import 'dart:async';
import 'dart:typed_data';

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

import '../network/dio_provider.dart';
import 'notification_permission.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;
  int _attempt = 0;

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

  Future<void> stop() async => _subscription?.cancel();
  Future<void> refresh() => UmengPushService.refreshDeviceToken();
  void forceRegisterCurrentToken() {
    _lastToken = null;
    _lastPermission = null;
    UmengPushService.emitCachedToken();
  }

  Future<void> _register(String token) async {
    final permission = await NotificationPermission.isGranted();
    if (token == _lastToken && permission == _lastPermission) return;
    try {
      final package = await PackageInfo.fromPlatform();
      await _read(dioProvider).post<List<int>>(
        '/api/v1/push/devices',
        data: _PushRegisterRequest(
          token: token,
          platform: defaultTargetPlatform == TargetPlatform.iOS ? 1 : 2,
          version: package.version,
          permission: permission,
        ).toBytes(),
        options: protobufOptions(),
      );
      _lastToken = token;
      _lastPermission = permission;
      _attempt = 0;
    } catch (_) {
      if (_attempt++ >= 3) return;
      await Future<void>.delayed(Duration(seconds: 1 << (_attempt - 1)));
      await _register(token);
    }
  }
}

class _PushRegisterRequest {
  const _PushRegisterRequest({
    required this.token,
    required this.platform,
    required this.version,
    required this.permission,
  });
  final String token;
  final int platform;
  final String version;
  final bool permission;
  Uint8List toBytes() {
    final bytes = BytesBuilder(copy: false);
    void putInt(int value) {
      while (value > 0x7f) {
        bytes.addByte((value & 0x7f) | 0x80);
        value >>= 7;
      }
      bytes.addByte(value);
    }

    void putString(int tag, String value) {
      final raw = value.codeUnits;
      putInt((tag << 3) | 2);
      putInt(raw.length);
      bytes.add(raw);
    }

    putString(1, token);
    putInt(2 << 3);
    putInt(platform);
    putString(3, version);
    putInt(4 << 3);
    putInt(permission ? 1 : 0);
    return bytes.toBytes();
  }
}