/*
 * Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source 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.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *   Free SoftwareFoundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.xpath.functions;

import com.caucho.util.L10N;
import com.caucho.xml.QAbstractNode;
import com.caucho.xpath.Expr;
import com.caucho.xpath.ExprEnvironment;
import com.caucho.xpath.XPathException;
import com.caucho.xpath.XPathParseException;
import com.caucho.xpath.expr.AbstractStringExpr;

import org.w3c.dom.Node;

/**
 * Returns a relative URI against another.
 */
public class ResolveURI extends AbstractStringExpr {
  private static final L10N L = new L10N(ResolveURI.class);
  
  private Expr _relExpr;
  private Expr _baseExpr;

  public ResolveURI(Expr relExpr, Expr baseExpr)
    throws XPathParseException
  {
    _relExpr = relExpr;
    _baseExpr = baseExpr;

    if (relExpr == null)
      throw new XPathParseException(L.l("fn:resolve-uri(relative,[base])"));
  }

  /**
   * Evaluates the expression as an string.
   *
   * @param node the current node
   * @param env the variable environment.
   *
   * @return the string representation of the expression.
   */
  public String evalString(Node node, ExprEnvironment env)
    throws XPathException
  {
    String rel = _relExpr.evalString(node, env);

    if (rel.startsWith("/") ||
        rel.indexOf(':') > 0 && rel.indexOf(':') < '/')
      return rel;

    String base;

    if (_baseExpr != null)
      base = _baseExpr.evalString(node, env);
    else
      base = QAbstractNode.baseURI(node);

    int last = base.lastIndexOf('/');

    if (last < 0)
      return rel;
    else
      return base.substring(0, last + 1) + rel;
  }

  public String toString()
  {
    if (_baseExpr != null)
      return "fn:resolve-uri(" + _relExpr + "," + _baseExpr + ")";
    else
      return "fn:resolve-uri(" + _relExpr + ")";
  }
}