import 'dart:typed_data';
import 'package:flutter/material.dart';
import '../../core/service_locator.dart';
import '../../core/logger.dart';
import '../../data/recipes/recipe_service.dart';
import '../../data/recipes/models/recipe_model.dart';
import '../add_recipe/add_recipe_screen.dart';
import '../photo_gallery/photo_gallery_screen.dart';

/// Favourites screen displaying user's favorite recipes.
class FavouritesScreen extends StatefulWidget {
  const FavouritesScreen({super.key});

  @override
  State<FavouritesScreen> createState() => _FavouritesScreenState();
}

class _FavouritesScreenState extends State<FavouritesScreen> {
  List<RecipeModel> _recipes = [];
  bool _isLoading = false;
  String? _errorMessage;
  RecipeService? _recipeService;
  bool _wasLoggedIn = false;
  bool _isCompactMode = false;

  @override
  void initState() {
    super.initState();
    _initializeService();
    _checkLoginState();
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _checkLoginState();
    if (_recipeService != null) {
      _loadFavourites();
    }
  }

  @override
  void didUpdateWidget(FavouritesScreen oldWidget) {
    super.didUpdateWidget(oldWidget);
    _checkLoginState();
    if (_recipeService != null) {
      _loadFavourites();
    }
  }

  void _checkLoginState() {
    final sessionService = ServiceLocator.instance.sessionService;
    final isLoggedIn = sessionService?.isLoggedIn ?? false;
    
    if (isLoggedIn != _wasLoggedIn) {
      _wasLoggedIn = isLoggedIn;
      if (mounted) {
        setState(() {});
        if (isLoggedIn && _recipeService != null) {
          _loadFavourites();
        }
      }
    }
  }

  Future<void> _initializeService() async {
    try {
      _recipeService = ServiceLocator.instance.recipeService;
      
      if (_recipeService == null) {
        throw Exception('RecipeService not available in ServiceLocator');
      }

      _loadFavourites();
    } catch (e) {
      Logger.error('Failed to initialize RecipeService', e);
      if (mounted) {
        setState(() {
          _errorMessage = 'Failed to initialize recipe service: $e';
          _isLoading = false;
        });
      }
    }
  }

  Future<void> _loadFavourites() async {
    if (_recipeService == null) return;

    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    try {
      final recipes = await _recipeService!.getFavouriteRecipes();
      Logger.info('FavouritesScreen: Loaded ${recipes.length} favourite recipe(s)');
      if (mounted) {
        setState(() {
          _recipes = recipes;
          _isLoading = false;
        });
      }
    } catch (e) {
      Logger.error('Failed to load favourites', e);
      if (mounted) {
        setState(() {
          _errorMessage = 'Failed to load favourites: $e';
          _isLoading = false;
        });
      }
    }
  }

  Future<void> _deleteRecipe(RecipeModel recipe) async {
    if (_recipeService == null) return;

    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('Delete Recipe'),
        content: Text('Are you sure you want to delete "${recipe.title}"?'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.of(context).pop(true),
            style: TextButton.styleFrom(foregroundColor: Colors.red),
            child: const Text('Delete'),
          ),
        ],
      ),
    );

    if (confirmed != true) return;

    try {
      await _recipeService!.deleteRecipe(recipe.id);
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Recipe deleted successfully'),
            backgroundColor: Colors.green,
          ),
        );
        _loadFavourites();
      }
    } catch (e) {
      Logger.error('Failed to delete recipe', e);
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Failed to delete recipe: $e'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  void _viewRecipe(RecipeModel recipe) async {
    await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (context) => AddRecipeScreen(recipe: recipe, viewMode: true),
      ),
    );
    // Reload favourites after viewing (in case favorite was toggled)
    if (mounted) {
      _loadFavourites();
    }
  }

  void _editRecipe(RecipeModel recipe) async {
    final result = await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (context) => AddRecipeScreen(recipe: recipe),
      ),
    );
    if (result == true || mounted) {
      _loadFavourites();
    }
  }

  Future<void> _toggleFavorite(RecipeModel recipe) async {
    if (_recipeService == null) return;

    try {
      final updatedRecipe = recipe.copyWith(isFavourite: !recipe.isFavourite);
      await _recipeService!.updateRecipe(updatedRecipe);
      if (mounted) {
        _loadFavourites();
      }
    } catch (e) {
      Logger.error('Failed to toggle favorite', e);
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Failed to update favorite: $e'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Favourites'),
        actions: [
          // View mode toggle icons
          IconButton(
            icon: Icon(
              _isCompactMode ? Icons.view_list : Icons.view_list_outlined,
              color: _isCompactMode ? Theme.of(context).primaryColor : Colors.grey,
            ),
            onPressed: () {
              setState(() {
                _isCompactMode = true;
              });
            },
            tooltip: 'List View',
          ),
          IconButton(
            icon: Icon(
              !_isCompactMode ? Icons.grid_view : Icons.grid_view_outlined,
              color: !_isCompactMode ? Theme.of(context).primaryColor : Colors.grey,
            ),
            onPressed: () {
              setState(() {
                _isCompactMode = false;
              });
            },
            tooltip: 'Grid View',
          ),
        ],
      ),
      body: _buildBody(),
    );
  }

