protocol.ts

/**
 * Mirror of the backend's WsMessage envelope (see WsMessage.java).
 * Every frame on the wire, in either direction, has this shape.
 */

export type Role = 'control' | 'display' | 'observer'

export type MessageType =
  | 'JOIN'
  | 'WELCOME'
  | 'PRESENCE'
  | 'EVENT'
  | 'BROADCAST'
  | 'RENAME'
  | 'ERROR'

/** Who a message came from: server-assigned id, current name, declared role. */
export interface Sender {
  id: string
  name: string
  role: Role
}

export const ROLE_ICONS: Record<Role, string> = {
  control: '🎛',
  display: '📺',
  observer: '👁',
}

export interface WsMessage {
  type: MessageType
  /**
   * Stamped by the server on routed messages; null on client-sent messages
   * (the server never trusts a client-supplied identity) and on
   * server-originated ones (WELCOME, PRESENCE, ERROR).
   */
  sender: Sender | null
  payload: unknown
  /** Epoch millis, stamped by the server. */
  timestamp: number
}

/** Payload of a WELCOME message: this client's own identity. */
export type WelcomePayload = Sender

/** Payload of a PRESENCE message: everyone currently connected. */
export interface PresencePayload {
  roster: Sender[]
}

/** Application-level events the UIs exchange (the payload of EVENT and BROADCAST). */
export type AppEvent =
  | { kind: 'announcement'; text: string }
  | { kind: 'set-color'; color: string }
  | { kind: 'reaction'; emoji: string }
  | { kind: 'ack'; of: string }