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

import '../providers/auth_provider.dart';

/// Sticky banner shown when the backend is unreachable. Surfaces a retry
/// action and reserves space for future "last sync X min ago" messaging once
/// Tier 2 offline caching lands.
class OfflineBanner extends ConsumerStatefulWidget {
  const OfflineBanner({super.key});

  @override
  ConsumerState<OfflineBanner> createState() => _OfflineBannerState();
}

class _OfflineBannerState extends ConsumerState<OfflineBanner> {
  bool _retrying = false;

  Future<void> _retry() async {
    if (_retrying) return;
    setState(() => _retrying = true);
    try {
      await ref.read(authProvider.notifier).verify();
    } finally {
      if (mounted) setState(() => _retrying = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final status = ref.watch(authProvider);
    if (status != AuthStatus.offline) return const SizedBox.shrink();

    final scheme = Theme.of(context).colorScheme;
    return Material(
      color: scheme.errorContainer,
      child: SafeArea(
        bottom: false,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
          child: Row(
            children: [
              Icon(Icons.cloud_off_outlined,
                  size: 18, color: scheme.onErrorContainer),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  'Offline — showing cached data.',
                  style: TextStyle(color: scheme.onErrorContainer),
                ),
              ),
              TextButton(
                onPressed: _retrying ? null : _retry,
                style: TextButton.styleFrom(
                  foregroundColor: scheme.onErrorContainer,
                  padding: const EdgeInsets.symmetric(horizontal: 12),
                ),
                child: _retrying
                    ? const SizedBox(
                        width: 14,
                        height: 14,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Text('Retry'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}