#!/usr/bin/env python
#  -*- 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:
#   Markus Zolliker <markus.zolliker@psi.ch>
# *****************************************************************************
"""oxford instruments mercury family"""


import math
import re
import time

<<<<<<< HEAD
from secop.core import Drivable, HasIodev, \
    Parameter, Property, Readable, StringIO
from secop.datatypes import EnumType, FloatRange, StringType, StructOf
from secop.errors import HardwareError
from secop.lib.statemachine import StateMachine


class MercuryIO(StringIO):
    identification = [('*IDN?', r'IDN:OXFORD INSTRUMENTS:MERCURY*')]


VALUE_UNIT = re.compile(r'(.*\d)([A-Za-z]*)$')


def make_map(**kwds):
    """create a dict converting internal names to values and vice versa"""
    kwds.update({v: k for k, v in kwds.items()})
    return kwds


MODE_MAP = make_map(OFF=0, ON=1)
SAMPLE_RATE = make_map(OFF=1, ON=0)  # invert the codes used by OI


class MercuryChannel(HasIodev):
    slots = Property('''slot uids
    
                     example: DB6.T1,DB1.H1
                     slot ids for sensor (and control output)''',
                     StringType())
    channel_name = Parameter('mercury nick name', StringType())
    channel_type = ''  #: channel type(s) for sensor (and control)

    def query(self, adr, value=None):
        """get or set a parameter in mercury syntax

        :param adr: for example "TEMP:SIG:TEMP"
        :param value: if given and not None, a write command is executed
        :return:  the value

        remark: the DEV:<slot> is added automatically, when adr starts with the channel type
                in addition, when addr starts with '0:' or '1:', the channel type is added
        """
        for i, (channel_type, slot) in enumerate(zip(self.channel_type.split(','), self.slots.split(','))):
            if adr.startswith('%d:' % i):
                adr = 'DEV:%s:%s:%s' % (slot, channel_type, adr[2:])  # assume i <= 9
                break
            if adr.startswith(channel_type + ':'):
                adr = 'DEV:%s:%s' % (slot, adr)
                break
        if value is not None:
            try:
                value = '%g' % value  # this works for float, integers and enums
            except ValueError:
                value = str(value)  # this alone would not work for enums, and not be nice for floats
            cmd = 'SET:%s:%s' % (adr, value)
            reply = self._iodev.communicate(cmd)
            if reply != 'STAT:%s:VALID' % cmd:
                raise HardwareError('bad response %r to %r' % (reply, cmd))
            # chain a read command anyway
        cmd = 'READ:%s' % adr
        reply = self._iodev.communicate(cmd)
        head, _, result = reply.rpartition(':')
        if head != 'STAT:%s' % adr:
            raise HardwareError('bad response %r to %r' % (reply, cmd))
        match = VALUE_UNIT.match(result)
        if match:  # result can be interpreted as a float with optional units
            return float(match.group(1))
        return result

    def read_channel_name(self):
        return self.query('')
=======
from secop.core import Drivable, HasIO, Writable, \
    Parameter, Property, Readable, StringIO, Attached, Done, IDLE, nopoll
from secop.datatypes import EnumType, FloatRange, StringType, StructOf, BoolType
from secop.errors import HardwareError
from secop_psi.convergence import HasConvergence
from secop.lib.enum import Enum


VALUE_UNIT = re.compile(r'(.*\d|inf)([A-Za-z/%]*)$')
SELF = 0


def as_float(value):
    if isinstance(value, str):
        return float(VALUE_UNIT.match(value).group(1))
    return '%g' % value


def as_string(value):
    return value


class Mapped:
    def __init__(self, **kwds):
        self.mapping = kwds
        self.mapping.update({v: k for k, v in kwds.items()})

    def __call__(self, value):
        return self.mapping[value]


off_on = Mapped(OFF=False, ON=True)
fast_slow = Mapped(ON=0, OFF=1)  # maps OIs slow=ON/fast=OFF to sample_rate.slow=0/sample_rate.fast=1


