import 'device_fingerprint_native.dart'
    // ignore: uri_does_not_exist
    if (dart.library.html) 'device_fingerprint_web.dart';

import 'dart:convert';

import 'package:crypto/crypto.dart';

/// 设备指纹工具类
///
/// SDK 内部自动调用，业务方无需手动传入。
///
/// **生成规则**
/// 1. 现行外层 `device_fingerprint` 使用 v3 规则：
///    基于 `sdk_init` payload 内的平台稳定字段，按固定顺序规范化后做
///    SHA-256，输出 64 位小写十六进制。
/// 2. 网络、电量、页面、行为等易变字段不参与 v3 指纹。
/// 3. [getFingerprint] 保留为旧调用方兼容入口；SDK 自动上报链路使用
///    [generateV3FromSdkInitPayload]。
///
/// **平台差异**
/// - Native（Android/iOS/桌面）：降级 UUID 存于 `applicationDocumentsDirectory/analytics_fingerprint.txt`
/// - Web：降级 UUID 存于 `localStorage['analytics_fp']`
///
/// **失败兜底**：任何异常均返回空字符串，事件正常上报，仅 `device_fingerprint` 字段为空。
///
/// **注意**：`device_fingerprint` 不参与 `event_id` 的计算。
class DeviceFingerprintUtil {
  /// 指纹生成规则版本号。
  ///
  /// 每次生成规则（因子组合、哈希算法）发生变更时，此版本号必须同步递增，
  /// 以便服务端区分不同规则下生成的指纹，支持跨版本数据对比分析。
  ///
  /// 版本历史：
  /// - `3.0.0`：按 sdk_init 启动快照中的平台稳定字段生成。
  static const String kVersion = '3.0.0';

  static String? _cache;

  /// 获取设备指纹。
  ///
  /// 首次调用时根据传入的设备因子计算并内存缓存，后续直接返回缓存值。
  /// 若设备因子发生变化需重新计算，请先调用 [clearCache]。
  static Future<String> getFingerprint({
    String deviceId = '',
    String device = '',
    String deviceBrand = '',
    String deviceModel = '',
    String systemName = '',
    String systemVersion = '',
    String userAgent = '',
  }) async {
    if (_cache != null) return _cache!;
    _cache = await generateOrLoadFingerprint(
      deviceId: deviceId,
      device: device,
      deviceBrand: deviceBrand,
      deviceModel: deviceModel,
      systemName: systemName,
      systemVersion: systemVersion,
      userAgent: userAgent,
    );
    return _cache!;
  }

  /// 清除内存缓存（通常仅测试时使用，不会删除本地存储文件）
  static void clearCache() {
    _cache = null;
  }

  /// 按产品文档 v3 规则，基于 sdk_init payload 生成外层设备指纹。
  ///
  /// 该方法只使用启动快照内相对稳定的字段；网络、电量、页面、行为等
  /// 易变字段不参与。输入缺失时保留字段名并使用文档默认值，确保同一
  /// 平台的参与字段顺序稳定。
  static String generateV3FromSdkInitPayload(Map<String, dynamic> payload) {
    try {
      final platform = _fingerprintPlatform(payload);
      final values = platform == 'web'
          ? _webFingerprintValues(payload)
          : platform == 'ios'
              ? _iosFingerprintValues(payload)
              : _androidFingerprintValues(payload);
      final canonical =
          'fp_v3|fingerprint_platform=$platform|${values.join('|')}';
      return sha256.convert(utf8.encode(canonical)).toString();
    } catch (_) {
      return '';
    }
  }

  static String _fingerprintPlatform(Map<String, dynamic> payload) {
    if (_string(payload['platform']) == 'web') return 'web';
    final osFamily = _string(payload['os_family']);
    if (osFamily == 'ios') return 'ios';
    return 'android';
  }

