import 'package:flutter/material.dart';
import 'package:shuffle/core/theme/app_spacing.dart';

enum AppBannerType { info, error }

/// Inline message banner (info / error) above forms.
///
/// Type is conveyed by icon + [typeLabel] (spoken prefix, e.g. "Error"),
/// never by color alone. The message is a live region, so screen readers
/// announce it when it appears. The optional action is a separate 48 dp text
/// button. All texts come from the caller (l10n).
class AppBanner extends StatelessWidget {
  const AppBanner({
    required this.type,
    required this.message,
    required this.typeLabel,
    super.key,
    this.actionLabel,
    this.onAction,
  }) : assert(
         (actionLabel == null) == (onAction == null),
         'actionLabel and onAction belong together',
       );

  final AppBannerType type;
  final String message;
  final String typeLabel;
  final String? actionLabel;
  final VoidCallback? onAction;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final scheme = theme.colorScheme;
    final isError = type == AppBannerType.error;
    final background = isError
        ? scheme.errorContainer
        : scheme.secondaryContainer;
    final foreground = isError
        ? scheme.onErrorContainer
        : scheme.onSecondaryContainer;

    return DecoratedBox(
      decoration: BoxDecoration(
        color: background,
        borderRadius: AppRadius.mdAll,
        border: Border.all(color: foreground.withValues(alpha: 0.5)),
      ),
      child: Padding(
        padding: const EdgeInsets.all(AppSpacing.lg),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          mainAxisSize: MainAxisSize.min,
          children: [
            Semantics(
              container: true,
              liveRegion: true,
              label: '$typeLabel: $message',
              child: ExcludeSemantics(
                child: Row(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Icon(
                      isError ? Icons.error_outline : Icons.info_outline,
                      color: foreground,
                    ),
                    const SizedBox(width: AppSpacing.md),
                    Expanded(
                      child: Text(
                        message,
                        style: theme.textTheme.bodyMedium?.copyWith(
                          color: foreground,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
            if (actionLabel != null)
              Align(
                alignment: AlignmentDirectional.centerEnd,
                child: TextButton(
                  onPressed: onAction,
                  style: TextButton.styleFrom(foregroundColor: foreground),
                  child: Text(actionLabel!),
                ),
              ),
          ],
        ),
      ),
    );
  }
}