import 'package:chicken_farm/components/vb_select.dart';
import 'package:chicken_farm/core/utils/logger.dart';
import 'package:flutter/material.dart';

/// 搜索API函数签名
/// T 为数据类型
typedef SearchApiFunction<T> =
    Future<Map<String, dynamic>> Function({
      required Map<String, dynamic> queryParams,
    });

/// 选项转换器，将数据类型T转换为SelectOption
typedef SelectOptionConverter<T> = SelectOption Function(T data);

/// 搜索选择组件
class VberSearchSelect<T> extends StatefulWidget {
  /// 搜索API函数
  final SearchApiFunction<T> searchApi;

  /// 数据转换方法，将原始数据转换为SelectOption
  final SelectOptionConverter<T> converter;

  /// 根据value获取对应label的函数
  final Future<String?> Function(String?)? getValueLabel;

  /// 当前选中的值
  final String? value;

  /// 值改变回调
  final ValueChanged<String?>? onChanged;

  /// 提示文字
  final String? hint;

  /// 是否启用
  final bool enabled;

  /// 每页数据条数
  final int pageSize;

  /// 额外参数，用于传递给搜索API
  final Map<String, dynamic>? extraParams;

  /// 是否隐藏下划线
  final bool hideUnderline;

  /// 是否显示清空按钮
  final bool showClearButton;

  const VberSearchSelect({
    super.key,
    required this.searchApi,
    required this.converter,
    this.getValueLabel,
    this.value,
    this.onChanged,
    this.hint,
    this.enabled = true,
    this.pageSize = 10,
    this.extraParams,
    this.hideUnderline = false,
    this.showClearButton = true,
  });

  @override
  State<VberSearchSelect<T>> createState() => _VberSearchSelectState<T>();
}

class _VberSearchSelectState<T> extends State<VberSearchSelect<T>> {
  final TextEditingController _searchController = TextEditingController();
  final FocusNode _searchFocusNode = FocusNode();
  String? _selectedValue;
  SelectOption? _selectedOption;
  final List<T> _items = [];

  @override
  void initState() {
    super.initState();
    _selectedValue = widget.value;
    _initSelectedOption();
  }

  /// 初始化选中选项
  void _initSelectedOption() async {
    if (widget.value != null && widget.getValueLabel != null) {
      try {
        final label = await widget.getValueLabel!(widget.value);
        if (mounted) {
          setState(() {
            _selectedOption = SelectOption(
              label: label ?? widget.value ?? '',
              value: widget.value!,
            );
          });
        }
      } catch (e) {
        logger.e('Failed to get label for value: ${widget.value}', e);
      }
    }
  }

  @override
  void didUpdateWidget(covariant VberSearchSelect<T> oldWidget) {
    super.didUpdateWidget(oldWidget);
    // 当外部传入的value发生变化时，同步更新内部状态
    if (oldWidget.value != widget.value) {
      _syncValueAndText(widget.value);
    }
  }

  /// 同步外部value和内部_selectedValue以及_selectedOption
  void _syncValueAndText(String? newValue) async {
    setState(() {
      _selectedValue = newValue;
    });

    // 优先使用存储的选项
    String? label;
    if (_selectedOption != null && _selectedOption!.value == newValue) {
      label = _selectedOption!.label;
    }

    // 尝试在现有选项中查找匹配的标签
    if (label == null && newValue != null) {
      for (var item in _items) {
        final option = widget.converter(item);
        if (option.value == newValue) {
          label = option.label;
          break;
        }
      }
    }

    // 如果在现有选项中没找到，且提供了getValueLabel函数，则尝试通过它获取
    if (label == null && newValue != null && widget.getValueLabel != null) {
      try {
        label = await widget.getValueLabel!(newValue);
      } catch (e) {
        logger.e('Failed to get label for value: $newValue', e);
      }
    }

    // 更新选中选项
    if (mounted) {
      setState(() {
        // 优先级: 找到的label > value本身 > 空字符串
        if (newValue != null) {
          _selectedOption = SelectOption(
            label: label ?? newValue,
            value: newValue,
          );
        } else {
          _selectedOption = null;
        }
      });
    }
  }

