/*
 * Copyright (c) 2003 The Visigoth Software Society. All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Visigoth Software Society (http://www.visigoths.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the 
 *    project contributors may be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact visigoths@visigoths.org.
 *
 * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
 *    nor may "FreeMarker" or "Visigoth" appear in their names
 *    without prior written permission of the Visigoth Software Society.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Visigoth Software Society. For more
 * information on the Visigoth Software Society, please see
 * http://www.visigoths.org/
 */

package freemarker.core;

import java.io.*;
import java.util.*;
import freemarker.template.*;

/**
 * A template element that contains a nested block
 * that is transformed according to an instance of T
 * TemplateTransformModel
 */
final class TransformBlock extends TemplateElement {

    private Expression transformExpression;
    Map namedArgs;

    /**
     * Creates new TransformBlock, with a given transformation
     */
    TransformBlock(Expression transformExpression, 
                   Map namedArgs,
                   TemplateElement nestedBlock) {
        this.transformExpression = transformExpression;
        this.namedArgs = namedArgs;
        this.nestedBlock = nestedBlock;
    }

    void accept(Environment env) 
    throws TemplateException, IOException
    {
        TemplateTransformModel ttm = env.getTransform(transformExpression);
        if (ttm != null) {
            Map args;
            if (namedArgs != null && !namedArgs.isEmpty()) {
                args = new HashMap();
                for (Iterator it = namedArgs.entrySet().iterator(); it.hasNext();) {
                    Map.Entry entry = (Map.Entry) it.next();
                    String key = (String) entry.getKey();
                    Expression valueExp = (Expression) entry.getValue();
                    TemplateModel value = valueExp.getAsTemplateModel(env);
                    args.put(key, value);
                }
            } else {
                args = EmptyMap.instance;
            }
            env.visit(nestedBlock, ttm, args);
        }
        else {
            TemplateModel tm = transformExpression.getAsTemplateModel(env);
            throw invalidTypeException(tm, transformExpression, env, "transform");
        }
    }

    public String getCanonicalForm() {
        StringBuffer buf = new StringBuffer("<#transform ");
        buf.append(transformExpression);
        if (namedArgs != null) {
            for (Iterator it = namedArgs.entrySet().iterator(); it.hasNext();) {
                Map.Entry entry = (Map.Entry) it.next();
                buf.append(' ');
                buf.append(entry.getKey());
                buf.append('=');
                Expression val = (Expression) entry.getValue();
                buf.append(val.getCanonicalForm());
            }
        }
        buf.append(">");
        if (nestedBlock != null) {
            buf.append(nestedBlock.getCanonicalForm());
        }
        buf.append("</#transform>");
        return buf.toString();
    }

    public String getDescription() {
        return "transform " + transformExpression;
    }
}
