web-chat/backend/socket.js

const { Server } = require('socket.io');
const jwt = require('jsonwebtoken');
const jwtSecret = process.env.JWT_SECRET;
const { db } = require('./db.js');
const {json} = require("express");

function initializeSocket(server) {
    const io = new Server(server, {
        cookie: {
            httpOnly: true,
            sameSite: "strict",
            maxAge: 30 * 24 * 60 * 60 * 1000
        }
    });

    io.use((socket, next) => {
        // user auth
        const token = socket.handshake.auth.token;
        if(token) {
            jwt.verify(token, jwtSecret, (err, user) => {
                if(err) {
                    console.log(err);
                    return next(new Error('Authentication error'));
                }
                socket.user = user;
                next();
            });
        } else {
            next(new Error('Not logged in'));
        }
    });

    // open main socket connection
    io.on('connection', (socket) => {
        if (!socket.user) {
            socket.emit('socket error', 'User not authenticated')
            socket.disconnect();
            return;
        }
        const username = socket.user.username;
        // Join a room with the user's username
        socket.join(username);

        io.to(username).emit('username', username);

        // chat message event
        socket.on('chat message', async (msgData) => {
            const { content, recipient } = msgData;
            let insertedId;
            try {
                // Insert the new message into the database
                const result = await db.query('INSERT INTO messages (content, username, recipient) VALUES ($1, $2, $3) RETURNING id', [content, username, recipient]);
                insertedId = result.rows[0].id;

            } catch (err) {
                console.error('Error inserting message:', err);
                socket.emit('socket error', "Error inserting message, try refreshing the page")
                return;
            }

            // Fetch the newly inserted message from the database
            try {
                const query = 'SELECT id, content, username, recipient FROM messages WHERE id = $1';
                const result = await db.query(query, [insertedId]);

                if (result.rows.length > 0) {
                    const newMessage = result.rows[0];

                    // Emit message to the sender's and recipient's rooms
                    io.to(username).to(recipient).emit('chat message', { username: newMessage.username, recipient: newMessage.recipient, content: newMessage.content });
                }
            } catch (err) {
                console.error('Error fetching inserted message:', err);
                socket.emit('socket error', 'Failed to send message')
            }
        });

        socket.on('get messages', async (recipient) => {
            const username = socket.user.username;
            try {
                const query = `
            SELECT id, content, username, recipient
            FROM messages
            WHERE (username = $1 AND recipient = $2) OR (username = $2 AND recipient = $1)
            ORDER BY id ASC
        `;
                const result = await db.query(query, [username, recipient]);

                if (result.rows.length > 0) {
                    //const { username: sender, recipient: receiver, content: content, id: id } = result.rows;

                    io.to(username).emit('messages history', result.rows);
                } else {
                    io.to(username).emit('no messages');
                }
            } catch (e) {
                console.error('Error retrieving messages:', e);
                socket.emit('socket error', 'Error retrieving messages, refresh the page (server error)')
            }
        });

        // Contacts socket
        socket.on('contacts', async (contactUsername) => {
            const username = socket.user.username;
            const status = (contactUsername.status === "read") ? "read" : "unread";

            // Update contact list in db
            try {
                const query = `
            INSERT INTO contacts (username, contact, status)
            SELECT $1, $2, $3
            WHERE NOT EXISTS (
                SELECT 1 FROM contacts WHERE username = $1 AND contact = $2
            )
            `;
                await db.query(query, [username, contactUsername.contact, status]);
            } catch (err) {
                console.error('Failed to update contacts ', err)
                socket.emit('socket error', 'Failed to update contacts (server error)')
            }
            // Get contact list from db
            try {
                const query = (`
            SELECT contact, username, status
            FROM contacts
            WHERE username = $1
            `);
            const result = await db.query(query, [username]);
            io.to(username).emit('contacts', result.rows);

            } catch(err) {
                console.error('Failed to get contacts from db');
                io.to(username).emit('socket error', 'Failed to get contacts (server error)');
            }
        })

        socket.on('get contacts', async () => {
            const username = socket.user.username;
            try {
                const query = (`
            SELECT contact, username, status
            FROM contacts
            WHERE username = $1
        `);
                const result = await db.query(query, [username]);
                io.to(username).emit('contacts', result.rows);

            } catch(err) {
                console.error('Failed to get contacts from db');
                io.to(username).emit('socket error', 'Failed to get contacts (server error)');
            }
        })
        socket.on('delete contact', async (contactUsername) => {
            const username = socket.user.username;
            try {
                const query = ('DELETE FROM contacts WHERE (username = $1 AND contact = $2)');
                await db.query(query, [username, contactUsername]);

            } catch(err) {
                console.error('Failed to remove contact from db');
                io.to(username).emit('socket error', 'Failed to remove contact (server error)');
            }
        })

        socket.on('status', async (username) => {
            const userUsername = socket.user.username;
            const status = 'unread';
            try {
                const query = (
                    'UPDATE contacts SET status = $1 WHERE username = $2 AND contact = $3'
                );
                await db.query(query, [status, userUsername, username]);
                io.to(userUsername).emit('status', username);
            } catch(err) {
                console.error('Failed to update unread status:', err);
            }
        })

        socket.on('read', async(contactUsername) => {
            const userUsername = socket.user.username;
            const status = 'read';
            try {
                const query = ('UPDATE contacts SET status = $1 WHERE username = $2 AND contact = $3');
                await db.query(query, [status, userUsername, contactUsername]);
                io.to(userUsername).emit('status', contactUsername);
            } catch(err) {
                console.error('Failed to update unread status:', err)
            }
        })
        // disconnect event
        socket.on('disconnect', () => {
            return "Disconnected";
        });
    });

    return io;
}

module.exports = { initializeSocket };