# Copyright 2012 Cloudbase Solutions Srl
# All Rights Reserved.
#
#    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.

"""
Management class for host operations.
"""
import datetime
import os
import platform
import time

from oslo.config import cfg
from oslo.serialization import jsonutils
from oslo.utils import units

from nova.compute import arch
from nova.compute import hvtype
from nova.compute import vm_mode
from nova.i18n import _
from nova.openstack.common import log as logging
from nova.virt.hyperv import constants
from nova.virt.hyperv import utilsfactory

CONF = cfg.CONF
CONF.import_opt('my_ip', 'nova.netconf')
LOG = logging.getLogger(__name__)


class HostOps(object):
    def __init__(self):
        self._hostutils = utilsfactory.get_hostutils()
        self._pathutils = utilsfactory.get_pathutils()

    def _get_cpu_info(self):
        """Get the CPU information.
        :returns: A dictionary containing the main properties
        of the central processor in the hypervisor.
        """
        cpu_info = dict()

        processors = self._hostutils.get_cpus_info()

        w32_arch_dict = constants.WMI_WIN32_PROCESSOR_ARCHITECTURE
        cpu_info['arch'] = w32_arch_dict.get(processors[0]['Architecture'],
                                             'Unknown')
        cpu_info['model'] = processors[0]['Name']
        cpu_info['vendor'] = processors[0]['Manufacturer']

        topology = dict()
        topology['sockets'] = len(processors)
        topology['cores'] = processors[0]['NumberOfCores']
        topology['threads'] = (processors[0]['NumberOfLogicalProcessors'] /
                               processors[0]['NumberOfCores'])
        cpu_info['topology'] = topology

        features = list()
        for fkey, fname in constants.PROCESSOR_FEATURE.items():
            if self._hostutils.is_cpu_feature_present(fkey):
                features.append(fname)
        cpu_info['features'] = features

        return cpu_info

    def _get_memory_info(self):
        (total_mem_kb, free_mem_kb) = self._hostutils.get_memory_info()
        total_mem_mb = total_mem_kb / 1024
        free_mem_mb = free_mem_kb / 1024
        return (total_mem_mb, free_mem_mb, total_mem_mb - free_mem_mb)

    def _get_local_hdd_info_gb(self):
        drive = os.path.splitdrive(self._pathutils.get_instances_dir())[0]
        (size, free_space) = self._hostutils.get_volume_info(drive)

        total_gb = size / units.Gi
        free_gb = free_space / units.Gi
        used_gb = total_gb - free_gb
        return (total_gb, free_gb, used_gb)

    def _get_hypervisor_version(self):
        """Get hypervisor version.
        :returns: hypervisor version (ex. 12003)
        """
        version = self._hostutils.get_windows_version().replace('.', '')
        LOG.debug('Windows version: %s ', version)
        return version

    def get_available_resource(self):
        """Retrieve resource info.

        This method is called when nova-compute launches, and
        as part of a periodic task.

        :returns: dictionary describing resources

        """
        LOG.debug('get_available_resource called')

        (total_mem_mb,
         free_mem_mb,
         used_mem_mb) = self._get_memory_info()

        (total_hdd_gb,
         free_hdd_gb,
         used_hdd_gb) = self._get_local_hdd_info_gb()

        cpu_info = self._get_cpu_info()
        cpu_topology = cpu_info['topology']
        vcpus = (cpu_topology['sockets'] *
                 cpu_topology['cores'] *
                 cpu_topology['threads'])

        dic = {'vcpus': vcpus,
               'memory_mb': total_mem_mb,
               'memory_mb_used': used_mem_mb,
               'local_gb': total_hdd_gb,
               'local_gb_used': used_hdd_gb,
               'hypervisor_type': "hyperv",
               'hypervisor_version': self._get_hypervisor_version(),
               'hypervisor_hostname': platform.node(),
               'vcpus_used': 0,
               'cpu_info': jsonutils.dumps(cpu_info),
               'supported_instances': jsonutils.dumps(
                   [(arch.I686, hvtype.HYPERV, vm_mode.HVM),
                    (arch.X86_64, hvtype.HYPERV, vm_mode.HVM)]),
               'numa_topology': None,
               }

        return dic

    def host_power_action(self, action):
        """Reboots, shuts down or powers up the host."""
        if action in [constants.HOST_POWER_ACTION_SHUTDOWN,
                      constants.HOST_POWER_ACTION_REBOOT]:
            self._hostutils.host_power_action(action)
        else:
            if action == constants.HOST_POWER_ACTION_STARTUP:
                raise NotImplementedError(
                    _("Host PowerOn is not supported by the Hyper-V driver"))

    def get_host_ip_addr(self):
        host_ip = CONF.my_ip
        if not host_ip:
            # Return the first available address
            host_ip = self._hostutils.get_local_ips()[0]
        LOG.debug("Host IP address is: %s", host_ip)
        return host_ip

    def get_host_uptime(self):
        """Returns the host uptime."""

        tick_count64 = self._hostutils.get_host_tick_count64()

        # format the string to match libvirt driver uptime
        # Libvirt uptime returns a combination of the following
        # - curent host time
        # - time since host is up
        # - number of logged in users
        # - cpu load
        # Since the Windows function GetTickCount64 returns only
        # the time since the host is up, returning 0s for cpu load
        # and number of logged in users.
        # This is done to ensure the format of the returned
        # value is same as in libvirt
        return "%s up %s,  0 users,  load average: 0, 0, 0" % (
                   str(time.strftime("%H:%M:%S")),
                   str(datetime.timedelta(milliseconds=long(tick_count64))))
