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

import '../../../events/domain/event.dart';
import '../../application/admin_events_notifier.dart';

class AdminEventsScreen extends ConsumerWidget {
  const AdminEventsScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final eventsAsync = ref.watch(adminEventsStreamProvider);
    final theme = Theme.of(context);

    return Scaffold(
      body: eventsAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (err, _) => _ErrorState(
          message: '$err',
          onRetry: () => ref.invalidate(adminEventsStreamProvider),
        ),
        data: (events) {
          if (events.isEmpty) {
            return Center(
              child: Padding(
                padding: const EdgeInsets.all(32),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[
                    Icon(
                      Icons.event_busy_outlined,
                      size: 64,
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                    const SizedBox(height: 16),
                    Text(
                      'No events yet',
                      style: theme.textTheme.titleMedium,
                    ),
                    const SizedBox(height: 8),
                    Text(
                      'Tap the + button to create your first event.',
                      style: theme.textTheme.bodyMedium?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                  ],
                ),
              ),
            );
          }
          return ListView.builder(
            padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 16),
            itemCount: events.length,
            itemBuilder: (context, index) => _EventRow(event: events[index]),
          );
        },
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () => context.go('/admin/events/new'),
        icon: const Icon(Icons.add),
        label: const Text('NEW EVENT'),
      ),
    );
  }
}

class _EventRow extends ConsumerWidget {
  const _EventRow({required this.event});

  final Event event;

  Future<void> _confirmDelete(BuildContext context, WidgetRef ref) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Delete event?'),
        content: Text(
          '"${event.title}" will be permanently removed. This cannot be undone.',
        ),
        actions: <Widget>[
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(false),
            child: const Text('Cancel'),
          ),
          FilledButton.tonal(
            onPressed: () => Navigator.of(ctx).pop(true),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
    if (confirmed != true) return;
    if (!context.mounted) return;
    try {
      await ref.read(adminEventsNotifierProvider.notifier).delete(event.id);
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Deleted "${event.title}"')),
        );
      }
    } catch (e) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Delete failed: $e')),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final theme = Theme.of(context);
    final dateLabel = DateFormat.yMMMd().add_jm().format(event.date);

    return Card(
      margin: const EdgeInsets.symmetric(vertical: 6),
      child: Padding(
        padding: const EdgeInsets.all(14),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Row(
              children: <Widget>[
                Expanded(
                  child: Text(
                    event.title,
                    style: theme.textTheme.titleMedium,
                    maxLines: 2,
                    overflow: TextOverflow.ellipsis,
                  ),
                ),
                if (event.isCancelled)
                  Container(
                    padding: const EdgeInsets.symmetric(
                      horizontal: 8,
                      vertical: 2,
                    ),
                    decoration: BoxDecoration(
                      color: theme.colorScheme.errorContainer,
                      borderRadius: BorderRadius.circular(2),
                    ),
                    child: Text(
                      'CANCELLED',
                      style: theme.textTheme.labelSmall?.copyWith(
                        color: theme.colorScheme.onErrorContainer,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                  ),
              ],
            ),
            const SizedBox(height: 8),
            Row(
              children: <Widget>[
                Icon(
                  Icons.schedule,
                  size: 14,
                  color: theme.colorScheme.onSurfaceVariant,
                ),
                const SizedBox(width: 4),
                Expanded(
                  child: Text(
                    dateLabel,
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                  ),
                ),
                Text(
                  '${event.teamsRegistered}/${event.maxTeams} teams',
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: theme.colorScheme.onSurfaceVariant,
                  ),
                ),
              ],
            ),
            const SizedBox(height: 4),
            Row(
              children: <Widget>[
                Icon(
                  Icons.location_on_outlined,
                  size: 14,
                  color: theme.colorScheme.onSurfaceVariant,
                ),
                const SizedBox(width: 4),
                Expanded(
                  child: Text(
                    event.location,
                    style: theme.textTheme.bodySmall?.copyWith(
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                  ),
                ),
              ],
            ),
            const SizedBox(height: 12),
            Row(
              mainAxisAlignment: MainAxisAlignment.end,
              children: <Widget>[
                TextButton.icon(
                  onPressed: () => _confirmDelete(context, ref),
                  icon: const Icon(Icons.delete_outline, size: 18),
                  label: const Text('Delete'),
                ),
                const SizedBox(width: 8),
                OutlinedButton.icon(
                  onPressed: () =>
                      context.go('/admin/events/${event.id}/edit'),
                  icon: const Icon(Icons.edit_outlined, size: 18),
                  label: const Text('Edit'),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _ErrorState extends StatelessWidget {
  const _ErrorState({required this.message, required this.onRetry});

  final String message;
  final VoidCallback onRetry;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Icon(
              Icons.error_outline,
              size: 48,
              color: theme.colorScheme.error,
            ),
            const SizedBox(height: 12),
            Text(
              'Could not load events',
              style: theme.textTheme.titleMedium,
            ),
            const SizedBox(height: 6),
            Text(
              message,
              textAlign: TextAlign.center,
              style: theme.textTheme.bodySmall?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
            ),
            const SizedBox(height: 16),
            FilledButton.tonalIcon(
              onPressed: onRetry,
              icon: const Icon(Icons.refresh),
              label: const Text('Try again'),
            ),
          ],
        ),
      ),
    );
  }
}