/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.dialect.function;

import java.util.List;

import org.hibernate.QueryException;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.type.StandardBasicTypes;
import org.hibernate.type.Type;

/**
 * A function that returns a {@link org.hibernate.type.StandardBasicTypes#TIMESTAMP}
 * with static fractional seconds precision (fsp).
 *
 * @author Gail Badner
 */
public class StaticPrecisionFspTimestampFunction extends NoArgSQLFunction {
	private final String renderedString;

	/**
	 * Constructs a {@link org.hibernate.type.StandardBasicTypes#TIMESTAMP} function using the
	 * default fractional second precision as defined by the database.
	 *
	 * @param name The function name
	 * @param hasParenthesesIfNoArguments Does the function call need parenthesis if there are no arguments?
	 */
	public StaticPrecisionFspTimestampFunction(String name, boolean hasParenthesesIfNoArguments) {
		super( name, StandardBasicTypes.TIMESTAMP, hasParenthesesIfNoArguments );
		renderedString = null;
	}

	/**
	 * Constructs a {@link org.hibernate.type.StandardBasicTypes#TIMESTAMP} function using
	 * the specified fractional seconds precision.
	 * @param name The function name
	 * @param fsp The explicit fractional seconds precision to render
	 *
	 * @throws java.lang.IllegalArgumentException if {@code fsp} < 0.
	 */
	public StaticPrecisionFspTimestampFunction(String name, int fsp) {
		super( name, StandardBasicTypes.TIMESTAMP);
		if ( fsp < 0 ) {
			throw new IllegalArgumentException( "fsp must be >= 0" );
		}
		renderedString = name + '(' + fsp + ')';
	}

	@Override
	public String render(Type argumentType, List args, SessionFactoryImplementor factory) throws QueryException {
		if ( args.size() > 0 ) {
			throw new QueryException( "function takes no arguments: " + getName() );
		}
		return renderedString == null ?
				super.render( argumentType, args, factory ) :
				renderedString;
	}
}