import time
import math

from setup.classes import read_config


def reread_limits_from_hw(motor):
    """
    sinqMotor drivers usually read their limits from the hardware at each poll,
    hence any values manually written to DHLM or DLLM should be overwritten
    after the next poll at latest
    """

    (high_limit, low_limit) = motor.limits()
    motor.put_pv('dialhighlimit', high_limit+10)
    motor.put_pv('diallowlimit', low_limit-10)

    # Wait two idle poll periods
    time.sleep(2 * motor.idlepoll)

    # Values should have been reread
    assert math.isclose(motor.get_pv('highlimit'),
                        high_limit, rel_tol=1e-9, abs_tol=0.001)
    assert math.isclose(motor.get_pv('lowlimit'),
                        low_limit, rel_tol=1e-9, abs_tol=0.001)
    assert math.isclose(motor.get_pv('dialhighlimit'),
                        high_limit, rel_tol=1e-9, abs_tol=0.001)
    assert math.isclose(motor.get_pv('diallowlimit'),
                        low_limit, rel_tol=1e-9, abs_tol=0.001)