/* Copyright 2004-2005 the original author or authors.
 *
 * 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.
 */
package grails.orm;

import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.criterion.CriteriaQuery;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.MatchMode;
import org.hibernate.dialect.*;
import org.hibernate.engine.TypedValue;

/**
 * 
 * Adds support for rlike to Hibernate in supported dialects
 *
 * @author Graeme Rocher
 * @since 1.1.1
 */
public class RlikeExpression implements Criterion
{
    private final String propertyName;
    private final Object value;

    public RlikeExpression(String propertyName, Object value) {
        this.propertyName = propertyName;
        this.value = value;
    }

    public RlikeExpression(String propertyName, String value, MatchMode matchMode) {
        this( propertyName, matchMode.toMatchString(value) );
    }

    public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery)
    throws HibernateException {
        Dialect dialect = criteriaQuery.getFactory().getDialect();
        String[] columns = criteriaQuery.getColumnsUsingProjection(criteria, propertyName);
        if (columns.length!=1) throw new HibernateException("ilike may only be used with single-column properties");
        if ( dialect instanceof MySQLDialect) {
            return columns[0] + " rlike ?";

        }
        else if (isOracleDialect(dialect))
        {
            return " REGEXP_LIKE ( " + columns[0] + ", ? )";
        }
        else
        {
            return columns[0] + " like ?";
        }
    }

    private boolean isOracleDialect(Dialect dialect) {
        return (dialect instanceof Oracle8iDialect);
    }

    public TypedValue[] getTypedValues(Criteria criteria, CriteriaQuery criteriaQuery)
    throws HibernateException {
        return new TypedValue[] { criteriaQuery.getTypedValue( criteria, propertyName, value.toString().toLowerCase() ) };
    }

    public String toString() {
        return propertyName + " rlike " + value;
    }

}
