/*
 * 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 Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Alex Rojkov
 */

package com.caucho.jstl.rt;

import javax.el.ELContext;
import javax.el.ValueExpression;

public final class CoreStringTokenValueExpression
  extends ValueExpression {
  private Integer _i;
  private ValueExpression _orig;
  private char []_delims;

  public CoreStringTokenValueExpression(ValueExpression orig, Integer i, String delims)
  {
    _orig = orig;
    _i = i;
    _delims = delims.toCharArray();
  }

  @Override
  public String getExpressionString()
  {
    return _orig.getExpressionString() + "[" + _i + "]";
  }

  @Override
  public Class getExpectedType()
  {
    return String.class;
  }

  @Override
  public Class getType(ELContext context)
  {
    return String.class;
  }

  @Override
  public boolean isLiteralText()
  {
    return false;
  }

  @Override
  public boolean isReadOnly(ELContext context)
  {
    return true;
  }

  @Override
  public Object getValue(ELContext context)
  {
    Object base = _orig.getValue(context);

    if (! (base instanceof String))
      return null;

    String str = (String) base;

    int index = _i;

    int lastDelimPos = -1;

    char []chars = str.toCharArray();

    for (int i = 0; i < chars.length; i++) {
      char c = chars[i];

      for (int j = 0; j < _delims.length; j++) {
        char d = _delims[j];

        if (c == d) {
          if (lastDelimPos + 1 < i) {
            if (index == 0) {
              return new String(chars, lastDelimPos + 1, i - lastDelimPos - 1).trim();
            }

            index--;
          }

          lastDelimPos = i;
          break;
        }
      }
    }

    if (index == 0)
      return new String(chars,
                        lastDelimPos + 1,
                        chars.length - lastDelimPos - 1).trim();
    else
      return null;
  }

  @Override
  public void setValue(ELContext context, Object value)
  {
  }

  public int hashCode()
  {
    return 65521 * _orig.hashCode() + _i.hashCode();
  }

  public boolean equals(Object obj)
  {
    if (this == obj)
      return true;
    else if (! (obj instanceof CoreStringTokenValueExpression))
      return false;

    CoreStringTokenValueExpression expr = (CoreStringTokenValueExpression) obj;

    return _orig.equals(expr._orig) && _i.equals(expr._i);
  }
}