/*
 * 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.IOException;

import freemarker.template.SimpleSequence;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateNodeModel;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateSequenceModel;


/**
 * An instruction to visit an XML node.
 */
final class VisitNode extends TemplateElement {
    
    Expression targetNode, namespaces;
    
    VisitNode(Expression targetNode, Expression namespaces) {
        this.targetNode = targetNode;
        this.namespaces = namespaces;
    }

    void accept(Environment env) throws IOException, TemplateException {
        TemplateModel node = targetNode.eval(env);
        if (!(node instanceof TemplateNodeModel)) {
            throw new UnexpectedTypeException(targetNode, node, "node", env);
        }
        
        TemplateModel nss = namespaces == null ? null : namespaces.eval(env);
        if (namespaces instanceof StringLiteral) {
            nss = env.importLib(((TemplateScalarModel) nss).getAsString(), null);
        }
        else if (namespaces instanceof ListLiteral) {
            nss = ((ListLiteral) namespaces).evaluateStringsToNamespaces(env);
        }
        if (nss != null) {
            if (nss instanceof Environment.Namespace) {
                SimpleSequence ss = new SimpleSequence(1);
                ss.add(nss);
                nss = ss;
            }
            else if (!(nss instanceof TemplateSequenceModel)) {
                if (namespaces != null) {
                    throw new UnexpectedTypeException(namespaces, nss, "sequence", env);
                } else {
                    // Should not occur
                    throw new _MiscTemplateException(env, "Expecting a sequence of namespaces after \"using\"");
                }
            }
        }
        env.visit((TemplateNodeModel) node, (TemplateSequenceModel) nss);
    }

    protected String dump(boolean canonical) {
        StringBuffer sb = new StringBuffer();
        if (canonical) sb.append('<');
        sb.append(getNodeTypeSymbol());
        sb.append(' ');
        sb.append(targetNode.getCanonicalForm());
        if (namespaces != null) {
            sb.append(" using ");
            sb.append(namespaces.getCanonicalForm());
        }
        if (canonical) sb.append("/>");
        return sb.toString();
    }

    String getNodeTypeSymbol() {
        return "#visit";
    }
    
    int getParameterCount() {
        return 2;
    }

    Object getParameterValue(int idx) {
        switch (idx) {
        case 0: return targetNode;
        case 1: return namespaces;
        default: throw new IndexOutOfBoundsException();
        }
    }

    ParameterRole getParameterRole(int idx) {
        switch (idx) {
        case 0: return ParameterRole.NODE;
        case 1: return ParameterRole.NAMESPACE;
        default: throw new IndexOutOfBoundsException();
        }
    }
    
}