/**
 * Copyright 2015 CANAL+ Group
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { base64ToBytes } from "../../../utils/base64";
import { concat } from "../../../utils/byte_parsing";
import { hexToBytes } from "../../../utils/string_parsing";
import { getPlayReadyKIDFromPrivateData } from "../../containers/isobmff";

export interface IKeySystem {
  systemId: string;
  privateData: Uint8Array;
}

export interface IContentProtectionSmooth {
  keyId: Uint8Array;
  keySystems: IKeySystem[];
}

/**
 * @param {Uint8Array} keyIdBytes
 * @returns {Array.<Object>}
 */
function createWidevineKeySystem(keyIdBytes: Uint8Array): IKeySystem[] {
  return [
    {
      systemId: "edef8ba9-79d6-4ace-a3c8-27dcd51d21ed", // Widevine
      privateData: concat([0x08, 0x01, 0x12, 0x10], keyIdBytes),
    },
  ];
}

/**
 * Parse "Protection" Node, which contains DRM information
 * @param {Element} protectionNode
 * @returns {Object}
 */
export default function parseProtectionNode(
  protectionNode: Element,
  keySystemCreator: (keyId: Uint8Array) => IKeySystem[] = createWidevineKeySystem,
): IContentProtectionSmooth {
  if (
    protectionNode.firstElementChild === null ||
    protectionNode.firstElementChild.nodeName !== "ProtectionHeader"
  ) {
    throw new Error("Protection should have ProtectionHeader child");
  }
  const header = protectionNode.firstElementChild;
  const privateData = base64ToBytes(
    header.textContent === null ? "" : header.textContent,
  );
  const keyIdHex = getPlayReadyKIDFromPrivateData(privateData);
  const keyIdBytes = hexToBytes(keyIdHex);

  // remove possible braces
  const systemIdAttr = header.getAttribute("SystemID");
  const systemId = (systemIdAttr !== null ? systemIdAttr : "")
    .toLowerCase()
    .replace(/\{|\}/g, "");

  return {
    keyId: keyIdBytes,
    keySystems: [
      {
        systemId,
        privateData,
        /* keyIds: [keyIdBytes], */
      },
    ].concat(keySystemCreator(keyIdBytes)),
  };
}