#
# Copyright 2018 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 2.6+ and Openssl 1.0+
#

import os
import re
import pwd
import shutil
import socket
import array
import struct
import fcntl
import time
import base64
import azurelinuxagent.common.conf as conf
import azurelinuxagent.common.logger as logger
from azurelinuxagent.common.future import ustr, bytebuffer
from azurelinuxagent.common.exception import OSUtilError, CryptError
import azurelinuxagent.common.utils.fileutil as fileutil
import azurelinuxagent.common.utils.shellutil as shellutil
import azurelinuxagent.common.utils.textutil as textutil
from azurelinuxagent.common.utils.cryptutil import CryptUtil
from azurelinuxagent.common.osutil.default import DefaultOSUtil


class Redhat6xOSUtil(DefaultOSUtil):

    def __init__(self):
        super(Redhat6xOSUtil, self).__init__()
        self.jit_enabled = True

    def start_network(self):
        return shellutil.run("/sbin/service networking start", chk_err=False)

    def restart_ssh_service(self):
        return shellutil.run("/sbin/service sshd condrestart", chk_err=False)

    def stop_agent_service(self):
        return shellutil.run("/sbin/service {0} stop".format(self.service_name), chk_err=False)

    def start_agent_service(self):
        return shellutil.run("/sbin/service {0} start".format(self.service_name), chk_err=False)

    def register_agent_service(self):
        return shellutil.run("chkconfig --add {0}".format(self.service_name), chk_err=False)

    def unregister_agent_service(self):
        return shellutil.run("chkconfig --del {0}".format(self.service_name), chk_err=False)

    def openssl_to_openssh(self, input_file, output_file):
        pubkey = fileutil.read_file(input_file)
        try:
            cryptutil = CryptUtil(conf.get_openssl_cmd())
            ssh_rsa_pubkey = cryptutil.asn1_to_ssh(pubkey)
        except CryptError as e:
            raise OSUtilError(ustr(e))
        fileutil.append_file(output_file, ssh_rsa_pubkey)

    # Override
    def get_dhcp_pid(self):
        return self._get_dhcp_pid(["pidof", "dhclient"])

    def set_hostname(self, hostname):
        """
        Set /etc/sysconfig/network
        """
        fileutil.update_conf_file('/etc/sysconfig/network',
                                  'HOSTNAME',
                                  'HOSTNAME={0}'.format(hostname))
        shellutil.run("hostname {0}".format(hostname), chk_err=False)

    def set_dhcp_hostname(self, hostname):
        ifname = self.get_if_name()
        filepath = "/etc/sysconfig/network-scripts/ifcfg-{0}".format(ifname)
        fileutil.update_conf_file(filepath,
                                  'DHCP_HOSTNAME',
                                  'DHCP_HOSTNAME={0}'.format(hostname))

    def get_dhcp_lease_endpoint(self):
        return self.get_endpoint_from_leases_path('/var/lib/dhclient/dhclient-*.leases')


class RedhatOSUtil(Redhat6xOSUtil):
    def __init__(self):
        super(RedhatOSUtil, self).__init__()
        self.service_name = self.get_service_name()

    def set_hostname(self, hostname):
        """
        Unlike redhat 6.x, redhat 7.x will set hostname via hostnamectl
        Due to a bug in systemd in Centos-7.0, if this call fails, fallback
        to hostname.
        """
        hostnamectl_cmd = "hostnamectl set-hostname {0} --static".format(hostname)
        if shellutil.run(hostnamectl_cmd, chk_err=False) != 0:
            logger.warn("[{0}] failed, attempting fallback".format(hostnamectl_cmd))
            DefaultOSUtil.set_hostname(self, hostname)

    def publish_hostname(self, hostname):
        """
        Restart NetworkManager first before publishing hostname
        """
        shellutil.run("service NetworkManager restart")
        super(RedhatOSUtil, self).publish_hostname(hostname)

    def register_agent_service(self):
        return shellutil.run("systemctl enable {0}".format(self.service_name), chk_err=False)

    def unregister_agent_service(self):
        return shellutil.run("systemctl disable {0}".format(self.service_name), chk_err=False)

    def openssl_to_openssh(self, input_file, output_file):
        DefaultOSUtil.openssl_to_openssh(self, input_file, output_file)

    def get_dhcp_lease_endpoint(self):
        # dhclient
        endpoint = self.get_endpoint_from_leases_path('/var/lib/dhclient/dhclient-*.lease')

        if endpoint is None:
            # NetworkManager
            endpoint = self.get_endpoint_from_leases_path('/var/lib/NetworkManager/dhclient-*.lease')

        return endpoint
