# Copyright 2011 Justin Santa Barbara
# 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.

"""The volumes extension."""

from oslo_utils import strutils
from webob import exc

from nova.api.openstack import common
from nova.api.openstack.compute.schemas.v3 import volumes as volumes_schema
from nova.api.openstack import extensions
from nova.api.openstack import wsgi
from nova.api import validation
from nova import compute
from nova import exception
from nova.i18n import _
from nova import objects
from nova import volume

ALIAS = "os-volumes"
authorize = extensions.os_compute_authorizer(ALIAS)
authorize_attach = extensions.os_compute_authorizer('os-volumes-attachments')


def _translate_volume_detail_view(context, vol):
    """Maps keys for volumes details view."""

    d = _translate_volume_summary_view(context, vol)

    # No additional data / lookups at the moment

    return d


def _translate_volume_summary_view(context, vol):
    """Maps keys for volumes summary view."""
    d = {}

    d['id'] = vol['id']
    d['status'] = vol['status']
    d['size'] = vol['size']
    d['availabilityZone'] = vol['availability_zone']
    d['createdAt'] = vol['created_at']

    if vol['attach_status'] == 'attached':
        d['attachments'] = [_translate_attachment_detail_view(vol['id'],
            vol['instance_uuid'],
            vol['mountpoint'])]
    else:
        d['attachments'] = [{}]

    d['displayName'] = vol['display_name']
    d['displayDescription'] = vol['display_description']

    if vol['volume_type_id'] and vol.get('volume_type'):
        d['volumeType'] = vol['volume_type']['name']
    else:
        d['volumeType'] = vol['volume_type_id']

    d['snapshotId'] = vol['snapshot_id']

    if vol.get('volume_metadata'):
        d['metadata'] = vol.get('volume_metadata')
    else:
        d['metadata'] = {}

    return d


class VolumeController(wsgi.Controller):
    """The Volumes API controller for the OpenStack API."""

    def __init__(self):
        self.volume_api = volume.API()
        super(VolumeController, self).__init__()

    @extensions.expected_errors(404)
    def show(self, req, id):
        """Return data about the given volume."""
        context = req.environ['nova.context']
        authorize(context)

        try:
            vol = self.volume_api.get(context, id)
        except exception.VolumeNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())

        return {'volume': _translate_volume_detail_view(context, vol)}

    @wsgi.response(202)
    @extensions.expected_errors(404)
    def delete(self, req, id):
        """Delete a volume."""
        context = req.environ['nova.context']
        authorize(context)

        try:
            self.volume_api.delete(context, id)
        except exception.VolumeNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())

    @extensions.expected_errors(())
    def index(self, req):
        """Returns a summary list of volumes."""
        return self._items(req, entity_maker=_translate_volume_summary_view)

    @extensions.expected_errors(())
    def detail(self, req):
        """Returns a detailed list of volumes."""
        return self._items(req, entity_maker=_translate_volume_detail_view)

    def _items(self, req, entity_maker):
        """Returns a list of volumes, transformed through entity_maker."""
        context = req.environ['nova.context']
        authorize(context)

        volumes = self.volume_api.get_all(context)
        limited_list = common.limited(volumes, req)
        res = [entity_maker(context, vol) for vol in limited_list]
        return {'volumes': res}

    @extensions.expected_errors(400)
    @validation.schema(volumes_schema.create)
    def create(self, req, body):
        """Creates a new volume."""
        context = req.environ['nova.context']
        authorize(context)

        vol = body['volume']

        vol_type = vol.get('volume_type')
        metadata = vol.get('metadata')
        snapshot_id = vol.get('snapshot_id', None)

        if snapshot_id is not None:
            snapshot = self.volume_api.get_snapshot(context, snapshot_id)
        else:
            snapshot = None

        size = vol.get('size', None)
        if size is None and snapshot is not None:
            size = snapshot['volume_size']

        availability_zone = vol.get('availability_zone')

        try:
            new_volume = self.volume_api.create(
                context,
                size,
                vol.get('display_name'),
                vol.get('display_description'),
                snapshot=snapshot,
                volume_type=vol_type,
                metadata=metadata,
                availability_zone=availability_zone
                )
        except exception.InvalidInput as err:
            raise exc.HTTPBadRequest(explanation=err.format_message())

