# Copyright (c) 2013 Hewlett-Packard Development Company, L.P.
# Copyright (c) 2012 VMware, Inc.
# Copyright (c) 2011 Citrix Systems, Inc.
# Copyright 2011 OpenStack Foundation
#
#    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.

"""
A connection to the VMware vCenter platform.
"""

import re

from oslo_log import log as logging
from oslo_utils import excutils
from oslo_utils import versionutils as v_utils
from oslo_vmware import api
from oslo_vmware import exceptions as vexc
from oslo_vmware import pbm
from oslo_vmware import vim
from oslo_vmware import vim_util

from nova.compute import task_states
import nova.conf
from nova import exception
from nova.i18n import _, _LI, _LE, _LW
from nova.virt import driver
from nova.virt.vmwareapi import constants
from nova.virt.vmwareapi import error_util
from nova.virt.vmwareapi import host
from nova.virt.vmwareapi import vim_util as nova_vim_util
from nova.virt.vmwareapi import vm_util
from nova.virt.vmwareapi import vmops
from nova.virt.vmwareapi import volumeops

LOG = logging.getLogger(__name__)

CONF = nova.conf.CONF

TIME_BETWEEN_API_CALL_RETRIES = 1.0


class VMwareVCDriver(driver.ComputeDriver):
    """The VC host connection object."""

    capabilities = {
        "has_imagecache": True,
        "supports_recreate": False,
        "supports_migrate_to_same_host": True,
        "supports_attach_interface": True
    }

    # Legacy nodename is of the form: <mo id>(<cluster name>)
    # e.g. domain-26(TestCluster)
    # We assume <mo id> consists of alphanumeric, _ and -.
    # We assume cluster name is everything between the first ( and the last ).
    # We pull out <mo id> for re-use.
    LEGACY_NODENAME = re.compile('([\w-]+)\(.+\)')

    # The vCenter driver includes API that acts on ESX hosts or groups
    # of ESX hosts in clusters or non-cluster logical-groupings.
    #
    # vCenter is not a hypervisor itself, it works with multiple
    # hypervisor host machines and their guests. This fact can
    # subtly alter how vSphere and OpenStack interoperate.

    def __init__(self, virtapi, scheme="https"):
        super(VMwareVCDriver, self).__init__(virtapi)

        if (CONF.vmware.host_ip is None or
            CONF.vmware.host_username is None or
            CONF.vmware.host_password is None):
            raise Exception(_("Must specify host_ip, host_username and "
                              "host_password to use vmwareapi.VMwareVCDriver"))

        self._datastore_regex = None
        if CONF.vmware.datastore_regex:
            try:
                self._datastore_regex = re.compile(CONF.vmware.datastore_regex)
            except re.error:
                raise exception.InvalidInput(reason=
                    _("Invalid Regular Expression %s")
                    % CONF.vmware.datastore_regex)

        self._session = VMwareAPISession(scheme=scheme)

        self._check_min_version()

        # Update the PBM location if necessary
        if CONF.vmware.pbm_enabled:
            self._update_pbm_location()

        self._validate_configuration()
        self._cluster_name = CONF.vmware.cluster_name
        self._cluster_ref = vm_util.get_cluster_ref_by_name(self._session,
                                                            self._cluster_name)
        if self._cluster_ref is None:
            raise exception.NotFound(_("The specified cluster '%s' was not "
                                       "found in vCenter")
                                     % self._cluster_name)
        self._vcenter_uuid = self._get_vcenter_uuid()
        self._nodename = self._create_nodename(self._cluster_ref.value)
        self._volumeops = volumeops.VMwareVolumeOps(self._session,
                                                    self._cluster_ref)
        self._vmops = vmops.VMwareVMOps(self._session,
                                        virtapi,
                                        self._volumeops,
                                        self._cluster_ref,
                                        datastore_regex=self._datastore_regex)
        self._vc_state = host.VCState(self._session,
                                      self._nodename,
                                      self._cluster_ref,
                                      self._datastore_regex)

        # Register the OpenStack extension
        self._register_openstack_extension()

    def _check_min_version(self):
        min_version = v_utils.convert_version_to_int(constants.MIN_VC_VERSION)
        vc_version = vim_util.get_vc_version(self._session)
        LOG.info(_LI("VMware vCenter version: %s"), vc_version)
        if min_version > v_utils.convert_version_to_int(vc_version):
            # TODO(garyk): enforce this from M
            LOG.warning(_LW('Running Nova with a VMware vCenter version less '
                            'than %(version)s is deprecated. The required '
                            'minimum version of vCenter will be raised to '
                            '%(version)s in the 13.0.0 release.'),
                        {'version': constants.MIN_VC_VERSION})

