/**
 * 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 LoadedSessionsStore from "./loaded_sessions_store";

/**
 * Close sessions from the loadedSessionsStore to allow at maximum `limit`
 * stored MediaKeySessions in it.
 *
 * Emit event when a MediaKeySession begin to be closed and another when the
 * MediaKeySession is closed.
 * @param {Object} loadedSessionsStore
 * @returns {Promise}
 */
export default async function cleanOldLoadedSessions(
  loadedSessionsStore: LoadedSessionsStore,
  limit: number,
): Promise<void> {
  if (limit < 0 || limit >= loadedSessionsStore.getLength()) {
    return;
  }
  log.info("DRM", "LSS cache limit exceeded", {
    limit,
    length: loadedSessionsStore.getLength(),
  });
  const proms: Array<Promise<unknown>> = [];
  const entries = loadedSessionsStore.getAll().slice(); // clone
  const toDelete = entries.length - limit;
  for (let i = 0; i < toDelete; i++) {
    const entry = entries[i];
    proms.push(loadedSessionsStore.closeSession(entry.mediaKeySession));
  }
  await Promise.all(proms);
}