#    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.


from oslo_db.sqlalchemy import models
from sqlalchemy import Boolean
from sqlalchemy import Column
from sqlalchemy import DateTime
from sqlalchemy.dialects.mysql import MEDIUMTEXT
from sqlalchemy import Enum
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Float
from sqlalchemy import ForeignKey
from sqlalchemy import Index
from sqlalchemy import Integer
from sqlalchemy import orm
from sqlalchemy.orm import backref
from sqlalchemy import schema
from sqlalchemy import String
from sqlalchemy import Text
from sqlalchemy import Unicode


def MediumText():
    return Text().with_variant(MEDIUMTEXT(), 'mysql')


class _NovaAPIBase(models.ModelBase, models.TimestampMixin):
    pass


API_BASE = declarative_base(cls=_NovaAPIBase)


class AggregateHost(API_BASE):
    """Represents a host that is member of an aggregate."""
    __tablename__ = 'aggregate_hosts'
    __table_args__ = (schema.UniqueConstraint(
        "host", "aggregate_id",
         name="uniq_aggregate_hosts0host0aggregate_id"
        ),
    )
    id = Column(Integer, primary_key=True, autoincrement=True)
    host = Column(String(255))
    aggregate_id = Column(Integer, ForeignKey('aggregates.id'), nullable=False)


class AggregateMetadata(API_BASE):
    """Represents a metadata key/value pair for an aggregate."""
    __tablename__ = 'aggregate_metadata'
    __table_args__ = (
        schema.UniqueConstraint("aggregate_id", "key",
            name="uniq_aggregate_metadata0aggregate_id0key"
            ),
        Index('aggregate_metadata_key_idx', 'key'),
    )
    id = Column(Integer, primary_key=True)
    key = Column(String(255), nullable=False)
    value = Column(String(255), nullable=False)
    aggregate_id = Column(Integer, ForeignKey('aggregates.id'), nullable=False)


class Aggregate(API_BASE):
    """Represents a cluster of hosts that exists in this zone."""
    __tablename__ = 'aggregates'
    __table_args__ = (Index('aggregate_uuid_idx', 'uuid'),
                      schema.UniqueConstraint(
                      "name", name="uniq_aggregate0name")
        )
    id = Column(Integer, primary_key=True, autoincrement=True)
    uuid = Column(String(36))
    name = Column(String(255))
    _hosts = orm.relationship(AggregateHost,
                    primaryjoin='Aggregate.id == AggregateHost.aggregate_id',
                    cascade='delete')
    _metadata = orm.relationship(AggregateMetadata,
                primaryjoin='Aggregate.id == AggregateMetadata.aggregate_id',
                cascade='delete')

    @property
    def _extra_keys(self):
        return ['hosts', 'metadetails', 'availability_zone']

    @property
    def hosts(self):
        return [h.host for h in self._hosts]

    @property
    def metadetails(self):
        return {m.key: m.value for m in self._metadata}

    @property
    def availability_zone(self):
        if 'availability_zone' not in self.metadetails:
            return None
        return self.metadetails['availability_zone']


class CellMapping(API_BASE):
    """Contains information on communicating with a cell"""
    __tablename__ = 'cell_mappings'
    __table_args__ = (Index('uuid_idx', 'uuid'),
                      schema.UniqueConstraint('uuid',
                          name='uniq_cell_mappings0uuid'))

    id = Column(Integer, primary_key=True)
    uuid = Column(String(36), nullable=False)
    name = Column(String(255))
    transport_url = Column(Text())
    database_connection = Column(Text())
    host_mapping = orm.relationship('HostMapping',
                            backref=backref('cell_mapping', uselist=False),
                            foreign_keys=id,
                            primaryjoin=(
                                  'CellMapping.id == HostMapping.cell_id'))


class InstanceMapping(API_BASE):
    """Contains the mapping of an instance to which cell it is in"""
    __tablename__ = 'instance_mappings'
    __table_args__ = (Index('project_id_idx', 'project_id'),
                      Index('instance_uuid_idx', 'instance_uuid'),
                      schema.UniqueConstraint('instance_uuid',
                          name='uniq_instance_mappings0instance_uuid'))

    id = Column(Integer, primary_key=True)
    instance_uuid = Column(String(36), nullable=False)
    cell_id = Column(Integer, ForeignKey('cell_mappings.id'),
            nullable=True)
    project_id = Column(String(255), nullable=False)
    cell_mapping = orm.relationship('CellMapping',
            backref=backref('instance_mapping', uselist=False),
            foreign_keys=cell_id,
            primaryjoin=('InstanceMapping.cell_id == CellMapping.id'))


class HostMapping(API_BASE):
    """Contains mapping of a compute host to which cell it is in"""
    __tablename__ = "host_mappings"
    __table_args__ = (Index('host_idx', 'host'),
                      schema.UniqueConstraint('host',
                        name='uniq_host_mappings0host'))

    id = Column(Integer, primary_key=True)
    cell_id = Column(Integer, ForeignKey('cell_mappings.id'),
            nullable=False)
    host = Column(String(255), nullable=False)


class RequestSpec(API_BASE):
    """Represents the information passed to the scheduler."""

    __tablename__ = 'request_specs'
    __table_args__ = (
        Index('request_spec_instance_uuid_idx', 'instance_uuid'),
        schema.UniqueConstraint('instance_uuid',
            name='uniq_request_specs0instance_uuid'),
        )

    id = Column(Integer, primary_key=True)
    instance_uuid = Column(String(36), nullable=False)
    spec = Column(Text, nullable=False)


class Flavors(API_BASE):
    """Represents possible flavors for instances"""
    __tablename__ = 'flavors'
    __table_args__ = (
        schema.UniqueConstraint("flavorid", name="uniq_flavors0flavorid"),
        schema.UniqueConstraint("name", name="uniq_flavors0name"))

    id = Column(Integer, primary_key=True)
    name = Column(String(255), nullable=False)
    memory_mb = Column(Integer, nullable=False)
    vcpus = Column(Integer, nullable=False)
    root_gb = Column(Integer)
    ephemeral_gb = Column(Integer)
    flavorid = Column(String(255), nullable=False)
    swap = Column(Integer, nullable=False, default=0)