# *****************************************************************************
#
# 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:
#   Markus Zolliker <markus.zolliker@psi.ch>
#
# *****************************************************************************

"""drivers for CCU4, the cryostat control unit at SINQ"""
import time
import math
import numpy as np
from frappy.lib.enum import Enum
from frappy.lib import clamp, formatExtendedTraceback
from frappy.lib.interpolation import Interpolation
# the most common Frappy classes can be imported from frappy.core
from frappy.core import HasIO, Parameter, Command, Readable, Writable, Drivable, \
    Property, StringIO, BUSY, IDLE, WARN, ERROR, DISABLED, Attached, nopoll
from frappy.datatypes import BoolType, EnumType, FloatRange, StructOf, \
    StatusType, IntRange, StringType, TupleOf, ArrayOf
from frappy.errors import CommunicationFailedError
from frappy.states import HasStates, status_code, Retry


M = Enum(idle=0, opening=1, closing=2, opened=3, closed=4, no_motor=5)
A = Enum(disabled=0, manual=1, auto=2)


class IO(StringIO):
    """communication with CCU4"""
    # for completeness: (not needed, as it is the default)
    end_of_line = '\n'
    # on connect, we send 'cid' and expect a reply starting with 'CCU4'
    identification = [('cid', r'cid=CCU4.*')]


class Base(HasIO):
    ioClass = IO

    def command(self, **kwds):
        """send a command and get the response

        :param kwds: <parameter>=<value> for changing a parameter <parameter>=<type> for querying a parameter
        :returns: the (new) values of the parameters
        """
        types = {}
        cmds = []
        for key, value in kwds.items():
            if isinstance(value, type):
                types[key] = value
                cmds.append(key)
            elif isinstance(value, str):
                types[key] = str
                cmds.append(f'{key}={value}')
            else:
                types[key] = float
                cmds.append(f'{key}={value:g}')
        reply = self.io.communicate(' '.join(cmds)).split()
        if len(reply) != len(types):
            raise CommunicationFailedError('number of reply items does not match')
        result = []
        for (given, typ), res in zip(types.items(), reply):
            name, txtvalue = res.split('=')
            if given != name:
                raise CommunicationFailedError('result keys do not match given keys')
            result.append(typ(txtvalue))
        if len(kwds) == 1:
            return result[0]
        return result


class HeLevel(Base, Readable):
    """He Level channel of CCU4"""

    value = Parameter(unit='%')
    empty_length = Parameter('warm length when empty', FloatRange(0, 2000, unit='mm'),
                             readonly=False)
    full_length = Parameter('warm length when full', FloatRange(0, 2000, unit='mm'),
                            readonly=False)
    sample_rate = Parameter('sample rate', EnumType(slow=0, fast=1), readonly=False)

    status = Parameter(datatype=StatusType(Readable, 'DISABLED'))

    # conversion of the code from the CCU4 parameter 'hsf'
    STATUS_MAP = {
        0: (IDLE, 'sensor ok'),
        1: (ERROR, 'sensor warm'),
        2: (ERROR, 'no sensor'),
        3: (ERROR, 'timeout'),
        4: (ERROR, 'not yet read'),
        5: (DISABLED, 'disabled'),
    }

    def read_value(self):
        return self.command(h=float)

    def read_status(self):
        return self.STATUS_MAP[int(self.command(hsf=int))]

    def read_sample_rate(self):
        value, self.empty_length, self.full_length = self.command(hf=int, hem=float, hfu=float)
        return value

    def write_sample_rate(self, value):
        return self.command(hf=value)

    def write_empty_length(self, value):
        return self.command(hem=value)

    def write_full_length(self, value):
        return self.command(hfu=value)


class Valve(Base, Writable):
    value = Parameter('relay state', BoolType())
    target = Parameter('relay target', BoolType())
    ioClass = IO
    STATE_MAP = {0: (0, (IDLE, 'off')),
                 1: (1, (IDLE, 'on')),
                 2: (0, (ERROR, 'no valve')),
                 3: (0, (WARN, 'timeout')),  # timeout in filling process (takes too long to fill)
                 4: (0, (WARN, 'timeout1')),  # timeout in filling process (takes too long to start)
                 5: (1, (IDLE, 'boost')),
                 }
    _open_command = None
    _close_command = None
    _query_state = None