class IO(StringIO):
    identification = [('*IDN?', r'IDN:OXFORD INSTRUMENTS:MERCURY*')]


class MercuryChannel(HasIO):
    slot = Property('''slot uids
    
                    example: DB6.T1,DB1.H1
                    slot ids for sensor (and control output)''',
                    StringType())
    channel_name = Parameter('mercury nick name', StringType(), default='')
    channel_type = ''  #: channel type(s) for sensor (and control) e.g. TEMP,HTR or PRES,AUX

    def _complete_adr(self, adr):
        """complete address from channel_type and slot"""
        head, sep, tail = adr.partition(':')
        for i, (channel_type, slot) in enumerate(zip(self.channel_type.split(','), self.slot.split(','))):
            if head == str(i):
                return 'DEV:%s:%s%s%s' % (slot, channel_type, sep, tail)
            if head == channel_type:
                return 'DEV:%s:%s%s%s' % (slot, head, sep, tail)
        return adr

    def multiquery(self, adr, names=(), convert=as_float):
        """get parameter(s) in mercury syntax

        :param adr: the 'address part' of the SCPI command
                    the DEV:<slot> is added automatically, when adr starts with the channel type
                    in addition, when adr starts with '0:' or '1:', channel type and slot are added
        :param names: the SCPI names of the parameter(s), for example ['TEMP']
        :param convert: a converter function (converts replied string to value)
        :return:  the values as tuple

        Example:
            adr='AUX:SIG'
            names = ('PERC',)
            self.channel_type='PRES,AUX'    # adr starts with 'AUX'
            self.slot='DB5.P1,DB3.G1'       # -> take second slot
        -> query command will be READ:DEV:DB3.G1:PRES:SIG:PERC
        """
        adr = self._complete_adr(adr)
        cmd = 'READ:%s:%s' % (adr, ':'.join(names))
        reply = self.communicate(cmd)
        head = 'STAT:%s:' % adr
        try:
            assert reply.startswith(head)
            replyiter = iter(reply[len(head):].split(':'))
            keys, result = zip(*zip(replyiter, replyiter))
            assert keys == tuple(names)
            return tuple(convert(r) for r in result)
        except (AssertionError, AttributeError, ValueError):
            raise HardwareError('invalid reply %r to cmd %r' % (reply, cmd)) from None

    def multichange(self, adr, values, convert=as_float):
        """set parameter(s) in mercury syntax

        :param adr: as in see multiquery method
        :param values: [(name1, value1), (name2, value2) ...]
        :param convert: a converter function (converts given value to string and replied string to value)
        :return:  the values as tuple

        Example:
            adr='0:LOOP'
            values = [('P', 5), ('I', 2), ('D', 0)]
            self.channel_type='TEMP,HTR'   # adr starts with 0: take TEMP
            self.slot='DB6.T1,DB1.H1'      # and take first slot
        -> change command will be SET:DEV:DB6.T1:TEMP:LOOP:P:5:I:2:D:0
        """
        adr = self._complete_adr(adr)
        params = ['%s:%s' % (k, convert(v)) for k, v in values]
        cmd = 'SET:%s:%s' % (adr, ':'.join(params))
        reply = self.communicate(cmd)
        head = 'STAT:SET:%s:' % adr

        try:
            assert reply.startswith(head)
            replyiter = iter(reply[len(head):].split(':'))
            keys, result, valid = zip(*zip(replyiter, replyiter, replyiter))
            assert keys == tuple(k for k, _ in values)
            assert any(v == 'VALID' for v in valid)
            return tuple(convert(r) for r in result)
        except (AssertionError, AttributeError, ValueError) as e:
            raise HardwareError('invalid reply %r to cmd %r' % (reply, cmd)) from e

    def query(self, adr, convert=as_float):
        """query a single parameter

        'adr' and 'convert' areg
        """
        adr, _, name = adr.rpartition(':')
        return self.multiquery(adr, [name], convert)[0]

    def change(self, adr, value, convert=as_float):
        adr, _, name = adr.rpartition(':')
        return self.multichange(adr, [(name, value)], convert)[0]

