interface BaseMessage {
  /** A string identifying the specific type of the message. */
  type: string;

  /** Optional timestamp indicating when the message was created. */
  timestamp?: Date;

  /** Optional session identifier, used for routing messages related to a specific user session. */
  sessionId?: string;
}

interface AppConnectionInit extends BaseMessage {
  type: AppToCloudMessageType.CONNECTION_INIT;
  packageName: string;
  sessionId: string; // Session ID obtained from webhook
  apiKey: string;    // App's API Key
}

interface AppSubscriptionUpdate extends BaseMessage {
  type: AppToCloudMessageType.SUBSCRIPTION_UPDATE;
  packageName: string;
  subscriptions: ExtendedStreamType[]; // List of StreamType or language-specific strings
}

interface DisplayRequest extends BaseMessage {
  type: AppToCloudMessageType.DISPLAY_REQUEST;
  packageName: string;
  view: ViewType;
  layout: Layout;
  durationMs?: number;
  forceDisplay?: boolean;
}

interface DashboardContentUpdate extends BaseMessage {
  type: AppToCloudMessageType.DASHBOARD_CONTENT_UPDATE;
  packageName: string;
  sessionId: string;
  content: string;
  modes: DashboardMode[]; // Target dashboard modes
  timestamp: Date;
}

interface AppConnectionAck extends BaseMessage {
  type: CloudToAppMessageType.CONNECTION_ACK;
  settings?: AppSettings; // Current user settings for this App
  config?: AppConfig;     // App configuration fetched by the cloud (optional)
}

interface AppConnectionError extends BaseMessage {
  type: CloudToAppMessageType.CONNECTION_ERROR;
  message: string; // Error description
  code?: string;    // Optional error code
}

interface AppStopped extends BaseMessage {
  type: CloudToAppMessageType.APP_STOPPED;
  reason: "user_disabled" | "system_stop" | "error"; // Reason for stopping
  message?: string; // Optional additional details
}

interface SettingsUpdate extends BaseMessage {
  type: CloudToAppMessageType.SETTINGS_UPDATE;
  packageName: string;
  settings: AppSettings; // The complete new set of settings
}

interface DataStream extends BaseMessage {
  type: CloudToAppMessageType.DATA_STREAM; // Wrapper type
  streamType: StreamType; // The actual type of the data payload
  data: unknown; // The payload, type depends on streamType
}

interface DashboardModeChanged extends BaseMessage {
  type: CloudToAppMessageType.DASHBOARD_MODE_CHANGED;
  mode: DashboardMode; // The new dashboard mode
}

interface DashboardAlwaysOnChanged extends BaseMessage {
  type: CloudToAppMessageType.DASHBOARD_ALWAYS_ON_CHANGED;
  enabled: boolean; // Whether always-on dashboard is now enabled
}

interface TranscriptionData extends BaseMessage {
  type: StreamType.TRANSCRIPTION;
  text: string;
  isFinal: boolean;
  // Other properties...
}

interface TranslationData extends BaseMessage {
  type: StreamType.TRANSLATION;
  text: string;
  isFinal: boolean;
  // Other properties...
}

interface AudioChunk extends BaseMessage {
  type: StreamType.AUDIO_CHUNK;
  arrayBuffer: ArrayBufferLike;
  sampleRate?: number;
}

interface WebSocketError {
  /** An error code string. */
  code: string;

  /** A human-readable description of the error. */
  message: string;

  /** Optional additional details about the error. */
  details?: unknown;
}

enum AppToCloudMessageType {
  CONNECTION_INIT = 'tpa_connection_init',
  SUBSCRIPTION_UPDATE = 'subscription_update',
  DISPLAY_REQUEST = 'display_event',
  DASHBOARD_CONTENT_UPDATE = 'dashboard_content_update'
}

enum CloudToAppMessageType {
  CONNECTION_ACK = 'tpa_connection_ack',
  CONNECTION_ERROR = 'tpa_connection_error',
  APP_STOPPED = 'app_stopped',
  SETTINGS_UPDATE = 'settings_update',
  DATA_STREAM = 'data_stream',
  DASHBOARD_MODE_CHANGED = 'dashboard_mode_changed',
  DASHBOARD_ALWAYS_ON_CHANGED = 'dashboard_always_on_changed',
  WEBSOCKET_ERROR = 'websocket_error'
}

enum GlassesToCloudMessageType {
  CONNECTION_INIT = 'connection_init',
  START_APP = 'start_app',
  STOP_APP = 'stop_app',
  // Many more types...
}

enum CloudToGlassesMessageType {
  CONNECTION_ACK = 'connection_ack',
  CONNECTION_ERROR = 'connection_error',
  AUTH_ERROR = 'auth_error',
  // More types...
}

// For App to Cloud messages
function isAppConnectionInit(message: AppToCloudMessage): message is AppConnectionInit;
function isAppSubscriptionUpdate(message: AppToCloudMessage): message is AppSubscriptionUpdate;
function isDisplayRequest(message: AppToCloudMessage): message is DisplayRequest;
function isDashboardContentUpdate(message: AppToCloudMessage): message is DashboardContentUpdate;
function isDashboardModeChange(message: AppToCloudMessage): message is DashboardModeChange;
function isDashboardSystemUpdate(message: AppToCloudMessage): message is DashboardSystemUpdate;

// For Cloud to App messages
function isAppConnectionAck(message: CloudToAppMessage): message is AppConnectionAck;
function isAppConnectionError(message: CloudToAppMessage): message is AppConnectionError;
function isAppStopped(message: CloudToAppMessage): message is AppStopped;
function isSettingsUpdate(message: CloudToAppMessage): message is SettingsUpdate;
function isDataStream(message: CloudToAppMessage): message is DataStream | AudioChunk;
function isAudioChunk(message: CloudToAppMessage): message is AudioChunk;
function isDashboardModeChanged(message: CloudToAppMessage): message is DashboardModeChanged;
function isDashboardAlwaysOnChanged(message: CloudToAppMessage): message is DashboardAlwaysOnChanged;