    def write_target(self, target):
        if target:
            self.command(**self._open_command)
        else:
            self.command(**self._close_command)

    def read_status(self):
        state = int(self.command(**self._query_state))
        self.value, status = self.STATE_MAP[state]
        return status


class HeFillValve(Valve):
    _open_command = {'hcd': 1, 'hf': 1}
    _close_command = {'hcd': 0,  'hf': 0}
    _query_state = {'hv': int}


class N2FillValve(Valve):
    _open_command = {'nc': 1}
    _close_command = {'nc': 0}
    _query_state = {'nv': int}


class AuxValve(Valve):
    channel = Property('valve number', IntRange(1, 12))

    def initModule(self):
        self._open_command = {f'vc{self.channel}': 1}
        self._close_command = {f'vc{self.channel}': 0}
        self._query_state = {f'v{self.channel}': int}


class N2TempSensor(Readable):
    value = Parameter('LN2 T sensor', FloatRange(unit='K'), default=0)


class N2Level(Base, Readable):
    valve = Attached(Writable, mandatory=False)
    lower = Attached(Readable, mandatory=False)
    upper = Attached(Readable, mandatory=False)

    value = Parameter('vessel state', EnumType(empty=0, ok=1, full=2))
    status = Parameter(datatype=StatusType(Readable, 'DISABLED', 'BUSY'))
    mode = Parameter('auto mode', EnumType(A), readonly=False, default=A.manual)

    threshold = Parameter('threshold triggering start/stop filling',
                          FloatRange(unit='K'), readonly=False, default=90)
    cool_delay = Parameter('max. minutes needed to cool the lower sensor',
                           FloatRange(unit='s'), readonly=False, default=30)
    fill_timeout = Parameter('max. minutes needed to fill',
                             FloatRange(unit='s'), readonly=False)
    names = Property('''names of attached modules

                     configure members as empty strings to disable the creation
                     ''',
                     StructOf(valve=StringType(), lower=StringType(), upper=StringType()),
                     default={'valve': '$_valve', 'lower': '$_lower', 'upper': '$_upper'})

    # conversion of the code from the CCU4 parameter 'ns'
    STATUS_MAP = {
        0: (IDLE, 'sensor ok'),
        1: (ERROR, 'no sensor'),
        2: (ERROR, 'short circuit'),
        3: (ERROR, 'upside down'),
        4: (ERROR, 'sensor warm'),
        5: (WARN, 'empty'),
    }

    def initialReads(self):
        self.command(nav=1)  # tell CCU4 to activate LN2 sensor readings
        super().initialReads()

    def read_status(self):
        auto, nstate = self.command(na=int, ns=int)
        if not self.valve or not auto:
            if self.mode == A.auto:
                # no valve assigned
                self.mode = A.manual
        if self.mode == A.disabled:
            return DISABLED, ''
        status = self.STATUS_MAP[nstate]
        if status[0] // 100 != IDLE // 100:
            return status
        if self.mode == A.manual:
            return IDLE, ''
        vstatus = self.valve.status
        if vstatus[0] // 100 == WARN // 100:
            return ERROR, vstatus[1]
        if vstatus[0] // 100 != IDLE // 100:
            return vstatus
        if self.valve.value:
            return BUSY, 'filling'
        return IDLE, 'watching'

    def read_value(self):
        # read sensors
        lower, upper = self.command(nl=float, nu=float)
        if self.lower:
            self.lower.value = lower
        if self.upper:
            self.upper.value = upper
        if upper < self.threshold:
            return 'full'
        if lower < self.threshold:
            return 'ok'
        return 'empty'

    def write_mode(self, mode):
        if mode == A.auto:
            if self.isBusy():
                return mode
            # set to watching
            self.command(nc=3)
        else:
            # set to off
            self.command(nc=2)
        return mode

    def read_threshold(self):
        value, self.cool_delay, self.fill_timeout = self.command(nth=float, ntc=float, ntm=float)
        return value

    def write_threshold(self, value):
        return self.command(nth=value)

    def write_cool_delay(self, value):
        return self.command(ntc=value)

    def write_fill_timeout(self, value):
        return self.command(ntm=value)

    @Command()
    def fill(self):
        """start filling"""
        self.mode = A.auto
        self.command(nc=1)

