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

/// 金值统一的网络图片入口。
///
/// 图片会自动使用 [CachedNetworkImage] 的磁盘缓存；业务页面不应直接创建
/// `Image.network`，以保证加载和失败状态的视觉及缓存策略一致。
class AppNetworkImage extends StatelessWidget {
  const AppNetworkImage({
    super.key,
    required this.imageUrl,
    this.width,
    this.height,
    this.fit = BoxFit.cover,
    this.alignment = Alignment.center,
    this.borderRadius,
    this.cacheKey,
    this.httpHeaders,
    this.placeholder,
    this.errorWidget,
    this.semanticLabel,
  });

  final String imageUrl;
  final double? width;
  final double? height;
  final BoxFit fit;
  final Alignment alignment;
  final BorderRadius? borderRadius;
  final String? cacheKey;
  final Map<String, String>? httpHeaders;
  final Widget? placeholder;
  final Widget? errorWidget;
  final String? semanticLabel;

  @override
  Widget build(BuildContext context) {
    final child = imageUrl.trim().isEmpty
        ? _ImageFallback(errorWidget: errorWidget)
        : CachedNetworkImage(
            imageUrl: imageUrl,
            cacheKey: cacheKey,
            httpHeaders: httpHeaders,
            width: width,
            height: height,
            fit: fit,
            alignment: alignment,
            fadeInDuration: const Duration(milliseconds: 150),
            placeholder: (_, _) =>
                placeholder ?? const _ImageLoadingPlaceholder(),
            errorWidget: (_, _, _) => _ImageFallback(errorWidget: errorWidget),
          );

    final clipped = borderRadius == null
        ? child
        : ClipRRect(borderRadius: borderRadius!, child: child);
    if (semanticLabel == null) return clipped;
    return Semantics(image: true, label: semanticLabel, child: clipped);
  }
}

class _ImageLoadingPlaceholder extends StatelessWidget {
  const _ImageLoadingPlaceholder();

  @override
  Widget build(BuildContext context) {
    final colors = ShadTheme.of(context).colorScheme;
    return ColoredBox(
      color: colors.muted,
      child: Center(
        child: SizedBox(
          width: 20,
          height: 20,
          child: CircularProgressIndicator(
            strokeWidth: 2,
            color: colors.mutedForeground,
          ),
        ),
      ),
    );
  }
}

class _ImageFallback extends StatelessWidget {
  const _ImageFallback({required this.errorWidget});

  final Widget? errorWidget;

  @override
  Widget build(BuildContext context) {
    if (errorWidget != null) return errorWidget!;
    final colors = ShadTheme.of(context).colorScheme;
    return ColoredBox(
      color: colors.muted,
      child: Center(
        child: Icon(
          Icons.image_not_supported_outlined,
          color: colors.mutedForeground,
        ),
      ),
    );
  }
}