How do I use the data from subscribe part (mqtt)

Question

I am now doing a robot and I use mqtt to communicate between raspi and computer. Now, I want to use the string I have published from the computer. but I don't know where to check the string on this whole code. So can anyone can help me. And if you have any idea about sent the pygame event through the mqtt please help me.

#This is my code
import paho.mqtt.client as mqtt
import time

message = ""

def on_message(client, userdata, message):
    print(str(message.payload.decode("utf-8")))
    message = str(message.payload.decode("utf-8"))

mqttBroker ="mqtt.eclipseprojects.io"

client = mqtt.Client("Raspi")
client.connect(mqttBroker) 

client.loop_start()

client.subscribe("JOYSTICK")
client.on_message=on_message

# This is the part that I wanna move to check the data
if 'JoyAxisMotion' in message:
    axis = int(message[63])
    valueJoy = float(message[75:79])

elif 'JoyButtonDown' in message:
    button = int(message[64])

    if button == 0:
        print("A")
    elif button == 1:
        print("B")
    elif button == 2:
        print("X")
    elif button == 3:
        print("Y")
        
    elif 'JoyHatMotion' in message:
        valueArrow = message[73:79]
        print(valueArrow)
        if valueArrow == "(1, 0)":
            GPIO.output(6, GPIO.HIGH)
            GPIO.output(13, GPIO.LOW)
            GPIO.output(19, GPIO.LOW)
            GPIO.output(26, GPIO.LOW)
        elif valueArrow == "(0, 1)":
            GPIO.output(6, GPIO.LOW)
            GPIO.output(13, GPIO.HIGH)
            GPIO.output(19, GPIO.LOW)
            GPIO.output(26, GPIO.LOW) 
        elif valueArrow == "(-1, 0":
            GPIO.output(6, GPIO.LOW)
            GPIO.output(13, GPIO.LOW)
            GPIO.output(19, GPIO.HIGH)
            GPIO.output(26, GPIO.LOW)
        elif valueArrow == "(0, -1":
            GPIO.output(6, GPIO.LOW)
            GPIO.output(13, GPIO.LOW)
            GPIO.output(19, GPIO.LOW)
            GPIO.output(26, GPIO.HIGH) 
        elif valueArrow == "(0, 0)":
            GPIO.output(6, GPIO.LOW)
            GPIO.output(13, GPIO.LOW)
            GPIO.output(19, GPIO.LOW)
            GPIO.output(26, GPIO.LOW)

time.sleep(300)
client.loop_stop()

Thanks you for your attention.