// device_identity.dart — 设备身份:稳定 device_id + 名称/平台/客户端版本上报
//
// device_id 首次启动随机生成(UUID v4)、写入 flutter_secure_storage 持久化,之后
// 每次读取复用 → 同一安装跨重启恒定(替换早期硬编码 'mac-001')。名称/平台/版本
// 取自系统。随 登录/注册/连接 上报给控制面,用于「我的设备」登记与会话绑定。
import 'dart:io' show Platform;

import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:package_info_plus/package_info_plus.dart';
import 'package:uuid/uuid.dart';

/// 设备元数据,随认证/连接请求上报。
class DeviceMeta {
  const DeviceMeta({
    required this.id,
    required this.name,
    required this.platform,
    required this.clientVersion,
  });

  final String id;
  final String name;
  final String platform; // ios | android | windows | macos | linux
  final String clientVersion;

  Map<String, dynamic> toJson() => {
        'id': id,
        'name': name,
        'platform': platform,
        'client_version': clientVersion,
      };
}

/// 极简键值存储接缝(便于单测注入;默认走 flutter_secure_storage)。
abstract class SecureKV {
  Future<String?> read(String key);
  Future<void> write(String key, String value);
}

class _SecureStorageKV implements SecureKV {
  // 与 TokenStore 一致:macOS 文件式 keychain,避免未签名 app 报 -34018。
  static const _s = FlutterSecureStorage(
    mOptions: MacOsOptions(useDataProtectionKeyChain: false),
  );
  @override
  Future<String?> read(String key) => _s.read(key: key);
  @override
  Future<void> write(String key, String value) => _s.write(key: key, value: value);
}

/// 设备身份服务。device_id 持久于安全存储;其余字段取自系统(缓存)。
class DeviceIdentity {
  DeviceIdentity({SecureKV? store}) : _kv = store ?? _SecureStorageKV();

  final SecureKV _kv;
  static const _kDeviceId = 'pangolin_device_id';
  static const _uuid = Uuid();

  String? _cachedId;
  DeviceMeta? _cachedMeta;

  /// 稳定 device_id。读到→复用;读到空→生成并持久化;
  /// 读**失败**(平台异常)≠ 不存在 → 退回进程内临时 id,**不写库**,避免冲掉真实 id。
  Future<String> deviceId() async {
    if (_cachedId != null) return _cachedId!;
    String? existing;
    try {
      existing = await _kv.read(_kDeviceId);
    } catch (_) {
      return _cachedId ??= _uuid.v4(); // 临时,不持久化
    }
    if (existing != null && existing.isNotEmpty) return _cachedId = existing;
    final id = _uuid.v4();
    try {
      await _kv.write(_kDeviceId, id);
    } catch (_) {
      // 写失败:本次用内存值,下次再尝试持久化。
    }
    return _cachedId = id;
  }

  /// 完整设备元数据(缓存,首次解析后复用)。
  Future<DeviceMeta> meta() async {
    if (_cachedMeta != null) return _cachedMeta!;
    final m = DeviceMeta(
      id: await deviceId(),
      name: await _name(),
      platform: currentPlatform(),
      clientVersion: await _clientVersion(),
    );
    return _cachedMeta = m;
  }

  /// 当前平台标识(与服务端 devices.platform 枚举对齐)。
  static String currentPlatform() {
    if (Platform.isIOS) return 'ios';
    if (Platform.isAndroid) return 'android';
    if (Platform.isMacOS) return 'macos';
    if (Platform.isWindows) return 'windows';
    if (Platform.isLinux) return 'linux';
    return 'unknown';
  }

  /// 平台简写(默认名前缀,保持短)。
  static String _shortPlatform(String p) => switch (p) {
        'windows' => 'Win',
        'macos' => 'Mac',
        'linux' => 'Linux',
        'ios' => 'iOS',
        'android' => 'Andr',
        _ => p,
      };

  // 默认名 = 平台简写·主机名(桌面用主机名,移动用机型);主机名截到 8、总长≈12,尽量短。
  // 用户可在「我的设备」改名覆盖。
  Future<String> _name() async {
    var host = '';
    try {
      if (Platform.isIOS) {
        final i = await DeviceInfoPlugin().iosInfo;
        host = i.name.isNotEmpty ? i.name : i.utsname.machine;
      } else if (Platform.isAndroid) {
        final a = await DeviceInfoPlugin().androidInfo;
        host = a.model;
      } else {
        host = Platform.localHostname;
      }
    } catch (_) {
      host = '';
    }
    host = host.trim();
    if (host.length > 8) host = host.substring(0, 8);
    final short = _shortPlatform(currentPlatform());
    return host.isEmpty ? short : '$short·$host';
  }

  Future<String> _clientVersion() async {
    try {
      final info = await PackageInfo.fromPlatform();
      return 'v${info.version}';
    } catch (_) {
      return '';
    }
  }
}

/// 单例 DeviceIdentity(测试可 override)。
final deviceIdentityProvider = Provider<DeviceIdentity>((ref) => DeviceIdentity());

/// 本机 device_id(供「本机」高亮;未就绪时为空)。
final localDeviceIdProvider =
    FutureProvider<String>((ref) => ref.read(deviceIdentityProvider).deviceId());