package org.madore.damlengine;

import java.io.OutputStream;
import java.io.OutputStreamWriter;
import javax.xml.XMLConstants;
import javax.xml.namespace.NamespaceContext;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
// import org.xml.sax.EntityResolver;
import org.apache.xerces.jaxp.DocumentBuilderFactoryImpl;

public final class DamlEngine {

    public static final String XML_NS = XMLConstants.XML_NS_URI;
    public static final String XHTML_NS = "http://www.w3.org/1999/xhtml";
    public static final String DAML_NS = "http://www.madore.org/~david/NS/daml/";

    public static final class DamlNSMapping implements NamespaceContext {
	// This is used for XPath resolution (_not_ for parsing the document).
	public String getNamespaceURI(String prefix) {
	    if ( prefix == null )
		throw new IllegalArgumentException("getNamespaceURI() called with null prefix");
	    else if ( prefix.equals("") )
		return XHTML_NS;
	    else if ( prefix.equals("d") )
		return DAML_NS;
	    else if ( prefix.equals("xml") )
		return XML_NS;
	    else if ( prefix.equals("xmlns") )
		return XMLConstants.XMLNS_ATTRIBUTE_NS_URI;
	    else
		return XMLConstants.NULL_NS_URI;
	}
	public String getPrefix(String uri) {
	    throw new UnsupportedOperationException("getPrefix() not implemented");
	}
	public java.util.Iterator<String> getPrefixes(String uri) {
	    throw new UnsupportedOperationException("getPrefixes() not implemented");
	}
    }

    private DamlEngine() { // Forbid instantiation
	throw new AssertionError("DamlEngine cannot be instantiated");
    }

    public static class RootTodo extends TodoItem {
	public RootTodo(Context ctx) {
	    super(ctx, null);
	}
	public void handle() {
	    TodoItem it
		= TodoElement.getTodoElement(ctx.doc.getDocumentElement(),
					     ctx, this);
	    this.ownerDeque.registerAtEnd(it);
	}
    }

    public static void processDocument(Document doc,
				       Context.WeblogSelectionContext wsc) {
	TodoDeque todoDeque = new TodoDeque();
	Context ctx = new Context(doc);
	ctx.wsc = wsc;
	todoDeque.registerAtEnd(new RootTodo(ctx));
	todoDeque.dispatchLoop();
    }

    public static void processDocument(Document doc) {
	processDocument(doc, null);
    }

    public static void fullProcess(String fname, OutputStream out,
				   Context.WeblogSelectionContext wsc)
	throws Exception {

	final Resolver resolver = new Resolver();
        final DocumentBuilderFactory dbf = new DocumentBuilderFactoryImpl();
        dbf.setNamespaceAware(true);
        dbf.setValidating(false);
	final DocumentBuilder db = dbf.newDocumentBuilder();
	db.setEntityResolver(resolver);

	Document doc = db.parse(fname);
	processDocument(doc, wsc);
	doc.normalizeDocument();
	Unparser unparser
	    = new Unparser(doc, new OutputStreamWriter(out, "UTF-8"),
			   "html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\"");
	unparser.unparse();

    }

    public static void fullProcess(String fname, OutputStream out)
	throws Exception {
	fullProcess(fname, out, null);
    }

    public static void main(String[] args)
	throws Exception {

	if ( args.length == 0 ) {
	    System.err.println("expecting filename as argument");
	}

	for (String fname : args) {
	    fullProcess (fname, System.out);
	}

    }

}