server.js

/**
 * @file Application Entry Point
 * @description Bootstraps the Cards Against Humanity web game server. Sets up Express for
 *   serving static assets and REST API routes, attaches Socket.IO for real-time game
 *   communication, and schedules periodic cleanup of abandoned games.
 * @requires dotenv
 * @requires express
 * @requires http
 * @requires socket.io
 * @requires path
 * @requires ./routes/decks
 * @requires ./routes/games
 * @requires ./sockets/index
 * @requires ./services/gameService
 */

// Load environment variables from .env before any other module reads them
require('dotenv').config();

const express = require('express');
const http = require('http');
const { Server } = require('socket.io');
const path = require('path');

const app = express();

// Wrap Express in a raw HTTP server so Socket.IO can share the same port
const server = http.createServer(app);

// Initialise Socket.IO on the shared HTTP server; clients connect via the default `/socket.io` path
const io = new Server(server);

// ---------------------------------------------------------------------------
// Middleware
// ---------------------------------------------------------------------------

// Parse JSON request bodies (used by the REST API for game creation, etc.)
app.use(express.json());

// Parse URL-encoded form data (used by the deck upload form)
app.use(express.urlencoded({ extended: true }));

// Serve the front-end static files (HTML, CSS, client-side JS) from the public directory
app.use(express.static(path.join(__dirname, 'public')));

// ---------------------------------------------------------------------------
// REST API Routes
// ---------------------------------------------------------------------------

// Deck management endpoints: list, upload (CSV), and delete decks
app.use('/api/decks', require('./routes/decks'));

// Game management endpoints: create a game and retrieve game state
app.use('/api/games', require('./routes/games'));

/**
 * Catch-all route for the game page. The game code is parsed client-side from
 * the URL, so we always serve the same static HTML regardless of the code value.
 *
 * @param {string} req.params.code - The 6-character game code embedded in the URL.
 */
app.get('/game/:code', (req, res) => {
  res.sendFile(path.join(__dirname, 'public', 'game.html'));
});

// ---------------------------------------------------------------------------
// Socket.IO — Real-time Game Communication
// ---------------------------------------------------------------------------

// Register all Socket.IO event handlers (lobby + gameplay) on the shared `io` instance
require('./sockets/index')(io);

// ---------------------------------------------------------------------------
// Periodic Cleanup of Abandoned Games
// ---------------------------------------------------------------------------

const { cleanupAbandonedGames } = require('./services/gameService');

// Run cleanup immediately on startup to purge any stale games left over from a previous crash
cleanupAbandonedGames();

// Re-run cleanup every 5 minutes (300 000 ms) to keep the database tidy
setInterval(cleanupAbandonedGames, 5 * 60 * 1000);

// ---------------------------------------------------------------------------
// Start Listening
// ---------------------------------------------------------------------------

const PORT = process.env.PORT || 3000;
const HOST = process.env.HOST || '0.0.0.0'; // Bind to all interfaces by default
server.listen(PORT, HOST, () => {
  console.log(`Cards Against Humanity server running on http://${HOST}:${PORT}`);
});