/* SAXEventSink.java -- 
   Copyright (C) 1999,2000,2001 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath 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
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package gnu.xml.dom.ls;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import javax.xml.XMLConstants;
import org.w3c.dom.Attr;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Element;
import org.w3c.dom.Entity;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.Text;
import org.xml.sax.Attributes;
import org.xml.sax.DTDHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.ext.Attributes2;
import org.xml.sax.ext.DeclHandler;
import org.xml.sax.ext.LexicalHandler;
import gnu.xml.aelfred2.ContentHandler2;
import gnu.xml.dom.DomAttr;
import gnu.xml.dom.DomDocument;
import gnu.xml.dom.DomDoctype;

/**
 * A SAX content and lexical handler used to construct a DOM document.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
class SAXEventSink
  implements ContentHandler2, LexicalHandler, DTDHandler, DeclHandler
{

  private static final String XMLNS_URI = XMLConstants.XMLNS_ATTRIBUTE_NS_URI;
  private static final String XMLNS_PREFIX = XMLConstants.XMLNS_ATTRIBUTE;

  boolean namespaceAware;
  boolean ignoreWhitespace;
  boolean expandEntityReferences;
  boolean ignoreComments;
  boolean coalescing;
  
  DomDocument doc; // document being constructed
  Node ctx; // current context (parent node)
  LinkedList entityCtx; // entity context
  List pending; // namespace nodes waiting for a declaring element
  Locator locator;
  boolean inCDATA;
  boolean inDTD;
  boolean interrupted;

  void interrupt()
  {
    interrupted = true;
  }

  // -- ContentHandler2 --
  
  public void setDocumentLocator(Locator locator)
  {
    this.locator = locator;
  }

  public void startDocument()
    throws SAXException
  {
    if (namespaceAware)
      {
        pending = new LinkedList();
      }
    doc = new DomDocument();
    doc.setStrictErrorChecking(false);
    doc.setBuilding(true);
    ctx = doc;
  }

  public void xmlDecl(String version, String encoding, boolean standalone,
                      String inputEncoding)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    doc.setXmlVersion(version);
    doc.setXmlEncoding(encoding);
    doc.setXmlStandalone(standalone);
    doc.setInputEncoding(inputEncoding);
  }

  public void endDocument()
    throws SAXException
  {
    doc.setStrictErrorChecking(true);
    doc.setBuilding(false);
    DomDoctype doctype = (DomDoctype) doc.getDoctype();
    if (doctype != null)
      {
        doctype.makeReadonly();
      }
    ctx = null;
    locator = null;
  }

  public void startPrefixMapping(String prefix, String uri)
    throws SAXException
  {
    if (namespaceAware)
      {
        String nsName = (prefix != null && prefix.length() > 0) ?
          XMLNS_PREFIX + ":" + prefix : XMLNS_PREFIX;
        DomAttr ns = (DomAttr) doc.createAttributeNS(XMLNS_URI, nsName);
        ns.setNodeValue(uri);
        if (ctx.getNodeType() == Node.ATTRIBUTE_NODE)
          {
            // Add to owner element
            Node target = ((Attr) ctx).getOwnerElement();
            target.getAttributes().setNamedItemNS(ns);
          }
        else
          {
            // Add to pending list; namespace node will be inserted when
            // element is seen
            pending.add(ns);
          }
      }
  }

  public void endPrefixMapping(String prefix)
    throws SAXException
  {
  }

  public void startElement(String uri, String localName, String qName,
                           Attributes atts)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    Element element = createElement(uri, localName, qName, atts);
    // add element to context
    ctx.appendChild(element);
    ctx = element;
  }

  protected Element createElement(String uri, String localName, String qName,
                                  Attributes atts)
    throws SAXException
  {
    // create element node
    Element element = namespaceAware ?
      doc.createElementNS(uri, qName) :
      doc.createElement(qName);
    NamedNodeMap attrs = element.getAttributes();
    if (namespaceAware && !pending.isEmpty())
      {
        // add pending namespace nodes
        for (Iterator i = pending.iterator(); i.hasNext(); )
          {
            Node ns = (Node) i.next();
            attrs.setNamedItemNS(ns);
          }
        pending.clear();
      }
    // add attributes
    int len = atts.getLength();
    for (int i = 0; i < len; i++)
      {
        // create attribute
        Attr attr = createAttr(atts, i);
        if (attr != null)
          {
            // add attribute to element
            if (namespaceAware)
              {
                attrs.setNamedItemNS(attr);
              }
            else
              {
                attrs.setNamedItem(attr);
              }
          }
      }
    return element;
  }

  protected Attr createAttr(Attributes atts, int index)
  {
    DomAttr attr;
    if (namespaceAware)
      {
        String a_uri = atts.getURI(index);
        String a_qName = atts.getQName(index);
        attr = (DomAttr) doc.createAttributeNS(a_uri, a_qName);
      }
    else
      {
        String a_qName = atts.getQName(index);
        attr = (DomAttr) doc.createAttribute(a_qName);
      }
    attr.setNodeValue(atts.getValue(index));
    if (atts instanceof Attributes2)
      {
        Attributes2 atts2 = (Attributes2) atts;
        // TODO attr.setDeclared(atts2.isDeclared(index));
        attr.setSpecified(atts2.isSpecified(index));
      }
    return attr;
  }

  public void endElement(String uri, String localName, String qName)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    if (namespaceAware)
      {
        pending.clear();
      }
    ctx = ctx.getParentNode();
  }

