import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../providers/announcements_provider.dart';

/// A persistent, globally visible banner that appears at the top of every
/// authenticated screen when one or more [Announcement]s have an active banner.
///
/// Mirrors the pattern used by [PassSlipCountdownBanner] and
/// [ShiftCountdownBanner]. Registered in [_ShellBackground] so it wraps all
/// shell-route screens.
///
/// Tapping the banner navigates to `/announcements`. The X button dismisses
/// the leading announcement for the current session; if more remain they
/// continue to be shown.
class AnnouncementBanner extends ConsumerStatefulWidget {
  const AnnouncementBanner({required this.child, super.key});

  final Widget child;

  @override
  ConsumerState<AnnouncementBanner> createState() =>
      _AnnouncementBannerState();
}

class _AnnouncementBannerState extends ConsumerState<AnnouncementBanner> {
  /// IDs of banners the user has dismissed for this session.
  final Set<String> _sessionDismissed = {};

  @override
  Widget build(BuildContext context) {
    final visible = ref
        .watch(activeBannerAnnouncementsProvider)
        .where((a) => !_sessionDismissed.contains(a.id))
        .toList();

    if (visible.isEmpty) return widget.child;

    final first = visible.first;
    final extra = visible.length - 1;

    final cs = Theme.of(context).colorScheme;
    final tt = Theme.of(context).textTheme;

    return Column(
      children: [
        Material(
          child: InkWell(
            onTap: () => context.go('/announcements'),
            child: Container(
              width: double.infinity,
              padding:
                  const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
              decoration: BoxDecoration(color: cs.primaryContainer),
              child: Row(
                crossAxisAlignment: CrossAxisAlignment.center,
                children: [
                  Icon(
                    Icons.campaign_rounded,
                    size: 22,
                    color: cs.onPrimaryContainer,
                  ),
                  const SizedBox(width: 10),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Text(
                          extra > 0
                              ? 'Announcement  ·  +$extra more'
                              : 'Announcement',
                          style: tt.labelSmall?.copyWith(
                            color:
                                cs.onPrimaryContainer.withValues(alpha: 0.75),
                            letterSpacing: 0.3,
                          ),
                        ),
                        const SizedBox(height: 1),
                        Text(
                          first.title,
                          style: tt.bodyMedium?.copyWith(
                            color: cs.onPrimaryContainer,
                            fontWeight: FontWeight.w600,
                          ),
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ],
                    ),
                  ),
                  Text(
                    'Tap to view',
                    style: tt.bodySmall?.copyWith(
                      color: cs.onPrimaryContainer.withValues(alpha: 0.7),
                    ),
                  ),
                  Icon(
                    Icons.chevron_right,
                    size: 18,
                    color: cs.onPrimaryContainer.withValues(alpha: 0.7),
                  ),
                  const SizedBox(width: 4),
                  // Dismiss for session
                  InkWell(
                    borderRadius: BorderRadius.circular(16),
                    onTap: () =>
                        setState(() => _sessionDismissed.add(first.id)),
                    child: Padding(
                      padding: const EdgeInsets.all(4),
                      child: Icon(
                        Icons.close,
                        size: 18,
                        color: cs.onPrimaryContainer,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
        ),
        Expanded(child: widget.child),
      ],
    );
  }
}