#  -*- coding: utf-8 -*-
# *****************************************************************************
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Module authors:
#   M. Zolliker <markus.zolliker@psi.ch>
#
# *****************************************************************************
"""use transducer and motor to adjust force"""

import time
from secop.core import Drivable, Parameter, FloatRange, Done, Attached, Command


class Uniax(Drivable):
    motor = Attached()
    transducer = Attached()
    step = Parameter('maximum motor step', FloatRange(unit='deg'), default=5, readonly=False)
    fine_step = Parameter('motor step for fine adjustment', FloatRange(unit='deg'), default=1, readonly=False)
    tolerance = Parameter('force tolerance', FloatRange(), readonly=False, default=1)
    filter_interval = Parameter('filter time', FloatRange(0, 60, unit='s'), readonly=False, default=1)
    span = Parameter('difference between max and min', FloatRange(), needscfg=False)
    pollinterval = 0.1
    fast_pollfactor = 1

    _target = None
    _mot_target = None
    _direction = 0
    _last_era = 0
    _cnt = 0
    _sum = 0
    _min = None
    _max = None
    _last_min = None
    _last_max = None

    def read_value(self):
        force = self._transducer
        mot = self._motor
        era = int(time.time() / self.filter_interval)
        newera = era != self._last_era
        value = force.read_value()
        if newera:
            self._last_era = era
            if self._min is None:
                self._min = self._max = self._last_max = self._last_min = value
            if self._cnt > 0:
                self.value = self._sum / self._cnt
                self._sum = self._cnt = 0
                self.span = self._max - self._min
                self._last_min = self._min
                self._last_max = self._max
                self._min = self._max = value
        self._min = min(self._min, value)
        self._max = max(self._max, value)
        self._sum += value
        self._cnt += 1
        high_value = max(self._max, self._last_max)
        low_value = min(self._min, self._last_min)
        if self._target is None:
            if mot.isBusy():
                self.status = self.Status.IDLE, 'stopping'
            else:
                self.status = self.Status.IDLE, ''
            return Done
        step = 0
        if self._direction > 0:
            if high_value < self._target:
                step = self.step
        else:
            if low_value > self._target:
                step = -self.step
        if not step:
            if self._direction * (self._target - value) < self.tolerance:
                self.stop()
                self.status = self.Status.IDLE, 'target reached'
                return Done
            if newera:
                step = self.fine_step * self._direction
        if step and not mot.isBusy():
            mot_target = mot.value + step
            self._mot_target = mot.write_target(mot_target)
        return Done

    def write_target(self, target):
        self._target = target
        if target - self.value > 0:
            self._direction = 1
        else:
            self._direction = -1
        if self._motor.status[0] == self.Status.ERROR:
            self._motor.reset()
        self.status = self.Status.BUSY, 'changed target'
        self._mot_target = self._motor.target
        self.read_value()
        return target

    @Command()
    def stop(self):
        self._target = None
        self._motor.stop()
        self.status = self.Status.IDLE, 'stopped'