DefaultPrivateChannel.ts

import {
  ApiEvent,
  ContextHandler,
  EventHandler,
  Listener,
  PrivateChannel,
  PrivateChannelEventTypes,
} from '@finos/fdc3-standard';
import { DefaultChannel } from './DefaultChannel';
import { Messaging } from '../Messaging';
import {
  PrivateChannelNullEventListener,
  PrivateChannelAddContextEventListener,
  PrivateChannelDisconnectEventListener,
  PrivateChannelUnsubscribeEventListener,
} from '../listeners/PrivateChannelEventListener';
import { DefaultContextListener } from '../listeners/DefaultContextListener';
import { RegisterableListener } from '../listeners/RegisterableListener';
import {
  PrivateChannelDisconnectRequest,
  PrivateChannelDisconnectResponse,
} from '@finos/fdc3-schema/dist/generated/api/BrowserTypes';

export class DefaultPrivateChannel extends DefaultChannel implements PrivateChannel {
  constructor(messaging: Messaging, messageExchangeTimeout: number, id: string) {
    super(messaging, messageExchangeTimeout, id, 'private');
  }

  async addEventListener(type: PrivateChannelEventTypes | null, handler: EventHandler): Promise<Listener> {
    let a: RegisterableListener;
    switch (type) {
      case 'addContextListener':
        a = new PrivateChannelAddContextEventListener(this.messaging, this.messageExchangeTimeout, this.id, handler);
        break;
      case 'unsubscribe':
        a = new PrivateChannelUnsubscribeEventListener(this.messaging, this.messageExchangeTimeout, this.id, handler);
        break;
      case 'disconnect':
        a = new PrivateChannelDisconnectEventListener(this.messaging, this.messageExchangeTimeout, this.id, handler);
        break;
      case null:
        a = new PrivateChannelNullEventListener(this.messaging, this.messageExchangeTimeout, this.id, handler);
        break;
      default:
        throw new Error('Unsupported event type: ' + type);
    }
    await a.register();
    return a;
  }

  //implementations of the deprecated listener functions
  onAddContextListener(handler: (contextType?: string) => void): Listener {
    //Adapt handler type for differences between addEventListener and onAddContextListener handler types
    const adaptorHandler: EventHandler = (event: ApiEvent) => {
      handler(event.details.contextType ?? undefined);
    };
    const l = new PrivateChannelAddContextEventListener(
      this.messaging,
      this.messageExchangeTimeout,
      this.id,
      adaptorHandler
    );
    l.register();
    return l;
  }

  onUnsubscribe(handler: (contextType?: string) => void): Listener {
    //Adapt handler type for differences between addEventListener and onUnsubscribeListener handler types
    const adaptorHandler: EventHandler = (event: ApiEvent) => {
      handler(event.details.contextType ?? undefined);
    };
    const l = new PrivateChannelUnsubscribeEventListener(
      this.messaging,
      this.messageExchangeTimeout,
      this.id,
      adaptorHandler
    );
    l.register();
    return l;
  }

  onDisconnect(handler: () => void): Listener {
    //Adapt handler type for differences between addEventListener and onDisconnectListener handler types
    const adaptorHandler: EventHandler = () => {
      handler();
    };
    const l = new PrivateChannelDisconnectEventListener(
      this.messaging,
      this.messageExchangeTimeout,
      this.id,
      adaptorHandler
    );
    l.register();
    return l;
  }

  async disconnect(): Promise<void> {
    const msg: PrivateChannelDisconnectRequest = {
      meta: this.messaging.createMeta(),
      payload: {
        channelId: this.id,
      },
      type: 'privateChannelDisconnectRequest',
    };
    await this.messaging.exchange<PrivateChannelDisconnectResponse>(
      msg,
      'privateChannelDisconnectResponse',
      this.messageExchangeTimeout
    );
  }

  async addContextListenerInner(contextType: string | null, theHandler: ContextHandler): Promise<Listener> {
    const listener = new DefaultContextListener(
      this.messaging,
      this.messageExchangeTimeout,
      this.id,
      contextType,
      theHandler
    );
    await listener.register();
    return listener;
  }
}