import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:hooks_riverpod/hooks_riverpod.dart';
import 'package:package_info_plus/package_info_plus.dart';

import '../../models/pb/jinzhi/v1/push.pb.dart' as pb;
import '../network/api_exception.dart';
import 'notification_permission.dart';
import 'push_api_client.dart';
import 'umeng_push_service.dart';

class DevicePushRegistrar {
  DevicePushRegistrar(this._read);
  final T Function<T>(ProviderListenable<T>) _read;
  StreamSubscription<String>? _subscription;
  String? _lastToken;
  bool? _lastPermission;
  Future<void> _registrationQueue = Future.value();

  void start() {
    _subscription ??= UmengPushService.onDeviceToken.listen(_enqueue);
    UmengPushService.emitCachedToken();
  }

  Future<void> stop() async => _subscription?.cancel();
  Future<void> refresh() => UmengPushService.refreshDeviceToken();
  void forceRegisterCurrentToken() {
    // BLOCKED(server contract): guest registration is intentionally preserved.
    // Do not add a client-side unbind call until the backend confirms whether
    // guest registration reliably clears the previous user binding.
    _lastToken = null;
    _lastPermission = null;
    UmengPushService.emitCachedToken();
  }

  void _enqueue(String token) {
    _registrationQueue = _registrationQueue
        .catchError((_) {})
        .then((_) => _register(token));
  }

  Future<void> _register(String token) async {
    final permission = await NotificationPermission.isGranted();
    if (token == _lastToken && permission == _lastPermission) return;
    final package = await PackageInfo.fromPlatform();
    final request = pb.RegisterPushDeviceRequest(
      umengDeviceToken: token,
      platform: defaultTargetPlatform == TargetPlatform.iOS
          ? pb.Platform.PLATFORM_IOS
          : pb.Platform.PLATFORM_ANDROID,
      appVersion: package.version,
      permissionGranted: permission,
    );
    for (var attempt = 0; attempt < 4; attempt++) {
      try {
        await _read(pushApiClientProvider).registerDevice(request);
        _lastToken = token;
        _lastPermission = permission;
        return;
      } catch (error) {
        if (attempt == 3 || !ApiException.from(error).isRetryable) return;
        await Future<void>.delayed(Duration(seconds: 1 << attempt));
      }
    }
  }
}