/**
 * 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 { IEMSG } from "../../../parsers/containers/isobmff";
import type {
  ILocalIndexSegment,
  ILocalManifestInitSegmentLoader,
  ILocalManifestSegmentLoader,
} from "../../../parsers/manifest/local";
import type { IPlayerError } from "../../../public_types";
import type { ISegmentInformation } from "../../../transports";

/**
 * Supplementary information specific to Smooth Initialization segments.
 * Contains every information needed to generate an initialization segment.
 */
export interface ISmoothInitSegmentPrivateInfos {
  /**
   * Timescale the segments are in, in the Manifest.
   * Needed because Smooth segment are created in JS based on timing information
   * as found in the Manifest.
   */
  timescale: number;
  codecPrivateData?: string | undefined;
  bitsPerSample?: number | undefined;
  channels?: number | undefined;
  packetSize?: number | undefined;
  samplingRate?: number | undefined;
  protection?: { keyId: Uint8Array } | undefined;
  height?: number | undefined;
  width?: number | undefined;
}

/**
 * Supplementary information specific to Smooth media segments (that is, every
 * segments but the initialization segment).
 */
export interface ISmoothMediaSegmentPrivateInfos {
  /**
   * Start time of the segment as announced in the Manifest, in the same
   * timescale than the one indicated through `ISmoothInitSegmentPrivateInfos`.
   */
  time: number;
  /**
   * Duration of the segment as announced in the Manifest, in the same timescale
   * than the one indicated through `ISmoothInitSegmentPrivateInfos`.
   */
  duration: number;
}

/** Supplementary information needed for segments in the "metaplaylist" transport. */
export interface IMetaPlaylistPrivateInfos {
  /** The original transport protocol (e.g. "dash", "smooth" etc.) */
  transportType: string;
  contentStart: number;
  contentEnd?: number | undefined;

  /** The segment originally created by this transport's RepresentationIndex. */
  originalSegment: ISegment;

  isLive: boolean;
  manifestPublishTime?: number | undefined;
  periodEnd?: number | undefined;
  periodStart: number;
}

/**
 * Supplementary information needed for initialization segments of the "local"
 * transport.
 */
export interface ILocalManifestInitSegmentPrivateInfos {
  /** Callback used to load that segment. */
  load: ILocalManifestInitSegmentLoader;
}

/** Supplementary information needed for media segments of the "local" transport. */
export interface ILocalManifestSegmentPrivateInfos {
  /** Callback used to load that segment. */
  load: ILocalManifestSegmentLoader;

  /**
   * Exact same segment than the one given in a local manifest.
   * Stored (with at best the same reference than in it) to facilitate the job
   * of retrieving the wanted segment (this task will generally be done by the
   * content downloader tool) when the RxPlayer asks for it.
   */
  segment: ILocalIndexSegment;
}

/**
 * Supplementary information that can be added to any segment depending on the
 * tranport logic used.
 * Called "private" as it won't be read or exploited by any code in the core
 * logic of the player. That information is only here to be retrieved and
 * exploited by the corresponding transport logic when loading or parsing the
 * corresponding segment.
 */
export interface IPrivateInfos {
  /** Smooth-specific information allowing to generate an initialization segment. */
  smoothInitSegment?: ISmoothInitSegmentPrivateInfos;

  /** Smooth-specific information linked to all Smooth media segments. */
  smoothMediaSegment?: ISmoothMediaSegmentPrivateInfos;

  /** Information that should be present on all MetaPlaylist segments. */
  metaplaylistInfos?: IMetaPlaylistPrivateInfos;

  /**
   * Local Manifest-specific information allowing to request the
   * initialization segment.
   */
  localManifestInitSegment?: ILocalManifestInitSegmentPrivateInfos;

  /** Local Manifest-specific information allowing to request any media segment. */
  localManifestSegment?: ILocalManifestSegmentPrivateInfos;

  /**
   * Function allowing to know if a given emsg's event name has been
   * explicitely authorized.
   */
  isEMSGWhitelisted?: (evt: IEMSG) => boolean;
}