    @Command()
    def stop(self):
        """stop filling"""
        if self.mode == A.auto:
            # set to watching
            self.command(nc=3)
        else:
            # set to off
            self.command(nc=0)


class N2LevelGuess(N2Level):
    """guess the current level from hold time"""
    value = Parameter('estimated level', FloatRange(unit='%'), default=20)
    fill_time = Parameter('min fill time - for raw level indicator',
                          FloatRange(unit='s'), default=600)
    hold_time = Parameter('min hold time - for raw level indicator',
                          FloatRange(unit='s'), default=24 * 3600)
    _full_since = None
    _empty_since = None
    _fill_state = ''  # may also be 'empty', 'full' or 'unknown'
    _lower = 0
    _upper = 0

    def read_status(self):
        status = super().read_status()
        if status == (IDLE, ''):
            return IDLE, self._fill_state
        return status

    def read_value(self):
        # read sensors
        now = time.time()
        lower, upper = self.command(nl=float, nu=float)
        if self.lower:
            self.lower.value = lower
        if self.upper:
            self.upper.value = upper
        if upper < self.threshold:
            self._full_since = now
            if self._empty_since is not None:
                self.fill_time = now - self._empty_since
                self._empty_since = None
                self._fill_state = 'full'
            return 100
        if lower < self.threshold:
            if self._empty_since is None:
                if self._full_since is None:
                    self._fill_state = 'unknown'
                    return 20
                delay = now - self._full_since
                value = max(10, 100 * 1 - delay / self.hold_time)
                if value < 99:
                    self._fill_state = ''
                return value
            delay = now - self._empty_since - self.cool_delay
            value = min(90, 100 * max(0, delay / self.fill_time))
            if value >= 10:
                self._fill_state = ''
            return value
        if self._full_since is not None:
            self.hold_time = now - self._full_since
            self._full_since = None
        self.log.info('lower %g upper %g threshold %g', lower, upper, self.threshold)
        self._empty_since = now
        self._fill_state = 'empty'
        return 0


class HasFilter:
    __value1 = None
    __value = None
    __last = None

    def filter(self, filter_time, value):
        now = time.time()
        if self.__value is None:
            self.__last = now
            self.__value1 = value
            self.__value = value
        weight = (now - self.__last) / filter_time
        self.__value1 += weight * (value - self.__value)
        self.__value += weight * (self.__value1 - self.__value)
        self.__last = now
        return self.__value


class Pressure(HasFilter, Base, Readable):
    value = Parameter(unit='mbar')
    mbar_offset = Parameter('offset in mbar', FloatRange(unit='mbar'), default=0.8, readonly=False)
    filter_time = Parameter('filter time', FloatRange(unit='sec'), readonly=False, default=3)
    pollinterval = Parameter(default=0.25)

    def read_value(self):
        return self.filter(self.filter_time, self.command(f=float)) - self.mbar_offset


def Table(miny=None, maxy=None):
    return ArrayOf(TupleOf(FloatRange(), FloatRange(miny, maxy)))


class NeedleValveFlow(HasStates, Base, Drivable):
    flow_sensor = Attached(Readable, mandatory=False)
    pressure = Attached(Pressure, mandatory=False)
    use_pressure = Parameter('flag (use pressure instead of flow meter)', BoolType(),
                             readonly=False, default=False)
    lnm_per_mbar = Parameter('scale factor', FloatRange(unit='lnm/mbar'), readonly=False, default=0.6)
    pump_type = Parameter('pump type', EnumType(unknown=0, neodry=1, xds35=2, sv65=3),
                          readonly=False, value=0)

    value = Parameter(unit='ln/min')
    target = Parameter(unit='ln/min')

    motor_state = Parameter('motor_state', EnumType(M), default=0)
    speed = Parameter('speed moving time / passed time', FloatRange())
    tolerance = Parameter('tolerance', Table(0), value=[(2,0.1),(4,0.4)], readonly=False)
    prop_open = Parameter('proportional term for opening', Table(0), readonly=False, value=[(1,0.05)])
    prop_close = Parameter('proportional term for closing', Table(0), readonly=False, value=[(1,0.02)])
    deriv = Parameter('min progress time constant', FloatRange(unit='s'),
                      default=30, readonly=False)
    control_active = Parameter('control active flag', BoolType(), readonly=False, default=1)
    min_open_pulse = Parameter('minimal open step', FloatRange(0, unit='s'),
                               readonly=False, default=0.02)
    min_close_pulse = Parameter('minimal close step', FloatRange(0, unit='s'),
                                readonly=False, default=0.0)
    flow_closed = Parameter('flow when needle valve is closed', FloatRange(unit='ln/min'),
                            readonly=False, default=0.0)
    # raw_open_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.12)
    # raw_close_step = Parameter('step after direction change', FloatRange(unit='s'), readonly=False, default=0.04)

