/*
 * SortKey.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP 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 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAXP 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 this program; 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
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package gnu.xml.transform;

import javax.xml.namespace.QName;
import javax.xml.transform.TransformerException;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Node;
import gnu.xml.xpath.Expr;

/**
 * An XSL sort key.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
final class SortKey
{

  static final int DEFAULT = 0;
  static final int UPPER_FIRST = 1;
  static final int LOWER_FIRST = 2;

  final Expr select;
  final TemplateNode langTemplate;
  final TemplateNode dataTypeTemplate;
  final TemplateNode orderTemplate;
  final TemplateNode caseOrderTemplate;

  transient String lang;
  transient String dataType;
  transient boolean descending;
  transient int caseOrder;

  SortKey(Expr select, TemplateNode lang, TemplateNode dataType,
          TemplateNode order, TemplateNode caseOrder)
  {
    this.select = select;
    this.langTemplate = lang;
    this.dataTypeTemplate = dataType;
    this.orderTemplate = order;
    this.caseOrderTemplate = caseOrder;
  }

  String key(Node node)
  {
    Object ret = select.evaluate(node, 1, 1);
    if (ret instanceof String)
      {
        return (String) ret;
      }
    else
      {
        return Expr._string(node, ret);
      }
  }

  /**
   * Prepare for a sort.
   * This sets all transient variables from their AVTs.
   */
  void init(Stylesheet stylesheet, QName mode,
            Node context, int pos, int len,
            Node parent, Node nextSibling)
    throws TransformerException
  {
    Document doc = (context instanceof Document) ? (Document) context :
      context.getOwnerDocument();
    if (langTemplate == null)
      {
        lang = null;
      }
    else
      {
        DocumentFragment fragment = doc.createDocumentFragment();
        langTemplate.apply(stylesheet, mode, context, pos, len,
                           fragment, null);
        lang = Expr.stringValue(fragment);
      }
    if (dataTypeTemplate == null)
      {
        dataType = "text";
      }
    else
      {
        DocumentFragment fragment = doc.createDocumentFragment();
        dataTypeTemplate.apply(stylesheet, mode, context, pos, len,
                               fragment, null);
        dataType = Expr.stringValue(fragment);
      }
    if (orderTemplate == null)
      {
        descending = false;
      }
    else
      {
        DocumentFragment fragment = doc.createDocumentFragment();
        orderTemplate.apply(stylesheet, mode, context, pos, len,
                            fragment, null);
        String order = Expr.stringValue(fragment);
        descending = "descending".equals(order);
      }
    if (caseOrderTemplate == null)
      {
        caseOrder = DEFAULT;
      }
    else
      {
        DocumentFragment fragment = doc.createDocumentFragment();
        caseOrderTemplate.apply(stylesheet, mode, context, pos, len,
                                fragment, null);
        String co = Expr.stringValue(fragment);
        caseOrder = "upper-first".equals(co) ? UPPER_FIRST :
          "lower-first".equals(co) ? LOWER_FIRST :
          DEFAULT;
      }
  }

}
