package com.sun.msv.writer.relaxng;

import com.sun.msv.grammar.*;
import com.sun.msv.writer.*;
import java.util.Stack;

/**
 * Visits NameClass and writes its XML representation.
 * 
 * this class can only handle canonicalized name class.
 */
public class NameClassWriter implements NameClassVisitor {
	
	public NameClassWriter( Context ctxt ) {
		this.writer = ctxt.getWriter();
		this.defaultNs = ctxt.getTargetNamespace();
	}
	private final XMLWriter writer;
	
	/**
	 * Namespace URI of the inherited "ns" attribute, if any.
	 * Otherwise null.
	 */
	private final String defaultNs;
	
	public Object onAnyName(AnyNameClass nc) {
		writer.element("anyName");
		return null;
	}
		
	protected void startWithNs( String name, String ns ) {
		if( ns.equals(defaultNs) )
			writer.start(name);
		else
			writer.start(name, new String[]{"ns",ns});
	}
		
	public Object onSimple( SimpleNameClass nc ) {
		startWithNs( "name", nc.namespaceURI );
		writer.characters(nc.localName);
		writer.end("name");
		return null;
	}
		
	public Object onNsName( NamespaceNameClass nc ) {
		startWithNs( "nsName", nc.namespaceURI );
		writer.end("nsName");
		return null;
	}
		
	public Object onNot( NotNameClass nc ) {
		// should not be called.
		throw new Error();
	}
		
	public Object onChoice( ChoiceNameClass nc ) {
		writer.start("choice");
		processChoice(nc);
		writer.end("choice");
		return null;
	}
			
	private void processChoice( ChoiceNameClass nc ) {
		Stack s = new Stack();
		s.push(nc.nc1);
		s.push(nc.nc2);
			
		while(!s.empty()) {
			NameClass n = (NameClass)s.pop();
			if(n instanceof ChoiceNameClass ) {
				s.push( ((ChoiceNameClass)n).nc1 );
				s.push( ((ChoiceNameClass)n).nc2 );
				continue;
			}
				
			n.visit(this);
		}
	}
		
	public Object onDifference( DifferenceNameClass nc ) {
		if( nc.nc1 instanceof AnyNameClass ) {
			writer.start("anyName");
			writer.start("except");
			if( nc.nc2 instanceof ChoiceNameClass )
				processChoice( (ChoiceNameClass)nc.nc2 );
			else
				nc.nc2.visit(this);
			writer.end("except");
			writer.end("anyName");
		}
		else
		if( nc.nc1 instanceof NamespaceNameClass ) {
			startWithNs("nsName", ((NamespaceNameClass)nc.nc1).namespaceURI );
			writer.start("except");
			if( nc.nc2 instanceof ChoiceNameClass )
				processChoice( (ChoiceNameClass)nc.nc2 );
			else
				nc.nc2.visit(this);
			writer.end("except");
			writer.end("nsName");
		}
		else
			throw new Error();
			
		return null;
	}
}