/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.xpath.internal.functions;

import com.sun.org.apache.xml.internal.dtm.DTMIterator;

import com.sun.org.apache.xml.internal.utils.QName;

import com.sun.org.apache.xpath.internal.XPathContext;

import com.sun.org.apache.xpath.internal.axes.SubContextList;

import com.sun.org.apache.xpath.internal.compiler.Compiler;

import com.sun.org.apache.xpath.internal.objects.XNumber;

import com.sun.org.apache.xpath.internal.objects.XObject;

import java.util.List;

/**

 * Execute the Last() function.

 * @xsl.usage advanced

 */

public class FuncLast extends Function

{

    static final long serialVersionUID = 9205812403085432943L;

  private boolean m_isTopLevel;

  /**

   * Figure out if we're executing a toplevel expression.

   * If so, we can't be inside of a predicate.

   */

  public void postCompileStep(Compiler compiler)

  {

    m_isTopLevel = compiler.getLocationPathDepth() == -1;

  }

  /**

   * Get the position in the current context node list.

   *

   * @param xctxt non-null reference to XPath runtime context.

   *

   * @return The number of nodes in the list.

   *

   * @throws javax.xml.transform.TransformerException

   */

  public int getCountOfContextNodeList(XPathContext xctxt)

          throws javax.xml.transform.TransformerException

  {

    // assert(null != m_contextNodeList, "m_contextNodeList must be non-null");

    // If we're in a predicate, then this will return non-null.

    SubContextList iter = m_isTopLevel ? null : xctxt.getSubContextList();

    // System.out.println("iter: "+iter);

    if (null != iter)

      return iter.getLastPos(xctxt);

    DTMIterator cnl = xctxt.getContextNodeList();

    int count;

    if(null != cnl)

    {

      count = cnl.getLength();

      // System.out.println("count: "+count);

    }

    else

      count = 0;

    return count;

  }

  /**

   * Execute the function.  The function must return

   * a valid object.

   * @param xctxt The current execution context.

   * @return A valid XObject.

   *

   * @throws javax.xml.transform.TransformerException

   */

  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException

  {

    XNumber xnum = new XNumber((double) getCountOfContextNodeList(xctxt));

    // System.out.println("last: "+xnum.num());

    return xnum;

  }

  /**

   * No arguments to process, so this does nothing.

   */

  public void fixupVariables(List<QName> vars, int globalsSize)

  {

    // no-op

  }

}