currentIndex);
                _currentIndex = index;
                _initializeVideo(_currentIndex);
              });
            },
            itemBuilder: (context, index) {
              if (_isVideo(index)) {
                return _buildVideo(index);
              } else {
                return Center(
                  child: InteractiveViewer(
                    minScale: 0.5,
                    maxScale: 3.0,
                    child: _buildImage(widget.imageUrls[index]),
                  ),
                );
              }
            },
          ),
          // Navigation arrows
          if (_allMediaUrls.length > 1) ...[
            // Previous arrow (left)
            if (_currentIndex > 0)
              Positioned(
                left: 16,
                top: 0,
                bottom: 0,
                child: Center(
                  child: Container(
                    decoration: BoxDecoration(
                      color: Colors.black.withValues(alpha: 0.5),
                      shape: BoxShape.circle,
                    ),
                    child: IconButton(
                      icon: const Icon(
                        Icons.chevron_left,
                        color: Colors.white,
                        size: 32,
                      ),
                      onPressed: _goToPrevious,
                      padding: const EdgeInsets.all(16),
                    ),
                  ),
                ),
              ),
            // Next arrow (right)
            if (_currentIndex < _allMediaUrls.length - 1)
              Positioned(
                right: 16,
                top: 0,
                bottom: 0,
                child: Center(
                  child: Container(
                    decoration: BoxDecoration(
                      color: Colors.black.withValues(alpha: 0.5),
                      shape: BoxShape.circle,
                    ),
                    child: IconButton(
                      icon: const Icon(
                        Icons.chevron_right,
                        color: Colors.white,
                        size: 32,
                      ),
                      onPressed: _goToNext,
                      padding: const EdgeInsets.all(16),
                    ),
                  ),
                ),
              ),
          ],
        ],
      ),
    );
  }

  /// Builds an image widget using MediaService for authenticated access.
  Widget _buildImage(String imageUrl) {
    final mediaService = ServiceLocator.instance.mediaService;
    if (mediaService == null) {
      return Image.network(imageUrl, fit: BoxFit.contain);
    }
    
    // Try to extract asset ID from Immich URL (format: .../api/assets/{id}/original)
    final assetIdMatch = RegExp(r'/api/assets/([^/]+)/').firstMatch(imageUrl);
    String? assetId;
    
    if (assetIdMatch != null) {
      assetId = assetIdMatch.group(1);
    } else {
      // For Blossom URLs, use the full URL
      assetId = imageUrl;
    }
    
    if (assetId != null) {
      // Use MediaService to fetch full image (not thumbnail) for gallery view
      return FutureBuilder<Uint8List?>(
        future: mediaService.fetchImageBytes(assetId, isThumbnail: false),
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.waiting) {
              return const Center(
                child: CircularProgressIndicator(
                  valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
                ),
              );
            }

            if (snapshot.hasError || !snapshot.hasData || snapshot.data == null) {
              return const Center(
                child: Icon(
                  Icons.image_not_supported,
                  size: 64,
                  color: Colors.white54,
                ),
              );
            }

            return Image.memory(
              snapshot.data!,
              fit: BoxFit.contain,
            );
          },
        );
    }
    
    // Fallback to direct network image if not an Immich URL or service unavailable
    return Image.network(
      imageUrl,
      fit: BoxFit.contain,
      errorBuilder: (context, error, stackTrace) {
        return const Center(
          child: Icon(
            Icons.image_not_supported,
            size: 64,
            color: Colors.white54,
          ),
        );
      },
      loadingBuilder: (context, child, loadingProgress) {
        if (loadingProgress == null) return child;
        return Center(
          child: CircularProgressIndicator(
            value: loadingProgress.expectedTotalBytes != null
                ? loadingProgress.cumulativeBytesLoaded /
                    loadingProgress.expectedTotalBytes!
                : null,
            valueColor: const AlwaysStoppedAnimation<Color>(Colors.white),
          ),
        );
      },
    );
  }

  /// Builds a video player widget.
  Widget _buildVideo(int index) {
    final controller = _videoControllers[index];
    if (controller == null || !controller.value.isInitialized) {
      return const Center(
        child: CircularProgressIndicator(
          valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
        ),
      );
    }

    return Center(
      child: AspectRatio(
        aspectRatio: controller.value.aspectRatio,
        child: VideoPlayer(controller),
      ),
    );
  }
}