import type { ITextTrackSegmentData } from "../../transports";
import type { IRange } from "../../utils/ranges";

/**
 * Interface for an Object implementing timed text media data rendering at the
 * right time.
 */
export interface ITextDisplayer {
  /**
   * Start/restart `ITextDisplayer` (e.g. when changing text tracks).
   */
  reset(): void;

  /**
   * Add timed text media data to the displayer so it can later be displayed at
   * the right time.
   * @param {Object} infos
   * @returns {Array.<Object>} - Contiguous time ranges where text media data is
   * buffered by the `ITextDisplayer` _AFTER_ the timed media data is pushed.
   */
  pushTextData(infos: ITextDisplayerData): IRange[];
  /**
   * Remove media data corresponding to a given range of time, in seconds.
   * @param {number} start
   * @param {number} end
   * @returns {Array.<Object>} - Contiguous time ranges where text media data is
   * buffered by the `ITextDisplayer` _AFTER_ the removal operation is finished.
   */
  removeBuffer(start: number, end: number): IRange[];
  /**
   * Returns current contiguous time ranges where text media data is buffered by
   * the `ITextDisplayer` currently.
   * @returns {Array.<Object>}
   */
  getBufferedRanges(): IRange[];
  /**
   * Stop the `ITextDisplayer` from running and using resources.
   * @param {string | undefined} reason - Human-inspectable reason behind the
   * stop. Used for debugging matters, especially for debug log inspection.
   */
  stop(reason: string | undefined): void;
}

/** Interface describing a timed text media data "chunk". */
export interface ITextDisplayerData {
  /**
   * Chunk you want to push.
   * This can be the whole decodable segment's data or just a decodable sub-part
   * of it.
   * `null` if you just want to push the initialization segment.
   */
  chunk: ITextTrackSegmentData;
  /**
   * Time offset in seconds to apply to this segment.
   * A `timestampOffset` set to `5` will mean that the segment will be decoded
   * 5 seconds after its decode time which was found from the segment data
   * itself.
   */
  timestampOffset: number;
  /**
   * Append windows for the segment. This is a tuple of two elements.
   *
   * The first indicates the "start append window". The media data of that
   * segment that should have been decoded BEFORE that time (after taking the
   * `timestampOffset` property in consideration) will be ignored.
   * This can be set to `0` or `undefined` to not apply any start append window
   * to that chunk.
   *
   * The second indicates the "end append window". The media data of that
   * segment that should have been decoded AFTER that time (after taking the
   * `timestampOffset` property in consideration) will be ignored.
   * This can be set to `0` or `undefined` to not apply any end append window
   * to that chunk.
   */
  appendWindow: [number | undefined, number | undefined];
}