import { OT } from '../../types/opentok';

import { AverageStats, Bandwidth, HasAudioVideo } from '../types/stats';

export default class MOSState {
  subscriberStatsLog: OT.SubscriberStats[];
  publisherStatsLog: OT.PublisherStats[];
  audioScoresLog: number[];
  videoScoresLog: number[];
  stats: HasAudioVideo<AverageStats> = { audio: {}, video: {} };
  bandwidth: Bandwidth = { audio: 0, video: 0 };
  intervalId?: number;
  audioOnlyFallback: boolean;

  constructor(audioOnly?: boolean) {
    this.subscriberStatsLog = [];
    this.publisherStatsLog = [];
    this.audioScoresLog = [];
    this.videoScoresLog = [];
    this.audioOnlyFallback = !!audioOnly;
  }

  static readonly maxLogLength: number = 1000;
  static readonly scoreInterval: number = 1000;

  readonly hasAudioTrack = (): boolean => this.subscriberStatsLog[0] && !!this.subscriberStatsLog[0].audio;
  readonly hasVideoTrack = (): boolean => this.subscriberStatsLog[0] && !!this.subscriberStatsLog[0].video;

  public getLastPublisherStats = (): OT.PublisherStats | undefined =>
    this.publisherStatsLog[this.publisherStatsLog.length - 1] ?? undefined;

  private audioScore(): number {
    return this.audioScoresLog.reduce((acc, score) => acc + score, 0) / this.audioScoresLog.length;
  }

  private videoScore(): number {
    return this.videoScoresLog.reduce((acc, score) => acc + score, 0) / this.videoScoresLog.length;
  }

  clearInterval() {
    if (this.intervalId) {
      window.clearInterval(this.intervalId);
    }
    this.intervalId = undefined;
  }

  private pruneAudioScores() {
    const audioScoresLog = this.audioScoresLog;
    while (audioScoresLog.length > MOSState.maxLogLength) {
      audioScoresLog.shift();
    }
    this.audioScoresLog = audioScoresLog;
  }

  private pruneVideoScores() {
    const videoScoresLog = this.videoScoresLog;
    while (videoScoresLog.length > MOSState.maxLogLength) {
      videoScoresLog.shift();
    }
    this.videoScoresLog = videoScoresLog;
  }

  pruneScores() {
    this.pruneAudioScores();
    this.pruneVideoScores();
  }

  audioQualityScore(): number {
    return this.hasAudioTrack() ? this.audioScore() : 1;
  }

  videoQualityScore(): number {
    return this.hasVideoTrack() ? this.videoScore() : 1;
  }
}