    def read_channel_name(self):
        if self.channel_name:
            return Done  # channel name will not change
        return self.query('0:NICK', as_string)
>>>>>>> d3379d5... support for OI mercury series


class TemperatureSensor(MercuryChannel, Readable):
    channel_type = 'TEMP'
    value = Parameter(unit='K')
<<<<<<< HEAD
    raw = Parameter('raw value', FloatRange())
=======
    raw = Parameter('raw value', FloatRange(unit='Ohm'))
>>>>>>> d3379d5... support for OI mercury series

    def read_value(self):
        return self.query('TEMP:SIG:TEMP')

    def read_raw(self):
        return self.query('TEMP:SIG:RES')


<<<<<<< HEAD
class HasProgressCheck:
    """mixin for progress checks

    Implements progress checks based on tolerance, settling time and timeout.
    The algorithm does its best to support changes of these parameters on the
    fly. However, the full history is not considered, which means for example
    that the spent time inside tolerance stored already is not altered when
    changing tolerance.
    """
    tolerance = Parameter('absolute tolerance', FloatRange(0), readonly=False, default=0)
    min_slope = Parameter('minimal abs(slope)', FloatRange(0), readonly=False, default=0)
    settling_time = Parameter(
        '''settling time

        total amount of time the value has to be within tolerance before switching to idle.
        ''', FloatRange(0), readonly=False, default=0)
    timeout = Parameter(
        '''timeout

        timeout = 0: disabled, else:
        A timeout event happens, when the difference (target - value) is not improved by
        at least min_slope * timeout over any interval (t, t + timeout).
        As soon as the value is the first time within tolerance, the criterium is changed:
        then the timeout event happens after this time + settling_time + timeout.
        ''', FloatRange(0, unit='sec'), readonly=False, default=3600)
    status = Parameter('status determined from progress check')
    value = Parameter()
    target = Parameter()

    def earlyInit(self):
        super().earlyInit()
        self.__state = StateMachine()

    def prepare_state(self, state):
        tol = self.tolerance
        if not tol:
            tol = 0.01 * max(abs(self.target), abs(self.value))
        dif = abs(self.target - self.value)
        return dif, tol, state.now, state.delta(0)

    def state_approaching(self, state):
        if self.init():
            self.status = 'BUSY', 'approaching'
        dif, tol, now, delta = self.prepare_state(state)
        if dif < tol:
            state.timeout_base = now
            state.next_step(self.state_inside)
            return
        if not self.timeout:
            return
        if state.init():
            state.timeout_base = now
            state.dif_crit = dif
            return
        min_slope = getattr(self, 'ramp', 0) or getattr('min_slope', 0)
        state.dif_crit -= min_slope * delta
        if dif < state.dif_crit:
            state.timeout_base = now
        elif now > state.timeout_base:
            self.status = 'WARNING', 'convergence timeout'
            state.next_action(self.state_idle)

    def state_inside(self, state):
        if state.init():
            self.status = 'BUSY', 'inside tolerance'
        dif, tol, now, delta = self.prepare_state(state)
        if dif > tol:
            state.next_action(self.state_outside)
        state.spent_inside += delta
        if state.spent_inside > self.settling_time:
            self.status = 'IDLE', 'reached target'
            state.next_action(self.state_idle)

    def state_outside(self, state, now, dif, tol, delta):
        if state.init():
            self.status = 'BUSY', 'outside tolerance'
        dif, tol, now, delta = self.prepare_state(state)
        if dif < tol:
            state.next_action(self.state_inside)
        elif now > self.timeout_base + self.settling_time + self.timeout:
            self.status = 'WARNING', 'settling timeout'
            state.next_action(self.state_idle)

    def start_state(self):
        """must be called from write_target, whenever the target changes"""
        self.__state.start(self.state_approach)

    def poll(self):
        super().poll()
        self.__state.poll()

    def read_status(self):
        if self.status[0] == 'IDLE':
            # do not change when idle already
            return self.status
        return self.check_progress(self.value, self.target)

