import 'package:flutter/foundation.dart';
import '../models/book.dart';

/// 搜索状态管理类
///
/// 提供实时搜索功能，支持书名和作者的模糊搜索
/// 使用防抖机制优化性能，避免频繁搜索请求
class SearchProvider with ChangeNotifier {
  String _searchQuery = '';
  bool _isSearching = false;
  List<Book> _searchResults = [];
  List<Book> _allBooks = [];

  // 公开访问器
  String get searchQuery => _searchQuery;
  bool get isSearching => _isSearching;
  List<Book> get searchResults => _searchResults;
  bool get hasQuery => _searchQuery.isNotEmpty;
  bool get hasResults => _searchResults.isNotEmpty;

  /// 初始化书籍数据源
  ///
  /// [books] 完整的书籍列表，用于搜索过滤
  void loadBooks(List<Book> books) {
    _allBooks = books;
    _searchResults = books;
    notifyListeners();
  }

  /// 更新搜索关键词并触发搜索
  ///
  /// [query] 新的搜索关键词，支持部分匹配
  void updateQuery(String query) {
    if (_searchQuery == query) return;
    _searchQuery = query;
    _performSearch();
  }

  /// 清空搜索状态
  ///
  /// 重置搜索关键词并显示所有书籍
  void clearSearch() {
    _searchQuery = '';
    _searchResults = _allBooks;
    notifyListeners();
  }

  /// 执行搜索逻辑
  ///
  /// 使用300ms防抖延迟，避免频繁搜索请求
  /// 支持书名和作者的不区分大小写模糊匹配
  void _performSearch() {
    _isSearching = true;
    notifyListeners();

    if (_searchQuery.isEmpty) {
      _searchResults = List.from(_allBooks);
      _isSearching = false;
      notifyListeners();
      return;
    }

    Future.delayed(const Duration(milliseconds: 300), () {
      if (_searchQuery.isEmpty) {
        _searchResults = List.from(_allBooks);
      } else {
        final query = _searchQuery.toLowerCase();
        _searchResults = _allBooks.where((book) {
          return book.title.toLowerCase().contains(query) ||
                 (book.author?.toLowerCase().contains(query) ?? false);
        }).toList();
      }

      _isSearching = false;
      notifyListeners();
    });
  }
}