#  -*- 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>
#
# *****************************************************************************
"""Define base classes for real Modules implemented in the server"""


import os
import json

from secop.errors import BadValueError, ConfigError, InternalError, \
    ProgrammingError, SECoPError, SilentError, secop_error

class PersistentMixin:

    def __init__(*args, **kwds):
        super().__init__(*args, **kwds)
        # self.persistentFile = None
        # self.persistentData = {}
        self.writeDict.update(self.loadParameters())

    def writeInitParams(self, started_callback=None):
        super().writeInitParams()
        self.saveParameters()
        if started_callback:
            started_callback()

    def loadParameters(self):
        """load persistent parameters

        :return: persistent parameters which have to be written

        is called upon startup and may be called from a module
        when a hardware powerdown is detected
        """
        persistentdir = os.path.join(getGeneralConfig()['logdir'], 'persistent')
        self.persistentFile = os.path.join(persistentdir, '%s.%s.json' % (self.DISPATCHER.equipment_id, self.name))
        try:
            with open(self.persistentFile, 'r') as f:
                self.persistentData = json.load(f)
        except FileNotFoundError:
            self.persistentData = {}
        writeDict = {}
        for pname, pobj in self.parameters.items():
            if pobj.persistent and pname in self.persistentData:
                value = pobj.datatype.import_value(self.persistentData[pname])
                try:
                    pobj.value = value
                    if not pobj.readonly:
                        writeDict[pname] = value
                except Exception as e:
                    self.log.warning('can not restore %r to %r (%r)' % (pname, value, e))
        return writeDict

    def saveParameters(self):
        """save persistent parameters

        to be called regularely explicitly by the module
        """
        data = {k: v.export_value() for k, v in self.parameters.items() if v.persistent}
        if data != self.persistentData:
            self.persistentData = data
            persistentdir = os.path.basename(self.persistentFile)
            tmpfile = self.persistentFile + '.tmp'
            if not os.path.isdir(persistentdir):
                os.makedirs(persistentdir, exist_ok=True)
            try:
                with open(tmpfile, 'w') as f:
                    json.dump(self.persistentData, f, indent=2)
                    f.write('\n')
                os.rename(tmpfile, self.persistentFile)
            finally:
                try:
                    os.remove(tmpfile)
                except FileNotFoundError:
                    pass