from sqlalchemy import *
from sqlalchemy import orm
from sqlalchemy.orm import create_session, relation

from sqlalchemy.ext.sessioncontext import SessionContext
from sqlalchemy.ext.assignmapper import assign_mapper

__all__ = ['meta',
           'session',
           'clear_cache',
           'machine_table',
           'machine_access_table',
           'nic_table',
           'disk_table',
           'types_table',
           'cdroms_table',
           'autoinstalls_table',
           'Machine',
           'MachineAccess',
           'NIC',
           'Disk',
           'Type',
           'CDROM',
           'Autoinstall',
           'or_',
           ]

meta = ThreadLocalMetaData()
session = orm.scoped_session(orm.sessionmaker())

machine_table = Table('machines', meta,
       Column('machine_id', Integer, primary_key=True, nullable=False),
       Column('name', String, nullable=False),
       Column('description', String, nullable=False),
       Column('memory', Integer, nullable=False),
       Column('owner', String, nullable=False),
       Column('contact', String, nullable=False),
       Column('uuid', String, nullable=False),
       Column('administrator', String, nullable=False, default=False),
       Column('type_id', String, ForeignKey('types.type_id'), nullable=False),
       Column('autorestart', Boolean, nullable=False, default=False),
       Column('cpus', Integer, nullable=False, default=1),
       Column('adminable', Boolean, nullable=False, default=False))

nic_table = Table('nics', meta,
       Column('machine_id', Integer, ForeignKey('machines.machine_id'), nullable=True),
       Column('mac_addr', String, nullable=False, primary_key=True),
       Column('ip', String, nullable=False, unique=True),
       Column('hostname', String, nullable=True))

disk_table = Table('disks', meta,
       Column('machine_id', Integer, ForeignKey('machines.machine_id'), nullable=False),
       Column('guest_device_name', String, nullable=False),
       Column('size', Integer, nullable=False),
       PrimaryKeyConstraint('machine_id', 'guest_device_name'))

types_table = Table('types', meta,
       Column('type_id', String, primary_key=True, nullable=False),
       Column('description', String, nullable=False),
       Column('hvm', Boolean, nullable=False),
       Column('apic', Boolean, nullable=False),
       Column('acpi', Boolean, nullable=False),
       Column('pae', Boolean, nullable=False))

cdroms_table = Table('cdroms', meta,
       Column('cdrom_id', String, primary_key=True, nullable=False),
       Column('description', String, nullable=False))

autoinstalls_table = Table('autoinstalls', meta,
       Column('autoinstall_id', String, primary_key=True, nullable=False),
       Column('description', String, nullable=False),
       Column('type_id', String, ForeignKey('types.type_id'), nullable=False),
       Column('distribution', String, nullable=False),
       Column('mirror', String, nullable=False))

machine_access_table = Table('machine_access', meta,
       Column('machine_id', Integer, ForeignKey('machines.machine_id'), nullable=False, index=True),
       Column('user', String, nullable=False, index=True),
       PrimaryKeyConstraint('machine_id', 'user', ondelete='CASCADE'))

class Machine(object):
    def __repr__(self):
        return "<Machine %s: name='%s' owner='%s'>" % (self.machine_id, self.name, self.owner)

class MachineAccess(object):
    def __repr__(self):
        return "<MachineAccess machine='%s' user='%s'>" % (self.machine, self.user)

class NIC(object):
    def __repr__(self):
        return "<NIC: mac='%s' machine='%s' ip='%s' hostname='%s'>" % (self.mac_addr, self.machine_id, self.ip, self.hostname)

class Disk(object):
    def __repr__(self):
        return "<Disk: machine=%s device=%s size=%s>" % (self.machine_id, self.guest_device_name, self.size)

class Type(object):
    def __repr__(self):
        return "<Type %s: %s>" % (self.type_id, self.description)

class CDROM(object):
    def __repr__(self):
        return "<CDROM %s: %s>" % (self.cdrom_id, self.description)

class Autoinstall(object):
    def __repr__(self):
        return "<Autoinstall %s: %s (%s)>" % (self.autoinstall_id, self.description, self.type.type_id)

session.mapper(Machine, machine_table,
              properties={'nics': relation(NIC, backref="machine", lazy=False),
                          'disks': relation(Disk, backref="machine", lazy=False),
                          'type': relation(Type, lazy=False),
                          'acl': relation(MachineAccess, backref="machine", lazy=False, passive_deletes=True, cascade="all, delete-orphan")});
session.mapper(MachineAccess, machine_access_table)
session.mapper(NIC, nic_table)
session.mapper(Disk, disk_table)
session.mapper(Type, types_table)
session.mapper(CDROM, cdroms_table)
session.mapper(Autoinstall, autoinstalls_table)

def clear_cache():
    """Clear sqlalchemy's cache.

    This _seems_ to be the way; it works, but the docs don't mention
    it.  Why is this so obscure?"""

    # XXX maybe we still need to do this, but it's not doc'd how.
    #ctx.registry.clear()