import type { RemoteTransport } from './transport'

export interface TransportPair<Server, Client> {
  readonly server: RemoteTransport<Server, Client>
  readonly client: RemoteTransport<Client, Server>
}

export const inMemoryTransportPair = <Server, Client>(): TransportPair<Server, Client> => {
  const serverHandlers = new Set<(message: Client) => void>()
  const clientHandlers = new Set<(message: Server) => void>()
  return {
    server: {
      send: (message) => clientHandlers.forEach((handler) => handler(message)),
      onMessage: (handler) => {
        serverHandlers.add(handler)
        return () => void serverHandlers.delete(handler)
      },
    },
    client: {
      send: (message) => serverHandlers.forEach((handler) => handler(message)),
      onMessage: (handler) => {
        clientHandlers.add(handler)
        return () => void clientHandlers.delete(handler)
      },
    },
  }
}