// 共享空状态组件 — 统一所有页面的空数据展示
//
// 使用: EmptyStateWidget(icon: Icons.xxx, title: '暂无数据', subtitle: '下拉刷新试试')
// 样式参考: home_page._EmptyJournalState — 大图标淡化 + 标题 + 副标题 + 暖色按钮

import 'package:flutter/material.dart';

import '../core/constants/design_tokens.dart';
import '../core/theme/app_colors.dart';
import '../core/theme/app_radius.dart';

/// 统一空状态组件 — 图标 + 标题 + 可选副标题 + 可选操作按钮
class EmptyStateWidget extends StatelessWidget {
  const EmptyStateWidget({
    super.key,
    required this.icon,
    required this.title,
    this.subtitle,
    this.actionLabel,
    this.onAction,
    this.iconSize = 64,
  });

  /// 主图标
  final IconData icon;

  /// 图标大小
  final double iconSize;

  /// 标题文字
  final String title;

  /// 副标题（灰色小字）
  final String? subtitle;

  /// 操作按钮文字（不传则不显示按钮）
  final String? actionLabel;

  /// 操作按钮回调
  final VoidCallback? onAction;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Center(
      child: Padding(
        padding: const EdgeInsets.symmetric(vertical: DesignTokens.spacing40),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(
              icon,
              size: iconSize,
              color: theme.colorScheme.onSurface.withValues(alpha: 0.2),
            ),
            const SizedBox(height: DesignTokens.spacing16),
            Text(
              title,
              style: theme.textTheme.bodyLarge?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
              textAlign: TextAlign.center,
            ),
            if (subtitle != null) ...[
              const SizedBox(height: DesignTokens.spacing8),
              Text(
                subtitle!,
                style: theme.textTheme.bodyMedium?.copyWith(
                  color: theme.colorScheme.onSurfaceVariant.withValues(alpha: 0.6),
                ),
                textAlign: TextAlign.center,
              ),
            ],
            if (actionLabel != null && onAction != null) ...[
              const SizedBox(height: DesignTokens.spacing24),
              FilledButton.icon(
                onPressed: onAction,
                icon: const Icon(Icons.add_rounded),
                label: Text(actionLabel!),
                style: FilledButton.styleFrom(
                  backgroundColor: AppColors.accent,
                  foregroundColor: AppColors.bgLight,
                  shape: RoundedRectangleBorder(
                    borderRadius: AppRadius.pillBorder,
                  ),
                  padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
                ),
              ),
            ],
          ],
        ),
      ),
    );
  }
}