/** Represent a single Segment from a Representation. */
export interface ISegment {
  /** ID of the Segment. Should be unique for this Representation. */
  id: string;
  /**
   * If true, this segment is an initialization segment with no decodable data.
   *
   * Those types of segment contain no decodable data and are only there for
   * initialization purposes, such as giving initial infos to the decoder on
   * subsequent media segments that will be pushed.
   *
   * Note that if `isInit` is false, it only means that the segment contains
   * decodable media, it can also contain important initialization information.
   *
   * Also, a segment which would contain both all initialization data and the
   * decodable data would have `isInit` set to `false` as it is not purely an
   * initialization segment.
   *
   * Segments which are not purely an initialization segments are called "media
   * segments" in the code.
   */
  isInit: boolean;
  /**
   * Store supplementary information on a segment that can be later exploited by
   * the transport logic.
   */
  privateInfos: IPrivateInfos;
  /**
   * Estimated time, in seconds, at which the concerned segment should be
   * offseted when decoded.
   */
  timestampOffset?: number | undefined;
  /**
   * Estimated start time for the segment, in seconds.
   * Note that some rounding errors and some differences between what the
   * Manifest says and what the content really is might make that time not
   * exact.
   *
   * `0` for initialization segments.
   */
  time: number;
  /**
   * Estimated end time for the segment, in seconds.
   * Note that some rounding errors and some differences between what the
   * Manifest says and what the content really is might make that time not
   * exact.
   *
   * `0` for initialization segments.
   */
  end: number;
  /**
   * Estimated duration for the segment, in seconds.
   *
   * Note that this may not reflect the exact segment duration:
   *
   *   1. In some very specific cases, segments might be generated and served
   *      progressively. In this case, the full duration of a segment might not
   *      be yet known and thus this property only reflect the currently known
   *      `duration` of the segment, which may be inferior to its final duration.
   *
   *      You can know if we're in that case when the `complete` property of
   *      this same segment is set to `false`.
   *
   *   2. some rounding errors and some differences between what the
   *      Manifest says and what the content really is might make that time not
   *      exact.
   *
   * `0` for initialization segments.
   */
  duration: number;
  /**
   * Always set to 1 for API compatibility with v3.X.X.
   * This was intended for conversion of the `time` and `duration` properties
   * into seconds.
   *
   * As both are always in seconds now, this property became unneeded.
   */
  timescale: 1;
  /**
   * If `false`, this segment's `duration` property may not be the duration of
   * the full segment as it could still be in the process of being generated
   * on the server-side (when this `ISegment` had been constructed).
   *
   * Note that if the `duration` is sure to be the final one, `complete`
   * should be set to `true` even if the segment is still being
   * generated.
   */
  complete: boolean;
  /**
   * Optional relative or absolute URL to load the resource.
   *
   * If the URL is absolute (it contains the scheme at the beginning), it is the
   * complete URL on which the resource should be requested.
   *
   * If the URL is relative (it does not contain a scheme at the beginning), it
   * should be relative to the chosen CDN that should be recuperated through
   * another mean
   *
   * If `null`, it means either:
   *
   *   - that there is no way to reach the resource through a URL.
   *
   *   - that there may be an URL, but is already communicated through another
   *     mean, like the currently chosen CDN.
   *
   * An empty string is equivalent to indicating that the chosen CDN's URL
   * should be directly requested instead.
   * In that way, it is equivalent to setting it to `null`.
   */
  url: string | null;

  /**
   * Optional byte range to retrieve the Segment from its URL(s).
   * TODO this should probably moved to `privateInfos` as this is
   * transport-specific metadata only useful for performing requests, but it is
   * sadly documented in the API, so moving it is actuall a v3.X.X breaking
   * change.
   */
  range?: [number, number] | undefined;
  /**
   * If set, the corresponding byte-range in the downloaded segment will
   * contain an index describing other Segments
   * TODO this should probably moved to `privateInfos` as this is
   * transport-specific metadata only useful for performing requests, but it is
   * sadly documented in the API, so moving it is actuall a v3.X.X breaking
   * change.
   */
  indexRange?: [number, number] | undefined;
  /**
   * Optional number of the Segment.
   * TODO this should probably moved to `privateInfos` as this is
   * transport-specific metadata only useful for performing requests, but it is
   * sadly documented in the API, so moving it is actuall a v3.X.X breaking
   * change.
   */
  number?: number | undefined;
}

/** Interface that should be implemented by any Representation's `index` value. */
export interface IRepresentationIndex {
  /**
   * Returns Segment object for the initialization segment, allowing to do the
   * Init Segment request.
   *
   * `null` if there's no initialization segment.
   * @returns {Object}
   */
  getInitSegment(): ISegment | null;

  /**
   * Returns an array of Segments needed for the amount of time given.
   * @param {number} up - The first wanted position, in seconds.
   * @param {number} duration - The amount of time in seconds you want from the
   * starting position given in `up`.
   * @returns {Array.<Object>} - The list of segments corresponding to your
   * wanted range.
   */
  getSegments(up: number, duration: number): ISegment[];

  /**
   * Returns `true` if, from the given situation, the manifest has to be
   * refreshed.
   * @param {number} up - Beginning time in seconds of the range that is
   * currently wanted.
   * @param {number} to - Ending time in seconds of the range that is
   * currently wanted.
   * @returns {Boolean}
   */
  shouldRefresh(up: number, to: number): boolean;

  /**
   * Returns the starting time, in seconds, of the earliest segment currently
   * available in this index.
   * Returns `null` if nothing is in the index
   * Returns `undefined` if we cannot know this value.
   * @returns {Number|null}
   */
  getFirstAvailablePosition(): number | null | undefined;

  /**
   * Returns the ending time, in seconds, of the last playable position
   * currently available in this index.
   * Returns `null` if nothing is in the index
   * Returns `undefined` if we cannot know this value.
   *
   * The last playable position is generally equivalent to the end of the last
   * segment associated to this index, excepted when it goes over the end limit
   * of the corresponding `Period`, in which case it will be equal to this end
   * instead.
   * @returns {Number|null|undefined}
   */
  getLastAvailablePosition(): number | null | undefined;

