import 'package:flutter/material.dart';

/// An asset's picture: the issuer's logo from the broker, and while it loads or when the
/// broker has none, a circle in the brand colour with the icon of the asset class.
///
/// The logo URL and colour come from the API as they are; a failed load (offline, a logo
/// the CDN has since dropped) quietly falls back rather than showing a broken image.
class AssetIcon extends StatelessWidget {
  const AssetIcon({
    super.key,
    required this.assetClass,
    this.logoUrl,
    this.logoColor,
    this.size = 32,
  });

  final String? assetClass;
  final String? logoUrl;
  final String? logoColor;
  final double size;

  @override
  Widget build(BuildContext context) {
    final url = logoUrl;
    final fallback = _Fallback(
      assetClass: assetClass,
      logoColor: logoColor,
      size: size,
    );
    return SizedBox.square(
      dimension: size,
      child: ClipOval(
        child: url == null
            ? fallback
            : Image.network(
                url,
                width: size,
                height: size,
                fit: BoxFit.cover,
                filterQuality: FilterQuality.medium,
                gaplessPlayback: true,
                errorBuilder: (_, _, _) => fallback,
                loadingBuilder: (_, child, progress) =>
                    progress == null ? child : fallback,
              ),
      ),
    );
  }
}

class _Fallback extends StatelessWidget {
  const _Fallback({
    required this.assetClass,
    required this.logoColor,
    required this.size,
  });

  final String? assetClass;
  final String? logoColor;
  final double size;

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    final brand = parseBrandColor(logoColor);
    final background = brand ?? scheme.surfaceContainerHigh;
    final foreground = brand == null
        ? scheme.onSurfaceVariant
        : (ThemeData.estimateBrightnessForColor(brand) == Brightness.dark
              ? Colors.white
              : Colors.black87);
    return ColoredBox(
      color: background,
      child: Icon(
        assetClassIcon(assetClass),
        size: size * 0.55,
        color: foreground,
      ),
    );
  }
}

/// `#21A038` (or `#AA21A038`) as a colour; null for anything else, so a malformed value
/// from the broker degrades to the neutral fallback instead of throwing.
Color? parseBrandColor(String? hex) {
  if (hex == null) return null;
  final digits = hex.startsWith('#') ? hex.substring(1) : hex;
  if (digits.length != 6 && digits.length != 8) return null;
  final value = int.tryParse(digits, radix: 16);
  if (value == null) return null;
  return Color(digits.length == 6 ? 0xFF000000 | value : value);
}

IconData assetClassIcon(String? assetClass) => switch (assetClass) {
  'share' => Icons.trending_up,
  'bond' => Icons.receipt_long_outlined,
  'etf' || 'fund' => Icons.pie_chart_outline,
  'currency' => Icons.currency_exchange,
  'index' => Icons.show_chart,
  'deposit' => Icons.savings_outlined,
  'real_estate' => Icons.home_outlined,
  'crypto' => Icons.currency_bitcoin,
  _ => Icons.circle_outlined,
};