# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2013 IBM Corp.
#
#    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.

import socket
import time

from oslo.config import cfg

from nova.compute import flavors
from nova.image import glance
from nova.openstack.common.gettextutils import _
from nova.openstack.common import log as logging
from nova.virt import driver
from nova.virt.powervm import exception
from nova.virt.powervm import operator

LOG = logging.getLogger(__name__)

powervm_opts = [
    cfg.StrOpt('powervm_mgr_type',
               default='ivm',
               help='PowerVM manager type (ivm, hmc)'),
    cfg.StrOpt('powervm_mgr',
               help='PowerVM manager host or ip'),
    cfg.StrOpt('powervm_mgr_user',
               help='PowerVM manager user name'),
    cfg.StrOpt('powervm_mgr_passwd',
               help='PowerVM manager user password',
               secret=True),
    cfg.StrOpt('powervm_img_remote_path',
               default='/home/padmin',
               help='PowerVM image remote path where images will be moved.'
               ' Make sure this path can fit your biggest image in glance'),
    cfg.StrOpt('powervm_img_local_path',
               default='/tmp',
               help='Local directory to download glance images to.'
               ' Make sure this path can fit your biggest image in glance')
    ]

CONF = cfg.CONF
CONF.register_opts(powervm_opts)


class PowerVMDriver(driver.ComputeDriver):

    """PowerVM Implementation of Compute Driver."""

    def __init__(self, virtapi):
        super(PowerVMDriver, self).__init__(virtapi)
        self._powervm = operator.PowerVMOperator()

    @property
    def host_state(self):
        pass

    def init_host(self, host):
        """Initialize anything that is necessary for the driver to function,
        including catching up with currently running VM's on the given host.
        """
        pass

    def get_info(self, instance):
        """Get the current status of an instance."""
        return self._powervm.get_info(instance['name'])

    def get_num_instances(self):
        return len(self.list_instances())

    def instance_exists(self, instance_name):
        return self._powervm.instance_exists(instance_name)

    def list_instances(self):
        return self._powervm.list_instances()

    def get_host_stats(self, refresh=False):
        """Return currently known host stats."""
        return self._powervm.get_host_stats(refresh=refresh)

    def get_host_uptime(self, host):
        """Returns the result of calling "uptime" on the target host."""
        return self._powervm.get_host_uptime(host)

    def plug_vifs(self, instance, network_info):
        pass

    def macs_for_instance(self, instance):
        return self._powervm.macs_for_instance(instance)

    def spawn(self, context, instance, image_meta, injected_files,
              admin_password, network_info=None, block_device_info=None):
        """Create a new instance/VM/domain on powerVM."""
        self._powervm.spawn(context, instance, image_meta['id'], network_info)

    def destroy(self, instance, network_info, block_device_info=None,
                destroy_disks=True):
        """Destroy (shutdown and delete) the specified instance."""
        self._powervm.destroy(instance['name'], destroy_disks)

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

        :param instance: Instance object as returned by DB layer.
        :param network_info:
           :py:meth:`~nova.network.manager.NetworkManager.get_instance_nw_info`
        :param reboot_type: Either a HARD or SOFT reboot
        :param block_device_info: Info pertaining to attached volumes
        :param bad_volumes_callback: Function to handle any bad volumes
            encountered
        """
        pass

    def get_host_ip_addr(self):
        """Retrieves the IP address of the hypervisor host."""
        LOG.debug(_("In get_host_ip_addr"))
        # TODO(mrodden): use operator get_hostname instead
        hostname = CONF.powervm_mgr
        LOG.debug(_("Attempting to resolve %s") % hostname)
        ip_addr = socket.gethostbyname(hostname)
        LOG.debug(_("%(hostname)s was successfully resolved to %(ip_addr)s") %
                  {'hostname': hostname, 'ip_addr': ip_addr})
        return ip_addr

    def snapshot(self, context, instance, image_id, update_task_state):
        """Snapshots the specified instance.

        :param context: security context
        :param instance: Instance object as returned by DB layer.
        :param image_id: Reference to a pre-created image that will
                         hold the snapshot.
        :param update_task_state: Function reference that allows for updates
                                  to the instance task state.
        """
        snapshot_start = time.time()

        # get current image info
        glance_service, old_image_id = glance.get_remote_image_service(
                context, instance['image_ref'])
        image_meta = glance_service.show(context, old_image_id)
        img_props = image_meta['properties']

        # build updated snapshot metadata
        snapshot_meta = glance_service.show(context, image_id)
        new_snapshot_meta = {'is_public': False,
                             'name': snapshot_meta['name'],
                             'status': 'active',
                             'properties': {'image_location': 'snapshot',
                                            'image_state': 'available',
                                            'owner_id': instance['project_id']
                                           },
                             'disk_format': image_meta['disk_format'],
                             'container_format': image_meta['container_format']
                            }

        # disk capture and glance upload
        self._powervm.capture_image(context, instance, image_id,
                                    new_snapshot_meta, update_task_state)

        snapshot_time = time.time() - snapshot_start
        inst_name = instance['name']
        LOG.info(_("%(inst_name)s captured in %(snapshot_time)s seconds"),
                 {'inst_name': inst_name, 'snapshot_time': snapshot_time})

    def pause(self, instance):
        """Pause the specified instance."""
        msg = _("pause is not supported for PowerVM")
        raise NotImplementedError(msg)

    def unpause(self, instance):
        """Unpause paused VM instance."""
        msg = _("unpause is not supported for PowerVM")
        raise NotImplementedError(msg)

    def suspend(self, instance):
        """suspend the specified instance."""
        pass

    def resume(self, instance, network_info, block_device_info=None):
        """resume the specified instance."""
        pass

    def power_off(self, instance):
        """Power off the specified instance."""
        self._powervm.power_off(instance['name'])

    def power_on(self, context, instance, network_info,
                 block_device_info=None):
        """Power on the specified instance."""
        self._powervm.power_on(instance['name'])

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

    def host_power_action(self, host, action):
        """Reboots, shuts down or powers up the host."""
        pass

    def legacy_nwinfo(self):
        """
        Indicate if the driver requires the legacy network_info format.
        """
        return False

    def manage_image_cache(self, context, all_instances):
        """
        Manage the driver's local image cache.

