/**
 * Подставной `livekit-client` для тестов: комната, участники и события под
 * управлением теста. В jsdom настоящий SDK не работает (нет WebRTC), поэтому
 * `vi.mock('livekit-client', () => import('./fakeLiveKit'))` подменяет его
 * целиком, а логика `lib/livekit.ts` и стора проверяется настоящая.
 */

export const RoomEvent = {
  ParticipantConnected: 'participantConnected',
  ParticipantDisconnected: 'participantDisconnected',
  TrackSubscribed: 'trackSubscribed',
  TrackUnsubscribed: 'trackUnsubscribed',
  TrackPublished: 'trackPublished',
  TrackUnpublished: 'trackUnpublished',
  TrackMuted: 'trackMuted',
  TrackUnmuted: 'trackUnmuted',
  LocalTrackPublished: 'localTrackPublished',
  LocalTrackUnpublished: 'localTrackUnpublished',
  ConnectionQualityChanged: 'connectionQualityChanged',
  ActiveSpeakersChanged: 'activeSpeakersChanged',
  Reconnecting: 'reconnecting',
  Reconnected: 'reconnected',
  Disconnected: 'disconnected',
  DataReceived: 'dataReceived',
} as const;

export const ConnectionQuality = {
  Excellent: 'excellent',
  Good: 'good',
  Poor: 'poor',
  Lost: 'lost',
  Unknown: 'unknown',
} as const;

/** Уровни качества публикации: значения совпадают с `VideoQuality` из SDK. */
export const VideoQuality = {
  LOW: 0,
  MEDIUM: 1,
  HIGH: 2,
} as const;

export const Track = {
  Source: {
    Camera: 'camera',
    Microphone: 'microphone',
    ScreenShare: 'screen_share',
    ScreenShareAudio: 'screen_share_audio',
  },
} as const;

/** Дорожка: помнит, к каким элементам её подключили. */
export class FakeTrack {
  readonly kind: 'audio' | 'video';
  readonly attached: HTMLMediaElement[] = [];
  /** Качество публикации, выставленное `setPublishingQuality` (тесты ждут). */
  readonly publishingQuality: number[] = [];
  /** Сколько раз спросили отчёт WebRTC: по нему проверяют опрос статистики. */
  statsRequests = 0;
  private readonly report: () => [string, unknown][];

  constructor(kind: 'audio' | 'video', report: () => [string, unknown][] = () => []) {
    this.kind = kind;
    this.report = report;
  }

  attach(element: HTMLMediaElement): HTMLMediaElement {
    this.attached.push(element);
    return element;
  }

  detach(element: HTMLMediaElement): HTMLMediaElement[] {
    const index = this.attached.indexOf(element);
    if (index >= 0) {
      this.attached.splice(index, 1);
    }
    return [];
  }

  /** Отчёт WebRTC: `Map`, как настоящий `RTCStatsReport`. */
  getRTCStatsReport(): Promise<Map<string, unknown>> {
    this.statsRequests += 1;
    return Promise.resolve(new Map(this.report()));
  }

  /** Смена качества публикации: SDK-метод `LocalVideoTrack`. */
  setPublishingQuality(quality: number): void {
    this.publishingQuality.push(quality);
  }
}

export class FakePublication {
  constructor(
    readonly source: string,
    readonly track: FakeTrack,
    public isMuted: boolean,
  ) {}
}

type Handler = (...args: never[]) => void;

