/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * JBoss, Home of Professional Open Source
 * Copyright 2011 Red Hat Inc. and/or its affiliates and other contributors
 * as indicated by the @authors tag. All rights reserved.
 * See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License, v. 2.1.
 * This program is distributed in the hope that it will be useful, but WITHOUT A
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License,
 * v.2.1 along with this distribution; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 */
package org.hibernate.search.query.hibernate.impl;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import org.hibernate.search.engine.spi.DocumentBuilderIndexedEntity;
import org.hibernate.search.engine.spi.SearchFactoryImplementor;
import org.hibernate.search.util.logging.impl.Log;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.Disjunction;
import org.hibernate.criterion.Restrictions;
import org.hibernate.search.query.engine.spi.EntityInfo;
import org.hibernate.search.query.engine.spi.TimeoutManager;
import org.hibernate.search.util.logging.impl.LoggerFactory;

/**
 * Initialize object using one or several criteria queries.
 *
 * @author Emmanuel Bernard <emmanuel@hibernate.org>
 */
public class CriteriaObjectsInitializer implements ObjectsInitializer {

	private static final Log log = LoggerFactory.make();
	private static final int MAX_IN_CLAUSE = 500;
	
	public static final CriteriaObjectsInitializer INSTANCE = new CriteriaObjectsInitializer();
	
	private CriteriaObjectsInitializer() {
		// use INSTANCE instead of constructor
	}

	public void initializeObjects(EntityInfo[] entityInfos,
										 Criteria criteria, Class<?> entityType,
										 SearchFactoryImplementor searchFactoryImplementor,
										 TimeoutManager timeoutManager,
										 Session session) {
		//Do not call isTimeOut here as the caller might be the last biggie on the list.
		final int maxResults = entityInfos.length;
		if ( log.isTraceEnabled() ) log.tracef( "Load %d objects using criteria queries", maxResults );

		if ( maxResults == 0 ) {
			return;
		}

		//criteria query not overridden, define one
		if ( criteria == null ) {
			criteria = session.createCriteria( entityType );
		}

		Set<Class<?>> indexedEntities = searchFactoryImplementor.getIndexedTypesPolymorphic( new Class<?>[] { entityType } );
		DocumentBuilderIndexedEntity<?> builder = searchFactoryImplementor.getIndexBindingForEntity(
				indexedEntities.iterator().next()
		).getDocumentBuilder();
		String idName = builder.getIdentifierName();
		Disjunction disjunction = Restrictions.disjunction();

		int loop = maxResults / MAX_IN_CLAUSE;
		boolean exact = maxResults % MAX_IN_CLAUSE == 0;
		if ( !exact ) {
			loop++;
		}
		for ( int index = 0; index < loop; index++ ) {
			int max = index * MAX_IN_CLAUSE + MAX_IN_CLAUSE <= maxResults ?
					index * MAX_IN_CLAUSE + MAX_IN_CLAUSE :
					maxResults;
			List<Serializable> ids = new ArrayList<Serializable>( max - index * MAX_IN_CLAUSE );
			for ( int entityInfoIndex = index * MAX_IN_CLAUSE; entityInfoIndex < max; entityInfoIndex++ ) {
				ids.add( entityInfos[entityInfoIndex].getId() );
			}
			disjunction.add( Restrictions.in( idName, ids ) );
		}
		criteria.add( disjunction );
		//not best effort so fail fast
		if ( timeoutManager.getType() != TimeoutManager.Type.LIMIT ) {
			Long timeLeftInSecond = timeoutManager.getTimeoutLeftInSeconds();
			if ( timeLeftInSecond != null ) {
				if (timeLeftInSecond == 0) {
					timeoutManager.reactOnQueryTimeoutExceptionWhileExtracting(null);
				}
				criteria.setTimeout( timeLeftInSecond.intValue() );
			}
		}
		criteria.list(); //load all objects
	}
}