/**
 * 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";
/**
 * Avoid periods to overlap.
 *
 * According to DASH guidelines, if a period has media duration longer than
 * the distance between the start of this period and the start of the next period,
 * use of start times implies that the client will start the playout of the next
 * period at the time stated, rather than finishing the playout of the last period.
 *
 * Even if that case if defined when period last(s) segment(s) is/are a bit longer,
 * it can be meaningful when two periods are overlapping. We will always shorten
 * the first period, and even erase it if its duration is equal to zero.
 *
 * Example (Periods are numbered under their manifest order) :
 *
 * [ Period 1 ][ Period 2 ]       ------>  [ Period 1 ][ Period 3 ]
 *             [ Period 3 ]
 *
 * [ Period 1 ][ Period 2 ]       ------>  [ Period 1 ][  2  ][ Period 3 ]
 *                  [ Period 3 ]
 *
 * [ Period 1 ][ Period 2 ]       ------>  [  1  ][      Period 3     ]
 *        [      Period 3     ]
 *
 * @param {Array.<Object>} parsedPeriods
 * @return {Array.<Object>}
 */
export default function flattenOverlappingPeriods(parsedPeriods) {
    if (parsedPeriods.length === 0) {
        return [];
    }
    var flattenedPeriods = [parsedPeriods[0]];
    for (var i = 1; i < parsedPeriods.length; i++) {
        var parsedPeriod = parsedPeriods[i];
        var lastFlattenedPeriod = flattenedPeriods[flattenedPeriods.length - 1];
        while (lastFlattenedPeriod.duration === undefined ||
            (lastFlattenedPeriod.start + lastFlattenedPeriod.duration) > parsedPeriod.start) {
            log.warn("DASH: Updating overlapping Periods.", lastFlattenedPeriod === null || lastFlattenedPeriod === void 0 ? void 0 : lastFlattenedPeriod.start, parsedPeriod.start);
            lastFlattenedPeriod.duration = parsedPeriod.start - lastFlattenedPeriod.start;
            lastFlattenedPeriod.end = parsedPeriod.start;
            if (lastFlattenedPeriod.duration > 0) {
                // Note: Calling `break` to quit the while loop should theoritically be
                // unnecessary as the previous operations should ensure we do not re-enter
                // the loop's condition.
                // Yet we dit encounter infinite loops without it because of float-related
                // rounding errors.
                break;
            }
            else {
                // `lastFlattenedPeriod` has now a negative or `0` duration.
                // Remove it, consider the next Period in its place, and re-start the loop.
                flattenedPeriods.pop();
                if (flattenedPeriods.length === 0) {
                    // There's no remaining Period to compare to `parsedPeriod`
                    break;
                }
                // Take the previous Period as reference and compare it now to `parsedPeriod`
                lastFlattenedPeriod = flattenedPeriods[flattenedPeriods.length - 1];
            }
        }
        flattenedPeriods.push(parsedPeriod);
    }
    return flattenedPeriods;
}
