brackt/server/socket.js

import { Server as SocketIOServer } from "socket.io";

/** @type {SocketIOServer | null} */
let io = null;

/**
 * Initialize Socket.IO server
 * @param {import('http').Server} httpServer
 * @returns {SocketIOServer}
 */
export function initializeSocketIO(httpServer) {
  if (io) {
    console.log("Socket.IO already initialized");
    return io;
  }

  // Create Socket.IO server
  io = new SocketIOServer(httpServer, {
    // CORS only needed if clients connect from different origin
    cors: process.env.NODE_ENV === "production" && process.env.APP_URL
      ? {
          origin: process.env.APP_URL,
          credentials: true,
        }
      : undefined, // No CORS in dev (same origin)
  });

  // Connection handling
  io.on("connection", (socket) => {
    console.log("Client connected:", socket.id);

    // Join draft room
    socket.on("join-draft", (seasonId) => {
      if (!seasonId) {
        console.error("No seasonId provided for join-draft");
        return;
      }
      socket.join(`draft-${seasonId}`);
      console.log(`Socket ${socket.id} joined draft-${seasonId}`);
    });

    // Leave draft room
    socket.on("leave-draft", (seasonId) => {
      if (!seasonId) return;
      socket.leave(`draft-${seasonId}`);
      console.log(`Socket ${socket.id} left draft-${seasonId}`);
    });

    socket.on("disconnect", () => {
      console.log("Client disconnected:", socket.id);
    });
  });

  // Store globally for access in route handlers
  // This is safe because server.js controls the lifecycle
  global.__socketIO = io;

  console.log("Socket.IO initialized");
  return io;
}

/**
 * Get the Socket.IO server instance
 * @returns {SocketIOServer}
 */
export function getSocketIO() {
  // Check both local and global storage
  const instance = io || global.__socketIO;
  if (!instance) {
    throw new Error("Socket.IO not initialized. Call initializeSocketIO first.");
  }
  return instance;
}