import 'dart:io';
import 'package:flutter_test/flutter_test.dart';
import 'package:app_boilerplate/data/local/local_storage_service.dart';
import 'package:app_boilerplate/data/local/models/item.dart';
import 'package:path/path.dart' as path;
import 'package:sqflite_common_ffi/sqflite_ffi.dart';

void main() {
  // Initialize Flutter bindings for path_provider to work in tests
  TestWidgetsFlutterBinding.ensureInitialized();

  // Initialize sqflite for testing (required for VM/desktop tests)
  sqfliteFfiInit();
  databaseFactory = databaseFactoryFfi;

  late LocalStorageService service;
  late Directory testDir;
  late String testDbPath;
  late Directory testCacheDir;

  setUp(() async {
    // Create a temporary directory for testing
    testDir = await Directory.systemTemp.createTemp('local_storage_test_');
    testDbPath = path.join(testDir.path, 'test_local_storage.db');
    testCacheDir = Directory(path.join(testDir.path, 'image_cache'));
    
    // Create service with test paths (bypasses path_provider platform channels)
    service = LocalStorageService(
      testDbPath: testDbPath,
      testCacheDir: testCacheDir,
    );
    await service.initialize();
  });

  tearDown(() async {
    await service.close();
    // Clean up test files and directory
    try {
      if (await testDir.exists()) {
        await testDir.delete(recursive: true);
      }
    } catch (_) {
      // Ignore cleanup errors
    }
  });

  group('LocalStorageService - CRUD Operations', () {
    /// Tests that inserting an item successfully stores it in the database.
    test('insertItem - success', () async {
      // Arrange
      final item = Item(
        id: 'test-1',
        data: {'name': 'Test Item', 'value': 123},
      );

      // Act
      await service.insertItem(item);

      // Assert
      final retrieved = await service.getItem('test-1');
      expect(retrieved, isNotNull);
      expect(retrieved!.id, equals('test-1'));
      expect(retrieved.data['name'], equals('Test Item'));
      expect(retrieved.data['value'], equals(123));
    });

    /// Tests that inserting an item with existing ID replaces it.
    test('insertItem - replaces existing item', () async {
      // Arrange
      final item1 = Item(
        id: 'test-1',
        data: {'name': 'Original'},
      );
      final item2 = Item(
        id: 'test-1',
        data: {'name': 'Updated'},
      );

      // Act
      await service.insertItem(item1);
      await service.insertItem(item2);

      // Assert
      final retrieved = await service.getItem('test-1');
      expect(retrieved, isNotNull);
      expect(retrieved!.data['name'], equals('Updated'));
    });

    /// Tests that getting a non-existent item returns null.
    test('getItem - returns null for non-existent item', () async {
      // Act
      final result = await service.getItem('non-existent');

      // Assert
      expect(result, isNull);
    });

    /// Tests that getting an item returns the correct data.
    test('getItem - success', () async {
      // Arrange
      final item = Item(
        id: 'test-2',
        data: {'title': 'Test Title', 'count': 42},
      );
      await service.insertItem(item);

      // Act
      final retrieved = await service.getItem('test-2');

      // Assert
      expect(retrieved, isNotNull);
      expect(retrieved!.id, equals('test-2'));
      expect(retrieved.data['title'], equals('Test Title'));
      expect(retrieved.data['count'], equals(42));
    });

    /// Tests that getAllItems returns all stored items.
    test('getAllItems - returns all items', () async {
      // Arrange
      final item1 = Item(id: 'test-1', data: {'name': 'Item 1'});
      final item2 = Item(id: 'test-2', data: {'name': 'Item 2'});
      final item3 = Item(id: 'test-3', data: {'name': 'Item 3'});

      await service.insertItem(item1);
      await service.insertItem(item2);
      await service.insertItem(item3);

      // Act
      final items = await service.getAllItems();

      // Assert
      expect(items.length, equals(3));
      expect(items.map((i) => i.id).toList(), containsAll(['test-1', 'test-2', 'test-3']));
    });

    /// Tests that getAllItems returns empty list when no items exist.
    test('getAllItems - returns empty list when no items', () async {
      // Act
      final items = await service.getAllItems();

      // Assert
      expect(items, isEmpty);
    });

    /// Tests that getAllItems returns items in descending order by creation date.
    test('getAllItems - returns items in descending order', () async {
      // Arrange
      final item1 = Item(id: 'test-1', data: {'name': 'First'});
      await Future.delayed(const Duration(milliseconds: 10));
      final item2 = Item(id: 'test-2', data: {'name': 'Second'});
      await Future.delayed(const Duration(milliseconds: 10));
      final item3 = Item(id: 'test-3', data: {'name': 'Third'});

      await service.insertItem(item1);
      await service.insertItem(item2);
      await service.insertItem(item3);

      // Act
      final items = await service.getAllItems();

      // Assert
      expect(items.length, equals(3));
      expect(items[0].id, equals('test-3')); // Newest first
      expect(items[2].id, equals('test-1')); // Oldest last
    });

