/*
 * Template.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 java.io.PrintStream;
import javax.xml.namespace.QName;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.xpath.XPathExpressionException;
import org.w3c.dom.Node;
import gnu.xml.xpath.Expr;
import gnu.xml.xpath.NameTest;
import gnu.xml.xpath.NodeTypeTest;
import gnu.xml.xpath.Pattern;
import gnu.xml.xpath.Selector;
import gnu.xml.xpath.Test;

/**
 * A template in an XSL stylesheet.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
class Template
  implements Comparable
{

  static final double DEFAULT_PRIORITY = 0.5d;

  final Stylesheet stylesheet;
  final QName name;
  final Pattern match;
  final TemplateNode node;
  final double priority;
  final int precedence;
  final QName mode;

  Template(Stylesheet stylesheet, 
           QName name, Pattern match, TemplateNode node,
           int precedence, double priority, QName mode)
  {
    this.stylesheet = stylesheet;
    this.name = name;
    this.match = match;
    this.node = node;
    // adjust priority if necessary
    // see XSLT section 5.5
    Test test = getNodeTest(match);
    if (test != null)
      {
        if (test instanceof NameTest)
          {
            NameTest nameTest = (NameTest) test;
            if (nameTest.matchesAny() ||
                nameTest.matchesAnyLocalName())
              {
                priority = -0.25d;
              }
            else
              {
                priority = 0.0d;
              }
          }
        else
          {
            NodeTypeTest nodeTypeTest = (NodeTypeTest) test;
            if (nodeTypeTest.getNodeType() ==
                Node.PROCESSING_INSTRUCTION_NODE &&
                nodeTypeTest.getData() != null)
              {
                priority = 0.0d;
              }
            else
              {
                priority = -0.5d;
              }
          }
      }
    this.precedence = precedence;
    this.priority = priority;
    this.mode = mode;
  }

  Template clone(Stylesheet stylesheet)
  {
    // FIXME by cloning we lose the imports() functionality, so
    // apply-imports will be broken.
    return new Template(stylesheet,
                        name,
                        (match == null) ? null :
                        (Pattern) match.clone(stylesheet),
                        (node == null) ? null : node.clone(stylesheet),
                        precedence,
                        priority,
                        mode);
  }
  
  public int compareTo(Object other)
  {
    if (other instanceof Template)
      {
        Template t = (Template) other;
        int d = t.precedence - precedence;
        if (d != 0)
          {
            return d;
          }
        double d2 = t.priority - priority;
        if (d2 != 0.0d)
          {
            return (int) Math.round(d2 * 1000.0d);
          }
      }
    return 0;
  }

  Test getNodeTest(Expr expr)
  {
    if (expr instanceof Selector)
      {
        Selector selector = (Selector) expr;
        Test[] tests = selector.getTests();
        if (tests.length > 0)
          {
            return tests[0];
          }
      }
    return null;
  }

  boolean matches(QName mode, Node node)
  {
    if ((mode == null && this.mode != null) ||
        (mode != null && !mode.equals(this.mode)))
      {
        return false;
      }
    if (match == null)
      {
        return false;
      }
    return match.matches(node);
  }

  boolean matches(QName name)
  {
    return name.equals(this.name);
  }

  boolean imports(Template other)
  {
    for (Stylesheet ctx = other.stylesheet.parent;
         ctx != null;
         ctx = ctx.parent)
      {
        if (ctx == stylesheet)
          {
            return true;
          }
      }
    return false;
  }

  /**
   * @param stylesheet the stylesheet
   * @param parent the parent of result nodes
   * @param context the context node in the source document
   * @param pos the context position
   * @param len the context size
   * @param nextSibling if non-null, add result nodes before this node
   */
  void apply(Stylesheet stylesheet, QName mode,
             Node context, int pos, int len,
             Node parent, Node nextSibling)
    throws TransformerException
  {
    //System.err.println("...applying " + toString() + " to " + context);
    if (node != null)
      {
        node.apply(stylesheet, mode,
                   context, pos, len,
                   parent, nextSibling);
      }
  }

  public String toString()
  {
    StringBuffer buf = new StringBuffer(getClass().getName());
    buf.append('[');
    if (name != null)
      {
        buf.append("name=");
        buf.append(name);
      }
    else if (match != null)
      {
        buf.append("match=");
        buf.append(match);
      }
    if (mode != null)
      {
        buf.append(",mode=");
        buf.append(mode);
      }
    buf.append(']');
    return buf.toString();
    
    //return (name != null) ? name.toString() : match.toString();
  }

  void list(PrintStream out)
  {
    out.println(toString());
    if (node != null)
      {
        node.list(1, out, true);
      }
  }

}
