message-port.ts

import { DesktopAgent } from '@kite9/fdc3-standard';
import {
  BasicDesktopAgent,
  DefaultChannelSupport,
  DefaultAppSupport,
  DefaultIntentSupport,
  DefaultHandshakeSupport,
  ChannelSupport,
} from '@kite9/fdc3-agent-proxy';
import { ConnectionDetails, MessagePortMessaging } from './MessagePortMessaging';
import { DefaultDesktopAgentIntentResolver } from '../ui/DefaultDesktopAgentIntentResolver';
import { DefaultDesktopAgentChannelSelector } from '../ui/DefaultDesktopAgentChannelSelector';
import { NullIntentResolver } from '../ui/NullIntentResolver';
import { NullChannelSelector } from '../ui/NullChannelSelector';
import { ChannelSelector } from '@kite9/fdc3-standard';

/**
 * Given a message port, constructs a desktop agent to communicate via that.
 */
export async function createDesktopAgentAPI(cd: ConnectionDetails): Promise<DesktopAgent> {
  cd.messagePort.start();

  function string(o: string | boolean): string | null {
    if (o == true || o == false) {
      return null;
    } else {
      return o;
    }
  }

  const messaging = new MessagePortMessaging(cd);

  const useResolver = cd.handshake.payload.intentResolverUrl && cd.options.intentResolver;
  const useSelector = cd.handshake.payload.channelSelectorUrl && cd.options.channelSelector;

  const intentResolver = useResolver
    ? new DefaultDesktopAgentIntentResolver(string(cd.handshake.payload.intentResolverUrl))
    : new NullIntentResolver();

  const channelSelector = useSelector
    ? new DefaultDesktopAgentChannelSelector(string(cd.handshake.payload.channelSelectorUrl))
    : new NullChannelSelector();

  const cs = new DefaultChannelSupport(messaging, channelSelector);
  const hs = new DefaultHandshakeSupport(messaging);
  const is = new DefaultIntentSupport(messaging, intentResolver);
  const as = new DefaultAppSupport(messaging);
  const da = new BasicDesktopAgent(hs, cs, is, as, [hs, intentResolver, channelSelector]);
  await da.connect();

  await populateChannelSelector(cs, channelSelector);

  return da;
}

async function populateChannelSelector(cs: ChannelSupport, channelSelector: ChannelSelector): Promise<void> {
  const channel = await cs.getUserChannel();
  const userChannels = await cs.getUserChannels();
  channelSelector.updateChannel(channel?.id ?? null, userChannels);
}