POSITION_TOLERANCE = 50

def enable_power():
    """
    Check safety and enable arm power
    """
    release_psys()  
    time.sleep(0.1)   
    if feedback_psys_safety.read() == False:
        raise Exception("Cannot enable power: check doors")
    release_local()
    if feedback_local_safety.read() == False:
        raise Exception("Cannot enable power: check sample changer emergency stop button")
    time.sleep(0.25)    
    if not robot.state.isNormal():
        raise Exception("Cannot enable power: robot state is " + str(robot.state))
    robot.enable()
    


def wait_end_of_move():
    robot.update()
    while (not robot.settled) or (not robot.empty) or (not robot.isReady()) :
        time.sleep(0.01)


def move_home():        
    #robot.reset_motion("jHome")
    robot.movej("pHome", robot.tool , DESC_SCAN)    
    wait_end_of_move()

def move_to_laser():
    robot.reset_motion()
    tool = robot.tool
    d = robot.get_distance_to_pnt("pLaser")
    if d<0:
        raise Exception ("Error calculating distance to laser: " + str(d))
    if d<POSITION_TOLERANCE:
        print "FROM LASER"
        robot.movel("pLaser", robot.tool, DESC_SCAN, sync = True)
        return
    d = robot.get_distance_to_pnt("pLaserHome")
    if d<0:
        raise Exception ("Error calculating distance to laser appro: " + str(d))
    if d<POSITION_TOLERANCE:
        print "FROM APPRO"
        robot.movel("pLaser", robot.tool, DESC_SCAN, sync = True)
        return
    d = robot.get_distance_to_pnt("pHome")
    if d<0:
        raise Exception ("Error calculating distance to home: " + str(d))
    if d<POSITION_TOLERANCE:
        print "FROM HOME"
        robot.movej("pLaserHome", robot.tool, DESC_DEFAULT)
        robot.movel("pLaser", robot.tool, DESC_SCAN, sync = True)    
        return
    raise Exception ("Must be in home position to start move to laser")
    



def update_tool(tool=None, x_offset=0.0, y_offset=0.0, z_offset=0.0):
    #Updating tool:
    t=robot.get_tool_trsf(tool)
    t[0]=t[0] - x_offset
    t[1]=t[1] - y_offset
    t[2]=t[2] - z_offset
    robot.set_tool_trsf(t, tool)
    print "Updated " + (str(robot.tool) if (tool is None) else tool) + ": " + str(t) 
    robot.save_program()