        Some drivers chose to cache images for instances on disk. This method
        is an opportunity to do management of that cache which isn't directly
        related to other calls into the driver. The prime example is to clean
        the cache and remove images which are no longer of interest.
        """
        pass

    def migrate_disk_and_power_off(self, context, instance, dest,
                                   instance_type, network_info,
                                   block_device_info=None):
        """Transfers the disk of a running instance in multiple phases, turning
           off the instance before the end.

        :returns: disk_info dictionary that is passed as the
                  disk_info parameter to finish_migration
                  on the destination nova-compute host
        """
        src_host = self.get_host_ip_addr()
        pvm_op = self._powervm._operator
        lpar_obj = pvm_op.get_lpar(instance['name'])
        vhost = pvm_op.get_vhost_by_instance_id(lpar_obj['lpar_id'])
        diskname = pvm_op.get_disk_name_by_vhost(vhost)

        self._powervm.power_off(instance['name'], timeout=120)
        # NOTE(ldbragst) Here we need to check if the resize or migrate is
        # happening on the same host. If yes, then we need to assign a temp
        # mac address to the source LPAR so we don't have a conflict when
        # another LPAR is booted with the same mac address as the
        # original LPAR
        if src_host == dest:
            macs = self.macs_for_instance(instance)
            temp_mac = macs.pop()
            self._powervm._operator.set_lpar_mac_base_value(instance['name'],
                                                            temp_mac)

        disk_info = self._powervm.migrate_disk(
                diskname, src_host, dest, CONF.powervm_img_remote_path,
                instance['name'])
        disk_info['old_lv_size'] = pvm_op.get_logical_vol_size(diskname)
        new_name = self._get_resize_name(instance['name'])
        pvm_op.rename_lpar(instance['name'], new_name)
        return disk_info

    def _get_resize_name(self, instance_name):
        """Rename the instance to be migrated to avoid naming conflicts

        :param instance_name: name of instance to be migrated
        :returns: the new instance name
        """
        name_tag = 'rsz_'

        # if the current name would overflow with new tag
        if ((len(instance_name) + len(name_tag)) > 31):
            # remove enough chars for the tag to fit
            num_chars = len(name_tag)
            old_name = instance_name[num_chars:]
        else:
            old_name = instance_name

        return ''.join([name_tag, old_name])

    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

        :param network_info:
           :py:meth:`~nova.network.manager.NetworkManager.get_instance_nw_info`
        :param image_meta: image object returned by nova.image.glance that
                           defines the image from which this instance
                           was created
        """
        lpar_obj = self._powervm._create_lpar_instance(instance, network_info)

        instance_type = flavors.extract_flavor(instance)
        new_lv_size = instance_type['root_gb']
        old_lv_size = disk_info['old_lv_size']
        if 'root_disk_file' in disk_info:
            disk_size = max(int(new_lv_size), int(old_lv_size))
            disk_size_bytes = disk_size * 1024 * 1024 * 1024
            self._powervm.deploy_from_migrated_file(
                    lpar_obj, disk_info['root_disk_file'], disk_size_bytes,
                    power_on)
        else:
            # this shouldn't get hit unless someone forgot to handle
            # a certain migration type
            raise exception.PowerVMUnrecognizedRootDevice(disk_info=disk_info)

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

        new_name = self._get_resize_name(instance['name'])
        self._powervm.destroy(new_name)

    def finish_revert_migration(self, instance, network_info,
                                block_device_info=None, power_on=True):
        """Finish reverting a resize."""

        new_name = self._get_resize_name(instance['name'])

        # NOTE(ldbragst) In the case of a resize_revert on the same host
        # we reassign the original mac address, replacing the temp mac
        # on the old instance that will be started
        # NOTE(guochbo) We can't judge if a resize_revert on the same host
        # due to the instance on destination host has been destoryed.
        # Original mac address is always kept in network_info, we can
        # reassign the original mac address here without negative effects
        # even the old instance kept the original mac address
        if self.instance_exists(new_name):
            original_mac = network_info[0]['address']
            self._powervm._operator.set_lpar_mac_base_value(new_name,
                                                            original_mac)
        # Make sure we don't have a failed same-host migration still
        # hanging around
            if self.instance_exists(instance['name']):
                self._powervm.destroy(instance['name'])
            # undo instance rename and start
            self._powervm._operator.rename_lpar(new_name, instance['name'])

        if power_on:
            self._powervm.power_on(instance['name'])

    def add_to_aggregate(self, context, aggregate, host, **kwargs):
        """Add a compute host to an aggregate."""
        pass

    def remove_from_aggregate(self, context, aggregate, host, **kwargs):
        """Remove a compute host from an aggregate."""
        pass

    def undo_aggregate_operation(self, context, op, aggregate,
                                  host, set_error=True):
        """Undo for Resource Pools."""
        pass
