/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2009 by Red Hat Inc and/or its affiliates or by
 * third-party contributors as indicated by either @author tags or express
 * copyright attribution statements applied by the authors.  All
 * third-party contributions are distributed under license by Red Hat Inc.
 *
 * 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.jpa.criteria.expression.function;

import java.io.Serializable;
import javax.persistence.criteria.CriteriaBuilder.Trimspec;
import javax.persistence.criteria.Expression;

import org.hibernate.jpa.criteria.CriteriaBuilderImpl;
import org.hibernate.jpa.criteria.ParameterRegistry;
import org.hibernate.jpa.criteria.Renderable;
import org.hibernate.jpa.criteria.compile.RenderingContext;
import org.hibernate.jpa.criteria.expression.LiteralExpression;

Models the ANSI SQL TRIM function.
Author:
Steve Ebersole, Brett Meyer/**
 * Models the ANSI SQL <tt>TRIM</tt> function.
 *
 * @author Steve Ebersole
 * @author Brett Meyer
 */
public class TrimFunction
		extends BasicFunctionExpression<String>
		implements Serializable {
	public static final String NAME = "trim";
	public static final Trimspec DEFAULT_TRIMSPEC = Trimspec.BOTH;
	public static final char DEFAULT_TRIM_CHAR = ' ';

	private final Trimspec trimspec;
	private final Expression<Character> trimCharacter;
	private final Expression<String> trimSource;

	public TrimFunction(
			CriteriaBuilderImpl criteriaBuilder,
			Trimspec trimspec,
			Expression<Character> trimCharacter,
			Expression<String> trimSource) {
		super( criteriaBuilder, String.class, NAME );
		this.trimspec = trimspec;
		this.trimCharacter = trimCharacter;
		this.trimSource = trimSource;
	}

	public TrimFunction(
			CriteriaBuilderImpl criteriaBuilder,
			Trimspec trimspec,
			char trimCharacter,
			Expression<String> trimSource) {
		super( criteriaBuilder, String.class, NAME );
		this.trimspec = trimspec;
		this.trimCharacter = new LiteralExpression<Character>( criteriaBuilder, trimCharacter );
		this.trimSource = trimSource;
	}

	public TrimFunction(
			CriteriaBuilderImpl criteriaBuilder,
			Expression<String> trimSource) {
		this( criteriaBuilder, DEFAULT_TRIMSPEC, DEFAULT_TRIM_CHAR, trimSource );
	}

	public TrimFunction(
			CriteriaBuilderImpl criteriaBuilder,
			Expression<Character> trimCharacter,
			Expression<String> trimSource) {
		this( criteriaBuilder, DEFAULT_TRIMSPEC, trimCharacter, trimSource );
	}

	public TrimFunction(
			CriteriaBuilderImpl criteriaBuilder,
			char trimCharacter,
			Expression<String> trimSource) {
		this( criteriaBuilder, DEFAULT_TRIMSPEC, trimCharacter, trimSource );
	}

	public TrimFunction(
			CriteriaBuilderImpl criteriaBuilder,
			Trimspec trimspec,
			Expression<String> trimSource) {
		this( criteriaBuilder, trimspec, DEFAULT_TRIM_CHAR, trimSource );
	}

	public Expression<Character> getTrimCharacter() {
		return trimCharacter;
	}

	public Expression<String> getTrimSource() {
		return trimSource;
	}

	public Trimspec getTrimspec() {
		return trimspec;
	}

	@Override
	public void registerParameters(ParameterRegistry registry) {
		Helper.possibleParameter( getTrimCharacter(), registry );
		Helper.possibleParameter( getTrimSource(), registry );
	}

	@Override
	public String render(RenderingContext renderingContext) {
		String renderedTrimChar;
		if ( trimCharacter.getClass().isAssignableFrom( 
				LiteralExpression.class ) ) {
			// If the character is a literal, treat it as one.  A few dialects
			// do not support parameters as trim() arguments.
			renderedTrimChar = ( ( LiteralExpression<Character> ) 
					trimCharacter ).getLiteral().toString();
		} else {
			renderedTrimChar = ( (Renderable) trimCharacter ).render( 
					renderingContext );
		}
		return new StringBuilder()
				.append( "trim(" )
				.append( trimspec.name() )
				.append( ' ' )
				.append( renderedTrimChar )
				.append( " from " )
				.append( ( (Renderable) trimSource ).render( renderingContext ) )
				.append( ')' )
				.toString();
	}
}