    def write_target(self, value):
        raise NotImplementedError()


class Loop(HasProgressCheck, MercuryChannel):
    """common base class for loops"""
    mode = Parameter('control mode', EnumType(manual=0, pid=1), readonly=False)
    ctrlpars = Parameter(
        'pid (proportional nad, integral time, differential time',
        StructOf(p=FloatRange(0, unit='$'), i=FloatRange(0, unit='min'), d=FloatRange(0, unit='min')),
        readonly=False, poll=True
    )
    """pid = Parameter('control parameters', StructOf(p=FloatRange(), i=FloatRange(), d=FloatRange()),readonly=False)"""
    pid_table_mode = Parameter('', EnumType(off=0, on=1), readonly=False)

    def read_ctrlpars(self):
        return self.query('0:LOOP:P')

    def read_integ(self):
        return self.query('0:LOOP:I')

    def read_deriv(self):
        return self.query('0:LOOP:D')

    def write_prop(self, value):
        return self.query('0:LOOP:P', value)

    def write_integ(self, value):
        return self.query('0:LOOP:I', value)

    def write_deriv(self, value):
        return self.query('0:LOOP:D', value)

    def read_enable_pid_table(self):
        return self.query('0:LOOP:PIDT').lower()

    def write_enable_pid_table(self, value):
        return self.query('0:LOOP:PIDT', value.upper()).lower()

    def read_mode(self):
        return MODE_MAP[self.query('0:LOOP:ENAB')]

    def write_mode(self, value):
        if value == 'manual':
            self.status = 'IDLE', 'manual mode'
        elif self.status[0] == 'IDLE':
            self.status = 'IDLE', ''
        return MODE_MAP[self.query('0:LOOP:ENAB', value)]

    def write_target(self, value):
        raise NotImplementedError

    # def read_pid(self):
    #     # read all in one go, in order to reduce comm. traffic
    #     cmd = 'READ:DEV:%s:TEMP:LOOP:P:I:D' % self.slots.split(',')[0]
    #     reply = self._iodev.communicate(cmd)
    #     result = list(reply.split(':'))
    #     pid = result[6::2]
    #     del result[6::2]
    #     if ':'.join(result) != cmd:
    #         raise HardwareError('bad response %r to %r' % (reply, cmd))
    #     return dict(zip('pid', pid))
    #
    # def write_pid(self, value):
    #     # for simplicity use single writes
    #     return {k: self.query('LOOP:%s' % k.upper(), value[k]) for k in 'pid'}


class TemperatureLoop(Loop, TemperatureSensor, Drivable):
    channel_type = 'TEMP,HTR'
    heater_limit = Parameter('heater output limit', FloatRange(0, 100, unit='W'), readonly=False)
    heater_resistivity = Parameter('heater resistivity', FloatRange(10, 1000, unit='Ohm'), readonly=False)
    ramp = Parameter('ramp rate', FloatRange(0, unit='K/min'), readonly=False)
    enable_ramp = Parameter('enable ramp rate', EnumType(off=0, on=1), readonly=False)
    auto_flow = Parameter('enable auto flow', EnumType(off=0, on=1), readonly=False)
    heater_output = Parameter('heater output', FloatRange(0, 100, unit='W'), readonly=False)

    def read_heater_limit(self):
        return self.query('HTR:VLIM') ** 2 / self.heater_resistivity

    def write_heater_limit(self, value):
        result = self.query('HTR:VLIM', math.sqrt(value * self.heater_resistivity))
        return result ** 2 / self.heater_resistivity

    def read_heater_resistivity(self):
        value = self.query('HTR:RES')
        if value:
            return value
        return self.heater_resistivity

    def write_heater_resistivity(self, value):
        return self.query('HTR:RES', value)

    def read_enable_ramp(self):
        return self.query('TEMP:LOOP:RENA').lower()

    def write_enable_ramp(self, value):
        return self.query('TEMP:LOOP:RENA', EnumType(off=0, on=1)(value).name).lower()