  public void characters(char[] c, int off, int len)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    ctx.appendChild(createText(c, off, len));
  }

  protected Text createText(char[] c, int off, int len)
    throws SAXException
  {
    Text text = (inCDATA && !coalescing) ?
      doc.createCDATASection(new String(c, off, len)) :
      doc.createTextNode(new String(c, off, len));
    return text;
  }

  public void ignorableWhitespace(char[] c, int off, int len)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    if (!ignoreWhitespace)
      {
        characters(c, off, len);
      }
  }

  public void processingInstruction(String target, String data)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    if (!inDTD)
      {
        Node pi = createProcessingInstruction(target, data);
        ctx.appendChild(pi);
      }
  }

  protected Node createProcessingInstruction(String target, String data)
  {
    return doc.createProcessingInstruction(target, data);
  }

  public void skippedEntity(String name)
    throws SAXException
  {
    // This callback is totally pointless
  }

  // -- LexicalHandler --
  
  public void startDTD(String name, String publicId, String systemId)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    Node doctype = createDocumentType(name, publicId, systemId);
    doc.appendChild(doctype);
    ctx = doctype;
    inDTD = true;
  }

  protected Node createDocumentType(String name, String publicId,
                                    String systemId)
  {
    return new DomDoctype(doc, name, publicId, systemId);
  }

  public void endDTD()
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    inDTD = false;
    ctx = ctx.getParentNode();
  }

  public void startEntity(String name)
    throws SAXException
  {
    DocumentType doctype = doc.getDoctype();
    if (doctype == null)
      {
        throw new SAXException("SAX parser error: " +
                               "reference to entity in undeclared doctype");
      }
    if ("[dtd]".equals(name) || name.charAt(0) == '%')
      {
        // Ignore DTD and parameter entities
        ctx = doctype;
        return;
      }
    if ("lt".equals(name) ||
        "gt".equals(name) ||
        "amp".equals(name) ||
        "apos".equals(name) ||
        "quot".equals(name))
      {
        return;
      }
    // Get entity
    NamedNodeMap entities = doctype.getEntities();
    Entity entity = (Entity) entities.getNamedItem(name);
    if (entity == null)
      {
        throw new SAXException("SAX parser error: " +
                               "reference to undeclared entity: " + name);
      }
    pushEntity(entity);
  }

  public void endEntity(String name)
    throws SAXException
  {
    if ("[dtd]".equals(name) || name.charAt(0) == '%')
      {
        // Ignore DTD and parameter entities
        return;
      }
    if ("lt".equals(name) ||
        "gt".equals(name) ||
        "amp".equals(name) ||
        "apos".equals(name) ||
        "quot".equals(name))
      {
        return;
      }
    // Get entity
    Entity entity = popEntity();
    // TODO resolve external entities to ensure that entity has content
    if (expandEntityReferences)
      {
        // Get entity content
        for (Node child = entity.getFirstChild(); child != null;
             child = child.getNextSibling())
          {
            ctx.appendChild(child);
          }
      }
    else
      {
        Node entityReference = doc.createEntityReference(name);
        ctx.appendChild(entityReference);
      }
  }

  void pushEntity(Node entity)
  {
    if (entityCtx == null)
      {
        entityCtx = new LinkedList();
      }
    entityCtx.addLast(ctx);
    ctx = entity;
  }

  Entity popEntity()
  {
    Entity ret = (Entity) ctx;
    ctx = (Node) entityCtx.removeLast();
    return ret;
  }

  public void startCDATA()
    throws SAXException
  {
    inCDATA = true;
  }

  public void endCDATA()
    throws SAXException
  {
    inCDATA = false;
  }

  public void comment(char[] c, int off, int len)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    if (!inDTD)
      {
        Node comment = createComment(c, off, len);
        ctx.appendChild(comment);
      }
  }

  protected Node createComment(char[] c, int off, int len)
  {
    return doc.createComment(new String(c, off, len));
  }

  // -- DTDHandler --

  public void notationDecl(String name, String publicId, String systemId)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    DomDoctype doctype = (DomDoctype) ctx;
    doctype.declareNotation(name, publicId, systemId);
  }

  public void unparsedEntityDecl(String name, String publicId, String systemId,
                                 String notationName)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    DomDoctype doctype = (DomDoctype) ctx;
    Entity entity = doctype.declareEntity(name, publicId, systemId,
                                          notationName);
  }

  // -- DeclHandler --
  
  public void elementDecl(String name, String model)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    // Ignore fake element declarations generated by ValidationConsumer.
    // If an element is not really declared in the DTD it will not be
    // declared in the document model.
    if (!(ctx instanceof DomDoctype))
      {
        return;
      }
    DomDoctype doctype = (DomDoctype) ctx;
    doctype.elementDecl(name, model);
  }

  public void attributeDecl(String eName, String aName, String type,
                            String mode, String value)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    DomDoctype doctype = (DomDoctype) ctx;
    doctype.attributeDecl(eName, aName, type, mode, value);
  }

  public void internalEntityDecl(String name, String value)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    DomDoctype doctype = (DomDoctype) ctx;
    Entity entity = doctype.declareEntity(name, null, null, null);
    if (entity != null)
      {
        Node text = doc.createTextNode(value);
        entity.appendChild(text);
      }
  }

  public void externalEntityDecl(String name, String publicId, String systemId)
    throws SAXException
  {
    if (interrupted)
      {
        return;
      }
    DomDoctype doctype = (DomDoctype) ctx;
    Entity entity = doctype.declareEntity(name, publicId, systemId, null);
  }
  
}