MqttVar.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
MqttVar.py
MIT License (c) Faure Systems

Class to track and publish variable changes.
"""

import gettext

try:
    gettext.find("MqttVar")
    traduction = gettext.translation('MqttVar', localedir='locale', languages=['fr'])
    traduction.install()
except:
    _ = gettext.gettext  # cool, this hides PyLint warning Undefined name '_'


class MqttVar:

    # __________________________________________________________________
    def __init__(self, name, type, initial, decimal=None, precision=1, alias=("1", "0"), logger=None):

        super().__init__()

        self._logger = logger

        self._name = name
        self._type = type
        self._decimal = decimal
        self._precision = precision
        self._true, self._false = alias

        if type == int:
            v = int(str(initial))
            self._value = v
            self._reference = v + 1
            if self._logger:
                self._logger.info(
                    "{0} '{1}' {2}={3} {4}={5}".format(_("New int Publishable"), self._name, _("with initial"), initial,
                                                       _("and precision"), self._precision))
        elif type == float:
            v = float(str(initial))
            self._value = v
            self._reference = v + 1.0
            if self._logger and self._decimal:
                self._logger.info("{0} '{1}' {2}={3} {4}={5} {6}={7}".format(_("New float Publishable"), self._name,
                                                                             _("with initial"), initial,
                                                                             _("and precision"), self._precision,
                                                                             _("and decimal"), self._decimal))
            elif self._logger:
                self._logger.info(
                    "{0} '{1}' {2}={3} {4}={5}".format(_("New float Publishable"), self._name, _("with initial"),
                                                       initial, _("and precision"), self._precision))
        elif type == str:
            self._value = initial
            self._reference = initial + "_"
            if self._logger:
                if initial:
                    self._logger.info(
                        "{0} '{1}' {2}={3}".format(_("New str Publishable"), self._name, _("with initial"), initial))
                else:
                    self._logger.info(
                        "{0} '{1}' {2}=''".format(_("New str Publishable"), self._name, _("with initial")))
        elif type == bool:
            self._value = initial
            self._reference = not initial
            if self._logger:
                self._logger.info(
                    "{0} '{1}' ({2}/{3}) {4}={5}".format(_("New boolean Publishable"), self._name, self._true,
                                                         self._false, _("with initial"), initial))
        else:
            self._type = int
            v = 0
            self._value = v
            self._reference = v + 1
            self._decimal = None
            self._precision = 1
            if self._logger:
                self._logger.info(
                    "{0} '{1}' {2}={3} {4}={5}".format(_("New incorrect Publishable created as int"), self._name,
                                                       _("with initial"), initial, _("and precision"), self._precision))

    # __________________________________________________________________
    def __str__(self):

        self._reference = self._value

        if self._type == float and self._decimal:
            return "{0}={1:.{prec}f}".format(self._name, self._value, prec=self._decimal)
        elif self._type == int:
            return "{0}={1}".format(self._name, str(self._value))
        elif self._type == bool:
            if self._value:
                return "{0}={1}".format(self._name, self._true)
            else:
                return "{0}={1}".format(self._name, self._false)
        else:
            if isinstance(self._value, str):
                if not self._value:
                    return "{0}=-".format(self._name)
                else:
                    return "{0}={1}".format(self._name, self._value)
            else:
                try:
                    v = str(self._value)
                    if v:
                        return "{0}={1}".format(self._name, v)
                except:
                    pass
                finally:
                    return "{0}=-".format(self._name)

    # __________________________________________________________________
    def change(self):

        if self._type == int or self._type == float:
            if abs(self._reference - self._value) > self._precision:
                return self.__str__()
            else:
                return None
        else:
            if self._reference != self._value:
                return self.__str__()
            else:
                return None

    # __________________________________________________________________
    def update(self, value):

        self._value = value

    # __________________________________________________________________
    def value(self):

        return self._value