yanting/lib/widgets/states.dart

import 'package:flutter/material.dart';
import 'package:shadcn_ui/shadcn_ui.dart';

import '../theme/yanting_tokens.dart';
import 'app_buttons.dart';
import 'app_card.dart';

class LoadingState extends StatelessWidget {
  const LoadingState({this.label = '正在加载研报解读', super.key});

  final String label;

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      padding: const EdgeInsets.all(YantingSpacing.screenX),
      itemCount: 4,
      separatorBuilder: (_, _) =>
          const SizedBox(height: YantingSpacing.cardGap),
      itemBuilder: (context, index) => const SkeletonCard(),
    );
  }
}

class SkeletonCard extends StatelessWidget {
  const SkeletonCard({super.key});

  @override
  Widget build(BuildContext context) {
    return AppCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: const [
          SkeletonLine(width: 96),
          SizedBox(height: YantingSpacing.cardGap),
          SkeletonLine(width: double.infinity, height: 18),
          SizedBox(height: YantingSpacing.x2),
          SkeletonLine(width: 240),
          SizedBox(height: YantingSpacing.cardGap),
          SkeletonLine(width: 160),
        ],
      ),
    );
  }
}

class SkeletonLine extends StatelessWidget {
  const SkeletonLine({required this.width, this.height = 12, super.key});

  final double width;
  final double height;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return _PulsingSkeleton(
      width: width,
      height: height,
      color: theme.colorScheme.muted,
    );
  }
}

class _PulsingSkeleton extends StatefulWidget {
  const _PulsingSkeleton({
    required this.color,
    required this.width,
    required this.height,
  });

  final Color color;
  final double width;
  final double height;

  @override
  State<_PulsingSkeleton> createState() => _PulsingSkeletonState();
}

class _PulsingSkeletonState extends State<_PulsingSkeleton>
    with SingleTickerProviderStateMixin {
  late final AnimationController _controller = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 1500),
  )..repeat(reverse: true);

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

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return FadeTransition(
      opacity: Tween<double>(
        begin: 0.4,
        end: 1,
      ).animate(CurvedAnimation(parent: _controller, curve: Curves.easeInOut)),
      child: Container(
        width: widget.width,
        height: widget.height,
        decoration: BoxDecoration(
          color: widget.color,
          borderRadius: theme.radius,
        ),
      ),
    );
  }
}

class EmptyState extends StatelessWidget {
  const EmptyState({
    required this.title,
    required this.message,
    this.icon = Icons.search_off,
    this.actionLabel,
    this.onAction,
    super.key,
  });

  final String title;
  final String message;
  final IconData icon;
  final String? actionLabel;
  final VoidCallback? onAction;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(YantingSpacing.x6),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(icon, size: 42, color: theme.colorScheme.foreground),
            const SizedBox(height: YantingSpacing.cardGap),
            Text(title, style: Theme.of(context).textTheme.titleMedium),
            const SizedBox(height: YantingSpacing.x2),
            Text(
              message,
              textAlign: TextAlign.center,
              style: Theme.of(context).textTheme.bodyMedium,
            ),
            if (actionLabel != null) ...[
              const SizedBox(height: YantingSpacing.x4),
              AppButton(
                label: actionLabel!,
                onPressed: onAction,
                kind: AppButtonKind.ghost,
              ),
            ],
          ],
        ),
      ),
    );
  }
}

class ErrorState extends StatelessWidget {
  const ErrorState({required this.message, this.onRetry, super.key});

  final String message;
  final VoidCallback? onRetry;

  @override
  Widget build(BuildContext context) {
    return EmptyState(
      icon: Icons.cloud_off_outlined,
      title: '内容暂时加载失败',
      message: message,
      actionLabel: onRetry == null ? null : '重试',
      onAction: onRetry,
    );
  }
}

void showAppToast(BuildContext context, String message) {
  ShadToaster.of(context).show(ShadToast(title: Text(message)));
}