Event System

interface HlsEventEmitter {
  /**
   * Add an event listener
   * @param event - Event name
   * @param listener - Event handler function
   * @param context - Optional context for the listener
   */
  on<E extends keyof HlsListeners>(
    event: E,
    listener: HlsListeners[E],
    context?: any
  ): void;
  
  /**
   * Add a one-time event listener
   * @param event - Event name
   * @param listener - Event handler function
   * @param context - Optional context for the listener
   */
  once<E extends keyof HlsListeners>(
    event: E,
    listener: HlsListeners[E],
    context?: any
  ): void;
  
  /**
   * Remove event listener(s)
   * @param event - Event name
   * @param listener - Specific listener to remove (optional)
   * @param context - Context to match (optional)
   */
  off<E extends keyof HlsListeners>(
    event: E,
    listener?: HlsListeners[E],
    context?: any
  ): void;
  
  /**
   * Remove all listeners for an event or all events
   * @param event - Event name (optional, removes all if not specified)
   */
  removeAllListeners<E extends keyof HlsListeners>(event?: E): void;
  
  /**
   * Emit an event
   * @param event - Event name
   * @param name - Event name (duplicate for consistency)
   * @param eventObject - Event data
   */
  emit<E extends keyof HlsListeners>(
    event: E,
    name: E,
    eventObject: Parameters<HlsListeners[E]>[1]
  ): boolean;
  
  /**
   * Get all listeners for an event
   * @param event - Event name
   */
  listeners<E extends keyof HlsListeners>(event: E): HlsListeners[E][];
  
  /**
   * Get listener count for an event
   * @param event - Event name
   */
  listenerCount<E extends keyof HlsListeners>(event: E): number;
}

const hls = new Hls();

// Add event listeners
hls.on(Hls.Events.MANIFEST_LOADED, (event, data) => {
  console.log("Manifest loaded:", data.url);
});

// One-time listener
hls.once(Hls.Events.FIRST_FRAG_CHANGED, (event, data) => {
  console.log("First fragment changed:", data.frag.url);
});

// Remove specific listener
const errorHandler = (event, data) => {
  console.error("HLS Error:", data);
};
hls.on(Hls.Events.ERROR, errorHandler);
hls.off(Hls.Events.ERROR, errorHandler);

// Remove all error listeners
hls.removeAllListeners(Hls.Events.ERROR);

// Check listener count
console.log("Error listeners:", hls.listenerCount(Hls.Events.ERROR));

enum Events {
  // Media lifecycle events
  MEDIA_ATTACHING = "hlsMediaAttaching",
  MEDIA_ATTACHED = "hlsMediaAttached", 
  MEDIA_DETACHING = "hlsMediaDetaching",
  MEDIA_DETACHED = "hlsMediaDetached",
  MEDIA_ENDED = "hlsMediaEnded",
  
  // Stall and buffer events
  STALL_RESOLVED = "hlsStallResolved",
  BUFFER_RESET = "hlsBufferReset",
  BUFFER_CODECS = "hlsBufferCodecs",
  BUFFER_CREATED = "hlsBufferCreated",
  BUFFER_APPENDING = "hlsBufferAppending",
  BUFFER_APPENDED = "hlsBufferAppended",
  BUFFER_EOS = "hlsBufferEos",
  BUFFERED_TO_END = "hlsBufferedToEnd",
  BUFFER_FLUSHING = "hlsBufferFlushing",
  BUFFER_FLUSHED = "hlsBufferFlushed",
  
  // Manifest events
  MANIFEST_LOADING = "hlsManifestLoading",
  MANIFEST_LOADED = "hlsManifestLoaded",
  MANIFEST_PARSED = "hlsManifestParsed",
  
  // Level/quality events
  LEVEL_SWITCHING = "hlsLevelSwitching",
  LEVEL_SWITCHED = "hlsLevelSwitched",
  LEVEL_LOADING = "hlsLevelLoading",
  LEVEL_LOADED = "hlsLevelLoaded",
  LEVEL_UPDATED = "hlsLevelUpdated",
  LEVEL_PTS_UPDATED = "hlsLevelPtsUpdated",
  LEVELS_UPDATED = "hlsLevelsUpdated",
  MAX_AUTO_LEVEL_UPDATED = "hlsMaxAutoLevelUpdated",
  
  // Audio track events
  AUDIO_TRACKS_UPDATED = "hlsAudioTracksUpdated",
  AUDIO_TRACK_SWITCHING = "hlsAudioTrackSwitching",
  AUDIO_TRACK_SWITCHED = "hlsAudioTrackSwitched",
  AUDIO_TRACK_LOADING = "hlsAudioTrackLoading",
  AUDIO_TRACK_LOADED = "hlsAudioTrackLoaded",
  AUDIO_TRACK_UPDATED = "hlsAudioTrackUpdated",
  
