/*
 Copyright (C) 2013 Marco Vassallo

 This program 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.

 This program 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. See the GNU General Public License for more
 details.

 You should have received a copy of the GNU General Public License along with
 this program; if not, see <http://www.gnu.org/licenses/>.
*/

#include "boundarycondition.h"
#include "functionspace.h"
#include "expression.h"

DEFUN_DLD (DirichletBC, args, , "-*- texinfo -*-\n\
@deftypefn {Function File} {[@var{bc}]} = \
DirichletBC (@var{Functional Space}, @var{Boundary Label}, @var{Function handle}) \n\
The input parameters are\n\
@itemize @bullet \n\
@item @var{Functional Space} is a fem-fenics functional space where\
we want to apply the BC\n\
@item @var{Function handle} is a function handle which contains the expression\
that we want to apply as BC. If we have a Vector field, we can just use a\n\
vector of function handle: @var{Function handle} = ['@'(x, y) f1, '@'(x, y) f2, ...]\n\
@item @var{Boundary} is an Array which contains the labels of the \
sides where the BC is applied\n\
@end itemize\n\
The output @var{BC} is an object which contains the boundary conditions\n\
@seealso{Mesh, FunctionSpace}\n\
@end deftypefn")
{
  int nargin = args.length ();
  octave_value retval;

  if (nargin < 3 || nargin > 3)
    print_usage ();
  else
    {

      if (! functionspace_type_loaded)
        {
          functionspace::register_type ();
          functionspace_type_loaded = true;
          mlock ();
        }

      if (! boundarycondition_type_loaded)
        {
          boundarycondition::register_type ();
          boundarycondition_type_loaded = true;
          mlock ();
        }

      if (args(0).type_id () == functionspace::static_type_id ())
        {
          const functionspace & fspo = static_cast<const functionspace&> (args(0).get_rep ());
          octave_fcn_handle * fh = args(1).fcn_handle_value ();
          Array<octave_idx_type> side = args(2).array_value ();


          if (!error_state)
            {
              std::cout <<"Building essential boundary condition..."<< std::endl;
              const boost::shared_ptr <const dolfin::FunctionSpace> & V (fspo.get_pfsp ());

              octave_value_list b (3, 1);
              octave_value_list tmp = feval (fh->function_value (), b);
              Array<double> res = tmp(0).array_value ();
              std::size_t l = res.length ();

              expression * pf;
              if (l > 1)
                pf = new expression (*fh, l);
              else
                pf = new expression (*fh);

              boost::shared_ptr<const expression> f (pf);
              boundarycondition * pbc = new boundarycondition ();

              for (octave_idx_type i = 0; i < side.length (); ++i)
                  pbc->add_bc (V, f, side(i));
              retval = octave_value (pbc);
            }
        }
    }
  return retval;
}