import axios from 'axios';
import {NativeModules, Platform} from 'react-native';

const buildAndroidUserAgent = () => {
  const platformConstants = Platform.constants as {
    Brand?: string;
    Model?: string;
  };

  const brand = platformConstants.Brand ?? 'UnknownBrand';
  const model = platformConstants.Model ?? 'UnknownModel';
  const androidVersion = String(Platform.Version ?? 'UnknownVersion');

  return `FacekiReactNativeSDK (Android ${androidVersion}; ${brand} ${model})`;
};

const buildIOSAgentContext = () => {
  const platformConstants = Platform.constants as {
    osVersion?: string;
    systemName?: string;
    interfaceIdiom?: string;
  };

  const settings = (NativeModules.SettingsManager?.settings ?? {}) as {
    CFBundleIdentifier?: string;
    CFBundleName?: string;
    CFBundleDisplayName?: string;
    CFBundleShortVersionString?: string;
    CFBundleVersion?: string;
  };

  const appName = settings.CFBundleDisplayName ?? settings.CFBundleName ?? 'UnknownApp';
  const appVersion = settings.CFBundleShortVersionString ?? settings.CFBundleVersion ?? '1';
  const bundleId = settings.CFBundleIdentifier ?? 'unknown.bundle';
  const systemName = platformConstants.systemName ?? 'iOS';
  const iosVersion = platformConstants.osVersion ?? String(Platform.Version ?? 'UnknownVersion');
  const deviceType = platformConstants.interfaceIdiom ?? 'UnknownDevice';

  return `${appName}/${appVersion} (${bundleId}; ${systemName} ${iosVersion}; ${deviceType})`;
};

const api = axios.create({
  baseURL: 'https://sdk.faceki.com',
  headers: {
    'Content-Type': 'application/json',
  },
});

api.interceptors.request.use(config => {
  config.headers = config.headers ?? {};

  if (Platform.OS === 'android') {
    config.headers['User-Agent'] = buildAndroidUserAgent();
    return config;
  }

  if (Platform.OS === 'ios') {
    const iosContext = buildIOSAgentContext();
    const existingUserAgent = config.headers['User-Agent'] ?? config.headers['user-agent'];

    if (typeof existingUserAgent === 'string' && existingUserAgent.trim().length > 0) {
      config.headers['User-Agent'] = `${existingUserAgent} ${iosContext}`;
      return config;
    }

    // Keep CFNetwork/Darwin User-Agent untouched when not directly available in JS.
    config.headers['X-Faceki-Client-Context'] = iosContext;
  }

  return config;
});

export default api;