  Widget _buildBody() {
    final sessionService = ServiceLocator.instance.sessionService;
    final isLoggedIn = sessionService?.isLoggedIn ?? false;
    
    if (!isLoggedIn) {
      return Center(
        child: Padding(
          padding: const EdgeInsets.all(24),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(Icons.lock_outline, size: 64, color: Colors.grey.shade400),
              const SizedBox(height: 16),
              Text(
                'Please log in to view favourites',
                style: Theme.of(context).textTheme.titleLarge?.copyWith(
                  color: Colors.grey.shade700,
                ),
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 8),
              Text(
                'Favourites are associated with your user account',
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: Colors.grey.shade600,
                ),
                textAlign: TextAlign.center,
              ),
            ],
          ),
        ),
      );
    }
    
    if (_isLoading) {
      return const Center(
        child: CircularProgressIndicator(),
      );
    }

    if (_errorMessage != null) {
      return Center(
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(Icons.error_outline, size: 64, color: Colors.red.shade300),
              const SizedBox(height: 16),
              Text(
                _errorMessage!,
                style: TextStyle(color: Colors.red.shade700),
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: _loadFavourites,
                child: const Text('Retry'),
              ),
            ],
          ),
        ),
      );
    }

    if (_recipes.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(Icons.favorite_outline, size: 64, color: Colors.grey.shade400),
            const SizedBox(height: 16),
            Text(
              'No favourites yet',
              style: TextStyle(
                fontSize: 18,
                color: Colors.grey.shade600,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              'Tap the heart icon on recipes to add them to favourites',
              style: TextStyle(
                fontSize: 14,
                color: Colors.grey.shade500,
              ),
              textAlign: TextAlign.center,
            ),
          ],
        ),
      );
    }

    return RefreshIndicator(
      onRefresh: _loadFavourites,
      child: ListView.builder(
        padding: const EdgeInsets.all(16),
        itemCount: _recipes.length,
        itemBuilder: (context, index) {
          final recipe = _recipes[index];
          return _RecipeCard(
            recipe: recipe,
            isCompact: _isCompactMode,
            onTap: () => _viewRecipe(recipe),
            onFavorite: () => _toggleFavorite(recipe),
            onEdit: () => _editRecipe(recipe),
            onDelete: () => _deleteRecipe(recipe),
          );
        },
      ),
    );
  }
}

/// Card widget for displaying a recipe (reused from RecipesScreen).
/// This is a copy of the _RecipeCard from recipes_screen.dart to avoid making it public.
class _RecipeCard extends StatelessWidget {
  final RecipeModel recipe;
  final bool isCompact;
  final VoidCallback onTap;
  final VoidCallback onFavorite;
  final VoidCallback onEdit;
  final VoidCallback onDelete;

  const _RecipeCard({
    required this.recipe,
    required this.isCompact,
    required this.onTap,
    required this.onFavorite,
    required this.onEdit,
    required this.onDelete,
  });

  void _openPhotoGallery(BuildContext context, int initialIndex) {
    if (recipe.imageUrls.isEmpty) return;
    Navigator.push(
      context,
      MaterialPageRoute(
        builder: (context) => PhotoGalleryScreen(
          imageUrls: recipe.imageUrls,
          initialIndex: initialIndex,
        ),
      ),
    );
  }

  /// Builds an image widget using ImmichService for authenticated access.
  Widget _buildRecipeImage(String imageUrl) {
    final immichService = ServiceLocator.instance.immichService;
    
    final assetIdMatch = RegExp(r'/api/assets/([^/]+)/').firstMatch(imageUrl);
    
    if (assetIdMatch != null && immichService != null) {
      final assetId = assetIdMatch.group(1);
      if (assetId != null) {
        return FutureBuilder<Uint8List?>(
          future: immichService.fetchImageBytes(assetId, isThumbnail: true),
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.waiting) {
              return Container(
                color: Colors.grey.shade200,
                child: const Center(
                  child: CircularProgressIndicator(),
                ),
              );
            }

            if (snapshot.hasError || !snapshot.hasData || snapshot.data == null) {
              return Container(
                color: Colors.grey.shade200,
                child: const Icon(Icons.broken_image, size: 48),
              );
            }

            return Image.memory(
              snapshot.data!,
              fit: BoxFit.cover,
              width: double.infinity,
              height: double.infinity,
            );
          },
        );
      }
    }
    