    def read_auto_flow(self):
        return self.query('TEMP:LOOP:FAUT').lower()

    def write_auto_flow(self, value):
        return self.query('TEMP:LOOP:FAUT', EnumType(off=0, on=1)(value).name).lower()

    def read_ramp(self):
        return self.query('TEMP:LOOP:RSET')

    def write_ramp(self, value):
        if not value:
            self.write_enable_ramp(0)
            return 0
        if value:
            self.write_enable_ramp(1)
        return self.query('TEMP:LOOP:RSET', value)

    def read_target(self):
        # TODO: check about working setpoint
        return self.query('TEMP:LOOP:TSET')

    def write_target(self, value):
        if self.mode != 'pid':
            self.log.warning('switch to pid loop mode')
            self.write_mode('pid')
        self.reset_progress(self.value, value)
        return self.query('TEMP:LOOP:TSET', value)

    def read_heater_output(self):
        # TODO: check that this really works, else next line
        return self.query('HTR:SIG:POWR')
        # return self.query('HTR:SIG:VOLT') ** 2 / self.heater_resistivity

    def write_heater_output(self, value):
        if self.mode != 'manual':
            self.log.warning('switch to manual heater mode')
            self.write_mode('manual')
        return self.query('HTR:SIG:VOLT', math.sqrt(value * self.heater_resistivity))
=======
class HasInput(MercuryChannel):
    controlled_by = Parameter('source of target value', EnumType(members={'self': SELF}), default=0)
    target = Parameter(readonly=False)
    input_modules = ()

    def add_input(self, modobj):
        if not self.input_modules:
            self.input_modules = []
        self.input_modules.append(modobj)
        prev_enum = self.parameters['controlled_by'].datatype._enum
        # add enum member, using autoincrement feature of Enum
        self.parameters['controlled_by'].datatype = EnumType(Enum(prev_enum, **{modobj.name: None}))

    def write_controlled_by(self, value):
        if self.controlled_by == value:
            return Done
        self.controlled_by = value
        if value == SELF:
            self.log.warning('switch to manual mode')
            for input_module in self.input_modules:
                if input_module.control_active:
                    input_module.write_control_active(False)
        return Done


class Loop(HasConvergence, MercuryChannel, Drivable):
    """common base class for loops"""
    control_active = Parameter('control mode', BoolType())
    output_module = Attached(HasInput, mandatory=False)
    ctrlpars = Parameter(
        'pid (proportional band, integral time, differential time',
        StructOf(p=FloatRange(0, unit='$'), i=FloatRange(0, unit='min'), d=FloatRange(0, unit='min')),
        readonly=False,
    )
    enable_pid_table = Parameter('', BoolType(), readonly=False)

    def initModule(self):
        super().initModule()
        if self.output_module:
            self.output_module.add_input(self)

    def set_output(self, active):
        if active:
            if self.output_module and self.output_module.controlled_by != self.name:
                self.output_module.controlled_by = self.name
        else:
            if self.output_module and self.output_module.controlled_by != SELF:
                self.output_module.write_controlled_by(SELF)
            status = IDLE, 'control inactive'
            if self.status != status:
                self.status = status

    def set_target(self, target):
        if self.control_active:
            self.set_output(True)
        else:
            self.log.warning('switch loop control on')
            self.write_control_active(True)
        self.target = target
        self.start_state()

    def read_enable_pid_table(self):
        return self.query('0:LOOP:PIDT', off_on)

    def write_enable_pid_table(self, value):
        return self.change('0:LOOP:PIDT', value, off_on)

    def read_ctrlpars(self):
        # read all in one go, in order to reduce comm. traffic
        pid = self.multiquery('0:LOOP', ('P', 'I', 'D'))
        return {k: float(v) for k, v in zip('pid', pid)}

    def write_ctrlpars(self, value):
        pid = self.multichange('0:LOOP', [(k, value[k.lower()]) for k in 'PID'])
        return {k.lower(): v for k, v in zip('PID', pid)}


