// Copyright (c) 2005  Stanford University (USA).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 3 of the License,
// or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
// 
//
// Author(s)     : Daniel Russel <drussel@alumni.princeton.edu>

#ifndef CGAL_POLYNOMIAL_DESCARTES_HAS_ROOT_H
#define CGAL_POLYNOMIAL_DESCARTES_HAS_ROOT_H

#include <CGAL/Polynomial/basic.h>
#include <CGAL/Polynomial/Tools/Alternation_counter.h>

namespace CGAL { namespace POLYNOMIAL { namespace internal {;

template <class Kernel>
class Descartes_has_root
{
    public:
        Descartes_has_root(const typename Kernel::Function &f,
        Kernel k= Kernel()): map_(k.map_rational_interval_to_positive_object(f)) {

        }

        typedef bool result_type;
        typedef typename Kernel::Function::NT first_argument_type;
        typedef typename Kernel::Function::NT second_argument_type;

//! Note, the result is an upper bound
/*!
  Bezier root counter needs the sign version of the function. This is added to make the two compatible.
*/
        template <class NTT>
            result_type operator()(const NTT &lb, const NTT &ub,
            POLYNOMIAL_NS::Sign, POLYNOMIAL_NS::Sign) const
        {
            return operator()(lb,ub);
        }
        template <class NTT>
            result_type operator()(const NTT &lb, const NTT &ub) const
        {
            typename Kernel::Function mf= map_(lb, ub);

            typename POLYNOMIAL_NS::Alternation_counter<first_argument_type> ac;
            for (int i=0; i<= mf.degree(); ++i) {
                ac.push_back(mf[i]);
                if (ac.number_of_alternations() >0) return true;

            }
//std::cout << "Num alternations is " << ac.number_of_alternations() << std::endl;
            return false;
        }
    protected:
        typename Kernel::Map_rational_interval_to_positive map_;
};
} } } //namespace CGAL::POLYNOMIAL::internal;
#endif