    return Image.network(
      imageUrl,
      fit: BoxFit.cover,
      width: double.infinity,
      height: double.infinity,
      errorBuilder: (context, error, stackTrace) {
        return Container(
          color: Colors.grey.shade200,
          child: const Icon(Icons.broken_image, size: 48),
        );
      },
      loadingBuilder: (context, child, loadingProgress) {
        if (loadingProgress == null) return child;
        return Container(
          color: Colors.grey.shade200,
          child: Center(
            child: CircularProgressIndicator(
              value: loadingProgress.expectedTotalBytes != null
                  ? loadingProgress.cumulativeBytesLoaded /
                      loadingProgress.expectedTotalBytes!
                  : null,
            ),
          ),
        );
      },
    );
  }

  /// Builds a mosaic-style image grid for multiple images.
  Widget _buildMosaicImages(BuildContext context, List<String> imageUrls) {
    if (imageUrls.isEmpty) return const SizedBox.shrink();
    if (imageUrls.length == 1) {
      return ClipRRect(
        borderRadius: const BorderRadius.vertical(top: Radius.circular(12)),
        child: AspectRatio(
          aspectRatio: 16 / 9,
          child: GestureDetector(
            onTap: () => _openPhotoGallery(context, 0),
            child: _buildRecipeImage(imageUrls.first),
          ),
        ),
      );
    }
    
    return ClipRRect(
      borderRadius: const BorderRadius.vertical(top: Radius.circular(12)),
      child: LayoutBuilder(
        builder: (context, constraints) {
          final width = constraints.maxWidth;
          final height = width * 0.6;
          
          if (imageUrls.length == 2) {
            return SizedBox(
              height: height,
              child: Row(
                children: [
                  Expanded(
                    child: GestureDetector(
                      onTap: () => _openPhotoGallery(context, 0),
                      child: ClipRect(
                        child: _buildRecipeImage(imageUrls[0]),
                      ),
                    ),
                  ),
                  Expanded(
                    child: GestureDetector(
                      onTap: () => _openPhotoGallery(context, 1),
                      child: ClipRect(
                        child: _buildRecipeImage(imageUrls[1]),
                      ),
                    ),
                  ),
                ],
              ),
            );
          } else if (imageUrls.length == 3) {
            return SizedBox(
              height: height,
              child: Row(
                children: [
                  Expanded(
                    flex: 2,
                    child: GestureDetector(
                      onTap: () => _openPhotoGallery(context, 0),
                      child: ClipRect(
                        child: _buildRecipeImage(imageUrls[0]),
                      ),
                    ),
                  ),
                  Expanded(
                    child: Column(
                      children: [
                        Expanded(
                          child: GestureDetector(
                            onTap: () => _openPhotoGallery(context, 1),
                            child: ClipRect(
                              child: _buildRecipeImage(imageUrls[1]),
                            ),
                          ),
                        ),
                        Expanded(
                          child: GestureDetector(
                            onTap: () => _openPhotoGallery(context, 2),
                            child: ClipRect(
                              child: _buildRecipeImage(imageUrls[2]),
                            ),
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            );
          } else {
            return SizedBox(
              height: height,
              child: GridView.builder(
                physics: const NeverScrollableScrollPhysics(),
                shrinkWrap: true,
                padding: EdgeInsets.zero,
                gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: 2,
                  crossAxisSpacing: 0,
                  mainAxisSpacing: 0,
                  childAspectRatio: 1.0,
                ),
                itemCount: imageUrls.length > 4 ? 4 : imageUrls.length,
                itemBuilder: (context, index) {
                  return GestureDetector(
                    onTap: () => _openPhotoGallery(context, index),
                    child: ClipRect(
                      child: Stack(
                        fit: StackFit.expand,
                        children: [
                          _buildRecipeImage(imageUrls[index]),
                          if (index == 3 && imageUrls.length > 4)
                            Container(
                              color: Colors.black.withOpacity(0.5),
                              child: Center(
                                child: Text(
                                  '+${imageUrls.length - 4}',
                                  style: const TextStyle(
                                    color: Colors.white,
                                    fontSize: 24,
                                    fontWeight: FontWeight.bold,
                                  ),
                                ),
                              ),
                            ),
                        ],
                      ),
                    ),
                  );
                },
              ),
            );
          }
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    if (isCompact) {
      return _buildCompactCard(context);
    } else {
      return _buildExpandedCard(context);
    }
  }