    FLOW_SCALE = {'unknown': 1, 'neodry': 0.55, 'xds35': 0.6, 'sv65': 0.9}

    pollinterval = Parameter(datatype=FloatRange(1, unit='s'), default=5)
    _last_dirchange = 0
    _ref_time = 0
    _ref_dif = 0
    _dir = 0
    _rawdir = 0
    _step = 0
    _speed_sum = 0
    _last_era = 0
    _value = None

    def doPoll(self):
        # poll at least every sec, but update value only
        # every pollinterval and status when changed
        if not self.pollInfo.fast_flag:
            self.pollInfo.interval = min(1, self.pollinterval)  # reduce internal poll interval
        self._value = self.get_value()
        self._last.append(self._value)
        del self._last[0:-300]
        self.read_motor_state()
        era = time.time() // self.pollinterval
        if era != self._last_era:
            self.speed = self._speed_sum / self.pollinterval
            self._speed_sum = 0
            self.value = self._value
            self._last_era = era
        self.read_status()
        self.cycle_machine()

    def get_value(self):
        p = self.pressure.read_value() * self.lnm_per_mbar
        f = self.flow_sensor.read_value()
        return p if self.use_pressure else f

    def initModule(self):
        self._last = []
        if self.pressure:
            self.pressure.addCallback('value', self.update_from_pressure)
        if self.flow_sensor:
            self.flow_sensor.addCallback('value', self.update_from_flow)
        super().initModule()

    def update_from_flow(self, value):
        if not self.use_pressure:
            self._value = value

    def update_from_pressure(self, value):
        if self.use_pressure:
            self._value = value * self.lnm_per_mbar
            # self.cycle_machine()

    def read_value(self):
        self._value = self.get_value()
        return self._value

    def read_use_pressure(self):
        if self.pressure:
            if self.flow_sensor:
                return self.use_pressure
            return True
        return False

    def write_target(self, value):
        self.log.debug('change target')
        self.start_machine(self.change_target, target=value, try_close=True)

    def write_pump_type(self, value):
        self.pressure_scale = self.FLOW_SCALE[value.name]

    def write_prop_open(self, value):
        self._prop_open = Interpolation(value)
        return self._prop_open

    def write_prop_close(self, value):
        self._prop_close = Interpolation(value)
        return self._prop_close

    def write_tolerance(self, value):
        self._tolerance = Interpolation(value)
        return self._tolerance

    @status_code(BUSY)
    def change_target(self, sm):
        self.target = sm.target
        sm.last_progress = sm.now
        sm.ref_time = 0
        sm.ref_dif = 0
        sm.last_pulse_time = 0
        sm.no_progress_pulse = (0.1, -0.05)
        self.log.debug('target %s value %s', self.target, self._value)
        tol = self._tolerance(self.target)
        if abs(self.target - self._value) < tol:
            self.log.debug('go to at_target')
            return self.at_target
        self.log.debug('go to controlling')
        return self.controlling

    def _dif_medians(self):
        return np.array([self.target - np.median(self._last[-m:]) for m in (1, 5, 12, 30, 60)])

    @status_code(BUSY)
    def controlling(self, sm):
        tol = self._tolerance(self.target)
        dif = self._dif_medians()
        if sm.init:
            self.log.debug('restart controlling')
            direction = math.copysign(1, dif[1])
            if direction != self._dir:
                self.log.debug('new dir %g dif=%g', direction, dif[1])
                self._dir = direction
                self._last_dirchange = sm.now
            sm.ref_dif = abs(dif[1])
            sm.ref_time = sm.now
        difdir = dif * self._dir  # negative when overshoot happend
        # difdif = dif - self._prev_dif
        # self._prev_dif = dif
        expected_dif = sm.ref_dif * math.exp((sm.ref_time - sm.now) / self.deriv)