class HeaterOutput(HasInput, MercuryChannel, Writable):
    """heater output

    Remark:
    The hardware calculates the power from the voltage and the configured
    resistivity. As the measured heater current is available, the resistivity
    will be adjusted automatically, when true_power is True.
    """
    channel_type = 'HTR'
    value = Parameter('heater output', FloatRange(unit='W'), readonly=False)
    target = Parameter('heater output', FloatRange(0, 100, unit='$'), readonly=False)
    resistivity = Parameter('heater resistivity', FloatRange(10, 1000, unit='Ohm'),
                            readonly=False)
    true_power = Parameter('calculate power from measured current', BoolType(), readonly=False, default=True)
    limit = Parameter('heater output limit', FloatRange(0, 1000, unit='W'), readonly=False)
    volt = 0.0  # target voltage
    _last_target = None
    _volt_target = None

    def read_limit(self):
        return self.query('HTR:VLIM') ** 2 / self.resistivity

    def write_limit(self, value):
        result = self.change('HTR:VLIM', math.sqrt(value * self.resistivity))
        return result ** 2 / self.resistivity

    def read_resistivity(self):
        if self.true_power:
            return self.resistivity
        return max(10, self.query('HTR:RES'))

    def write_resistivity(self, value):
        self.resistivity = self.change('HTR:RES', max(10, value))
        if self._last_target is not None:
            if not self.true_power:
                self._volt_target = math.sqrt(self._last_target * self.resistivity)
            self.change('HTR:SIG:VOLT', self._volt_target)
        return Done

    def read_status(self):
        status = IDLE, ('true power' if self.true_power else 'fixed resistivity')
        if self.status != status:
            return status
        return Done

    def read_value(self):
        if self._last_target is None:  # on init
            self.read_target()
        if not self.true_power:
            volt = self.query('HTR:SIG:VOLT')
            return volt ** 2 / max(10, self.resistivity)
        volt, current = self.multiquery('HTR:SIG', ('VOLT', 'CURR'))
        if volt > 0 and current > 0.0001 and self._last_target:
            res = volt / current
            tol = res * max(max(0.0003, abs(volt - self._volt_target)) / volt, 0.0001 / current, 0.0001)
            if abs(res - self.resistivity) > tol + 0.07 and self._last_target:
                self.write_resistivity(round(res, 1))
                if self.controlled_by == 0:
                    self._volt_target = math.sqrt(self._last_target * self.resistivity)
                    self.change('HTR:SIG:VOLT', self._volt_target)
        return volt * current

    def read_target(self):
        if self.controlled_by != 0 and self.target:
            return 0
        if self._last_target is not None:
            return Done
        self._volt_target = self.query('HTR:SIG:VOLT')
        self.resistivity = max(10, self.query('HTR:RES'))
        self._last_target = self._volt_target ** 2 / max(10, self.resistivity)
        return self._last_target

    def set_target(self, value):
        """set the target without switching to manual

        might be used by a software loop
        """
        self._volt_target = math.sqrt(value * self.resistivity)
        self.change('HTR:SIG:VOLT', self._volt_target)
        self._last_target = value
        return value

    def write_target(self, value):
        self.write_controlled_by(SELF)
        return self.set_target(value)


class TemperatureLoop(TemperatureSensor, Loop, Drivable):
    channel_type = 'TEMP,HTR'
    output_module = Attached(HeaterOutput, mandatory=False)
    ramp = Parameter('ramp rate', FloatRange(0, unit='K/min'), readonly=False)
    enable_ramp = Parameter('enable ramp rate', BoolType(), readonly=False)
    setpoint = Parameter('working setpoint (differs from target when ramping)', FloatRange(0, unit='$'))
    auto_flow = Parameter('enable auto flow', BoolType(), readonly=False)
    _last_setpoint_change = None

    def doPoll(self):
        super().doPoll()
        self.read_setpoint()

    def read_control_active(self):
        active = self.query('TEMP:LOOP:ENAB', off_on)
        self.set_output(active)
        return active

    def write_control_active(self, value):
        self.set_output(value)
        return self.change('TEMP:LOOP:ENAB', value, off_on)

