Convert reactive_move to class

tuto_kickoff/scripts/reactive_move

 #!/usr/bin/python3
 import rclpy
-import math
 from rclpy.node import Node
 from sensor_msgs.msg import PointCloud2
 from geometry_msgs.msg import Twist
 import sensor_msgs_py.point_cloud2
-from std_msgs.msg import Header
 
-rosNode= None
-velocity_publisher = None
+class ReactiveMove(Node):
     
-def scan_callback(scanMsg):
-    global rosNode
-    global velocity_publisher
+    def __init__(self, name="reactive_move"):
+        super().__init__(name) # Create the node
+
+        # Initialize a subscriber
+        self.create_subscription(PointCloud2, 'scan_points', self.scan_callback, 10)
+
+        # Initialize a publisher
+        self._velocity_publisher = self.create_publisher(Twist, 'cmd_vel', 10)
+
+
+
+    def scan_callback(self, scanMsg):
         points = sensor_msgs_py.point_cloud2.read_points(scanMsg)
 
         x, y = firstPointInFront(points, 0.5, 0.25)
@@ -28,7 +34,7 @@ def scan_callback(scanMsg):
         else:  # If there's not point in front, go straight
             velocity.linear.x = 0.2 
 
-    velocity_publisher.publish(velocity)    
+        self._velocity_publisher.publish(velocity)
         
         
 
@@ -42,20 +48,12 @@ def firstPointInFront(points:list, maxX, maxY):
 
 
 def main():
-    global velocity_publisher
-
     rclpy.init()
-    rosNode= Node('reactive_move')
-    # Initialize a subscriber:
-    rosNode.create_subscription( PointCloud2, 'scan_points', scan_callback, 10)
-    # Initialize a publisher:
-    velocity_publisher = rosNode.create_publisher(Twist, '/cmd_vel', 10)
-
-    while True :
-        rclpy.spin_once( rosNode )
+    rosNode = ReactiveMove()
+    rclpy.spin(rosNode)
 
 
-    scanInterpret.destroy_node()
+    rosNode.destroy_node()
     rclpy.shutdown()
 
 if __name__ == "__main__":