import {serve, ServerWebSocket} from "bun";

interface WSData {
  room: string;
}

const PORT = 8080;
const MAIN_CHANNEL = "central";

const msg = (data: Record<string, unknown>) => JSON.stringify(data);

const server = serve({
  fetch(req, server) {
    const url = new URL(req.url);
    const room = url.pathname.split("/")[1] ?? MAIN_CHANNEL;
    if (server.upgrade(req, {data: {room}})) {
      return;
    }
    return new Response("Upgrade failed :(", { status: 500 });
  },
  websocket: {
    open(ws: ServerWebSocket<WSData>) {
      const room = ws.data.room ?? MAIN_CHANNEL;
      console.log(`${ws.remoteAddress} connected to '${room}' room`);
      ws.subscribe(room);
    },
    message(ws, message) {
      const room = ws.data.room ?? MAIN_CHANNEL;
      ws.publish(room, message as unknown as BufferSource);
    },
    close(ws) {
      const room = ws.data.room ?? MAIN_CHANNEL;
      console.log(`${ws.remoteAddress} disconnected from '${room}' room`);
      ws.unsubscribe(room);
      ws.publish(room, msg({message: "someone left"}));
    },
  },
  port: PORT,
});

console.log(`Listening on ${server.hostname}:${server.port}`);