#!/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>
# *****************************************************************************
"""Software calibration"""

import os
from os.path import join, exists, basename
import math
import numpy as np
from scipy.interpolate import splrep, splev  # pylint: disable=import-error

from secop.core import Readable, Parameter, Attached, StringType, BoolType


def linear(x):
    return x


nplog = np.vectorize(math.log10)
npexp = np.vectorize(lambda x: 10 ** x)


class StdParser:
    """parser used for reading columns"""
    def __init__(self, **kwds):
        """keys may be other 'x' or 'logx' and either 'y' or 'logy'

        default is x=0, y=1
        """
        self.xcol = int(kwds.get('x', kwds.get('logx', 0)))
        self.ycol = int(kwds.get('y', kwds.get('logy', 1)))
        self.logx = 'logx' in kwds
        self.logy = 'logy' in kwds
        self.xdata, self.ydata = [], []

    def parse(self, line):
        """get numbers from a line and put them to self.xdata / self.ydata"""
        row = line.split()
        try:
            self.xdata.append(float(row[self.xcol]))
            self.ydata.append(float(row[self.ycol]))
        except (IndexError, ValueError):
            # skip bad lines
            return


class Parser340(StdParser):
    """parser for LakeShore *.340 files"""

    def __init__(self):
        super().__init__()
        self.header = True
        self.xcol, self.ycol = 1, 2
        self.logx, self.logy = False, False

    def parse(self, line):
        """scan header for data format"""
        if self.header:
            if line.startswith("Data Format"):
                dataformat = line.split(":")[1].strip()[0]
                if dataformat == '4':
                    self.logx, self.logy = True, False  # logOhm
                elif dataformat == '5':
                    self.logx, self.logy = True, True  # logOhm, logK
            elif line.startswith("No."):
                self.header = False
            return
        super().parse(line)


KINDS = {
    "340": (Parser340, {}),  # lakeshore 340 format
    "inp": (StdParser, {}),  # M. Zollikers *.inp calcurve format
    "caldat": (StdParser, dict(x=1, y=2)),  # format from sea/tcl/startup/calib_ext.tcl
    "dat": (StdParser, {}),  # lakeshore raw data *.dat format
}


class CalCurve:
    def __init__(self, calibspec):
        """calibspec format:
        [<full path> | <name>][,<key>=<value> ...]
        for <key>/<value> as in parser arguments
        """
        sensopt = calibspec.split(',')
        calibname = sensopt.pop(0)
        _, dot, ext = basename(calibname).rpartition('.')
        kind = None
        for path in os.environ.get('FRAPPY_CALIB_PATH', '').split(','):
            # first try without adding kind
            filename = join(path.strip(), calibname)
            if exists(filename):
                kind = ext if dot else None
                break
            # then try adding all kinds as extension
            for nam in calibname, calibname.upper(), calibname.lower():
                for kind in KINDS:
                    filename = join(path.strip(), '%s.%s' % (nam, kind))
                    if exists(filename):
                        break
                else:
                    continue
                break
            else:
                continue
            break
        else:
            raise FileNotFoundError(calibname)
        optargs = {}
        for opts in sensopt:
            key, _, value = opts.lower().rpartition('=')
            value = value.strip()
            if value:
                optargs[key.strip()] = value
        kind = optargs.pop('kind', kind)
        cls, args = KINDS.get(kind, (StdParser, {}))
        args.update(optargs)

        parser = cls(**args)
        with open(filename) as f:
            for line in f:
                parser.parse(line)
        self.convert_x = nplog if parser.logx else linear
        self.convert_y = npexp if parser.logy else linear
        self.spline = splrep(np.asarray(parser.xdata), np.asarray(parser.ydata), s=0)

    def __call__(self, value):
        """convert value

        value might be a single value or an numpy array
        """
        result = splev(self.convert_x(value), self.spline)
        return self.convert_y(result)


class Sensor(Readable):
    rawsensor = Attached()

    calib = Parameter('calibration name', datatype=StringType(), readonly=False)
    abs = Parameter('True: take abs(raw) before calib', datatype=BoolType(), readonly=False, default=True)
    value = Parameter(unit='K')
    pollinterval = Parameter(export=False)
    status = Parameter(default=(Readable.Status.ERROR, 'unintialized'))

    pollerClass = None
    description = 'a calibrated sensor value'
    _value_error = None

    def initModule(self):
        self._rawsensor.registerCallbacks(self, ['status'])  # auto update status
        self._calib = CalCurve(self.calib)

    def write_calib(self, value):
        self._calib = CalCurve(value)
        return value

    def update_value(self, value):
        if self.abs:
            value = abs(value)
        self.value = self._calib(value)
        self._value_error = None

    def error_update_value(self, err):
        if self.abs and str(err) == 'R_UNDER':  # hack: ignore R_UNDER from ls370
            self._value_error = None
            return None
        self._value_error = repr(err)
        raise err

    def update_status(self, value):
        if self._value_error is None:
            self.status = value
        else:
            self.status = self.Status.ERROR, self._value_error

    def read_value(self):
        return self._calib(self._rawsensor.read_value())