/**
 * Which external output is present, resolved from independent sources.
 *
 * An AirPlay route (audible elsewhere, local engine still plays) and an
 * owning session (e.g. Cast) each publish only their own contribution here;
 * this module decides what the store sees. A session wins over a route.
 */
import type { AviationStore } from '../store';
import type { CastDevice } from '../specs/types.nitro';

export interface OutputPresence {
  /** AirPlay-style route: audible elsewhere, but the local engine still plays. */
  setRoute(device: CastDevice | undefined): void;
  /** A session that owns playback, e.g. Cast. */
  setSession(device: CastDevice | undefined): void;
  reset(): void;
}

export function createOutputPresence(store: AviationStore): OutputPresence {
  let route: CastDevice | undefined;
  let session: CastDevice | undefined;

  function publish(): void {
    const device = session ?? route;
    store.setCastState({
      state: device ? 'connected' : 'disconnected',
      device,
      isConnected: device !== undefined,
    });
  }

  return {
    setRoute(device): void {
      if (route === device) return;
      route = device;
      publish();
    },

    setSession(device): void {
      if (session === device) return;
      session = device;
      publish();
    },

    reset(): void {
      route = undefined;
      session = undefined;
      publish();
    },
  };
}