import 'package:flutter/material.dart';

class SelectInputField extends StatefulWidget {
  final List<String> options;
  final String? value;
  final ValueChanged<String?>? onChanged;
  final String hintText;
  final String labelText;
  final bool enabled;
  final EdgeInsetsGeometry? padding;
  final InputBorder? border;

  const SelectInputField({
    Key? key,
    required this.options,
    this.value,
    this.onChanged,
    this.hintText = '请选择或输入',
    this.labelText = '',
    this.enabled = true,
    this.padding,
    this.border,
  }) : super(key: key);

  @override
  State<SelectInputField> createState() => _SelectInputFieldState();
}

class _SelectInputFieldState extends State<SelectInputField> {
  final TextEditingController _controller = TextEditingController();
  final FocusNode _focusNode = FocusNode();
  bool _showDropdown = false;
  String? _selectedValue;

  @override
  void initState() {
    super.initState();
    _selectedValue = widget.value;
    _controller.text = widget.value ?? '';
  }

  @override
  void didUpdateWidget(SelectInputField oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.value != oldWidget.value) {
      _selectedValue = widget.value;
      _controller.text = widget.value ?? '';
    }
  }

  void _onTextChanged(String text) {
    setState(() {
      _selectedValue = text.isEmpty ? null : text;
      _showDropdown = text.isNotEmpty;
    });
    widget.onChanged?.call(text.isEmpty ? null : text);
  }

  void _onOptionSelected(String option) {
    setState(() {
      _selectedValue = option;
      _controller.text = option;
      _showDropdown = false;
    });
    widget.onChanged?.call(option);
    _focusNode.unfocus();
  }

  void _onFieldTap() {
    setState(() {
      _showDropdown = !_showDropdown;
    });
  }

  void _onFocusChange(bool hasFocus) {
    setState(() {
      _showDropdown = hasFocus;
    });
  }

  List<String> get _filteredOptions {
    if (_controller.text.isEmpty) {
      return widget.options;
    }
    return widget.options
        .where((option) =>
        option.toLowerCase().contains(_controller.text.toLowerCase()))
        .toList();
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        if (widget.labelText.isNotEmpty) ...[
          Text(
            widget.labelText,
            style: TextStyle(
              fontSize: 14,
              fontWeight: FontWeight.w500,
              color: Colors.grey[700],
            ),
          ),
          const SizedBox(height: 8),
        ],
        Stack(
          children: [
            TextField(
              controller: _controller,
              focusNode: _focusNode,
              onChanged: _onTextChanged,
              onTap: _onFieldTap,
              enabled: widget.enabled,
              decoration: InputDecoration(
                hintText: widget.hintText,
                border: widget.border ?? const OutlineInputBorder(),
                contentPadding: const EdgeInsets.symmetric(
                  horizontal: 12,
                  vertical: 14,
                ),
                suffixIcon: IconButton(
                  icon: Icon(
                    _showDropdown ? Icons.arrow_drop_up : Icons.arrow_drop_down,
                    color: Colors.grey[600],
                  ),
                  onPressed: () {
                    setState(() {
                      _showDropdown = !_showDropdown;
                    });
                    if (_showDropdown) {
                      _focusNode.requestFocus();
                    } else {
                      _focusNode.unfocus();
                    }
                  },
                ),
              ),
            ),
            if (_showDropdown && _filteredOptions.isNotEmpty)
              Positioned(
                top: 60,
                left: 0,
                right: 0,
                child: _buildDropdownList(),
              ),
          ],
        ),
      ],
    );
  }

  Widget _buildDropdownList() {
    return Material(
      elevation: 4,
      borderRadius: BorderRadius.circular(8),
      child: Container(
        decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.circular(8),
          border: Border.all(color: Colors.grey[300]!),
        ),
        constraints: const BoxConstraints(maxHeight: 200),
        child: ListView.builder(
          shrinkWrap: true,
          padding: EdgeInsets.zero,
          itemCount: _filteredOptions.length,
          itemBuilder: (context, index) {
            final option = _filteredOptions[index];
            return ListTile(
              title: Text(option),
              onTap: () => _onOptionSelected(option),
              dense: true,
              visualDensity: VisualDensity.compact,
            );
          },
        ),
      ),
    );
  }

  @override
  void dispose() {
    _controller.dispose();
    _focusNode.dispose();
    super.dispose();
  }
}