    @property
    def need_legacy_block_device_info(self):
        return False

    def _update_pbm_location(self):
        if CONF.vmware.pbm_wsdl_location:
            pbm_wsdl_loc = CONF.vmware.pbm_wsdl_location
        else:
            version = vim_util.get_vc_version(self._session)
            pbm_wsdl_loc = pbm.get_pbm_wsdl_location(version)
        self._session.pbm_wsdl_loc_set(pbm_wsdl_loc)

    def _validate_configuration(self):
        if CONF.vmware.pbm_enabled:
            if not CONF.vmware.pbm_default_policy:
                raise error_util.PbmDefaultPolicyUnspecified()
            if not pbm.get_profile_id_by_name(
                            self._session,
                            CONF.vmware.pbm_default_policy):
                raise error_util.PbmDefaultPolicyDoesNotExist()
            if CONF.vmware.datastore_regex:
                LOG.warning(_LW(
                    "datastore_regex is ignored when PBM is enabled"))
                self._datastore_regex = None

    def init_host(self, host):
        vim = self._session.vim
        if vim is None:
            self._session._create_session()

    def cleanup_host(self, host):
        self._session.logout()

    def _register_openstack_extension(self):
        # Register an 'OpenStack' extension in vCenter
        LOG.debug('Registering extension %s with vCenter',
                  constants.EXTENSION_KEY)
        os_extension = self._session._call_method(vim_util, 'find_extension',
                                                  constants.EXTENSION_KEY)
        if os_extension is None:
            LOG.debug('Extension does not exist. Registering type %s.',
                      constants.EXTENSION_TYPE_INSTANCE)
            self._session._call_method(vim_util, 'register_extension',
                                       constants.EXTENSION_KEY,
                                       constants.EXTENSION_TYPE_INSTANCE)

    def cleanup(self, context, instance, network_info, block_device_info=None,
                destroy_disks=True, migrate_data=None, destroy_vifs=True):
        """Cleanup after instance being destroyed by Hypervisor."""
        pass

    def resume_state_on_host_boot(self, context, instance, network_info,
                                  block_device_info=None):
        """resume guest state when a host is booted."""
        # Check if the instance is running already and avoid doing
        # anything if it is.
        state = vm_util.get_vm_state(self._session, instance)
        ignored_states = ['poweredon', 'suspended']
        if state.lower() in ignored_states:
            return
        # Instance is not up and could be in an unknown state.
        # Be as absolute as possible about getting it back into
        # a known and running state.
        self.reboot(context, instance, network_info, 'hard',
                    block_device_info)

    def list_instance_uuids(self):
        """List VM instance UUIDs."""
        return self._vmops.list_instances()

    def list_instances(self):
        """List VM instances from the single compute node."""
        return self._vmops.list_instances()

    def migrate_disk_and_power_off(self, context, instance, dest,
                                   flavor, network_info,
                                   block_device_info=None,
                                   timeout=0, retry_interval=0):
        """Transfers the disk of a running instance in multiple phases, turning
        off the instance before the end.
        """
        # TODO(PhilDay): Add support for timeout (clean shutdown)
        return self._vmops.migrate_disk_and_power_off(context, instance,
                                                      dest, flavor)

    def confirm_migration(self, migration, instance, network_info):
        """Confirms a resize, destroying the source VM."""
        self._vmops.confirm_migration(migration, instance, network_info)

    def finish_revert_migration(self, context, instance, network_info,
                                block_device_info=None, power_on=True):
        """Finish reverting a resize, powering back on the instance."""
        self._vmops.finish_revert_migration(context, instance, network_info,
                                            block_device_info, power_on)

    def finish_migration(self, context, migration, instance, disk_info,
                         network_info, image_meta, resize_instance,
                         block_device_info=None, power_on=True):
        """Completes a resize, turning on the migrated instance."""
        self._vmops.finish_migration(context, migration, instance, disk_info,
                                     network_info, image_meta, resize_instance,
                                     block_device_info, power_on)

    def get_instance_disk_info(self, instance, block_device_info=None):
        pass

    def get_vnc_console(self, context, instance):
        """Return link to instance's VNC console using vCenter logic."""
        # vCenter does not actually run the VNC service
        # itself. You must talk to the VNC host underneath vCenter.
        return self._vmops.get_vnc_console(instance)

    def get_mks_console(self, context, instance):
        return self._vmops.get_mks_console(instance)

    def _get_vcenter_uuid(self):
        """Retrieves the vCenter UUID."""

        about = self._session._call_method(nova_vim_util, 'get_about_info')
        return about.instanceUuid

    def _create_nodename(self, mo_id):
        """Return a nodename which uniquely describes a cluster.

