/*
 * eXist Open Source Native XML Database
 * Copyright (C) 2005-2007 The eXist Project
 * http://exist-db.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *  
 * 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 program; if not, write to the Free Software Foundation
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *  
 *  $Id$
 */
package org.exist.xquery.functions.fn;

import org.exist.dom.QName;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Profiler;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.util.URIUtils;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;

/**
 *
 * @author perig
 *
 */
public class FunEscapeHTMLURI extends Function {

    public final static FunctionSignature signature =
        new FunctionSignature(
            new QName("escape-html-uri", Function.BUILTIN_FUNCTION_NS),
            "Replaces all non-printable ASCII characters in the string value of " +
            "$html-uri by an escape sequence represented as a hexadecimal octet " +
            "in the form %XX. If $html-uri is the empty sequence, " + 
            "returns the zero-length string.",
            new SequenceType[] {
                new FunctionParameterSequenceType("html-uri", Type.STRING,
                    Cardinality.ZERO_OR_ONE, "The html URI")
            },
            new FunctionReturnSequenceType(Type.STRING, Cardinality.EXACTLY_ONE,
                "all nonprintable ASCII characters in $html-uri encoded by escape sequences"));

    public FunEscapeHTMLURI(XQueryContext context, FunctionSignature signature) {
        super(context, signature);
    }

    public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
        if (context.getProfiler().isEnabled()) {
            context.getProfiler().start(this);
            context.getProfiler().message(this, Profiler.DEPENDENCIES,
                "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
            if (contextSequence != null)
                {context.getProfiler().message(this, Profiler.START_SEQUENCES,
                    "CONTEXT SEQUENCE", contextSequence);}
            if (contextItem != null)
                {context.getProfiler().message(this, Profiler.START_SEQUENCES,
                    "CONTEXT ITEM", contextItem.toSequence());}
        }
        Sequence result;
        final Sequence seq = getArgument(0).eval(contextSequence, contextItem);
        if (seq.isEmpty()) {
            result = StringValue.EMPTY_STRING;
        } else {
            final String value = URIUtils.escapeHtmlURI(seq.getStringValue());
            result =  new StringValue(value);
        }
        if (context.getProfiler().isEnabled()) 
            {context.getProfiler().end(this, "", result);}
        return result;
    }
}