# Microsoft Azure Linux Agent
#
# Copyright 2014 Microsoft Corporation
#
# 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.
#
# Requires Python 2.4+ and Openssl 1.0+
#

import platform
import os
import subprocess
from azurelinuxagent.future import ustr
import azurelinuxagent.logger as logger

if not hasattr(subprocess,'check_output'):
    def check_output(*popenargs, **kwargs):
        r"""Backport from subprocess module from python 2.7"""
        if 'stdout' in kwargs:
            raise ValueError('stdout argument not allowed, '
                             'it will be overridden.')
        process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
        output, unused_err = process.communicate()
        retcode = process.poll()
        if retcode:
            cmd = kwargs.get("args")
            if cmd is None:
                cmd = popenargs[0]
            raise subprocess.CalledProcessError(retcode, cmd, output=output)
        return output

    # Exception classes used by this module.
    class CalledProcessError(Exception):
        def __init__(self, returncode, cmd, output=None):
            self.returncode = returncode
            self.cmd = cmd
            self.output = output
        def __str__(self):
            return ("Command '{0}' returned non-zero exit status {1}"
                    "").format(self.cmd, self.returncode)

    subprocess.check_output=check_output
    subprocess.CalledProcessError=CalledProcessError


"""
Shell command util functions
"""
def run(cmd, chk_err=True):
    """
    Calls run_get_output on 'cmd', returning only the return code.
    If chk_err=True then errors will be reported in the log.
    If chk_err=False then errors will be suppressed from the log.
    """
    retcode,out=run_get_output(cmd,chk_err)
    return retcode

def run_get_output(cmd, chk_err=True, log_cmd=True):
    """
    Wrapper for subprocess.check_output.
    Execute 'cmd'.  Returns return code and STDOUT, trapping expected exceptions.
    Reports exceptions to Error if chk_err parameter is True
    """
    if log_cmd:
        logger.verb(u"run cmd '{0}'", cmd)
    try:
        output=subprocess.check_output(cmd,stderr=subprocess.STDOUT,shell=True)
        output = ustr(output, encoding='utf-8', errors="backslashreplace")
    except subprocess.CalledProcessError as e :
        output = ustr(e.output, encoding='utf-8', errors="backslashreplace")
        if chk_err:
            if log_cmd:
                logger.error(u"run cmd '{0}' failed", e.cmd)
            logger.error(u"Error Code:{0}", e.returncode)
            logger.error(u"Result:{0}", output)
        return e.returncode, output 
    return 0, output

#End shell command util functions