simsite/frontend/node_modules/hls.js/src/utils/mediakeys-helper.ts

import { optionalSelf } from './global';
import { changeEndianness } from './keysystem-util';
import { base64Decode } from './numeric-encoding-utils';
import type { DRMSystemOptions, EMEControllerConfig } from '../config';

/**
 * @see https://developer.mozilla.org/en-US/docs/Web/API/Navigator/requestMediaKeySystemAccess
 */
export const enum KeySystems {
  CLEARKEY = 'org.w3.clearkey',
  FAIRPLAY = 'com.apple.fps',
  PLAYREADY = 'com.microsoft.playready',
  WIDEVINE = 'com.widevine.alpha',
}

// Playlist #EXT-X-KEY KEYFORMAT values
export const enum KeySystemFormats {
  CLEARKEY = 'org.w3.clearkey',
  FAIRPLAY = 'com.apple.streamingkeydelivery',
  PLAYREADY = 'com.microsoft.playready',
  WIDEVINE = 'urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed',
}

export function keySystemFormatToKeySystemDomain(
  format: KeySystemFormats,
): KeySystems | undefined {
  switch (format) {
    case KeySystemFormats.FAIRPLAY:
      return KeySystems.FAIRPLAY;
    case KeySystemFormats.PLAYREADY:
      return KeySystems.PLAYREADY;
    case KeySystemFormats.WIDEVINE:
      return KeySystems.WIDEVINE;
    case KeySystemFormats.CLEARKEY:
      return KeySystems.CLEARKEY;
  }
}

// System IDs for which we can extract a key ID from "encrypted" event PSSH
export const enum KeySystemIds {
  CENC = '1077efecc0b24d02ace33c1e52e2fb4b',
  CLEARKEY = 'e2719d58a985b3c9781ab030af78d30e',
  FAIRPLAY = '94ce86fb07ff4f43adb893d2fa968ca2',
  PLAYREADY = '9a04f07998404286ab92e65be0885f95',
  WIDEVINE = 'edef8ba979d64acea3c827dcd51d21ed',
}

export function keySystemIdToKeySystemDomain(
  systemId: KeySystemIds,
): KeySystems | undefined {
  if (systemId === KeySystemIds.WIDEVINE) {
    return KeySystems.WIDEVINE;
  } else if (systemId === KeySystemIds.PLAYREADY) {
    return KeySystems.PLAYREADY;
  } else if (
    systemId === KeySystemIds.CENC ||
    systemId === KeySystemIds.CLEARKEY
  ) {
    return KeySystems.CLEARKEY;
  }
}

export function keySystemDomainToKeySystemFormat(
  keySystem: KeySystems,
): KeySystemFormats | undefined {
  switch (keySystem) {
    case KeySystems.FAIRPLAY:
      return KeySystemFormats.FAIRPLAY;
    case KeySystems.PLAYREADY:
      return KeySystemFormats.PLAYREADY;
    case KeySystems.WIDEVINE:
      return KeySystemFormats.WIDEVINE;
    case KeySystems.CLEARKEY:
      return KeySystemFormats.CLEARKEY;
  }
}

export function getKeySystemsForConfig(
  config: EMEControllerConfig,
): KeySystems[] {
  const { drmSystems, widevineLicenseUrl } = config;
  const keySystemsToAttempt: KeySystems[] = drmSystems
    ? [
        KeySystems.FAIRPLAY,
        KeySystems.WIDEVINE,
        KeySystems.PLAYREADY,
        KeySystems.CLEARKEY,
      ].filter((keySystem) => !!drmSystems[keySystem])
    : [];
  if (!keySystemsToAttempt[KeySystems.WIDEVINE] && widevineLicenseUrl) {
    keySystemsToAttempt.push(KeySystems.WIDEVINE);
  }
  return keySystemsToAttempt;
}

export type MediaKeyFunc = (
  keySystem: KeySystems,
  supportedConfigurations: MediaKeySystemConfiguration[],
) => Promise<MediaKeySystemAccess>;

export const requestMediaKeySystemAccess = (function (): MediaKeyFunc | null {
  if (optionalSelf?.navigator?.requestMediaKeySystemAccess) {
    return self.navigator.requestMediaKeySystemAccess.bind(self.navigator);
  } else {
    return null;
  }
})();

