// The worker's side: a replica of the editor's document and the room that
// reads it, ticking every TICK_MILLISECONDS.

import * as Y from 'yjs';
import { CHANNEL_ORIGIN, type ChannelMessage, type Port } from './channel.js';
import { SimulationRoom, TICK_MILLISECONDS, type RoomOptions } from './room.js';

export interface ServeOptions extends RoomOptions {
  /** Calls `tick` every so many milliseconds. */
  readonly every: (milliseconds: number, tick: () => void) => void;
}

export function serveRoom(port: Port, options: ServeOptions): SimulationRoom {
  const doc = new Y.Doc();
  doc.on('update', (update: Uint8Array, origin: unknown) => {
    if (origin !== CHANNEL_ORIGIN) port.postMessage({ type: 'doc', update });
  });
  const room = new SimulationRoom(doc, options);
  const client = room.connect((message) => port.postMessage({ type: 'host', message }));
  port.addEventListener('message', (event) => {
    const data = event.data as ChannelMessage;
    if (data?.type === 'doc') Y.applyUpdate(doc, data.update, CHANNEL_ORIGIN);
    else if (data?.type === 'client') room.receive(client, data.message);
  });
  port.start?.();
  options.every(TICK_MILLISECONDS, () => room.tick());
  return room;
}