/**
 * 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 log from "../../../log";
import type { IParsedPeriod } from "../types";
import getFirstPositionFromAdaptation from "./get_first_time_from_adaptation";

/**
 * @param {Array.<Object>} periods
 * @returns {number | undefined}
 */
export default function getMinimumPosition(periods: IParsedPeriod[]): number | undefined {
  for (let i = 0; i <= periods.length - 1; i++) {
    const periodAdaptations = periods[i].adaptations;
    const firstAudioAdaptationFromPeriod =
      periodAdaptations.audio === undefined ? undefined : periodAdaptations.audio[0];
    const firstVideoAdaptationFromPeriod =
      periodAdaptations.video === undefined ? undefined : periodAdaptations.video[0];

    if (
      firstAudioAdaptationFromPeriod !== undefined ||
      firstVideoAdaptationFromPeriod !== undefined
    ) {
      // null == no segment
      let minimumAudioPosition: number | null = null;
      let minimumVideoPosition: number | null = null;
      if (firstAudioAdaptationFromPeriod !== undefined) {
        const firstPosition = getFirstPositionFromAdaptation(
          firstAudioAdaptationFromPeriod,
        );
        if (firstPosition === undefined) {
          return undefined;
        }
        minimumAudioPosition = firstPosition;
      }
      if (firstVideoAdaptationFromPeriod !== undefined) {
        const firstPosition = getFirstPositionFromAdaptation(
          firstVideoAdaptationFromPeriod,
        );
        if (firstPosition === undefined) {
          return undefined;
        }
        minimumVideoPosition = firstPosition;
      }

      if (
        (firstAudioAdaptationFromPeriod !== undefined && minimumAudioPosition === null) ||
        (firstVideoAdaptationFromPeriod !== undefined && minimumVideoPosition === null)
      ) {
        log.info(
          "utils",
          "found Period with no segment. ",
          "Going to next one to calculate first position",
        );
        return undefined;
      }

      if (minimumVideoPosition !== null) {
        if (minimumAudioPosition !== null) {
          return Math.max(minimumAudioPosition, minimumVideoPosition);
        }
        return minimumVideoPosition;
      }
      if (minimumAudioPosition !== null) {
        return minimumAudioPosition;
      }
    }
  }
}