    @nopoll  # polled by read_setpoint
    def read_target(self):
        if self.read_enable_ramp():
            return self.target
        self.setpoint = self.query('TEMP:LOOP:TSET')
        return self.setpoint

    def read_setpoint(self):
        setpoint = self.query('TEMP:LOOP:TSET')
        if self.enable_ramp:
            if setpoint == self.setpoint:
                # update target when working setpoint does no longer change
                if setpoint != self.target and self._last_setpoint_change is not None:
                    unchanged_since = time.time() - self._last_setpoint_change
                    if unchanged_since > max(12.0, 0.06 / max(1e-4, self.ramp)):
                        self.target = self.setpoint
                return setpoint
            self._last_setpoint_change = time.time()
        else:
            self.target = setpoint
        return setpoint

    def write_target(self, value):
        target = self.change('TEMP:LOOP:TSET', value)
        if self.enable_ramp:
            self._last_setpoint_change = None
            self.set_target(value)
        else:
            self.set_target(target)
        return Done

    def read_enable_ramp(self):
        return self.query('TEMP:LOOP:RENA', off_on)

    def write_enable_ramp(self, value):
        return self.change('TEMP:LOOP:RENA', value, off_on)

    def read_auto_flow(self):
        return self.query('TEMP:LOOP:FAUT', off_on)

    def write_auto_flow(self, value):
        return self.change('TEMP:LOOP:FAUT', value, off_on)

    def read_ramp(self):
        result = self.query('TEMP:LOOP:RSET')
        return min(9e99, result)

    def write_ramp(self, value):
        # use 0 or a very big value for switching off ramp
        if not value:
            self.write_enable_ramp(0)
            return 0
        if value >= 9e99:
            self.change('TEMP:LOOP:RSET', 'inf', as_string)
            self.write_enable_ramp(0)
            return 9e99
        self.write_enable_ramp(1)
        return self.change('TEMP:LOOP:RSET', max(1e-4, value))
>>>>>>> d3379d5... support for OI mercury series


class PressureSensor(MercuryChannel, Readable):
    channel_type = 'PRES'
    value = Parameter(unit='mbar')

    def read_value(self):
        return self.query('PRES:SIG:PRES')


<<<<<<< HEAD
class PressureLoop(Loop, PressureSensor, Drivable):
    channel_type = 'PRES,AUX'

    valve_pos = Parameter('valve position', FloatRange(0, 100, unit='%'), readonly=False)

    def read_valve_pos(self):
        return self.query('AUX:SIG:PERC')

    def write_valve_pos(self, value):
        if self.mode != 'manual':
            self.log.warning('switch to manual valve mode')
            self.write_mode('manual')
        return self.query('AUX:SIG:PERC', value)

    def write_target(self, value):
        self.reset_progress(self.value, value)
        return self.query('PRES:LOOP:PRST', value)


class HeLevel(MercuryChannel, Readable):
    channel_type = 'LVL'
    sample_rate = Parameter('_', EnumType(slow=0, fast=1), readonly=False, poll=True)
    hysteresis = Parameter('hysteresis for detection of increase', FloatRange(0, 100, unit='%'), readonly=False)
    fast_timeout = Parameter('timeout for switching to slow', FloatRange(0, unit='sec'), readonly=False)
    _min_level = 200
    _max_level = -100
=======
class ValvePos(HasInput, MercuryChannel, Drivable):
    channel_type = 'PRES,AUX'
    value = Parameter('value pos', FloatRange(unit='%'), readonly=False)
    target = Parameter('valve pos target', FloatRange(0, 100, unit='$'), readonly=False)

    def doPoll(self):
        self.read_status()

    def read_value(self):
        return self.query('AUX:SIG:PERC')

    def read_status(self):
        self.read_value()
        if abs(self.value - self.target) < 0.01:
            return 'IDLE', 'at target'
        return 'BUSY', 'moving'