/**
 * @see https://developer.mozilla.org/en-US/docs/Web/API/MediaKeySystemConfiguration
 */
export function getSupportedMediaKeySystemConfigurations(
  keySystem: KeySystems,
  audioCodecs: string[],
  videoCodecs: string[],
  drmSystemOptions: DRMSystemOptions,
): MediaKeySystemConfiguration[] {
  let initDataTypes: string[];
  switch (keySystem) {
    case KeySystems.FAIRPLAY:
      initDataTypes = ['cenc', 'sinf'];
      break;
    case KeySystems.WIDEVINE:
    case KeySystems.PLAYREADY:
      initDataTypes = ['cenc'];
      break;
    case KeySystems.CLEARKEY:
      initDataTypes = ['cenc', 'keyids'];
      break;
    default:
      throw new Error(`Unknown key-system: ${keySystem}`);
  }
  return createMediaKeySystemConfigurations(
    initDataTypes,
    audioCodecs,
    videoCodecs,
    drmSystemOptions,
  );
}

function createMediaKeySystemConfigurations(
  initDataTypes: string[],
  audioCodecs: string[],
  videoCodecs: string[],
  drmSystemOptions: DRMSystemOptions,
): MediaKeySystemConfiguration[] {
  const baseConfig: MediaKeySystemConfiguration = {
    initDataTypes: initDataTypes,
    persistentState: drmSystemOptions.persistentState || 'optional',
    distinctiveIdentifier: drmSystemOptions.distinctiveIdentifier || 'optional',
    sessionTypes: drmSystemOptions.sessionTypes || [
      drmSystemOptions.sessionType || 'temporary',
    ],
    audioCapabilities: audioCodecs.map((codec) => ({
      contentType: `audio/mp4; codecs=${codec}`,
      robustness: drmSystemOptions.audioRobustness || '',
      encryptionScheme: drmSystemOptions.audioEncryptionScheme || null,
    })),
    videoCapabilities: videoCodecs.map((codec) => ({
      contentType: `video/mp4; codecs=${codec}`,
      robustness: drmSystemOptions.videoRobustness || '',
      encryptionScheme: drmSystemOptions.videoEncryptionScheme || null,
    })),
  };

  return [baseConfig];
}

export function isPersistentSessionType(
  drmSystemOptions: DRMSystemOptions | undefined,
): boolean {
  return (
    !!drmSystemOptions &&
    (drmSystemOptions.sessionType === 'persistent-license' ||
      !!drmSystemOptions.sessionTypes?.some(
        (type) => type === 'persistent-license',
      ))
  );
}

export function parsePlayReadyWRM(keyBytes: Uint8Array<ArrayBuffer>) {
  const keyBytesUtf16 = new Uint16Array(
    keyBytes.buffer,
    keyBytes.byteOffset,
    keyBytes.byteLength / 2,
  );
  const keyByteStr = String.fromCharCode.apply(null, Array.from(keyBytesUtf16));

  // Parse Playready WRMHeader XML
  const xmlKeyBytes = keyByteStr.substring(
    keyByteStr.indexOf('<'),
    keyByteStr.length,
  );
  const parser = new DOMParser();
  const xmlDoc = parser.parseFromString(xmlKeyBytes, 'text/xml');
  const keyData = xmlDoc.getElementsByTagName('KID')[0];
  if (keyData) {
    const keyId = keyData.childNodes[0]
      ? keyData.childNodes[0].nodeValue
      : keyData.getAttribute('VALUE');
    if (keyId) {
      const keyIdArray = base64Decode(keyId).subarray(0, 16);
      // KID value in PRO is a base64-encoded little endian GUID interpretation of UUID
      // KID value in ‘tenc’ is a big endian UUID GUID interpretation of UUID
      changeEndianness(keyIdArray);
      return keyIdArray;
    }
  }
  return null;
}