/**
 * 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 type { IMetaPlaylist } from "../../../parsers/manifest/metaplaylist";
import getDurationFromManifest from "./get_duration_from_manifest";

interface IMetaplaylistContentInfos {
  url: string;
  transport: "dash" | "smooth";
  duration?: number;
}

/**
 * From given information about wanted metaplaylist and contents,
 * get needed supplementary infos and build a standard metaplaylist.
 * @param {Array.<Object>} contentsInfos
 * @param {number|undefined} timeOffset
 * @returns {Promise<Object>} - metaplaylist
 */
function createMetaplaylist(
  contentsInfos: IMetaplaylistContentInfos[],
  timeOffset?: number,
): Promise<IMetaPlaylist> {
  const playlistStartTime = timeOffset ?? 0;
  const completeContentsInfoProms = contentsInfos.map((contentInfos) => {
    const { url, transport, duration } = contentInfos;
    if (duration !== undefined) {
      return Promise.resolve({ url, transport, duration });
    }
    return getDurationFromManifest(url, transport).then((manifestDuration) => {
      return { url, duration: manifestDuration, transport };
    });
  });

  return Promise.all(completeContentsInfoProms).then((completeContentsInfos) => {
    const contents = completeContentsInfos.reduce(
      (
        acc: Array<{
          url: string;
          transport: "dash" | "smooth" | "metaplaylist";
          startTime: number;
          endTime: number;
        }>,
        val,
      ) => {
        const lastElement = acc[acc.length - 1];
        const startTime = lastElement?.endTime ?? playlistStartTime;
        acc.push({
          url: val.url,
          transport: val.transport,
          startTime,
          endTime: startTime + val.duration,
        });
        return acc;
      },
      [],
    );
    return { type: "MPL" as const, version: "0.1", dynamic: false, contents };
  });
}

export default createMetaplaylist;