app.py

from flask import Flask, render_template, request
from flask_socketio import SocketIO, emit
import random

app = Flask(__name__)
socketio = SocketIO(app)

# python dict. Store connected users. Key is socketid value is username and avatarurl
users = {}

@app.route('/')
def index():
    return render_template('index.html')

# we're listening for the connect event
@socketio.on("connect")
def handle_connect():
    username = f"User_{random.randint(1000,9999)}"
    gender = random.choice(["girl","boy"])
    avatar_url = f" https://avatar.iran.liara.run/public/{gender}?username={username}"

    users[request.sid] = { "username":username,"avatar":avatar_url}

    emit("user_joined", {"username": username, "avatar": avatar_url}, broadcast=True)
    emit("set_username", {"username": username})

@socketio.on("disconnect")
def handle_disconnect():
    user = users.pop(request.sid, None)
    if user:
        emit("user_left", {"username": user["username"]}, broadcast=True)

@socketio.on("send_message")
def handle_message(data):
    user = users.get(request.sid)
    if user:
        emit("new_message", {
            "username": user["username"],
            "avatar":user["avatar"],
            "message":data["message"]
            }, broadcast=True)

@socketio.on("update_username")
def handle_update_username(data):
    old_username = users[request.sid]["username"]
    new_username = data["username"]
    users[request.sid]["username"] = new_username

    emit("username_updated", {
        "old_username":old_username,
        "new_username":new_username
    }, broadcast=True)

if __name__ == "__main__":
    socketio.run(app)