from flask import Flask, render_template

import socketio

# set async_mode to 'threading', 'eventlet' or 'gevent' to force a mode
# else, the best mode is selected automatically from what's installed
async_mode = None

sio = socketio.Server(async_mode=async_mode)
app = Flask(__name__)
app.wsgi_app = socketio.Middleware(sio, app.wsgi_app)


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


@sio.on('ping_from_client')
def ping(sid):
    sio.emit('pong_from_server', room=sid)


if __name__ == '__main__':
    if sio.async_mode == 'threading':
        # deploy with Werkzeug
        app.run(threaded=True)
    elif sio.async_mode == 'eventlet':
        # deploy with eventlet
        import eventlet
        from eventlet import wsgi
        wsgi.server(eventlet.listen(('', 5000)), app)
    elif sio.async_mode == 'gevent':
        # deploy with gevent
        from gevent import pywsgi
        try:
            from geventwebsocket.handler import WebSocketHandler
            websocket = True
        except ImportError:
            websocket = False
        if websocket:
            pywsgi.WSGIServer(('', 5000), app,
                              handler_class=WebSocketHandler).serve_forever()
        else:
            pywsgi.WSGIServer(('', 5000), app).serve_forever()
    else:
        print('Unknown async_mode: ' + sio.async_mode)