package com.icl.saxon.functions;
import com.icl.saxon.*;
import com.icl.saxon.om.NodeInfo;
import com.icl.saxon.om.NodeEnumeration;
import com.icl.saxon.expr.*;

import java.util.*;


public class NamespaceURI extends Function {

    /**
    * Function name (for diagnostics)
    */

    public String getName() {
        return "namespace-uri";
    };

    /**
    * Determine the data type of the expression
    * @return Value.STRING
    */

    public int getDataType() {
        return Value.STRING;
    }

    /**
    * Simplify and validate.
    */

    public Expression simplify() throws XPathException {
        int numArgs = checkArgumentCount(0, 1);
        if (numArgs==1) {
            argument[0] = argument[0].simplify();
        }
        return this;
    }

    /**
    * Evaluate the function in a string context
    */

    public String evaluateAsString(Context c) throws XPathException {
    	String uri;
        if (getNumberOfArguments()==1) {
            NodeEnumeration enum = argument[0].enumerate(c, true);
            if (enum.hasMoreElements()) {
                uri = enum.nextElement().getURI();
            } else {
                uri = null;
            }
        } else {
            uri = c.getContextNodeInfo().getURI();
        }
        return (uri==null ? "" : uri);
    }

    /**
    * Evaluate in a general context
    */

    public Value evaluate(Context c) throws XPathException {
        return new StringValue(evaluateAsString(c));
    }

    /**
    * Determine the dependencies
    */

    public int getDependencies() {
        if (getNumberOfArguments()==1) {
            return argument[0].getDependencies();
        } else {
            return Context.CONTEXT_NODE;
        }
    }

    /**
    * Reduce the dependencies
    */

    public Expression reduce(int dep, Context c) throws XPathException {
        if (getNumberOfArguments()==1) {     
            NamespaceURI f = new NamespaceURI();
            f.addArgument(argument[0].reduce(dep, c));
            f.setStaticContext(getStaticContext());
            return f.simplify();
        } else {
            if ((dep & Context.CONTEXT_NODE)!=0) {
                return evaluate(c);
            } else {
                return this;
            }
        }
    }

}




//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (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.mozilla.org/MPL/ 
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License. 
//
// The Original Code is: all this file. 
//
// The Initial Developer of the Original Code is
// Michael Kay of International Computers Limited (mhkay@iclway.co.uk).
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved. 
//
// Contributor(s): none. 
//