        # TODO(vish): Instance should be None at db layer instead of
        #             trying to lazy load, but for now we turn it into
        #             a dict to avoid an error.
        retval = _translate_volume_detail_view(context, dict(new_volume))
        result = {'volume': retval}

        location = '%s/%s' % (req.url, new_volume['id'])

        return wsgi.ResponseObject(result, headers=dict(location=location))


def _translate_attachment_detail_view(volume_id, instance_uuid, mountpoint):
    """Maps keys for attachment details view."""

    d = _translate_attachment_summary_view(volume_id,
            instance_uuid,
            mountpoint)

    # No additional data / lookups at the moment
    return d


def _translate_attachment_summary_view(volume_id, instance_uuid, mountpoint):
    """Maps keys for attachment summary view."""
    d = {}

    # NOTE(justinsb): We use the volume id as the id of the attachment object
    d['id'] = volume_id

    d['volumeId'] = volume_id

    d['serverId'] = instance_uuid
    if mountpoint:
        d['device'] = mountpoint

    return d


class VolumeAttachmentController(wsgi.Controller):
    """The volume attachment API controller for the OpenStack API.

    A child resource of the server.  Note that we use the volume id
    as the ID of the attachment (though this is not guaranteed externally)

    """

    def __init__(self):
        self.compute_api = compute.API(skip_policy_check=True)
        self.volume_api = volume.API()
        super(VolumeAttachmentController, self).__init__()

    @extensions.expected_errors(404)
    def index(self, req, server_id):
        """Returns the list of volume attachments for a given instance."""
        context = req.environ['nova.context']
        authorize_attach(context, action='index')
        return self._items(req, server_id,
                           entity_maker=_translate_attachment_summary_view)

    @extensions.expected_errors(404)
    def show(self, req, server_id, id):
        """Return data about the given volume attachment."""
        context = req.environ['nova.context']
        authorize(context)
        authorize_attach(context, action='show')

        volume_id = id
        instance = common.get_instance(self.compute_api, context, server_id)

        bdms = objects.BlockDeviceMappingList.get_by_instance_uuid(
                context, instance.uuid)

        if not bdms:
            msg = _("Instance %s is not attached.") % server_id
            raise exc.HTTPNotFound(explanation=msg)

        assigned_mountpoint = None

        for bdm in bdms:
            if bdm.volume_id == volume_id:
                assigned_mountpoint = bdm.device_name
                break

        if assigned_mountpoint is None:
            msg = _("volume_id not found: %s") % volume_id
            raise exc.HTTPNotFound(explanation=msg)

        return {'volumeAttachment': _translate_attachment_detail_view(
            volume_id,
            instance.uuid,
            assigned_mountpoint)}

    @extensions.expected_errors((400, 404, 409))
    @validation.schema(volumes_schema.create_volume_attachment)
    def create(self, req, server_id, body):
        """Attach a volume to an instance."""
        context = req.environ['nova.context']
        authorize(context)
        authorize_attach(context, action='create')

        volume_id = body['volumeAttachment']['volumeId']
        device = body['volumeAttachment'].get('device')

        instance = common.get_instance(self.compute_api, context, server_id)
        try:
            device = self.compute_api.attach_volume(context, instance,
                                                    volume_id, device)
        except exception.VolumeNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())
        except exception.InstanceIsLocked as e:
            raise exc.HTTPConflict(explanation=e.format_message())
        except exception.InstanceInvalidState as state_error:
            common.raise_http_conflict_for_instance_invalid_state(state_error,
                    'attach_volume', server_id)
        except (exception.InvalidVolume,
                exception.InvalidDevicePath) as e:
            raise exc.HTTPBadRequest(explanation=e.format_message())

        # The attach is async
        attachment = {}
        attachment['id'] = volume_id
        attachment['serverId'] = server_id
        attachment['volumeId'] = volume_id
        attachment['device'] = device

