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 '../../../brackets/domain/bracket.dart';
import '../../application/admin_brackets_notifier.dart';

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

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

    return Scaffold(
      body: bracketsAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (err, _) => 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 brackets',
                  style: theme.textTheme.titleMedium,
                ),
                const SizedBox(height: 6),
                Text(
                  '$err',
                  textAlign: TextAlign.center,
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: theme.colorScheme.onSurfaceVariant,
                  ),
                ),
              ],
            ),
          ),
        ),
        data: (brackets) {
          if (brackets.isEmpty) {
            return Center(
              child: Padding(
                padding: const EdgeInsets.all(32),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: <Widget>[
                    Icon(
                      Icons.account_tree_outlined,
                      size: 64,
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                    const SizedBox(height: 16),
                    Text(
                      'No brackets yet',
                      style: theme.textTheme.titleMedium,
                    ),
                    const SizedBox(height: 8),
                    Text(
                      'Tap the + button to create your first bracket.',
                      style: theme.textTheme.bodyMedium?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                  ],
                ),
              ),
            );
          }
          return ListView.builder(
            padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 16),
            itemCount: brackets.length,
            itemBuilder: (context, i) => _BracketRow(bracket: brackets[i]),
          );
        },
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: () => context.go('/admin/brackets/new'),
        icon: const Icon(Icons.add),
        label: const Text('NEW BRACKET'),
      ),
    );
  }
}

class _BracketRow extends ConsumerWidget {
  const _BracketRow({required this.bracket});

  final Bracket bracket;

  Future<void> _confirmDelete(BuildContext context, WidgetRef ref) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Delete bracket?'),
        content: Text(
          '"${bracket.name}" and all its match data will be permanently removed.',
        ),
        actions: <Widget>[
          TextButton(
            onPressed: () => Navigator.of(ctx).pop(false),
            child: const Text('Cancel'),
          ),
          FilledButton.tonal(
            onPressed: () => Navigator.of(ctx).pop(true),
            child: const Text('Delete'),
          ),
        ],
      ),
    );
    if (confirmed != true) return;
    if (!context.mounted) return;
    try {
      await ref.read(adminBracketsNotifierProvider.notifier).delete(bracket.id);
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Deleted "${bracket.name}"')),
        );
      }
    } 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 created = DateFormat.yMMMd().format(bracket.createdAt);
    final totalMatches = bracket.rounds.fold<int>(
      0,
      (sum, r) => sum + r.matches.length,
    );

    return Card(
      margin: const EdgeInsets.symmetric(vertical: 6),
      child: Padding(
        padding: const EdgeInsets.all(14),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Text(bracket.name, style: theme.textTheme.titleMedium),
            const SizedBox(height: 6),
            Text(
              '${bracket.rounds.length} round${bracket.rounds.length == 1 ? '' : 's'}  ·  $totalMatches match${totalMatches == 1 ? '' : 'es'}  ·  Created $created',
              style: theme.textTheme.bodySmall?.copyWith(
                color: theme.colorScheme.onSurfaceVariant,
              ),
            ),
            const SizedBox(height: 12),
            Row(
              mainAxisAlignment: MainAxisAlignment.end,
              children: <Widget>[
                TextButton.icon(
                  onPressed: () => _confirmDelete(context, ref),
                  icon: const Icon(Icons.delete_outline, size: 18),
                  label: const Text('Delete'),
                ),
                const SizedBox(width: 8),
                OutlinedButton.icon(
                  onPressed: () =>
                      context.go('/admin/brackets/${bracket.id}/edit'),
                  icon: const Icon(Icons.edit_outlined, size: 18),
                  label: const Text('Edit'),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}