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# Revision $Id$

## Simple talker demo that published std_msgs/Strings messages
## to the 'chatter' topic

import rospy
from std_msgs.msg import String
from nav_msgs.msg import Odometry
from tf.transformations import euler_from_quaternion
from geometry_msgs.msg import Point,Twist
from math import atan2

x = 0.0
y = 0.0
theta = 0.0


def newOdom (msg) :
	global x
	global y
	global theta

	x = msg.pose.pose.position.x
	y = msg.pose.pose.position.y
	rot_q = msg.pose.pose.orientation
	(roll,pith,theta) = euler_from_quaternion([rot_q.x,rot_q.y,rot_q.z,rot_q.w])


rospy.init_node("speed_controller")

subscriber = rospy.Subscriber("/odom",Odometry,newOdom)
publisher = rospy.Publisher("/cmd_vel",Twist,queue_size=1)

speed = Twist()

r = rospy.Rate(4)

goal = Point()
goal.x = input("set the x")
goal.y = input("set the y")


while not rospy.is_shutdown():
	inc_x = goal.x - x
	inc_y = goal.y - y
	angle_to_goal = atan2(inc_y,inc_x)
	
	if abs(angle_to_goal - theta) > 0.1:
		speed.linear.x=0.0
		speed.angular.z=0.3
	else:
		speed.linear.x=0.5
		speed.angular.z=0.0
	publisher.publish(speed)
	r.sleep()


