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

/// 币种图标组件：图标已在 app 启动时通过 coinCacheProvider 预缓存，
/// 切换到行情页时命中缓存直接显示。加载失败时显示字母占位。
class CoinIcon extends StatelessWidget {
  const CoinIcon({
    super.key,
    required this.symbol,
    this.iconUrl = '',
    this.size = 40,
    this.borderRadius,
    this.shape = BoxShape.rectangle,
  });

  final String symbol;
  final String iconUrl;
  final double size;

  /// 圆角半径，仅在 [shape] 为 [BoxShape.rectangle] 时生效
  final double? borderRadius;

  /// [BoxShape.circle] 或 [BoxShape.rectangle]（默认矩形+圆角）
  final BoxShape shape;

  @override
  Widget build(BuildContext context) {
    final letter = symbol.isNotEmpty ? symbol[0].toUpperCase() : '?';
    final cs = Theme.of(context).colorScheme;
    final fontSize = size * 0.42;

    Widget letterWidget = SizedBox(
      width: size,
      height: size,
      child: Center(
        child: Text(
          letter,
          style: TextStyle(
            color: cs.onSurface.withAlpha(153),
            fontSize: fontSize,
            fontWeight: FontWeight.w700,
          ),
        ),
      ),
    );

    if (iconUrl.isEmpty) return _clip(letterWidget);

    // Key 随 URL 变化，避免从行情等错误来源切回空 icon 时仍短暂显示旧图
    return _clip(
      CachedNetworkImage(
        key: ValueKey('$symbol|$iconUrl'),
        imageUrl: iconUrl,
        width: size,
        height: size,
        fit: BoxFit.cover,
        errorWidget: (_, __, ___) => letterWidget,
      ),
    );
  }

  Widget _clip(Widget child) {
    if (shape == BoxShape.circle) {
      return ClipOval(child: child);
    }
    final radius = borderRadius ?? size * 0.3;
    return ClipRRect(
      borderRadius: BorderRadius.circular(radius),
      child: child,
    );
  }
}