#!/bin/env python

 # -*- coding: utf-8 -*-

 # ------------------------------------------------------------

 # environment.py

 # 

 # pick some current environment infos

 #

 # Autor: Oliver Maurhart, <oliver.maurhart@ait.ac.at>

 #

 # Copyright 2013-2014 X-Net and AIT Austrian Institute of Technology

 # 

 # 

 #     X-Net Services GmbH

 #     Elisabethstrasse 1

 #     4020 Linz

 #     AUSTRIA

 #     https://www.x-net.at

 # 

 #     AIT Austrian Institute of Technology

 #     Donau City Strasse 1

 #     1220 Wien

 #     AUSTRIA

 #     http://www.ait.ac.at

 # 

 # 

 # Licensed under the Apache License, Version 2.0 (the "License");

 # you may not use this file except in compliance with the License.

 # You may obtain a copy of the License at

 # 

 #    http://www.apache.org/licenses/LICENSE-2.0

 # 

 # Unless required by applicable law or agreed to in writing, software

 # distributed under the License is distributed on an "AS IS" BASIS,

 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 # See the License for the specific language governing permissions and

 # limitations under the License.

 # ------------------------------------------------------------

 # ------------------------------------------------------------

 # imports

 import os

 import os.path

 import sys

 # ------------------------------------------------------------

 # code

 class Environment(object):

     """Hold some nifty environment stuff in a dedicated class."""

     _log_warning_shown = False

     _prefix_path = ''

     def __init__(self, application = None):

         # if we ain't got a path to start from, all is valid/lost

         if len(sys.path[0]) == 0:

             self._prefix_path = ''

             self._data_path = ''

             return

         # the prefix path

         #

         # - on Linux: this is ../../ to the current executable

         #   e.g. "/usr/bin/myprogram" --> "/usr"

         #

         # - on Windows (inkl. Cygwin): this is the installation folder

         #   e.g. "C:/Program Files/MyProgram/myprogam" --> "C:/Program Files/MyProgram"

         #

         if sys.platform == 'linux2':

             self._prefix_path = os.path.split(sys.path[0])[0]

         elif sys.platform == 'win32' or sys.platform == 'cygwin':

             for app_path in sys.path:

                 if 'OpenSecurity\\bin' in app_path:

                     self._prefix_path = os.path.normpath(os.path.join(app_path, '..'))

                     break

         if self._prefix_path == '':

             raise OSError()

         # the data path where all data files are stored

         if sys.platform == 'linux2':

             if not application is None:

                 self._data_path = os.path.join(self._prefix_path, os.path.join('share', application))

             else:

                 self._data_path = os.path.join(self._prefix_path, 'share')

         elif sys.platform == 'win32' or sys.platform == 'cygwin':

             self._data_path = self._prefix_path

         else:

             raise OSError()

     def data_path_get(self):

         """dat_path get"""

         return self._data_path

     data_path = property(data_path_get)

     def prefix_path_get(self):

         """prefix_path get"""

         return self._prefix_path

     prefix_path = property(prefix_path_get)

     def log_path_get(self):

         """the path where log files should be stored"""

         user_log_path = os.path.expanduser(os.path.join('~', '.log'))

         if sys.platform == 'linux2':

             if os.access('/var/log', os.W_OK):

                 return '/var/log'

             if not Environment._log_warning_shown:

                 print('no permissions to write log files in /var/log, switching to ~/.log')

                 Environment._log_warning_shown = True

             if not os.path.exists(user_log_path):

                 os.mkdir(user_log_path)

             elif not os.path.isdir(user_log_path):

                 raise IOError(user_log_path + ': not a folder')

             return user_log_path

         elif sys.platform == 'win32' or sys.platform == 'cygwin':

             # in OpenSecurity we expect the log path tp be

             # somewhere like C:\Program Files\OpenSecurity\log

             # having this script residing in 

             # C:\Progam Files\OpenSecurity\bin

             ideal_log_path = os.path.normpath(os.path.join(self.prefix_path, 'log'))

             # check ideal path first

             if not os.path.exists(ideal_log_path):

                 os.mkdir(ideal_log_path)

             elif not os.path.isdir(ideal_log_path):

                 raise IOError(ideal_log_path + ': not a folder')

             return ideal_log_path

         else:

             raise OSError()

     log_path = property(log_path_get)

 # test method

 def test():

     """Test: class Environment"""

     e = Environment('OpenSecurity')

     print('prefix_path: "{0}"'.format(e.prefix_path))

     print('  data_path: "{0}"'.format(e.data_path))

     print('   log_path: "{0}"'.format(e.log_path))

 # test the module			

 if __name__ == '__main__':

     test()