/** Участник комнаты: публикации, флаги и записанные вызовы SDK. */
export class FakeParticipant {
  isSpeaking = false;
  connectionQuality: string = ConnectionQuality.Excellent;
  identity: string;
  name: string;
  readonly isLocal: boolean;
  /** Вызовы, которые проверяют тесты: `setMicrophoneEnabled(false)` и т.п. */
  readonly calls: { method: string; value: unknown }[] = [];
  /** Отправленные data-пакеты: `{ payload, options }` каждого publishData. */
  readonly data: { payload: Uint8Array; options: unknown }[] = [];
  /** Параметры захвата экрана: `{ enabled, options }` каждого вызова. */
  readonly screenOptions: { enabled: boolean; options: unknown }[] = [];
  private readonly publications = new Map<string, FakePublication>();

  constructor(
    private readonly room: FakeRoom,
    identity: string,
    name: string,
    isLocal = false,
  ) {
    this.identity = identity;
    this.name = name;
    this.isLocal = isLocal;
  }

  get isMicrophoneEnabled(): boolean {
    return this.isLive(Track.Source.Microphone);
  }

  get isCameraEnabled(): boolean {
    return this.isLive(Track.Source.Camera);
  }

  get isScreenShareEnabled(): boolean {
    return this.isLive(Track.Source.ScreenShare);
  }

  getTrackPublication(source: string): FakePublication | undefined {
    return this.publications.get(source);
  }

  /** Публикация дорожки: используется и для своих, и для чужих участников. */
  setPublication(source: string, muted = false): FakePublication {
    const publication = new FakePublication(source, this.newTrack(source), muted);
    this.publications.set(source, publication);
    return publication;
  }

  /** Дорожка знает про отчёт WebRTC комнаты: тесты задают его через `setStats`. */
  private newTrack(source: string): FakeTrack {
    return new FakeTrack(source === Track.Source.Microphone ? 'audio' : 'video', () =>
      this.room.statsEntries(),
    );
  }

  removePublication(source: string): void {
    this.publications.delete(source);
    this.room.emit(RoomEvent.TrackUnsubscribed);
  }

  /** Отправка data-сообщения: тесты проверяют тему, payload и надёжность. */
  publishData(payload: Uint8Array, options?: unknown): Promise<void> {
    this.data.push({ payload, options });
    return Promise.resolve();
  }

  setSpeaking(speaking: boolean): void {
    this.isSpeaking = speaking;
  }

  private isLive(source: string): boolean {
    const publication = this.publications.get(source);
    return publication !== undefined && !publication.isMuted;
  }

  private setLocal(source: string, enabled: boolean, method: string): void {
    this.calls.push({ method, value: enabled });
    const existing = this.publications.get(source);
    const track = existing?.track ?? this.newTrack(source);
    this.publications.set(source, new FakePublication(source, track, !enabled));
    this.room.emit(RoomEvent.LocalTrackPublished);
  }

  setMicrophoneEnabled(enabled: boolean): Promise<void> {
    this.setLocal(Track.Source.Microphone, enabled, 'setMicrophoneEnabled');
    return Promise.resolve();
  }

  setCameraEnabled(enabled: boolean): Promise<void> {
    this.setLocal(Track.Source.Camera, enabled, 'setCameraEnabled');
    return Promise.resolve();
  }

  /** Демонстрация экрана: параметры захвата (разрешение и fps) запоминаем. */
  setScreenShareEnabled(enabled: boolean, options?: unknown): Promise<void> {
    this.screenOptions.push({ enabled, options });
    this.setLocal(Track.Source.ScreenShare, enabled, 'setScreenShareEnabled');
    return Promise.resolve();
  }
}

export interface RemoteOptions {
  muted?: boolean;
  camera?: boolean;
  screen?: boolean;
  quality?: string;
}

/** Подставная комната: те же методы, что использует `lib/livekit.ts`. */
export class FakeRoom {
  static instances: FakeRoom[] = [];

  static reset(): void {
    FakeRoom.instances = [];
  }

  static latest(): FakeRoom {
    const room = FakeRoom.instances.at(-1);
    if (room === undefined) {
      throw new Error('комната LiveKit ещё не создавалась');
    }
    return room;
  }

  readonly localParticipant: FakeParticipant;
  readonly remoteParticipants = new Map<string, FakeParticipant>();
  readonly connectCalls: { url: string; token: string }[] = [];
  readonly deviceSwitches: { kind: string; deviceId: string }[] = [];
  disconnectCalls = 0;
  startAudioCalls = 0;
  /** Отчёт WebRTC: пары «ключ → объект», как у `RTCStatsReport`. */
  private stats: [string, unknown][] = [];
  private readonly handlers = new Map<string, Set<Handler>>();

  constructor(readonly options?: unknown) {
    FakeRoom.instances.push(this);
    this.localParticipant = new FakeParticipant(this, 'user-1', 'Alice', true);
  }

