/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * 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, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY 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
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.sql;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.hibernate.internal.util.StringHelper;

/**
 * An SQL IN expression.
 * <br>
 * <code>... in(...)</code>
 * <br>
 * @author Gavin King
 */
public class InFragment {

	public static final String NULL = "null";
	public static final String NOT_NULL = "not null";

	private String columnName;
	private List values = new ArrayList();

	/**
	 * @param value, an SQL literal, NULL, or NOT_NULL
	 */
	public InFragment addValue(Object value) {
		values.add(value);
		return this;
	}

	public InFragment setColumn(String columnName) {
		this.columnName = columnName;
		return this;
	}

	public InFragment setColumn(String alias, String columnName) {
		this.columnName = StringHelper.qualify( alias, columnName );
		return setColumn(this.columnName);
	}

	public InFragment setFormula(String alias, String formulaTemplate) {
		this.columnName = StringHelper.replace(formulaTemplate, Template.TEMPLATE, alias);
		return setColumn(this.columnName);
	}

	public String toFragmentString() {

                if (values.size() == 0) {
                   return "1=2";
                }

                StringBuilder buf = new StringBuilder(values.size() * 5);

                if (values.size() == 1) {
                   Object value = values.get(0);
                   buf.append(columnName);

                   if (NULL.equals(value)) {
                      buf.append(" is null");
                   } else {
                      if (NOT_NULL.equals(value)) {
                         buf.append(" is not null");
                      } else {
                         buf.append('=').append(value);
                      }
                   }
                   return buf.toString();
                }
                   
                boolean allowNull = false;

                for (Object value : values) {
                   if (NULL.equals(value)) {
                      allowNull = true;
                   } else {
                      if (NOT_NULL.equals(value)) {
                         throw new IllegalArgumentException("not null makes no sense for in expression");
                      }
                   }
                }

                if (allowNull) {
                   buf.append('(').append(columnName).append(" is null or ").append(columnName).append(" in (");
                } else {
                   buf.append(columnName).append(" in (");
                }

                for (Object value : values) {
                   if (NULL.equals(value)) {
                      ;
                   } else {
                      buf.append(value);
                      buf.append(", ");
                   }
                }

                buf.setLength(buf.length() - 2);

                if (allowNull) {
                   buf.append("))");
                } else {
                   buf.append(')');
                }

                return buf.toString();

	}
}