/*******************************************************************************
 * Copyright (c) 2008 Standards for Technology in Automotive Retail
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     David Carver - STAR - bug 224197 - initial API and implementation
 *                    based on work from Apache Xalan 2.7.0
 *******************************************************************************/

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: ProcessorExsltFunction.java,v 1.2 2008/03/28 02:38:16 dacarver Exp $
 */
package org.eclipse.wst.xsl.core.internal.compiler.xslt10.processor;

import javax.xml.transform.SourceLocator;

import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemApplyImport;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemApplyTemplates;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemAttribute;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemCallTemplate;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemComment;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemCopy;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemCopyOf;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemElement;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemExsltFuncResult;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemExsltFunction;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemFallback;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemLiteralResult;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemNumber;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemPI;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemParam;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemTemplate;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemTemplateElement;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemText;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemTextLiteral;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemValueOf;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemVariable;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.ElemMessage;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates.Stylesheet;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

/**
 * This class processes parse events for an exslt func:function element.
 * 
 * @xsl.usage internal
 */
public class ProcessorExsltFunction extends ProcessorTemplateElem {
	static final long serialVersionUID = 2411427965578315332L;

	/**
	 * Start an ElemExsltFunction. Verify that it is top level and that it has a
	 * name attribute with a namespace.
	 */
	@Override
	public void startElement(StylesheetHandler handler, String uri,
			String localName, String rawName, Attributes attributes)
			throws SAXException {
		// System.out.println("ProcessorFunction.startElement()");
		String msg = "";
		if (!(handler.getElemTemplateElement() instanceof Stylesheet)) {
			msg = "func:function element must be top level.";
			handler.error(msg, new SAXException(msg));
		}
		super.startElement(handler, uri, localName, rawName, attributes);

		String val = attributes.getValue("name");
		int indexOfColon = val.indexOf(":");
		if (indexOfColon > 0) {
			String prefix = val.substring(0, indexOfColon);
			String localVal = val.substring(indexOfColon + 1);
			String ns = handler.getNamespaceSupport().getURI(prefix);
			// if (ns.length() > 0)
			// System.out.println("fullfuncname " + ns + localVal);
		} else {
			msg = "func:function name must have namespace";
			handler.error(msg, new SAXException(msg));
		}
	}

	/**
	 * Must include; super doesn't suffice!
	 */
	@Override
	protected void appendAndPush(StylesheetHandler handler,
			ElemTemplateElement elem) throws SAXException {
		// System.out.println("ProcessorFunction appendAndPush()" + elem);
		super.appendAndPush(handler, elem);
		// System.out.println("originating node " +
		// handler.getOriginatingNode());
		elem.setDOMBackPointer(handler.getOriginatingNode());
		handler.getStylesheet().setTemplate((ElemTemplate) elem);
	}

	/**
	 * End an ElemExsltFunction, and verify its validity.
	 */
	@Override
	public void endElement(StylesheetHandler handler, String uri,
			String localName, String rawName) throws SAXException {
		ElemTemplateElement function = handler.getElemTemplateElement();
		SourceLocator locator = handler.getLocator();
		validate(function, handler); // may throw exception
		super.endElement(handler, uri, localName, rawName);
	}

	/**
	 * Non-recursive traversal of FunctionElement tree based on TreeWalker to
	 * verify that there are no literal result elements except within a
	 * func:result element and that the func:result element does not contain any
	 * following siblings except xsl:fallback.
	 */
	public void validate(ElemTemplateElement elem, StylesheetHandler handler)
			throws SAXException {
		String msg = "";
		while (elem != null) {
			// System.out.println("elem " + elem);
			if (elem instanceof ElemExsltFuncResult
					&& elem.getNextSiblingElem() != null
					&& !(elem.getNextSiblingElem() instanceof ElemFallback)) {
				msg = "func:result has an illegal following sibling (only xsl:fallback allowed)";
				handler.error(msg, new SAXException(msg));
			}

			if ((elem instanceof ElemApplyImport
					|| elem instanceof ElemApplyTemplates
					|| elem instanceof ElemAttribute
					|| elem instanceof ElemCallTemplate
					|| elem instanceof ElemComment || elem instanceof ElemCopy
					|| elem instanceof ElemCopyOf
					|| elem instanceof ElemElement
					|| elem instanceof ElemLiteralResult
					|| elem instanceof ElemNumber || elem instanceof ElemPI
					|| elem instanceof ElemText
					|| elem instanceof ElemTextLiteral || elem instanceof ElemValueOf)
					&& !(ancestorIsOk(elem))) {
				msg = "misplaced literal result in a func:function container.";
				handler.error(msg, new SAXException(msg));
			}
			ElemTemplateElement nextElem = elem.getFirstChildElem();
			while (nextElem == null) {
				nextElem = elem.getNextSiblingElem();
				if (nextElem == null)
					elem = elem.getParentElem();
				if (elem == null || elem instanceof ElemExsltFunction)
					return; // ok
			}
			elem = nextElem;
		}
	}

	/**
	 * Verify that a literal result belongs to a result element, a variable, or
	 * a parameter.
	 */

	protected boolean ancestorIsOk(ElemTemplateElement child) {
		while (child.getParentElem() != null
				&& !(child.getParentElem() instanceof ElemExsltFunction)) {
			ElemTemplateElement parent = child.getParentElem();
			if (parent instanceof ElemExsltFuncResult
					|| parent instanceof ElemVariable
					|| parent instanceof ElemParam
					|| parent instanceof ElemMessage)
				return true;
			child = parent;
		}
		return false;
	}

}