import 'package:flutter/material.dart';

import 'cell.dart';

typedef VCheckBoxCellGroupItemBuilder<T> = Widget Function(T data);

typedef VCheckBoxCellGroupCheckChanged<T, TValue> = void Function(
  TValue value,
  bool isChecked,
  T data,
  List<TValue> checkedValues,
);

class CheckBoxCellGroupItem<T> {
  final T data;
  final bool isChecked;
  final bool isDisabled;

  CheckBoxCellGroupItem(
    this.data, {
    this.isChecked = false,
    this.isDisabled = false,
  });
}

class VCheckBoxCellGroup<T, TValue> extends StatefulWidget {
  final List<CheckBoxCellGroupItem<T>> source;

  /// 选项文本提取函数
  final String Function(T data) labelGetter;

  /// 选项值提取函数
  final TValue Function(T data) valueGetter;

  final VCheckBoxCellGroupCheckChanged<T, TValue>? onChanged;

  final bool isScrollable;
  final ScrollController? controller;

  const VCheckBoxCellGroup({
    super.key,
    required this.source,
    required this.labelGetter,
    required this.valueGetter,
    this.onChanged,
    this.isScrollable = true,
    this.controller,
  });

  @override
  State<StatefulWidget> createState() => _VCheckBoxCellGroupState<T, TValue>();
}

class _VCheckBoxCellGroupState<T, TValue>
    extends State<VCheckBoxCellGroup<T, TValue>> {
  List<TValue> _checkedValues = [];

  @override
  void initState() {
    _checkedValues = widget.source
        .where((e) => e.isChecked)
        .map((e) => widget.valueGetter.call(e.data))
        .toList();

    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    final divider = Divider(
      thickness: 1,
      color: Colors.grey.shade300,
      height: 2,
    );

    final children = <Widget>[];
    final count = widget.source.length;
    for (var i = 0; i < count; i++) {
      if (i > 0) {
        children.add(divider);
      }
      final item = widget.source[i];
      children.add(_buildItemWidget(item));
    }

    if (widget.isScrollable) {
      return ListView(
        shrinkWrap: true,
        controller: widget.controller ?? ScrollController(),
        children: children,
      );
    } else {
      return Column(
        mainAxisAlignment: MainAxisAlignment.center,
        mainAxisSize: MainAxisSize.min,
        children: children,
      );
    }
  }

  Widget _buildItemWidget(CheckBoxCellGroupItem<T> item) {
    final label = widget.labelGetter.call(item.data);
    final value = widget.valueGetter.call(item.data);
    final isChecked = _checkedValues.contains(value);
    return VCheckBoxCell<TValue>(
      label: label,
      value: value,
      isChecked: isChecked,
      isDisabled: item.isDisabled,
      onChanged: (_, isChecked) {
        _onCheckChanged(value, item.data, isChecked);
      },
    );
  }

  void _onCheckChanged(TValue value, T data, bool isChecked) {
    setState(() {
      if (isChecked) {
        if (_checkedValues.contains(value) == false) {
          _checkedValues.add(value);
        }
      } else {
        _checkedValues.remove(value);
      }
      widget.onChanged?.call(value, isChecked, data, _checkedValues);
    });
  }
}