// Copyright (c) 2009 Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v5.1/Polynomial/include/CGAL/Polynomial/Degree.h $
// $Id: Degree.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Michael Hemmer <hemmer@mpi-inf.mpg.de>
//
// ============================================================================


#ifndef CGAL_POLYNOMIAL_DEGREE_H
#define CGAL_POLYNOMIAL_DEGREE_H

#include <CGAL/Exponent_vector.h>
#include <CGAL/Polynomial/misc.h>


namespace CGAL {

namespace internal{

template <typename Polynomial > struct Degree;

// Polynomial musst be at least univariate !
template <typename Coeff_ >
struct Degree<Polynomial<Coeff_> >
  : public CGAL::cpp98::unary_function< Polynomial<Coeff_> , int  >{

private:
  typedef Polynomial<Coeff_> Polynomial_d;

  // for univariate polynomials
  template <typename Coeff>
  int degree(const Polynomial<Coeff>& p, int i) const {
    (void) i;
    CGAL_assertion(i == 0);
    return p.degree();
  }

  // for multivariate polynomials
  template <typename Coeff>
  int degree(const Polynomial<Polynomial<Coeff> >& p, int i) const {
    typedef Polynomial<Polynomial<Coeff> > Poly;

    if(i == (Dimension<Poly>::value-1))
      return p.degree();

    int result = 0;
    for(typename Poly::const_iterator it = p.begin(); it != p.end(); it++){
      result = (std::max)(result,degree(*it,i));
    }
    return result;
  }

public:
  int operator()(
      const Polynomial_d& p,
      int i = (Dimension<Polynomial_d>::value-1)) const {
    CGAL_assertion(i < Dimension<Polynomial_d>::value);
    CGAL_assertion(i >= 0);
    return this->degree(p,i);
  }

};

} // namespace internal
} //namespace CGAL

#endif //CGAL_POLYNOMIAL_DEGREE_H