"""
Migration script to add 'workflow' and 'history' columns for a sample.
"""

from sqlalchemy import *
from sqlalchemy.orm import *
from migrate import *
from migrate.changeset import *
from galaxy.model.custom_types import *

import logging
log = logging.getLogger( __name__ )

metadata = MetaData()

def upgrade(migrate_engine):
    metadata.bind = migrate_engine
    print __doc__
    metadata.reflect()
    try:
        Sample_table = Table( "sample", metadata, autoload=True )
        c1 = Column( "workflow", JSONType, nullable=True )
        c2 = Column( "history_id", Integer, ForeignKey( "history.id" ), nullable=True)
        c1.create( Sample_table )
        c2.create( Sample_table )
        assert c1 is Sample_table.c.workflow
        assert c2 is Sample_table.c.history_id
    except Exception, e:
        print "Adding history and workflow columns to sample table failed: %s" % str( e )
        log.debug( "Adding history and workflow columns to sample table failed: %s" % str( e ) )

def downgrade(migrate_engine):
    metadata.bind = migrate_engine
    metadata.reflect()
    try:
        Sample_table = Table( "sample", metadata, autoload=True )
        Sample_table.c.workflow.drop()
    except Exception, e:
        print "Dropping workflow column from sample table failed: %s" % str( e )
        log.debug( "Dropping workflow column from sample table failed: %s" % str( e ) )
    try:
        Sample_table = Table( "sample", metadata, autoload=True )
        Sample_table.c.history_id.drop()
    except Exception, e:
        print "Dropping history column from sample table failed: %s" % str( e )
        log.debug( "Dropping history column from sample table failed: %s" % str( e ) )