  Widget _buildCompactCard(BuildContext context) {
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      elevation: 1,
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(8),
        child: Padding(
          padding: const EdgeInsets.all(8),
          child: Row(
            children: [
              if (recipe.imageUrls.isNotEmpty)
                GestureDetector(
                  onTap: () => _openPhotoGallery(context, 0),
                  child: ClipRRect(
                    borderRadius: BorderRadius.circular(6),
                    child: SizedBox(
                      width: 80,
                      height: 80,
                      child: _buildRecipeImage(recipe.imageUrls.first),
                    ),
                  ),
                ),
              if (recipe.imageUrls.isNotEmpty) const SizedBox(width: 12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Row(
                      children: [
                        Expanded(
                          child: Text(
                            recipe.title,
                            style: const TextStyle(
                              fontSize: 14,
                              fontWeight: FontWeight.bold,
                            ),
                            maxLines: 1,
                            overflow: TextOverflow.ellipsis,
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 4),
                    Row(
                      mainAxisAlignment: MainAxisAlignment.end,
                      children: [
                        IconButton(
                          icon: Icon(
                            recipe.isFavourite ? Icons.favorite : Icons.favorite_border,
                            color: recipe.isFavourite ? Colors.red : Colors.grey,
                            size: 24,
                          ),
                          onPressed: onFavorite,
                          padding: EdgeInsets.zero,
                          constraints: const BoxConstraints(),
                          tooltip: recipe.isFavourite ? 'Remove from favorites' : 'Add to favorites',
                        ),
                        const SizedBox(width: 8),
                        const Icon(
                          Icons.star,
                          size: 20,
                          color: Colors.amber,
                        ),
                        const SizedBox(width: 4),
                        Text(
                          recipe.rating.toString(),
                          style: Theme.of(context).textTheme.titleSmall?.copyWith(
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                      ],
                    ),
                  ],
                ),
              ),
              PopupMenuButton(
                icon: const Icon(Icons.more_vert, size: 20),
                itemBuilder: (context) => [
                  PopupMenuItem(
                    child: const Row(
                      children: [
                        Icon(Icons.edit, size: 18),
                        SizedBox(width: 8),
                        Text('Edit'),
                      ],
                    ),
                    onTap: () => Future.delayed(
                      const Duration(milliseconds: 100),
                      onEdit,
                    ),
                  ),
                  PopupMenuItem(
                    child: const Row(
                      children: [
                        Icon(Icons.delete, size: 18, color: Colors.red),
                        SizedBox(width: 8),
                        Text('Delete', style: TextStyle(color: Colors.red)),
                      ],
                    ),
                    onTap: () => Future.delayed(
                      const Duration(milliseconds: 100),
                      onDelete,
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildExpandedCard(BuildContext context) {
    return Card(
      margin: const EdgeInsets.only(bottom: 16),
      elevation: 2,
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            if (recipe.imageUrls.isNotEmpty)
              _buildMosaicImages(context, recipe.imageUrls),
            Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Row(
                    children: [
                      Expanded(
                        child: Text(
                          recipe.title,
                          style: const TextStyle(
                            fontSize: 20,
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                      ),
                      if (recipe.rating > 0)
                        Row(
                          children: List.generate(5, (index) {
                            return Icon(
                              index < recipe.rating
                                  ? Icons.star
                                  : Icons.star_border,
                              size: 16,
                              color: index < recipe.rating
                                  ? Colors.amber
                                  : Colors.grey,
                            );
                          }),
                        ),
                    ],
                  ),
                  if (recipe.description != null && recipe.description!.isNotEmpty) ...[
                    const SizedBox(height: 8),
                    Text(
                      recipe.description!,
                      style: TextStyle(
                        fontSize: 14,
                        color: Colors.grey.shade700,
                      ),
                      maxLines: 2,
                      overflow: TextOverflow.ellipsis,
                    ),
                  ],
                  if (recipe.tags.isNotEmpty) ...[
                    const SizedBox(height: 8),
                    Wrap(
                      spacing: 4,
                      runSpacing: 4,
                      children: recipe.tags.map((tag) {
                        return Chip(
                          label: Text(
                            tag,
                            style: const TextStyle(fontSize: 12),
                          ),
                          padding: EdgeInsets.zero,
                          materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
                          visualDensity: VisualDensity.compact,
                        );
                      }).toList(),
                    ),
                  ],
                  const SizedBox(height: 12),
                  Row(
                    mainAxisAlignment: MainAxisAlignment.end,
                    children: [
                      IconButton(
                        icon: Icon(
                          recipe.isFavourite ? Icons.favorite : Icons.favorite_border,
                          color: recipe.isFavourite ? Colors.red : Colors.grey,
                        ),
                        onPressed: onFavorite,
                        tooltip: recipe.isFavourite ? 'Remove from favorites' : 'Add to favorites',
                      ),
                      IconButton(
                        icon: const Icon(Icons.edit),
                        onPressed: onEdit,
                        tooltip: 'Edit',
                      ),
                      IconButton(
                        icon: const Icon(Icons.delete),
                        onPressed: onDelete,
                        tooltip: 'Delete',
                        color: Colors.red,
                      ),
                    ],
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}