/*
 * Copyright (c) 1998-2008 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.expr;

import com.caucho.util.CharBuffer;
import com.caucho.xpath.Expr;
import com.caucho.xpath.ExprEnvironment;
import com.caucho.xpath.XPathException;
import com.caucho.xpath.XPathFun;
import com.caucho.xpath.pattern.AbstractPattern;

import org.w3c.dom.Node;

import java.util.ArrayList;

/**
 * Expressions based on custom library extensions.
 */
public class FunExpr extends Expr {
  private String _name;
  private AbstractPattern _pattern;
  private ArrayList<Expr> _args;

  public FunExpr(String name, AbstractPattern pattern, ArrayList<Expr> args)
  {
    _name = name;
    _pattern = pattern;
    _args = args;
  }

  public boolean evalBoolean(Node node, ExprEnvironment env)
    throws XPathException
  {
    return toBoolean(evalObject(node, env));
  }

  public double evalNumber(Node node, ExprEnvironment env)
    throws XPathException
  {
    return toDouble(evalObject(node, env));
  }

  public String evalString(Node node, ExprEnvironment env)
    throws XPathException
  {
    return toString(evalObject(node, env));
  }

  public Object evalObject(Node node, ExprEnvironment env)
    throws XPathException
  {
    XPathFun fun = env.getFunction(_name);
    
    // XXX: need to propagate the exception
    if (fun == null)
      throw new RuntimeException("unknown function: " + _name);

    ArrayList<Object> values = new ArrayList<Object>();
    for (int i = 0; i < _args.size(); i++) {
      Expr expr = _args.get(i);
      values.add(expr.evalObject(node, env));
    }

    return fun.eval(node, env, _pattern, values);
  }

  public String toString()
  {
    CharBuffer cb = new CharBuffer();
    cb.append(_name);
    cb.append("(");
    for (int i = 0; i < _args.size(); i++) {
      if (i != 0)
	cb.append(", ");
      cb.append(_args.get(i));
    }
    cb.append(")");

    return cb.toString();
  }
}