  /** Отчёт WebRTC, который отдаёт `getRTCStatsReport()` своих дорожек. */
  statsEntries(): [string, unknown][] {
    return this.stats;
  }

  setStats(entries: [string, unknown][]): void {
    this.stats = entries;
  }

  /** Эмуляция входящего data-пакета: событие `DataReceived` от участника. */
  emitData(payload: Uint8Array, participant: FakeParticipant, topic: string): void {
    this.emit(RoomEvent.DataReceived, payload, participant, undefined, topic);
  }

  on(event: string, handler: Handler): this {
    const handlers = this.handlers.get(event) ?? new Set<Handler>();
    handlers.add(handler);
    this.handlers.set(event, handlers);
    return this;
  }

  off(event: string, handler: Handler): this {
    this.handlers.get(event)?.delete(handler);
    return this;
  }

  removeAllListeners(): this {
    this.handlers.clear();
    return this;
  }

  connect(url: string, token: string): Promise<void> {
    this.connectCalls.push({ url, token });
    return Promise.resolve();
  }

  disconnect(): Promise<void> {
    this.disconnectCalls += 1;
    this.emit(RoomEvent.Disconnected);
    return Promise.resolve();
  }

  startAudio(): Promise<void> {
    this.startAudioCalls += 1;
    return Promise.resolve();
  }

  switchActiveDevice(kind: string, deviceId: string): Promise<boolean> {
    this.deviceSwitches.push({ kind, deviceId });
    return Promise.resolve(true);
  }

  emit(event: string, ...args: unknown[]): void {
    for (const handler of [...(this.handlers.get(event) ?? [])]) {
      (handler as (...values: unknown[]) => void)(...args);
    }
  }

  /** Подключает удалённого участника: как `ParticipantConnected` из SDK. */
  addRemote(userId: string, name: string, options: RemoteOptions = {}): FakeParticipant {
    const participant = new FakeParticipant(this, userId, name);
    participant.connectionQuality = options.quality ?? ConnectionQuality.Excellent;
    participant.setPublication(Track.Source.Microphone, options.muted ?? false);
    if (options.camera === true) {
      participant.setPublication(Track.Source.Camera);
    }
    if (options.screen === true) {
      participant.setPublication(Track.Source.ScreenShare);
    }
    this.remoteParticipants.set(userId, participant);
    this.emit(RoomEvent.ParticipantConnected, participant);
    this.emit(RoomEvent.TrackSubscribed);
    return participant;
  }

  removeRemote(userId: string): void {
    const participant = this.remoteParticipants.get(userId);
    if (participant === undefined) {
      return;
    }
    this.remoteParticipants.delete(userId);
    this.emit(RoomEvent.ParticipantDisconnected, participant);
  }

  /** Кто-то заговорил: `ActiveSpeakersChanged` из SDK. */
  activeSpeakers(userIds: string[]): void {
    const speakerIds = new Set(userIds);
    this.localParticipant.setSpeaking(speakerIds.has(this.localParticipant.identity));
    for (const participant of this.remoteParticipants.values()) {
      participant.setSpeaking(speakerIds.has(participant.identity));
    }
    this.emit(RoomEvent.ActiveSpeakersChanged, []);
  }

  setQuality(userId: string, quality: string): void {
    const participant = this.remoteParticipants.get(userId);
    if (participant !== undefined) {
      participant.connectionQuality = quality;
      this.emit(RoomEvent.ConnectionQualityChanged, participant);
    }
  }
}