/**
 * 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 { getIndexSegmentEnd } from "../../utils/index_helpers";

export interface IIndexSegment {
  start: number;
  duration: number;
  repeatCount: number;
}

/**
 * Add a new segment to the index.
 *
 * /!\ Mutate the given index
 * @param {Array.<Object>} timeline
 * @param {number} timescale
 * @param {Object} newSegment
 * @param {Object} currentSegment
 * @returns {Boolean} - true if the segment has been added
 */
export default function _addSegmentInfos(
  timeline: IIndexSegment[],
  timescale: number,
  newSegment: { time: number; duration: number; timescale: number },
  currentSegment: { time: number; duration: number },
): boolean {
  const timelineLength = timeline.length;
  const last = timeline[timelineLength - 1];

  const scaledNewSegment =
    newSegment.timescale === timescale
      ? { time: newSegment.time, duration: newSegment.duration }
      : {
          time: (newSegment.time / newSegment.timescale) * timescale,
          duration: (newSegment.duration / newSegment.timescale) * timescale,
        };

  // in some circumstances, the new segment information are only duration
  // information that we could use to deduct the start of the next segment.
  // This is the case where the new segment are associated to a current
  // segment and have the same start.
  // However, we prefer to be sure of the duration of the new segments
  // before adding such segments.
  const shouldDeductNextSegment = currentSegment.time === scaledNewSegment.time;
  if (shouldDeductNextSegment) {
    return false;
  } else if (scaledNewSegment.time >= getIndexSegmentEnd(last, null)) {
    // if the given timing has a timestamp after the timeline end we
    // just need to push a new element in the timeline, or increase
    // the @r attribute of the last element.
    if (last.duration === scaledNewSegment.duration) {
      last.repeatCount++;
    } else {
      timeline.push({
        duration: scaledNewSegment.duration,
        start: scaledNewSegment.time,
        repeatCount: 0,
      });
    }
    return true;
  }

  return false;
}