halobestie-clone/client_app/lib/features/chat/widgets/bestie_unavailable_dialog.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import '../../../core/availability/mitra_availability_notifier.dart';
import '../../../core/constants.dart';
import '../../../core/pairing/pairing_notifier.dart';

/// Shown when a "Curhat lagi" attempt against a specific bestie can't proceed
/// — either a 409 `targeted_mitra_offline` response on the targeted POST, or
/// one of the intermediate WS events (`returning_chat_timeout`,
/// `returning_chat_rejected`).
///
/// CTAs:
/// - "Chat dengan bestie lain" — only rendered when
///   [mitraAvailabilityProvider] reports `available == true` at the time of
///   build. Tapping calls [Pairing.fallbackToBlast] (reuses the same payment
///   session — no double-charge) and closes the dialog. The caller is expected
///   to be the searching screen, which will transition into PairingSearchingData
///   and stay put.
/// - "Kembali" — pops dialog and routes home. Backend has already audit-logged
///   the targeted failure; payment session stays `confirmed` until the sweeper
///   expires it.
class BestieUnavailableDialog extends ConsumerWidget {
  final String paymentSessionId;
  final String mitraName;
  final TopicSensitivity topicSensitivity;

  const BestieUnavailableDialog({
    super.key,
    required this.paymentSessionId,
    required this.mitraName,
    required this.topicSensitivity,
  });

  /// Convenience: show this dialog and return when it closes. Per project
  /// memory ("Riverpod ref.listen in build is unsafe"), callers should
  /// invoke this from `ref.listenManual` callbacks in `initState`, not from
  /// `build`.
  static Future<void> show(
    BuildContext context, {
    required String paymentSessionId,
    required String mitraName,
    required TopicSensitivity topicSensitivity,
  }) {
    return showDialog<void>(
      context: context,
      barrierDismissible: false,
      builder: (_) => BestieUnavailableDialog(
        paymentSessionId: paymentSessionId,
        mitraName: mitraName,
        topicSensitivity: topicSensitivity,
      ),
    );
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    // Snapshot at dialog-open time — we don't keep listening, we just check
    // whether other bestie are around right now.
    final availabilityAsync = ref.watch(mitraAvailabilityProvider);
    final hasOtherAvailable = availabilityAsync.valueOrNull ?? false;

    return AlertDialog(
      title: const Text('Bestie sedang tidak online'),
      content: Text(
        '$mitraName sedang tidak bisa menerima chat saat ini. '
        'Kamu bisa coba chat dengan bestie lain atau kembali ke beranda.',
      ),
      actions: [
        TextButton(
          onPressed: () {
            // Reset pairing state and route home. Payment session stays
            // confirmed until sweeper expires it — no extra API call needed.
            ref.read(pairingProvider.notifier).reset();
            Navigator.of(context).pop();
            context.go('/home');
          },
          child: const Text('Kembali'),
        ),
        if (hasOtherAvailable)
          ElevatedButton(
            onPressed: () {
              // Close the dialog first, then kick off the fallback. The
              // searching screen will pick up the new PairingSearchingData
              // state and render normally (no targeted overlay).
              Navigator.of(context).pop();
              // ignore: discarded_futures
              ref.read(pairingProvider.notifier).fallbackToBlast(
                    paymentSessionId: paymentSessionId,
                    topicSensitivity: topicSensitivity,
                  );
            },
            child: const Text('Chat dengan bestie lain'),
          ),
      ],
    );
  }
}