app.js

const express = require("express");
const http = require("http");
const path = require("path");
const { Server } = require("socket.io");
const db = require("./database/db");
const session = require("express-session");
const sharedSession = require("express-socket.io-session");
require('dotenv').config();


const app = express();
const server = http.createServer(app);

const sessionMiddleware = session({
    secret: "booksocial_secret",
    resave: false,
    saveUninitialized: false,
    cookie: {
        httpOnly: true,
        secure: false,
        sameSite: "lax",
        maxAge: null 
    }
});

const io = new Server(server, {
    cors: {
        origin: "*"
    }
});


app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(sessionMiddleware);

io.use(sharedSession(sessionMiddleware, {
    autoSave: true
}));

app.use(express.static(path.join(__dirname, "public")));

const usersRoutes = require("./routes/users");
const postsRoutes = require("./routes/posts");
const roomsRoutes = require("./routes/rooms");

app.use("/api/rooms", roomsRoutes);
app.use("/api/users", usersRoutes);
app.use("/api/posts", postsRoutes);
app.use("/uploads", express.static(path.join(__dirname, "uploads")));


let roomsUsers = {};


function isValidRoom(room) {
    return /^[a-zA-Z0-9_-]{1,50}$/.test(room);
}

function sanitizeMessage(msg) {
    return String(msg).substring(0, 500);
}

//  SOCKET 
io.on("connection", (socket) => {

    const session = socket.handshake.session;

    if (!session || !session.user) {
        socket.disconnect();
        return;
    }

    const username = session.user;

    console.log("User connected:", username);

    socket.on("join_room", (data) => {

        const room = data.room;

        if (!isValidRoom(room)) return;

        socket.join(room);

        socket.username = username;
        socket.room = room;

        if (!roomsUsers[room]) {
            roomsUsers[room] = new Set();
        }

        roomsUsers[room].add(username);

        io.to(room).emit("update_users", Array.from(roomsUsers[room]));

        // cronologia
        db.query(
            "SELECT username, message, created_at FROM messages WHERE room = ? ORDER BY created_at ASC LIMIT 100",
            [room],
            (err, results) => {
                if (!err) {
                    socket.emit("chat_history", results);
                }
            }
        );
    });

    socket.on("send_message", (data) => {

        const room = socket.room;
        const user = socket.username;

        if (!room || !user) return;

        let message = sanitizeMessage(data.message);

        if (!message.trim()) return;

        const payload = {
            room,
            username: user,
            message
        };

        db.query(
            "INSERT INTO messages (room, username, message) VALUES (?, ?, ?)",
            [room, user, message]
        );

        io.to(room).emit("receive_message", payload);
    });

    socket.on("disconnect", () => {
 
        const room = socket.room;
        const username = socket.username;

        if (room && roomsUsers[room]) {

            roomsUsers[room].delete(username);

            io.to(room).emit("update_users", Array.from(roomsUsers[room]));
        }

    });

});

const PORT = process.env.PORT;

server.listen(PORT, () => {
    console.log(`Server running on http://localhost:${PORT}`);
});