nj/app/lib/features/editor/widgets/brush_panel.dart

// 画笔面板 -- 底部抽屉
// 提供画笔类型/粗细/颜色/透明度设置
// 遵循 StickerPickerSheet 底部面板模式

import 'package:flutter/material.dart';

import '../../../core/theme/app_colors.dart';
import '../bloc/editor_bloc.dart';
import 'stroke_model.dart';

/// 画笔面板 -- 底部抽屉
class BrushPanel extends StatelessWidget {
  final BrushType activeBrushType;
  final String activeColor;
  final double activeWidth;
  final double activeOpacity;
  final void Function(BrushType type) onBrushTypeChanged;
  final void Function(String color) onColorChanged;
  final void Function(double width) onWidthChanged;
  final void Function(double opacity) onOpacityChanged;

  const BrushPanel({
    super.key,
    required this.activeBrushType,
    required this.activeColor,
    required this.activeWidth,
    required this.activeOpacity,
    required this.onBrushTypeChanged,
    required this.onColorChanged,
    required this.onWidthChanged,
    required this.onOpacityChanged,
  });

  static const _brushTypes = [
    (BrushType.pen, '钢笔', Icons.gesture_rounded),
    (BrushType.pencil, '铅笔', Icons.edit_rounded),
    (BrushType.marker, '马克笔', Icons.brush_rounded),
    (BrushType.eraser, '橡皮', Icons.auto_fix_high_rounded),
  ];

  static const _colors = [
    '#2D2420', '#E07A5F', '#81B29A', '#F2CC8F',
    '#D4A5A5', '#42A5F5', '#9C27B0', '#FFFFFF',
  ];

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 280,
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.surface,
        borderRadius: const BorderRadius.vertical(top: Radius.circular(22)),
      ),
      child: Column(
        children: [
          // 拖拽指示条
          Padding(
            padding: const EdgeInsets.only(top: 12, bottom: 8),
            child: Container(
              width: 36,
              height: 4,
              decoration: BoxDecoration(
                color: Colors.grey[300],
                borderRadius: BorderRadius.circular(2),
              ),
            ),
          ),
          // 画笔类型行
          _buildBrushTypeRow(context),
          // 粗细滑块
          _buildSizeSlider(context),
          // 颜色行
          _buildColorRow(context),
          // 透明度滑块（仅马克笔）
          if (activeBrushType == BrushType.marker)
            _buildOpacitySlider(context),
        ],
      ),
    );
  }

  Widget _buildBrushTypeRow(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 8),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: _brushTypes.map((bt) {
          final isActive = activeBrushType == bt.$1;
          return GestureDetector(
            onTap: () => onBrushTypeChanged(bt.$1),
            child: Container(
              width: 64,
              height: 52,
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(12),
                border: isActive
                    ? Border.all(color: AppColors.accent, width: 2)
                    : Border.all(color: Colors.transparent),
                color: isActive
                    ? AppColors.accent.withValues(alpha: 0.1)
                    : null,
              ),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(
                    bt.$3,
                    size: 20,
                    color: isActive ? AppColors.accent : Colors.grey[600],
                  ),
                  const SizedBox(height: 2),
                  Text(
                    bt.$2,
                    style: TextStyle(
                      fontSize: 10,
                      color: isActive ? AppColors.accent : Colors.grey[600],
                      fontWeight:
                          isActive ? FontWeight.w600 : FontWeight.normal,
                    ),
                  ),
                ],
              ),
            ),
          );
        }).toList(),
      ),
    );
  }

  Widget _buildSizeSlider(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 4),
      child: Row(
        children: [
          Text('粗细',
              style: TextStyle(fontSize: 12, color: Colors.grey[600])),
          Expanded(
            child: Slider(
              value: activeWidth,
              min: 1,
              max: 20,
              divisions: 19,
              activeColor: AppColors.accent,
              label: activeWidth.round().toString(),
              onChanged: onWidthChanged,
            ),
          ),
          Text(
            activeWidth.round().toString(),
            style: TextStyle(fontSize: 12, color: Colors.grey[600]),
          ),
        ],
      ),
    );
  }

  Widget _buildColorRow(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 8),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: _colors.map((c) {
          final isActive = activeColor == c;
          final color = _parseHexColor(c);
          return GestureDetector(
            onTap: () => onColorChanged(c),
            child: Container(
              width: 24,
              height: 24,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                color: color,
                border: isActive
                    ? Border.all(color: AppColors.accent, width: 2)
                    : (c == '#FFFFFF'
                        ? Border.all(color: Colors.grey[300]!)
                        : null),
              ),
            ),
          );
        }).toList(),
      ),
    );
  }

  Widget _buildOpacitySlider(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 4),
      child: Row(
        children: [
          Text('透明度',
              style: TextStyle(fontSize: 12, color: Colors.grey[600])),
          Expanded(
            child: Slider(
              value: activeOpacity,
              min: 0.1,
              max: 1.0,
              activeColor: AppColors.accent,
              onChanged: onOpacityChanged,
            ),
          ),
          Text(
            '${(activeOpacity * 100).round()}%',
            style: TextStyle(fontSize: 12, color: Colors.grey[600]),
          ),
        ],
      ),
    );
  }

  Color _parseHexColor(String hex) {
    final code = hex.replaceFirst('#', '');
    return Color(int.parse('FF$code', radix: 16));
  }
}