        # NOTE(justinsb): And now, we have a problem...
        # The attach is async, so there's a window in which we don't see
        # the attachment (until the attachment completes).  We could also
        # get problems with concurrent requests.  I think we need an
        # attachment state, and to write to the DB here, but that's a bigger
        # change.
        # For now, we'll probably have to rely on libraries being smart

        # TODO(justinsb): How do I return "accepted" here?
        return {'volumeAttachment': attachment}

    @wsgi.response(202)
    @extensions.expected_errors((400, 404, 409))
    @validation.schema(volumes_schema.update_volume_attachment)
    def update(self, req, server_id, id, body):
        context = req.environ['nova.context']
        authorize(context)
        authorize_attach(context, action='update')

        old_volume_id = id
        try:
            old_volume = self.volume_api.get(context, old_volume_id)

            new_volume_id = body['volumeAttachment']['volumeId']
            new_volume = self.volume_api.get(context, new_volume_id)
        except exception.VolumeNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())

        instance = common.get_instance(self.compute_api, context, server_id)

        bdms = objects.BlockDeviceMappingList.get_by_instance_uuid(
                context, instance.uuid)
        found = False
        try:
            for bdm in bdms:
                if bdm.volume_id != old_volume_id:
                    continue
                try:
                    self.compute_api.swap_volume(context, instance, old_volume,
                                                 new_volume)
                    found = True
                    break
                except exception.VolumeUnattached:
                    # The volume is not attached.  Treat it as NotFound
                    # by falling through.
                    pass
                except exception.InvalidVolume as e:
                    raise exc.HTTPBadRequest(explanation=e.format_message())
        except exception.InstanceIsLocked as e:
            raise exc.HTTPConflict(explanation=e.format_message())
        except exception.InstanceInvalidState as state_error:
            common.raise_http_conflict_for_instance_invalid_state(state_error,
                    'swap_volume', server_id)

        if not found:
            msg = _("The volume was either invalid or not attached to the "
                    "instance.")
            raise exc.HTTPNotFound(explanation=msg)

    @wsgi.response(202)
    @extensions.expected_errors((400, 403, 404, 409))
    def delete(self, req, server_id, id):
        """Detach a volume from an instance."""
        context = req.environ['nova.context']
        authorize(context)
        authorize_attach(context, action='delete')

        volume_id = id

        instance = common.get_instance(self.compute_api, context, server_id)

        try:
            volume = self.volume_api.get(context, volume_id)
        except exception.VolumeNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())

        bdms = objects.BlockDeviceMappingList.get_by_instance_uuid(
                context, instance.uuid)
        if not bdms:
            msg = _("Instance %s is not attached.") % server_id
            raise exc.HTTPNotFound(explanation=msg)

        found = False
        try:
            for bdm in bdms:
                if bdm.volume_id != volume_id:
                    continue
                if bdm.is_root:
                    msg = _("Can't detach root device volume")
                    raise exc.HTTPForbidden(explanation=msg)
                try:
                    self.compute_api.detach_volume(context, instance, volume)
                    found = True
                    break
                except exception.VolumeUnattached:
                    # The volume is not attached.  Treat it as NotFound
                    # by falling through.
                    pass
                except exception.InvalidVolume as e:
                    raise exc.HTTPBadRequest(explanation=e.format_message())

        except exception.InstanceIsLocked as e:
            raise exc.HTTPConflict(explanation=e.format_message())
        except exception.InstanceInvalidState as state_error:
            common.raise_http_conflict_for_instance_invalid_state(state_error,
                    'detach_volume', server_id)

        if not found:
            msg = _("volume_id not found: %s") % volume_id
            raise exc.HTTPNotFound(explanation=msg)

    def _items(self, req, server_id, entity_maker):
        """Returns a list of attachments, transformed through entity_maker."""
        context = req.environ['nova.context']
        authorize(context)

        instance = common.get_instance(self.compute_api, context, server_id)

        bdms = objects.BlockDeviceMappingList.get_by_instance_uuid(
                context, instance.uuid)
        limited_list = common.limited(bdms, req)
        results = []

        for bdm in limited_list:
            if bdm.volume_id:
                results.append(entity_maker(bdm.volume_id,
                                            bdm.instance_uuid,
                                            bdm.device_name))

        return {'volumeAttachments': results}


def _translate_snapshot_detail_view(context, vol):
    """Maps keys for snapshots details view."""

