import time


def move_to_low_limit_switch(motor):

    low_limit = motor.limits()[0]
    motor.move_and_wait(low_limit)
    assert motor.at_target()
    # Field is currently not set in our drivers
    #assert motor.read_field('lowlimitswitch') == 1
    assert not motor.has_error()


def move_to_high_limit_switch(motor):

    low_limit = motor.limits()[1]
    motor.move_and_wait(low_limit)
    assert motor.at_target()
    # Field is currently not set in our drivers
    #assert motor.read_field('highlimitswitch') == 1
    assert not motor.has_error()


def move_while_move(motor, first_target, second_target):
    """
    Start moving to a position which is sufficiently far away, then interrupt
    this move command with another move command. This function assumes a
    sufficiently large distance between the current motor position and 
    first_target so it has enough time to issue the second move command.
    """
    motor.write_field('writepv', first_target)
    time.sleep(2)
    motor.move_and_wait(second_target)
    assert motor.at_target()
    assert not motor.has_error()

def stop_then_move(motor, target):
    motor.write_field('stop', 1)
    motor.write_field('writepv', target)


def stop(motor, target):
    """
    Stop an motor while it is moving to a target. This function assumes a
    sufficiently large distance between the current motor position and target.
    """
    motor.write_field('writepv', target)
    time.sleep(1)
    motor.write_field('stop', 1)
    motor.wait_for_done()
    assert not motor.at_target(target)
    assert not motor.has_error()