        if np.all(difdir < tol):
            if np.all(difdir < -tol):
                self.log.debug('overshoot %r', dif)
                return self.controlling
            if not np.any(difdir < -tol):
                # within tolerance
                self.log.debug('at target %r tol %g', dif, tol)
                return self.at_target
        if np.all(difdir > expected_dif):
            # not enough progress
            if sm.now > sm.last_progress + self.deriv:
                lim = self.flow_closed + 0.5
                if sm.try_close and self._value <= lim - tol and self.target >= lim + tol:
                    sm.try_close = False
                    self.command(mp=-60)
                    sm.after_close = self.open_until_flow_increase
                    self.log.debug('go to closing / open_until_flow_increase')
                    return self.closing
                if sm.no_progress_pulse:
                    pulse = abs(sm.no_progress_pulse[self._dir < 0]) * self._dir
                    self.log.debug('not enough progress %g %r', pulse, sm.try_close)
                    self.pulse(pulse)
                sm.last_progress = sm.now
            if sm.now < sm.last_pulse_time + 2.5:
                return Retry
            # TODO: check motor state for closed / opened ?
            difd = min(difdir[:2])
            sm.last_pulse_time = sm.now
            if self._dir > 0:
                minstep = self.min_open_pulse
                prop = self._prop_open(self._value)
            else:
                minstep = self.min_close_pulse
                prop = self._prop_close(self._value)
            if difd > 0:
                if prop * tol > minstep:
                    # step outside tol is already minstep
                    step = difd * prop
                else:
                    if difd > tol:
                        step = (minstep + (difd - tol) * prop)
                    else:
                        step = minstep * difd / tol
                step *= self._dir
                self.log.debug('MP %g dif=%g tol=%g', step, difd * self._dir, tol)
                self.command(mp=step)
                self._speed_sum += step
            return Retry
        # still approaching
        difmax = max(difdir)
        if difmax < expected_dif:
            sm.ref_time = sm.now
            sm.ref_dif = difmax
            # self.log.info('new ref %g', sm.ref_dif)
        sm.last_progress = sm.now
        return Retry  # progressing: no pulse needed

    @status_code(IDLE)
    def at_target(self, sm):
        tol = self._tolerance(self.target)
        dif = self._dif_medians()
        if np.all(dif > tol) or np.all(dif < -tol):
            self.log.debug('unstable %r %g', dif, tol)
            return self.unstable
        return Retry

    @status_code(IDLE, 'unstable')
    def unstable(self, sm):
        sm.no_progress_pulse = None
        return self.controlling(sm)

    def read_motor_state(self):
        return self.command(fm=int)

    @Command
    def close(self):
        """close valve fully"""
        self.command(mp=-60)
        self.motor_state = self.command(fm=int)
        self.start_machine(self.closing, after_close=None, fast_poll=0.1)

    @status_code(BUSY)
    def closing(self, sm):
        if sm.init:
            sm.start_time = sm.now
        self._speed_sum -= sm.delta()
        self.read_motor_state()
        if self.motor_state == M.closing:
            return Retry
        if self.motor_state == M.closed:
            if sm.after_close:
                return sm.after_close
            return self.final_status(IDLE, 'closed')
        if sm.now < sm.start_time + 1:
            return Retry
        return self.final_status(IDLE, 'fixed')

    @Command
    def open(self):
        """open valve fully"""
        self.command(mp=60)
        self.read_motor_state()
        self.start_machine(self.opening, threshold=None)

    @status_code(BUSY)
    def opening(self, sm):
        if sm.init:
            sm.start_time = sm.now
        self._speed_sum += sm.dleta()
        self.read_motor_state()
        if self.motor_state == M.opening:
            return Retry
        if self.motor_state == M.opened:
            return self.final_status(IDLE, 'opened')
        if sm.now < sm.start_time + 1:
            return Retry
        return self.final_status(IDLE, 'fixed')

    @Command
    def close_test(self):
        """close and then try to open until the flow starts to increase

        save a
        """

        self.command(mp=-60)
        self.start_machine(self.closing, fast_poll=0.1, after_close=self.open_until_flow_increase, target=0)

