import 'package:flutter/material.dart';
import '../pages/search_page.dart';
import '../services/epub_parser_service.dart';
import '../services/book_repository.dart';
import 'package:file_picker/file_picker.dart';

/// 应用顶部导航组件
///
/// 可复用的顶部导航栏组件，集成在搜索栏内的导入按钮。
/// 提供统一的搜索和文件导入功能，支持主题自适应。
class AppHeader extends StatefulWidget {
  /// 标题文本（可选），某些页面可以显示标题而非搜索栏
  final String? title;

  /// 搜索按钮点击回调函数
  final VoidCallback? onSearchPressed;

  /// 导入按钮点击回调函数
  final VoidCallback? onImportPressed;

  /// 是否显示搜索栏（默认值为true）
  final bool showSearchBar;

  /// 搜索栏占位符文本
  final String searchHint;

  const AppHeader({
    super.key,
    this.title,
    this.onSearchPressed,
    this.onImportPressed,
    this.showSearchBar = true,
    this.searchHint = '搜索书名或内容...',
  });

  @override
  State<AppHeader> createState() => _AppHeaderState();
}

class _AppHeaderState extends State<AppHeader> {
  final EpubParserService _epubParserService = EpubParserService();
  final BookRepository _bookRepository = BookRepository();

  /// 构建组件的UI结构
  @override
  Widget build(BuildContext context) {
    return Container(
      height: 60,
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.surface,
        border: Border(
          bottom: BorderSide(
            color: Theme.of(context).colorScheme.outline.withOpacity(0.2),
            width: 1,
          ),
        ),
      ),
      child: Row(
        children: [
          // 标题区域（条件渲染）
          if (widget.title != null) ...[
            Text(
              widget.title!,
              style: Theme.of(context).textTheme.headlineSmall?.copyWith(
                fontWeight: FontWeight.w600,
              ),
            ),
            const SizedBox(width: 16),
          ],

          // 搜索栏区域（占据剩余空间）
          if (widget.showSearchBar) ...[
            Expanded(
              child: _buildSearchBar(context),
            ),
          ]
        ],
      ),
    );
  }

  /// 构建搜索栏组件，包含搜索图标、占位符文本和导入按钮
  Widget _buildSearchBar(BuildContext context) {
    return Container(
      height: 44,
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.surfaceVariant,
        borderRadius: BorderRadius.circular(22),
        border: Border.all(
          color: Theme.of(context).colorScheme.outline.withOpacity(0.3),
        ),
      ),
      child: Material(
        color: Colors.transparent,
        child: InkWell(
          borderRadius: BorderRadius.circular(22),
          onTap: widget.onSearchPressed ?? () => _navigateToSearchPage(context),
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: Row(
              children: [
                Icon(
                  Icons.search,
                  size: 24,
                  color: Theme.of(context).colorScheme.onSurfaceVariant,
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: Text(
                    widget.searchHint,
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                      color: Theme.of(context)
                          .colorScheme
                          .onSurfaceVariant
                          .withOpacity(0.6),
                    ),
                  ),
                ),
                const SizedBox(width: 8),
                _buildImportButton(context),
              ],
            ),
          ),
        ),
      ),
    );
  }

  /// 构建导入按钮组件
  Widget _buildImportButton(BuildContext context) {
    return Container(
      height: 32,
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.primaryContainer,
        borderRadius: BorderRadius.circular(16),
      ),
      child: Material(
        color: Colors.transparent,
        child: InkWell(
          borderRadius: BorderRadius.circular(16),
          onTap: widget.onImportPressed ?? () => _importEpubFile(),
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                Text(
                  '导入',
                  style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                    color: Theme.of(context).colorScheme.onPrimaryContainer,
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }

  /// 导航到搜索页面
  void _navigateToSearchPage(BuildContext context) {
    Navigator.of(context).push(
      MaterialPageRoute(
        builder: (context) => const SearchPage(),
      ),
    );
  }

  /// 导入EPUB文件
  Future<void> _importEpubFile() async {
    try {
      // 1. 使用FilePicker选择EPUB文件
      FilePickerResult? result = await FilePicker.platform.pickFiles(
        type: FileType.custom,
        allowedExtensions: ['epub'],
      );

      if (result != null && result.files.single.path != null) {
        final filePath = result.files.single.path!;

        // 2. 检查文件是否已存在
        final existingBooks = await _bookRepository.getAllBooks();
        final isDuplicate = existingBooks.any((book) => book.filePath == filePath);

        if (isDuplicate) {
          if (mounted) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(
                content: Text('该文件已经导入过了'),
                backgroundColor: Colors.orange,
              ),
            );
          }
          return;
        }

        // 3. 解析EPUB文件
        final epubBook = await _epubParserService.parseEpubFile(filePath);

        // 4. 提取元数据并创建Book对象
        final book = await _epubParserService.extractBookMetadata(epubBook, filePath);

        // 5. 保存到数据库
        await _bookRepository.addBook(book);

        // 6. 显示成功消息
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text('成功导入: ${book.title}'),
              backgroundColor: Colors.green,
              duration: const Duration(seconds: 2),
            ),
          );
        }
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('导入失败: $e'),
            backgroundColor: Colors.red,
            duration: const Duration(seconds: 3),
          ),
        );
      }
    }
  }
}