/**
 * @license
 * Copyright 2016 Google Inc.
 *
 * 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.
 */

goog.provide('shaka.util.Pssh');

goog.require('goog.asserts');
goog.require('shaka.log');
goog.require('shaka.util.Iterables');
goog.require('shaka.util.Mp4Parser');
goog.require('shaka.util.Uint8ArrayUtils');


/**
 * @summary
 * Parse a PSSH box and extract the system IDs.
 */
shaka.util.Pssh = class {
  /**
   * @param {!Uint8Array} psshBox
   * @throws {shaka.util.Error} if a PSSH box is truncated or contains a size
   *   field over 53 bits.
   */
  constructor(psshBox) {
    /**
     * In hex.
     * @type {!Array.<string>}
     */
    this.systemIds = [];

    /**
     * In hex.
     * @type {!Array.<string>}
     */
    this.cencKeyIds = [];

    /*
    * Array of tuples that define the startIndex + size for each
    * discrete pssh within |psshBox|
    * */
    this.dataBoundaries = [];

    new shaka.util.Mp4Parser()
        .fullBox('pssh', (box) => this.parseBox_(box))
        .parse(psshBox.buffer);

    if (this.dataBoundaries.length == 0) {
      shaka.log.warning('No pssh box found!');
    }
  }


  /**
   * @param {!shaka.extern.ParsedBox} box
   * @private
   */
  parseBox_(box) {
    goog.asserts.assert(
        box.version != null,
        'PSSH boxes are full boxes and must have a valid version');

    goog.asserts.assert(
        box.flags != null,
        'PSSH boxes are full boxes and must have a valid flag');

    if (box.version > 1) {
      shaka.log.warning('Unrecognized PSSH version found!');
      return;
    }

    const systemId = shaka.util.Uint8ArrayUtils.toHex(box.reader.readBytes(16));
    const keyIds = [];
    if (box.version > 0) {
      const numKeyIds = box.reader.readUint32();
      for (const _ of shaka.util.Iterables.range(numKeyIds)) {
        shaka.util.Functional.ignored(_);
        const keyId =
            shaka.util.Uint8ArrayUtils.toHex(box.reader.readBytes(16));
        keyIds.push(keyId);
      }
    }

    const dataSize = box.reader.readUint32();
    box.reader.skip(dataSize);  // Ignore the data section.

    // Now that everything has been succesfully parsed from this box,
    // update member variables.
    this.cencKeyIds.push(...keyIds);
    this.systemIds.push(systemId);
    this.dataBoundaries.push({
      start: box.start,
      end: box.start + box.size - 1,
    });

    if (box.reader.getPosition() != box.reader.getLength()) {
      shaka.log.warning('Mismatch between box size and data size!');
    }
  }
};