  // Subtitle track events
  SUBTITLE_TRACKS_UPDATED = "hlsSubtitleTracksUpdated",
  SUBTITLE_TRACKS_CLEARED = "hlsSubtitleTracksCleared",
  SUBTITLE_TRACK_SWITCH = "hlsSubtitleTrackSwitch",
  SUBTITLE_TRACK_LOADING = "hlsSubtitleTrackLoading",
  SUBTITLE_TRACK_LOADED = "hlsSubtitleTrackLoaded",
  SUBTITLE_TRACK_UPDATED = "hlsSubtitleTrackUpdated",
  SUBTITLE_FRAG_PROCESSED = "hlsSubtitleFragProcessed",
  
  // Cue and text track events
  CUES_PARSED = "hlsCuesParsed",
  NON_NATIVE_TEXT_TRACKS_FOUND = "hlsNonNativeTextTracksFound",
  
  // Fragment events
  INIT_PTS_FOUND = "hlsInitPtsFound",
  FRAG_LOADING = "hlsFragLoading",
  FRAG_LOAD_EMERGENCY_ABORTED = "hlsFragLoadEmergencyAborted",
  FRAG_LOADED = "hlsFragLoaded",
  FRAG_DECRYPTED = "hlsFragDecrypted",
  FRAG_PARSING_INIT_SEGMENT = "hlsFragParsingInitSegment",
  FRAG_PARSING_USERDATA = "hlsFragParsingUserdata",
  FRAG_PARSING_METADATA = "hlsFragParsingMetadata",
  FRAG_PARSED = "hlsFragParsed",
  FRAG_BUFFERED = "hlsFragBuffered",
  FRAG_CHANGED = "hlsFragChanged",
  
  // Performance events
  FPS_DROP = "hlsFpsDrop",
  FPS_DROP_LEVEL_CAPPING = "hlsFpsDropLevelCapping",
  
  // Encryption key events
  KEY_LOADING = "hlsKeyLoading",
  KEY_LOADED = "hlsKeyLoaded",
  
  // Back buffer events
  LIVE_BACK_BUFFER_REACHED = "hlsLiveBackBufferReached", // deprecated
  BACK_BUFFER_REACHED = "hlsBackBufferReached",
  
  // Content steering events
  STEERING_MANIFEST_LOADED = "hlsSteeringManifestLoaded",
  
  // Interstitial events (ads/mid-rolls)
  ASSET_LIST_LOADING = "hlsAssetListLoading",
  ASSET_LIST_LOADED = "hlsAssetListLoaded",
  INTERSTITIALS_UPDATED = "hlsInterstitialsUpdated",
  INTERSTITIALS_BUFFERED_TO_BOUNDARY = "hlsInterstitialsBufferedToBoundary",
  INTERSTITIAL_ASSET_PLAYER_CREATED = "hlsInterstitialAssetPlayerCreated",
  INTERSTITIAL_STARTED = "hlsInterstitialStarted",
  INTERSTITIAL_ASSET_STARTED = "hlsInterstitialAssetStarted",
  INTERSTITIAL_ASSET_ENDED = "hlsInterstitialAssetEnded",
  INTERSTITIAL_ASSET_ERROR = "hlsInterstitialAssetError",
  INTERSTITIAL_ENDED = "hlsInterstitialEnded",
  INTERSTITIALS_PRIMARY_RESUMED = "hlsInterstitialsPrimaryResumed",
  PLAYOUT_LIMIT_REACHED = "hlsPlayoutLimitReached",
  
  // Special events
  EVENT_CUE_ENTER = "hlsEventCueEnter",
  ERROR = "hlsError",
  DESTROYING = "hlsDestroying"
}

const hls = new Hls();

// Media attachment
hls.on(Hls.Events.MEDIA_ATTACHED, () => {
  console.log("Media element attached");
});

// Manifest parsing
hls.on(Hls.Events.MANIFEST_PARSED, (event, data) => {
  console.log(`Manifest parsed with ${data.levels.length} levels`);
  console.log(`Audio tracks: ${data.audioTracks.length}`);
  console.log(`Subtitle tracks: ${data.subtitleTracks.length}`);
});

// Quality level changes
hls.on(Hls.Events.LEVEL_SWITCHED, (event, data) => {
  const level = hls.levels[data.level];
  console.log(`Switched to ${level.width}x${level.height} @ ${level.bitrate}bps`);
});

// Fragment loading
hls.on(Hls.Events.FRAG_LOADED, (event, data) => {
  console.log(`Fragment loaded: ${data.frag.url}`);
  console.log(`Load time: ${data.stats.loading.end - data.stats.loading.start}ms`);
});

enum Events {
  BUFFER_APPENDING = "hlsBufferAppending",
  BUFFER_APPENDED = "hlsBufferAppended", 
  BUFFER_EOS = "hlsBufferEos",
  BUFFER_FLUSHING = "hlsBufferFlushing",
  BUFFER_FLUSHED = "hlsBufferFlushed",
  BUFFER_RESET = "hlsBufferReset",
  BUFFER_CODECS = "hlsBufferCodecs"
}