        The name will be of the form:
          <mo id>.<vcenter uuid>
        e.g.
          domain-26.9d51f082-58a4-4449-beed-6fd205a5726b
        """

        return '%s.%s' % (mo_id, self._vcenter_uuid)

    def _get_available_resources(self, host_stats):
        return {'vcpus': host_stats['vcpus'],
               'memory_mb': host_stats['host_memory_total'],
               'local_gb': host_stats['disk_total'],
               'vcpus_used': 0,
               'memory_mb_used': host_stats['host_memory_total'] -
                                 host_stats['host_memory_free'],
               'local_gb_used': host_stats['disk_used'],
               'hypervisor_type': host_stats['hypervisor_type'],
               'hypervisor_version': host_stats['hypervisor_version'],
               'hypervisor_hostname': host_stats['hypervisor_hostname'],
                # The VMWare driver manages multiple hosts, so there are
                # likely many different CPU models in use. As such it is
                # impossible to provide any meaningful info on the CPU
                # model of the "host"
               'cpu_info': None,
               'supported_instances': host_stats['supported_instances'],
               'numa_topology': None,
               }

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

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

        :returns: dictionary describing resources

        """
        host_stats = self._vc_state.get_host_stats(refresh=True)
        stats_dict = self._get_available_resources(host_stats)
        return stats_dict

    def get_available_nodes(self, refresh=False):
        """Returns nodenames of all nodes managed by the compute service.

        This driver supports only one compute node.
        """
        return [self._nodename]

    def spawn(self, context, instance, image_meta, injected_files,
              admin_password, network_info=None, block_device_info=None):
        """Create VM instance."""
        self._vmops.spawn(context, instance, image_meta, injected_files,
                          admin_password, network_info, block_device_info)

    def attach_volume(self, context, connection_info, instance, mountpoint,
                      disk_bus=None, device_type=None, encryption=None):
        """Attach volume storage to VM instance."""
        return self._volumeops.attach_volume(connection_info, instance)

    def detach_volume(self, connection_info, instance, mountpoint,
                      encryption=None):
        """Detach volume storage to VM instance."""
        return self._volumeops.detach_volume(connection_info, instance)

    def get_volume_connector(self, instance):
        """Return volume connector information."""
        return self._volumeops.get_volume_connector(instance)

    def get_host_ip_addr(self):
        """Returns the IP address of the vCenter host."""
        return CONF.vmware.host_ip

    def snapshot(self, context, instance, image_id, update_task_state):
        """Create snapshot from a running VM instance."""
        self._vmops.snapshot(context, instance, image_id, update_task_state)

    def reboot(self, context, instance, network_info, reboot_type,
               block_device_info=None, bad_volumes_callback=None):
        """Reboot VM instance."""
        self._vmops.reboot(instance, network_info, reboot_type)

    def _detach_instance_volumes(self, instance, block_device_info):
        # We need to detach attached volumes
        block_device_mapping = driver.block_device_info_get_mapping(
            block_device_info)
        if block_device_mapping:
            # Certain disk types, for example 'IDE' do not support hot
            # plugging. Hence we need to power off the instance and update
            # the instance state.
            self._vmops.power_off(instance)
            for disk in block_device_mapping:
                connection_info = disk['connection_info']
                try:
                    self.detach_volume(connection_info, instance,
                                       disk.get('device_name'))
                except exception.DiskNotFound:
                    LOG.warning(_LW('The volume %s does not exist!'),
                                disk.get('device_name'),
                                instance=instance)
                except Exception as e:
                    with excutils.save_and_reraise_exception():
                        LOG.error(_LE("Failed to detach %(device_name)s. "
                                      "Exception: %(exc)s"),
                                  {'device_name': disk.get('device_name'),
                                   'exc': e},
                                  instance=instance)

    def destroy(self, context, instance, network_info, block_device_info=None,
                destroy_disks=True, migrate_data=None):
        """Destroy VM instance."""