    /// Tests that deleting an item removes it from the database.
    test('deleteItem - success', () async {
      // Arrange
      final item = Item(id: 'test-1', data: {'name': 'Test'});
      await service.insertItem(item);

      // Act
      await service.deleteItem('test-1');

      // Assert
      final retrieved = await service.getItem('test-1');
      expect(retrieved, isNull);
    });

    /// Tests that deleting a non-existent item throws an exception.
    test('deleteItem - throws exception for non-existent item', () async {
      // Act & Assert
      expect(
        () => service.deleteItem('non-existent'),
        throwsException,
      );
    });

    /// Tests that updating an item modifies it correctly.
    test('updateItem - success', () async {
      // Arrange
      final item = Item(id: 'test-1', data: {'name': 'Original'});
      await service.insertItem(item);
      final originalTimestamp = item.updatedAt;

      await Future.delayed(const Duration(milliseconds: 10));

      final updatedItem = item.copyWith(
        data: {'name': 'Updated'},
      );

      // Act
      await service.updateItem(updatedItem);

      // Assert
      final retrieved = await service.getItem('test-1');
      expect(retrieved, isNotNull);
      expect(retrieved!.data['name'], equals('Updated'));
      expect(retrieved.updatedAt, greaterThan(originalTimestamp));
    });

    /// Tests that updating a non-existent item throws an exception.
    test('updateItem - throws exception for non-existent item', () async {
      // Arrange
      final item = Item(id: 'non-existent', data: {'name': 'Test'});

      // Act & Assert
      expect(
        () => service.updateItem(item),
        throwsException,
      );
    });
  });

  group('LocalStorageService - Image Caching', () {
    /// Tests that getCachedImage throws exception for invalid URL.
    test('getCachedImage - throws exception for invalid URL', () async {
      // Act & Assert
      expect(
        () => service.getCachedImage('not-a-valid-url'),
        throwsException,
      );
    });

    /// Tests that getCachedImage throws exception when not initialized.
    test('getCachedImage - throws exception when not initialized', () async {
      // Arrange
      final uninitializedService = LocalStorageService();

      // Act & Assert
      expect(
        () => uninitializedService.getCachedImage('https://example.com/image.jpg'),
        throwsException,
      );
    });

    /// Tests that clearImageCache removes all cached images.
    test('clearImageCache - removes all cached images', () async {
      // Act
      await service.clearImageCache();

      // Assert - should not throw
      expect(service, isNotNull);
    });

    /// Tests cache hit scenario - file already exists in cache.
    test('getCachedImage - cache hit when file exists', () async {
      // Arrange - create a file in cache directory manually
      // Note: Full HTTP download test would require mocking http client
      // This test verifies the cache directory structure is correct
      
      // Act & Assert - service should be initialized
      expect(service, isNotNull);
      
      // The actual HTTP download test would require:
      // 1. Mocking http.get() with mockito or http_mock_adapter
      // 2. Verifying file creation in cache directory
      // For now, we verify error handling works correctly
    });
  });

  group('LocalStorageService - Error Handling', () {
    /// Tests that operations fail when service is not initialized.
    test('operations fail when not initialized', () async {
      // Arrange
      final uninitializedService = LocalStorageService();
      final item = Item(id: 'test-1', data: {'name': 'Test'});

      // Act & Assert
      expect(
        () => uninitializedService.insertItem(item),
        throwsException,
      );
      expect(
        () => uninitializedService.getItem('test-1'),
        throwsException,
      );
      expect(
        () => uninitializedService.deleteItem('test-1'),
        throwsException,
      );
      expect(
        () => uninitializedService.updateItem(item),
        throwsException,
      );
    });

    /// Tests that getCachedImage fails when cache directory not initialized.
    test('getCachedImage fails when not initialized', () async {
      // Arrange
      final uninitializedService = LocalStorageService();

      // Act & Assert
      expect(
        () => uninitializedService.getCachedImage('https://example.com/image.jpg'),
        throwsException,
      );
    });

    /// Tests handling of missing or invalid data.
    test('handles missing data gracefully', () async {
      // Arrange
      final item = Item(id: 'test-1', data: {});

      // Act
      await service.insertItem(item);
      final retrieved = await service.getItem('test-1');

      // Assert
      expect(retrieved, isNotNull);
      expect(retrieved!.data, isEmpty);
    });

    /// Tests handling of complex nested data structures.
    test('handles complex nested data', () async {
      // Arrange
      final item = Item(
        id: 'test-1',
        data: {
          'metadata': {
            'author': 'Test Author',
            'tags': ['tag1', 'tag2'],
            'nested': {
              'deep': 'value',
            },
          },
        },
      );

      // Act
      await service.insertItem(item);
      final retrieved = await service.getItem('test-1');

      // Assert
      expect(retrieved, isNotNull);
      expect(retrieved!.data['metadata']['author'], equals('Test Author'));
      expect(retrieved.data['metadata']['tags'], isA<List>());
      expect(retrieved.data['metadata']['nested']['deep'], equals('value'));
    });
  });
}