    d = _translate_snapshot_summary_view(context, vol)

    # NOTE(gagupta): No additional data / lookups at the moment
    return d


def _translate_snapshot_summary_view(context, vol):
    """Maps keys for snapshots summary view."""
    d = {}

    d['id'] = vol['id']
    d['volumeId'] = vol['volume_id']
    d['status'] = vol['status']
    # NOTE(gagupta): We map volume_size as the snapshot size
    d['size'] = vol['volume_size']
    d['createdAt'] = vol['created_at']
    d['displayName'] = vol['display_name']
    d['displayDescription'] = vol['display_description']
    return d


class SnapshotController(wsgi.Controller):
    """The Snapshots API controller for the OpenStack API."""

    def __init__(self):
        self.volume_api = volume.API()
        super(SnapshotController, self).__init__()

    @extensions.expected_errors(404)
    def show(self, req, id):
        """Return data about the given snapshot."""
        context = req.environ['nova.context']
        authorize(context)

        try:
            vol = self.volume_api.get_snapshot(context, id)
        except exception.SnapshotNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())

        return {'snapshot': _translate_snapshot_detail_view(context, vol)}

    @wsgi.response(202)
    @extensions.expected_errors(404)
    def delete(self, req, id):
        """Delete a snapshot."""
        context = req.environ['nova.context']
        authorize(context)

        try:
            self.volume_api.delete_snapshot(context, id)
        except exception.SnapshotNotFound as e:
            raise exc.HTTPNotFound(explanation=e.format_message())

    @extensions.expected_errors(())
    def index(self, req):
        """Returns a summary list of snapshots."""
        return self._items(req, entity_maker=_translate_snapshot_summary_view)

    @extensions.expected_errors(())
    def detail(self, req):
        """Returns a detailed list of snapshots."""
        return self._items(req, entity_maker=_translate_snapshot_detail_view)

    def _items(self, req, entity_maker):
        """Returns a list of snapshots, transformed through entity_maker."""
        context = req.environ['nova.context']
        authorize(context)

        snapshots = self.volume_api.get_all_snapshots(context)
        limited_list = common.limited(snapshots, req)
        res = [entity_maker(context, snapshot) for snapshot in limited_list]
        return {'snapshots': res}

    @extensions.expected_errors(400)
    @validation.schema(volumes_schema.snapshot_create)
    def create(self, req, body):
        """Creates a new snapshot."""
        context = req.environ['nova.context']
        authorize(context)

        snapshot = body['snapshot']
        volume_id = snapshot['volume_id']

        force = snapshot.get('force', False)
        force = strutils.bool_from_string(force, strict=True)
        if force:
            create_func = self.volume_api.create_snapshot_force
        else:
            create_func = self.volume_api.create_snapshot

        new_snapshot = create_func(context, volume_id,
                                   snapshot.get('display_name'),
                                   snapshot.get('display_description'))

        retval = _translate_snapshot_detail_view(context, new_snapshot)
        return {'snapshot': retval}


class Volumes(extensions.V3APIExtensionBase):
    """Volumes support."""

    name = "Volumes"
    alias = ALIAS
    version = 1

    def get_resources(self):
        resources = []

        res = extensions.ResourceExtension(
            ALIAS, VolumeController(), collection_actions={'detail': 'GET'})
        resources.append(res)

        res = extensions.ResourceExtension('os-volumes_boot',
                                           inherits='servers')
        resources.append(res)

        res = extensions.ResourceExtension('os-volume_attachments',
                                           VolumeAttachmentController(),
                                           parent=dict(
                                                member_name='server',
                                                collection_name='servers'))
        resources.append(res)

        res = extensions.ResourceExtension(
            'os-snapshots', SnapshotController(),
            collection_actions={'detail': 'GET'})
        resources.append(res)

        return resources

    def get_controller_extensions(self):
        return []