// Monitor buffer operations
hls.on(Hls.Events.BUFFER_APPENDING, (event, data) => {
  console.log(`Appending ${data.type} buffer`);
});

hls.on(Hls.Events.BUFFER_APPENDED, (event, data) => {
  console.log(`${data.type} buffer appended`);
});

hls.on(Hls.Events.BUFFER_FLUSHED, (event, data) => {
  console.log(`Buffer flushed from ${data.startOffset} to ${data.endOffset}`);
});

enum Events {
  // Audio tracks
  AUDIO_TRACKS_UPDATED = "hlsAudioTracksUpdated",
  AUDIO_TRACK_SWITCHING = "hlsAudioTrackSwitching",
  AUDIO_TRACK_SWITCHED = "hlsAudioTrackSwitched",
  AUDIO_TRACK_LOADING = "hlsAudioTrackLoading",
  AUDIO_TRACK_LOADED = "hlsAudioTrackLoaded",
  
  // Subtitle tracks
  SUBTITLE_TRACKS_UPDATED = "hlsSubtitleTracksUpdated",
  SUBTITLE_TRACK_SWITCH = "hlsSubtitleTrackSwitch",
  SUBTITLE_TRACK_LOADING = "hlsSubtitleTrackLoading",
  SUBTITLE_TRACK_LOADED = "hlsSubtitleTrackLoaded",
  CUES_PARSED = "hlsCuesParsed"
}

// Audio track events
hls.on(Hls.Events.AUDIO_TRACKS_UPDATED, (event, data) => {
  console.log("Audio tracks updated:", data.audioTracks.length);
});

hls.on(Hls.Events.AUDIO_TRACK_SWITCHED, (event, data) => {
  const track = hls.audioTracks[data.id];
  console.log(`Audio switched to: ${track?.name} (${track?.lang})`);
});

// Subtitle events
hls.on(Hls.Events.CUES_PARSED, (event, data) => {
  console.log(`${data.cues.length} subtitle cues parsed`);
});

enum Events {
  // Fragment parsing
  FRAG_PARSING_INIT_SEGMENT = "hlsFragParsingInitSegment",
  FRAG_PARSING_USERDATA = "hlsFragParsingUserdata", 
  FRAG_PARSING_METADATA = "hlsFragParsingMetadata",
  
  // Init segment
  INIT_PTS_FOUND = "hlsInitPtsFound",
  
  // Key loading
  KEY_LOADING = "hlsKeyLoading",
  KEY_LOADED = "hlsKeyLoaded",
  
  // FPS monitoring
  FPS_DROP = "hlsFpsDrop",
  FPS_DROP_LEVEL_CAPPING = "hlsFpsDropLevelCapping",
  
  // DRM
  KEY_SYSTEM_STATUS_CHANGED = "hlsKeySystemStatusChanged",
  
  // Steering
  STEERING_MANIFEST_LOADED = "hlsSteeringManifestLoaded"
}

// Monitor FPS drops
hls.on(Hls.Events.FPS_DROP, (event, data) => {
  console.log(`FPS drop detected: ${data.currentDropped}/${data.currentDecoded}`);
});

// Key loading for encrypted content
hls.on(Hls.Events.KEY_LOADED, (event, data) => {
  console.log("Decryption key loaded for:", data.frag.url);
});

// Metadata parsing
hls.on(Hls.Events.FRAG_PARSING_METADATA, (event, data) => {
  console.log("Metadata samples:", data.samples.length);
});

interface ManifestParsedData {
  levels: Level[];
  audioTracks: MediaPlaylist[];
  subtitleTracks: MediaPlaylist[];
  sessionData: any[];
  sessionKeys: any[];
  firstLevel: number;
  stats: LoadStats;
  audio: boolean;
  video: boolean;
  altAudio: boolean;
}

interface LevelSwitchingData {
  level: number;
  attrs: AttrList;
  url: string;
  bitrate: number;
  width: number;
  height: number;
  codecSet: string;
}

interface FragLoadedData {
  frag: Fragment;
  payload: ArrayBuffer;
  stats: LoadStats;
  networkDetails?: any;
}

interface ErrorData {
  type: ErrorTypes;
  details: ErrorDetails;
  fatal: boolean;
  reason?: string;
  level?: number;
  frag?: Fragment;
  url?: string;
  response?: Response;
  context?: any;
}

interface BufferAppendedData {
  type: string;
  frag: Fragment;
  part?: Part;
  chunkMeta: ChunkMetadata;
  parent: string;
  timeRanges: {
    video?: TimeRanges;
    audio?: TimeRanges;
    audiovideo?: TimeRanges;
  };
}