    def read_target(self):
        return self.query('PRES:LOOP:FSET')

    def write_target(self, value):
        self.write_controlled_by(SELF)
        return self.change('PRES:LOOP:FSET', value)


class PressureLoop(PressureSensor, Loop, Drivable):
    channel_type = 'PRES,AUX'
    output_module = Attached(ValvePos, mandatory=False)

    def read_control_active(self):
        active = self.query('PRES:LOOP:FAUT', off_on)
        self.set_output(active)
        return active

    def write_control_active(self, value):
        self.set_output(value)
        return self.change('PRES:LOOP:FAUT', value, off_on)

    def read_target(self):
        return self.query('PRES:LOOP:PRST')

    def write_target(self, value):
        target = self.change('PRES:LOOP:PRST', value)
        self.set_target(target)
        return Done


class HeLevel(MercuryChannel, Readable):
    """He level meter channel

    The Mercury system does not support automatic switching between fast
    (when filling) and slow (when consuming). We have to handle this by software.
    """
    channel_type = 'LVL'
    sample_rate = Parameter('_', EnumType(slow=0, fast=1), readonly=False)
    hysteresis = Parameter('hysteresis for detection of increase', FloatRange(0, 100, unit='%'),
                           default=5, readonly=False)
    fast_timeout = Parameter('time to switch to slow after last increase', FloatRange(0, unit='sec'),
                             default=300, readonly=False)
    _min_level = 999
    _max_level = -999
>>>>>>> d3379d5... support for OI mercury series
    _last_increase = None  # None when in slow mode, last increase time in fast mode

    def check_rate(self, sample_rate):
        """check changes in rate

        :param sample_rate:  (int or enum) 0: slow, 1: fast
        initialize affected attributes
        """
        if sample_rate != 0:  # fast
            if not self._last_increase:
                self._last_increase = time.time()
<<<<<<< HEAD
                self._max_level = -100
        elif self._last_increase:
            self._last_increase = None
            self._min_level = 200
        return sample_rate

    def read_sample_rate(self):
        return self.check_rate(SAMPLE_RATE[self.query('LVL:HEL:PULS:SLOW')])

    def write_sample_rate(self, value):
        self.check_rate(value)
        return SAMPLE_RATE[self.query('LVL:HEL:PULS:SLOW', SAMPLE_RATE[value])]
=======
                self._max_level = -999
        elif self._last_increase:
            self._last_increase = None
            self._min_level = 999
        return sample_rate

    def read_sample_rate(self):
        return self.check_rate(self.query('LVL:HEL:PULS:SLOW', fast_slow))

    def write_sample_rate(self, value):
        self.check_rate(value)
        return self.change('LVL:HEL:PULS:SLOW', value, fast_slow)
>>>>>>> d3379d5... support for OI mercury series

    def read_value(self):
        level = self.query('LVL:SIG:HEL:LEV')
        # handle automatic switching depending on increase
        now = time.time()
        if self._last_increase:  # fast mode
            if level > self._max_level:
                self._last_increase = now
                self._max_level = level
            elif now > self._last_increase + self.fast_timeout:
                # no increase since fast timeout -> slow
<<<<<<< HEAD
                self.write_sample_rate('slow')
        else:
            if level > self._min_level + self.hysteresis:
                # substantial increase -> fast
                self.write_sample_rate('fast')
=======
                self.write_sample_rate(self.sample_rate.slow)
        else:
            if level > self._min_level + self.hysteresis:
                # substantial increase -> fast
                self.write_sample_rate(self.sample_rate.fast)
>>>>>>> d3379d5... support for OI mercury series
            else:
                self._min_level = min(self._min_level, level)
        return level


class N2Level(MercuryChannel, Readable):
    channel_type = 'LVL'

    def read_value(self):
        return self.query('LVL:SIG:NIT:LEV')


<<<<<<< HEAD
class MagnetOutput(MercuryChannel, Drivable):
    pass
=======
# TODO: magnet power supply
>>>>>>> d3379d5... support for OI mercury series