    @status_code(BUSY)
    def open_until_flow_increase(self, sm):
        if sm.init:
            p = self.command(f=float)
            sm.threshold = 0.5
            sm.prev = [p]
            sm.ref = p
            sm.cnt = 0
            sm.low_flow = 0
        self.read_motor_state()
        if self.motor_state == M.opening:
            return Retry
        if self.motor_state == M.opened:
            return self.final_status(IDLE, 'opened')
        press, measured = self.command(f=float, mmp=float)
        sm.prev.append(press)
        if press > sm.ref + 0.2:
            sm.cnt += 1
            if sm.cnt > 5 or press > sm.ref + 0.5:
                self.flow_closed = sm.low_flow
                self.log.debug('flow increased %g', press)
                if sm.target == 0:
                    sm.target = sm.low_flow + 0.5
                return self.change_target
            self.log.debug('wait count %g', press)
            return Retry
        sm.low_flow = self.value
        sm.cnt = 0
        last5 = sm.prev[-5:]
        median = sorted(last5)[len(last5) // 2]
        if press > median:
            # avoid to pulse again after an even small increase
            self.log.debug('wait %g', press)
            return Retry
        sm.ref = min(sm.prev[0], median)
        if measured:
            self._speed_sum += measured
            if measured < 0.1:
                sm.threshold = round(sm.threshold * 1.1, 2)
            elif measured > 0.3:
                sm.threshold = round(sm.threshold * 0.9, 2)
            self.log.debug('measured %g new threshold %g press %g', measured, sm.threshold, press)
        else:
            self._speed_sum += 1
            self.log.debug('full pulse')
        sm.cnt = 0
        self.command(mft=sm.ref + sm.threshold, mp=1)
        return Retry

    @Command(FloatRange())
    def pulse(self, value):
        """perform a motor pulse"""
        self.command(mp=value)
        self._speed_sum += value
        if value > 0:
            self.motor_state = M.opening
            return self.opening
        self.motor_state = M.closing
        return self.closing

    @Command()
    def autopar(self):
        """adjust automatically needle valve parameters"""
        self.close()
        self.start_machine(self.auto_wait, open_pulse=0.1, close_pulse=0.05,
                           minflow=self.read_value(), last=None)
        return self.auto_wait

    def is_stable(self, sm, n, tol=0.01):
        """wait for a stable flow

        n: size of buffer
        tol: a tolerance
        """
        if sm.last is None:
            sm.last = []
            sm.cnt = 0
        v = self.read_value()
        sm.last.append(v)
        del sm.last[:-n]
        dif = v - sm.last[0]
        if dif < -tol:
            sm.cnt -= 1
        elif dif > tol:
            sm.cnt += 1
        else:
            sm.cnt -= clamp(-1, sm.cnt, 1)
        if len(sm.last) < n:
            return False
        return abs(sm.cnt) < n // 2

    def is_unstable(self, sm, n, tol=0.01):
        """wait for a stable flow

        return 0, -1 or 1
        """
        if sm.last is None:
            sm.last = []
            sm.cnt = 0
        v = self.read_value()
        prevmax = max(sm.last)
        prevmin = min(sm.last)
        sm.last.append(v)
        del sm.last[:-n]
        self.log.debug('unstable %g >? %g <? %g', v, prevmax, prevmin)
        if v > prevmax + tol:
            return 1
        if v < prevmin - tol:
            return -1
        return 0

    @status_code(BUSY)
    def auto_wait(self, sm):
        stable = self.is_stable(sm, 5, 0.01)
        if self._value < sm.minflow:
            sm.minflow = self._value
        if self.read_motor_state() == M.closing or not stable:
            return Retry
        return self.auto_open

    @status_code(BUSY)
    def auto_open(self, sm):
        stable = self.is_unstable(sm, 5, 0.1)
        if stable > 0:
            sm.start_time = sm.now
            sm.flow_before = sm.last[-1]
            self.pulse(sm.open_pulse)
            return self.auto_close
        if sm.delta(sm.open_pulse * 2) is not None:
            self.pulse(sm.open_pulse)
        return Retry

    @status_code(BUSY)
    def auto_open_stable(self, sm):
        if self.is_stable(sm, 5, 0.01):
            return Retry
        return self.auto_close

    @status_code(BUSY)
    def auto_close(self, sm):
        if not self.is_stable(sm, 10, 0.01):
            return Retry
        self.log.debug('before %g pulse %g, flowstep %g', sm.flow_before, sm.open_pulse, sm.last[-1] - sm.flow_before)
        self.close()
        return self.final_status(IDLE, '')