import 'dart:convert';
import 'dart:math';

import 'package:android_id/android_id.dart';
import 'package:client_proxy_framework/client_proxy_framework.dart';
import 'package:crypto/crypto.dart' show md5;
import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter/foundation.dart';
import 'package:shared_preferences/shared_preferences.dart';

import '../user/user_state.dart';

const _prefsKeyFallbackDeviceId = 'persisted_device_id';

Future<String> _persistedFallbackDeviceId() async {
  final prefs = await SharedPreferences.getInstance();
  var id = prefs.getString(_prefsKeyFallbackDeviceId);
  if (id != null && id.isNotEmpty) return id;
  final random = Random.secure();
  final bytes = List<int>.generate(16, (_) => random.nextInt(256));
  id = base64UrlEncode(bytes).replaceAll('=', '');
  await prefs.setString(_prefsKeyFallbackDeviceId, id);
  return id;
}

class AppAuthCallbacks implements AuthServiceCallbacks {
  /// 与 app_client 一致：Android 用 Settings.Secure.ANDROID_ID（android_id 包，非 Build.ID）；
  /// iOS 用 identifierForVendor；失败或其它平台用 SharedPreferences 持久化随机 id。
  @override
  Future<String> getDeviceId() async {
    switch (defaultTargetPlatform) {
      case TargetPlatform.android:
        final androidId = await const AndroidId().getId();
        if (androidId != null && androidId.isNotEmpty) {
          return androidId;
        }
        return _persistedFallbackDeviceId();
      case TargetPlatform.iOS:
        final ios = await DeviceInfoPlugin().iosInfo;
        final idfv = ios.identifierForVendor;
        if (idfv != null && idfv.isNotEmpty) return idfv;
        return _persistedFallbackDeviceId();
      default:
        return _persistedFallbackDeviceId();
    }
  }

  @override
  String computeSign(String deviceId) {
    return md5.convert(utf8.encode(deviceId)).toString().toUpperCase();
  }

  @override
  void onLoginSuccess(FastLoginResponse data) {
    if (data.userId != null) UserState.setUserId(data.userId!);
    if (data.credits != null) UserState.setCredits(data.credits!);
    if (data.avatar != null) UserState.setAvatar(data.avatar!);
    if (data.userName != null) UserState.setUserName(data.userName!);
  }

  @override
  void onCommonInfoLoaded(CommonInfoResponse data) {
    if (data.credits != null) UserState.setCredits(data.credits!);
    if (data.avatar != null) UserState.setAvatar(data.avatar!);
    if (data.userName != null) UserState.setUserName(data.userName!);
  }

  @override
  void onLoginFailed(String msg) {
    debugPrint('[AuthService] Login failed: $msg');
  }
}

/// 应用侧登录封装；Adjust 归因桥已由框架 [FrameworkAuthService.init] 默认注册。
class AuthService {
  static final _authCallbacks = AppAuthCallbacks();

  static Future<void> init() async {
    FrameworkAuthService.init(_authCallbacks);
    await FrameworkAuthService.start();
  }

  static Future<void> get loginComplete => FrameworkAuthService.loginComplete;
}