  /**
   * Returns the ending time, in seconds, of the Representation once it is
   * "finished" (@see isStillAwaitingFutureSegments).
   * Should thus be equivalent to `getLastAvailablePosition` once finished.
   *
   * Returns `null` if nothing is in the index
   * Returns `undefined` if we cannot know this value.
   *
   * @returns {number|undefined}
   */
  getEnd(): number | null | undefined;

  /**
   * Returns `true` if a Segment returned by this index is still considered
   * available.
   * Returns `false` if it is not available anymore.
   * Returns `undefined` if we cannot know whether it is still available or not.
   * @param {Object} segment
   * @returns {Boolean|undefined}
   */
  isSegmentStillAvailable(segment: ISegment): boolean | undefined;

  /**
   * Returns true if the `error` given following the request of `segment` can
   * indicate that the index became "de-synchronized" with the server.
   *
   * Reasons for de-synchronizations includes for example Manifest parsing
   * optimizations where a newer version will not be totally parsed. In those
   * conditions, we could be left with doing a segment request for a segment
   * that does not really exists.
   *
   * Note: This API assumes that the user first checked that the segment is
   * still available through `isSegmentStillAvailable`.
   * @param {Error} error
   * @param {Object} segment
   * @returns {Boolean}
   */
  canBeOutOfSyncError(error: IPlayerError, segment: ISegment): boolean;

  /**
   * Checks if the given time - in seconds - is in a discontinuity.
   * That is a "hole" in the stream with no segment defined.
   * If that's the case, return the next available position where a segment
   * should be available.
   * If that's not the case, return `null`.
   * @param {number} time - The time to check if it's in a discontinuity, in
   * seconds.
   * @returns {number | null} - If `null`, no discontinuity is encountered at
   * `time`. If this is a number instead, there is one and that number is the
   * position for which a segment is available in seconds.
   */
  checkDiscontinuity(time: number): number | null;

  /**
   * Returns `false` if the last segments in this index have already been
   * generated so that we can freely go to the next period.
   * Returns `true` if the index is still waiting on future segments to be
   * generated.
   * @returns {boolean}
   */
  isStillAwaitingFutureSegments(): boolean;

  /**
   * Returns `true` if this index has all the data it needs to give the list
   * of available segments.
   * Returns `false` if you first should load its initialization segment (or
   * the initialization segment's associated index file) to get the list of
   * available segments.
   *
   * Most index don't rely on the initialization segment to give an index and
   * as such, this method should return `true` directly.
   *
   * However in some index, the segment list might only be known after the
   * initialization has been loaded and parsed. In those case, it should return
   * `false` until the corresponding segment list is known, at which point you
   * can call the `initialize` method with that list so the `isInitialized` can
   * return `true`.
   * @returns {boolean}
   */
  isInitialized(): boolean;

  awaitSegmentBetween(start: number, end: number): boolean | undefined;

  /**
   * Some `RepresentationIndex` do not have the list of media segments known in
   * advance.
   * Instead, those are only known once the initialization segment is loaded and
   * parsed.
   *
   * Such `RepresentationIndex` whose list of media segments is still unknown
   * are called "uninitialized". You can know if a `RepresentationIndex` is
   * uninitialized by checking if its `isInitialized` method returns `false`.
   *
   * To initialize those `RepresentationIndex` and thus be able to obtain the
   * list of its linked media segments through its corresponding methods, you
   * have to initialize it with the list of segments once it is known
   * (presumably, after parsing the initialization segment) by giving them to
   * this `initialize` method.
   * @param {Array.<Object>} segmentList
   */
  initialize(segmentList: ISegmentInformation[]): void;

  /**
   * Returns an approximate for the duration of that `RepresentationIndex`s
   * segments, in seconds in the context of its Manifest (i.e. as the Manifest
   * anounces them, actual segment duration may be different due to
   * approximations), with the exception of the last one (that usually is
   * shorter).
   * @returns {number}
   */
  getTargetSegmentDuration():
    | {
        /** Approximate duration of any segments but the last one in seconds. */
        duration: number;
        /**
         * If `true`, the given duration should be relatively precize for all
         * segments but the last one.
         *
         * If `false`, `duration` indicates only a general idea of what can be
         * expected.
         */
        isPrecize: boolean;
      }
    | undefined;

  /**
   * Add segments to a RepresentationIndex that were predicted after parsing the
   * segment linked to `currentSegment`.
   * @param {Array.<Object>} nextSegments - The segment information parsed.
   * @param {Object} currentSegment - Information on the segment which contained
   * that new segment information.
   */
  addPredictedSegments(
    nextSegments: ISegmentInformation[],
    currentSegment: ISegment,
  ): void;

  /**
   * Replace the index with another one, such as after a Manifest update.
   * @param {Object} newIndex
   */
  _replace(newIndex: IRepresentationIndex): void;

  /**
   * Update the current index with a new, partial, version.
   * Unlike `replace`, this method do not completely overwrite the information
   * about this index's segments, it should mainly add new information about new
   * announced segments.
   * @param {Object} newIndex
   */
  _update(newIndex: IRepresentationIndex): void;
}