  @override
  void dispose() {
    _searchController.dispose();
    _searchFocusNode.dispose();
    super.dispose();
  }

  void _showSearchDialog() async {
    final result = await showDialog<SelectOption>(
      context: context,
      barrierDismissible: true,
      builder: (BuildContext context) {
        return _SearchDialog<T>(
          searchApi: widget.searchApi,
          converter: widget.converter,
          hint: widget.hint,
          pageSize: widget.pageSize,
          extraParams: widget.extraParams,
          searchController: _searchController,
          searchFocusNode: _searchFocusNode,
        );
      },
    );

    if (result != null) {
      setState(() {
        _selectedValue = result.value;
        _selectedOption = result;
      });
      widget.onChanged?.call(result.value);
    }
  }

  void _clearSelection() {
    setState(() {
      _selectedValue = null;
      _selectedOption = null;
    });
    widget.onChanged?.call(null);
  }

  @override
  Widget build(BuildContext context) {
    List<DropdownMenuItem<String>> dropdownItems = [];

    // 添加当前选中项到下拉列表（如果存在）
    if (_selectedOption != null) {
      dropdownItems.add(
        DropdownMenuItem<String>(
          value: _selectedOption!.value,
          child: Text(_selectedOption!.label),
        ),
      );
    }

    // 添加其他已加载的项到下拉列表
    if (_items.isNotEmpty) {
      for (var item in _items) {
        final option = widget.converter(item);
        // 避免重复添加选中项
        if (_selectedOption == null || option.value != _selectedOption!.value) {
          dropdownItems.add(
            DropdownMenuItem<String>(
              value: option.value,
              child: Text(option.label),
            ),
          );
        }
      }
    }

    // 创建一个不会真正展开下拉列表的DropdownButton
    Widget dropdownWidget = DropdownButton<String>(
      value: _selectedValue,
      hint: Text('请点击查询${widget.hint ?? ""}...'),
      items: dropdownItems.isEmpty ? null : dropdownItems,
      onChanged: null,
      isExpanded: true,
      icon: Icon(Icons.search), // 使用搜索图标表明这是搜索选择器
    );

    Widget selectWidget = widget.hideUnderline
        ? DropdownButtonHideUnderline(child: dropdownWidget)
        : dropdownWidget;

    // 使用 GestureDetector 包裹整个组件以确保点击事件能被正确捕获
    Widget wrappedWidget = GestureDetector(
      onTap: widget.enabled ? _showSearchDialog : null,
      child: selectWidget,
    );

    // 处理清空按钮显示
    if (widget.showClearButton && _selectedValue != null) {
      return Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Expanded(child: wrappedWidget),
          IconButton(
            icon: const Icon(Icons.clear, size: 20),
            onPressed: widget.enabled ? _clearSelection : null,
          ),
        ],
      );
    }

    return wrappedWidget;
  }
}

/// 搜索对话框
class _SearchDialog<T> extends StatefulWidget {
  final SearchApiFunction<T> searchApi;
  final SelectOptionConverter<T> converter;
  final String? hint;
  final int pageSize;
  final Map<String, dynamic>? extraParams;
  final TextEditingController searchController;
  final FocusNode searchFocusNode;

  const _SearchDialog({
    required this.searchApi,
    required this.converter,
    required this.hint,
    required this.pageSize,
    required this.extraParams,
    required this.searchController,
    required this.searchFocusNode,
  });

  @override
  _SearchDialogState<T> createState() => _SearchDialogState<T>();
}

class _SearchDialogState<T> extends State<_SearchDialog<T>> {
  List<T> _items = [];
  bool _isLoading = false;
  int _currentPage = 1;
  bool _hasMore = true;
  String _lastSearchText = '';
  final ScrollController _scrollController = ScrollController();

  @override
  void initState() {
    super.initState();
    // 清空搜索框
    widget.searchController.clear();
    _items.clear();
    _currentPage = 1;
    _hasMore = true;
    _lastSearchText = '';

    _performSearch('');

    // 移除自动获取焦点的代码，让用户手动点击输入框获取焦点
    // WidgetsBinding.instance.addPostFrameCallback((_) {
    //   widget.searchFocusNode.requestFocus();
    // });
    
