#!/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()