# -*- coding: utf-8 -*-

#    Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
#    Copyright (C) 2013 Rackspace Hosting Inc. 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.

from oslo.serialization import jsonutils
from oslo_utils import timeutils
from oslo_utils import uuidutils
from sqlalchemy import Column, String, DateTime, Enum
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import ForeignKey
from sqlalchemy.orm import backref
from sqlalchemy.orm import relationship
from sqlalchemy import types as types

from taskflow.persistence import logbook
from taskflow import states

BASE = declarative_base()


# TODO(harlowja): remove when oslo.db exists
class TimestampMixin(object):
    created_at = Column(DateTime, default=timeutils.utcnow)
    updated_at = Column(DateTime, onupdate=timeutils.utcnow)


class Json(types.TypeDecorator):
    impl = types.Text

    def process_bind_param(self, value, dialect):
        return jsonutils.dumps(value)

    def process_result_value(self, value, dialect):
        return jsonutils.loads(value)


class ModelBase(TimestampMixin):
    """Base model for all taskflow objects."""
    uuid = Column(String, default=uuidutils.generate_uuid,
                  primary_key=True, nullable=False, unique=True)
    name = Column(String, nullable=True)
    meta = Column(Json, nullable=True)


class LogBook(BASE, ModelBase):
    """Represents a logbook for a set of flows."""
    __tablename__ = 'logbooks'

    # Relationships
    flowdetails = relationship("FlowDetail",
                               single_parent=True,
                               backref=backref("logbooks",
                                               cascade="save-update, delete, "
                                                       "merge"))


class FlowDetail(BASE, ModelBase):
    __tablename__ = 'flowdetails'

    # Member variables
    state = Column(String)

    # Relationships
    parent_uuid = Column(String, ForeignKey('logbooks.uuid'))
    atomdetails = relationship("AtomDetail",
                               single_parent=True,
                               backref=backref("flowdetails",
                                               cascade="save-update, delete, "
                                                       "merge"))


class AtomDetail(BASE, ModelBase):
    __tablename__ = 'atomdetails'

    # Member variables
    atom_type = Column(Enum(*logbook.ATOM_TYPES, name='atom_types'))
    state = Column(String)
    intention = Column(Enum(*states.INTENTIONS, name='intentions'))
    results = Column(Json)
    failure = Column(Json)
    version = Column(Json)

    # Relationships
    parent_uuid = Column(String, ForeignKey('flowdetails.uuid'))