    _scrollController.addListener(_scrollListener);
  }

  @override
  void dispose() {
    _scrollController.removeListener(_scrollListener);
    _scrollController.dispose();
    super.dispose();
  }

  void _scrollListener() {
    if (_scrollController.position.pixels ==
            _scrollController.position.maxScrollExtent &&
        _hasMore &&
        !_isLoading) {
      _loadMore();
    }
  }

  void _loadMore() async {
    setState(() {
      _isLoading = true;
    });

    try {
      _currentPage++;

      final result = await _fetchData(_currentPage);

      final List<dynamic> rows = result['rows'] is List ? result['rows'] : [];
      final int total = result['total'] is int ? result['total'] : 0;
      final newItems = rows.cast<T>().toList();

      if (mounted) {
        setState(() {
          _items.addAll(newItems);
          _hasMore = _items.length < total;
          _isLoading = false;
        });
      }
    } catch (e) {
      logger.e('加载更多失败：$e');
      if (mounted) {
        setState(() {
          _currentPage--; // 回退页码
          _isLoading = false;
        });
      }
    }
  }

  void _performSearch(String keyword) async {
    setState(() {
      _isLoading = true;
    });

    try {
      _currentPage = 1;
      _hasMore = true;

      final result = await _fetchData(_currentPage, keyword: keyword);

      final List<dynamic> rows = result['rows'] is List ? result['rows'] : [];
      final int total = result['total'] is int ? result['total'] : 0;
      final newItems = rows.cast<T>().toList();

      if (mounted) {
        setState(() {
          _items = newItems;
          _hasMore = _items.length < total;
          _isLoading = false;
        });
      }
    } catch (e) {
      logger.e('搜索失败：$e');
      if (mounted) {
        setState(() {
          _items = [];
          _hasMore = false;
          _isLoading = false;
        });
      }
    }
  }

  Future<Map<String, dynamic>> _fetchData(
    int pageNum, {
    String? keyword,
  }) async {
    final Map<String, dynamic> queryParams = {
      'pageSize': widget.pageSize,
      'pageNum': pageNum,
    };

    if (keyword != null && keyword.isNotEmpty) {
      queryParams['keyword'] = keyword;
    }

    if (widget.extraParams != null) {
      queryParams.addAll(widget.extraParams!);
    }

    final r = await widget.searchApi(queryParams: queryParams);
    return r;
  }

  void _onSearchChanged(String value) {
    Future.delayed(const Duration(milliseconds: 300), () {
      if (_lastSearchText != widget.searchController.text) {
        _lastSearchText = widget.searchController.text;
        _items.clear();
        _currentPage = 1;
        _hasMore = true;
        _performSearch(widget.searchController.text);
      }
    });
  }

  void _selectItem(SelectOption option, T item) {
    Navigator.of(context).pop(option);
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: Text('查询${widget.hint ?? ""}'),
      content: SizedBox(
        width: MediaQuery.of(context).size.width * 0.8,
        height: MediaQuery.of(context).size.height * 0.6,
        child: Column(
          children: [
            TextField(
              controller: widget.searchController,
              focusNode: widget.searchFocusNode,
              decoration: InputDecoration(
                hintText: '请输入${widget.hint}搜索关键词',
                contentPadding: EdgeInsets.symmetric(
                  horizontal: 12,
                  vertical: 8,
                ),
                border: OutlineInputBorder(
                  borderRadius: BorderRadius.circular(4),
                ),
                isDense: true,
              ),
              onChanged: _onSearchChanged,
            ),
            SizedBox(height: 16),
            if (_isLoading && _items.isEmpty)
              Expanded(child: Center(child: CircularProgressIndicator()))
            else if (!_isLoading && _items.isEmpty)
              Expanded(
                child: Center(
                  child: Text(
                    '没有查询到结果',
                    style: TextStyle(color: Colors.grey, fontSize: 14),
                  ),
                ),
              )
            else
              Expanded(
                child: NotificationListener<ScrollNotification>(
                  onNotification: (notification) {
                    if (notification.metrics.pixels ==
                            notification.metrics.maxScrollExtent &&
                        _hasMore &&
                        !_isLoading) {
                      _loadMore();
                      return true;
                    }
                    return false;
                  },
                  child: ListView.builder(
                    itemCount: _items.length + (_hasMore ? 1 : 0),
                    itemBuilder: (context, index) {
                      if (index == _items.length) {
                        // 显示加载更多指示器
                        return Padding(
                          padding: const EdgeInsets.all(12.0),
                          child: Center(
                            child: _isLoading
                                ? CircularProgressIndicator()
                                : Text('上拉加载更多'),
                          ),
                        );
                      }
                      final item = _items[index];
                      final option = widget.converter(item);
                      return ListTile(
                        title: Text(option.label),
                        onTap: () => _selectItem(option, item),
                        dense: true,
                        contentPadding: EdgeInsets.symmetric(
                          horizontal: 16,
                          vertical: 4,
                        ),
                        visualDensity: VisualDensity.compact,
                      );
                    },
                  ),
                ),
              ),
          ],
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: Text('取消'),
        ),
      ],
    );
  }
}