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

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

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

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

class _PhotoGalleryScreenState extends State<PhotoGalleryScreen> {
  late PageController _pageController;
  late int _currentIndex;

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

  @override
  void dispose() {
    _pageController.dispose();
    super.dispose();
  }

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

  void _goToNext() {
    if (_currentIndex < widget.imageUrls.length - 1) {
      _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.withOpacity(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} / ${widget.imageUrls.length}',
          style: const TextStyle(color: Colors.white),
        ),
        centerTitle: true,
      ),
      body: Stack(
        children: [
          // Photo viewer
          PageView.builder(
            controller: _pageController,
            itemCount: widget.imageUrls.length,
            onPageChanged: (index) {
              setState(() {
                _currentIndex = index;
              });
            },
            itemBuilder: (context, index) {
              return Center(
                child: InteractiveViewer(
                  minScale: 0.5,
                  maxScale: 3.0,
                  child: _buildImage(widget.imageUrls[index]),
                ),
              );
            },
          ),
          // Navigation arrows
          if (widget.imageUrls.length > 1) ...[
            // Previous arrow (left)
            if (_currentIndex > 0)
              Positioned(
                left: 16,
                top: 0,
                bottom: 0,
                child: Center(
                  child: Container(
                    decoration: BoxDecoration(
                      color: Colors.black.withOpacity(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 < widget.imageUrls.length - 1)
              Positioned(
                right: 16,
                top: 0,
                bottom: 0,
                child: Center(
                  child: Container(
                    decoration: BoxDecoration(
                      color: Colors.black.withOpacity(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 ImmichService for authenticated access.
  Widget _buildImage(String imageUrl) {
    final immichService = ServiceLocator.instance.immichService;
    
    // Try to extract asset ID from URL (format: .../api/assets/{id}/original)
    final assetIdMatch = RegExp(r'/api/assets/([^/]+)/').firstMatch(imageUrl);
    
    if (assetIdMatch != null && immichService != null) {
      final assetId = assetIdMatch.group(1);
      if (assetId != null) {
        // Use ImmichService to fetch full image (not thumbnail) for gallery view
        return FutureBuilder<Uint8List?>(
          future: immichService.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),
          ),
        );
      },
    );
  }
}