  static List<String> _androidFingerprintValues(Map<String, dynamic> payload) {
    final id = _selectFirstId(payload, const [
      'oaid',
      'aaid',
      'android_id',
      'guid',
    ]);
    return [
      _kvString(payload, 'os_family'),
      _kvString(payload, 'brand'),
      _kvString(payload, 'manufacturer'),
      _kvString(payload, 'model'),
      _kvString(payload, 'abi'),
      _kvInt(payload, 'screen_width'),
      _kvInt(payload, 'screen_height'),
      _kvInt(payload, 'screen_dpi'),
      _kvInt(payload, 'device_pixel_ratio'),
      _kvInt(payload, 'cpu_cores'),
      _kvInt(payload, 'device_memory_gb'),
      _kvString(payload, 'build_hardware'),
      _kvString(payload, 'build_product'),
      _kvString(payload, 'build_fingerprint'),
      _kvInt(payload, 'has_baseband'),
      _kvString(payload, 'language'),
      _kvString(payload, 'timezone'),
      'id_source=${id.source}',
      'id_value=${id.value}',
    ];
  }

  static List<String> _iosFingerprintValues(Map<String, dynamic> payload) {
    final idfv = _string(payload['idfv']);
    return [
      _kvString(payload, 'os_family'),
      _kvString(payload, 'ios_device_model_raw'),
      _kvInt(payload, 'screen_width'),
      _kvInt(payload, 'screen_height'),
      _kvInt(payload, 'screen_dpi'),
      _kvInt(payload, 'device_pixel_ratio'),
      _kvInt(payload, 'cpu_cores'),
      _kvInt(payload, 'device_memory_gb'),
      _kvString(payload, 'language'),
      _kvString(payload, 'timezone'),
      'id_source=${idfv.isEmpty ? 'none' : 'idfv'}',
      'id_value=$idfv',
    ];
  }

  static List<String> _webFingerprintValues(Map<String, dynamic> payload) {
    return [
      _kvString(payload, 'os_family'),
      _kvString(payload, 'browser_kernel'),
      _kvString(payload, 'browser_platform'),
      _kvInt(payload, 'screen_width'),
      _kvInt(payload, 'screen_height'),
      _kvInt(payload, 'screen_dpi'),
      _kvInt(payload, 'device_pixel_ratio'),
      _kvInt(payload, 'color_depth'),
      _kvInt(payload, 'max_touch_points'),
      _kvInt(payload, 'hardware_concurrency'),
      _kvString(payload, 'language'),
      _kvString(payload, 'timezone'),
      _kvInt(payload, 'cookie_enabled'),
      _kvInt(payload, 'local_storage_enabled'),
      _kvInt(payload, 'session_storage_enabled'),
      _kvInt(payload, 'indexeddb_enabled'),
      _kvInt(payload, 'service_worker_enabled'),
      _kvString(payload, 'canvas_fp'),
      _kvString(payload, 'webgl_fp'),
      _kvString(payload, 'audio_fp'),
      _kvString(payload, 'fonts_hash'),
      _kvString(payload, 'plugins_hash'),
      _kvString(payload, 'mimes_hash'),
    ];
  }

  static _SelectedId _selectFirstId(
    Map<String, dynamic> payload,
    List<String> keys,
  ) {
    for (final key in keys) {
      final value = _string(payload[key]);
      if (value.isNotEmpty) return _SelectedId(key, value);
    }
    return const _SelectedId('none', '');
  }

  static String _kvString(Map<String, dynamic> payload, String key) =>
      '$key=${_string(payload[key])}';

  static String _kvInt(Map<String, dynamic> payload, String key) =>
      '$key=${_int(payload[key])}';

  static String _string(dynamic value) {
    if (value == null) return '';
    return value.toString().trim().toLowerCase();
  }

  static int _int(dynamic value) {
    if (value is int) return value;
    if (value is double && value.isFinite) return value.round();
    if (value is String) {
      final text = value.trim();
      final asInt = int.tryParse(text);
      if (asInt != null) return asInt;
      final asDouble = double.tryParse(text);
      if (asDouble != null && asDouble.isFinite) return asDouble.round();
    }
    return -1;
  }
}

class _SelectedId {
  final String source;
  final String value;

  const _SelectedId(this.source, this.value);
}