        # Destroy gets triggered when Resource Claim in resource_tracker
        # is not successful. When resource claim is not successful,
        # node is not set in instance. Perform destroy only if node is set
        if not instance.node:
            return

        # A resize uses the same instance on the VC. We do not delete that
        # VM in the event of a revert
        if instance.task_state == task_states.RESIZE_REVERTING:
            return

        # We need to detach attached volumes
        if block_device_info is not None:
            try:
                self._detach_instance_volumes(instance, block_device_info)
            except vexc.ManagedObjectNotFoundException:
                LOG.warning(_LW('Instance does not exists. Proceeding to '
                                'delete instance properties on datastore'),
                            instance=instance)
        self._vmops.destroy(instance, destroy_disks)

    def pause(self, instance):
        """Pause VM instance."""
        self._vmops.pause(instance)

    def unpause(self, instance):
        """Unpause paused VM instance."""
        self._vmops.unpause(instance)

    def suspend(self, context, instance):
        """Suspend the specified instance."""
        self._vmops.suspend(instance)

    def resume(self, context, instance, network_info, block_device_info=None):
        """Resume the suspended VM instance."""
        self._vmops.resume(instance)

    def rescue(self, context, instance, network_info, image_meta,
               rescue_password):
        """Rescue the specified instance."""
        self._vmops.rescue(context, instance, network_info, image_meta)

    def unrescue(self, instance, network_info):
        """Unrescue the specified instance."""
        self._vmops.unrescue(instance)

    def power_off(self, instance, timeout=0, retry_interval=0):
        """Power off the specified instance."""
        # TODO(PhilDay): Add support for timeout (clean shutdown)
        self._vmops.power_off(instance)

    def power_on(self, context, instance, network_info,
                 block_device_info=None):
        """Power on the specified instance."""
        self._vmops.power_on(instance)

    def poll_rebooting_instances(self, timeout, instances):
        """Poll for rebooting instances."""
        self._vmops.poll_rebooting_instances(timeout, instances)

    def get_info(self, instance):
        """Return info about the VM instance."""
        return self._vmops.get_info(instance)

    def get_diagnostics(self, instance):
        """Return data about VM diagnostics."""
        return self._vmops.get_diagnostics(instance)

    def get_instance_diagnostics(self, instance):
        """Return data about VM diagnostics."""
        return self._vmops.get_instance_diagnostics(instance)

    def host_power_action(self, action):
        """Host operations not supported by VC driver.

        This needs to override the ESX driver implementation.
        """
        raise NotImplementedError()

    def host_maintenance_mode(self, host, mode):
        """Host operations not supported by VC driver.

        This needs to override the ESX driver implementation.
        """
        raise NotImplementedError()

    def set_host_enabled(self, enabled):
        """Host operations not supported by VC driver.

        This needs to override the ESX driver implementation.
        """
        raise NotImplementedError()

    def get_host_uptime(self):
        """Host uptime operation not supported by VC driver."""

        msg = _("Multiple hosts may be managed by the VMWare "
                "vCenter driver; therefore we do not return "
                "uptime for just one host.")
        raise NotImplementedError(msg)

    def inject_network_info(self, instance, nw_info):
        """inject network info for specified instance."""
        self._vmops.inject_network_info(instance, nw_info)

    def manage_image_cache(self, context, all_instances):
        """Manage the local cache of images."""
        self._vmops.manage_image_cache(context, all_instances)

    def instance_exists(self, instance):
        """Efficient override of base instance_exists method."""
        return self._vmops.instance_exists(instance)

    def attach_interface(self, instance, image_meta, vif):
        """Attach an interface to the instance."""
        self._vmops.attach_interface(instance, image_meta, vif)

    def detach_interface(self, instance, vif):
        """Detach an interface from the instance."""
        self._vmops.detach_interface(instance, vif)


class VMwareAPISession(api.VMwareAPISession):
    """Sets up a session with the VC/ESX host and handles all
    the calls made to the host.
    """
    def __init__(self, host_ip=CONF.vmware.host_ip,
                 host_port=CONF.vmware.host_port,
                 username=CONF.vmware.host_username,
                 password=CONF.vmware.host_password,
                 retry_count=CONF.vmware.api_retry_count,
                 scheme="https",
                 cacert=CONF.vmware.ca_file,
                 insecure=CONF.vmware.insecure):
        super(VMwareAPISession, self).__init__(
                host=host_ip,
                port=host_port,
                server_username=username,
                server_password=password,
                api_retry_count=retry_count,
                task_poll_interval=CONF.vmware.task_poll_interval,
                scheme=scheme,
                create_session=True,
                wsdl_loc=CONF.vmware.wsdl_location,
                cacert=cacert,
                insecure=insecure)

    def _is_vim_object(self, module):
        """Check if the module is a VIM Object instance."""
        return isinstance(module, vim.Vim)

    def _call_method(self, module, method, *args, **kwargs):
        """Calls a method within the module specified with
        args provided.
        """
        if not self._is_vim_object(module):
            return self.invoke_api(module, method, self.vim, *args, **kwargs)
        else:
            return self.invoke_api(module, method, *args, **kwargs)

    def _wait_for_task(self, task_ref):
        """Return a Deferred that will give the result of the given task.
        The task is polled until it completes.
        """
        return self.wait_for_task(task_ref)