/*

Copyright (C) 2007-2015 John W. Eaton

This file is part of Octave.

Octave 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 3 of the License, or (at your
option) any later version.

Octave 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 Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

/*

To initialize:

  graphics_toolkit ("gnuplot");
  plot (randn (1e3, 1));

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "builtins.h"
#include "defun-dld.h"
#include "error.h"
#include "file-stat.h"
#include "graphics.h"
#include "oct-conf.h"
#include "oct-env.h"
#include "parse.h"
#include "utils.h"
#include "variables.h"

// PKG_ADD: if (__have_gnuplot__ ()) register_graphics_toolkit ("gnuplot"); endif

static bool toolkit_loaded = false;

class gnuplot_graphics_toolkit : public base_graphics_toolkit
{
public:
  gnuplot_graphics_toolkit (void)
    : base_graphics_toolkit ("gnuplot") { }

  ~gnuplot_graphics_toolkit (void) { }

  bool is_valid (void) const { return true; }

  bool initialize (const graphics_object& go)
  {
    return go.isa ("figure");
  }

  void finalize (const graphics_object& go)
  {
    if (go.isa ("figure"))
      {
        const figure::properties& props =
          dynamic_cast<const figure::properties&> (go.get_properties ());

        send_quit (props.get___plot_stream__ ());
      }
  }

  void update (const graphics_object& go, int id)
  {
    if (go.isa ("figure"))
      {
        graphics_object obj (go);

        figure::properties& props =
          dynamic_cast<figure::properties&> (obj.get_properties ());

        switch (id)
          {
          case base_properties::ID_VISIBLE:
            if (! props.is_visible ())
              {
                send_quit (props.get___plot_stream__ ());
                props.set___plot_stream__ (Matrix ());
                props.set___enhanced__ (false);
              }
            break;
          }
      }
  }

  void redraw_figure (const graphics_object& go) const
  {
    octave_value_list args;
    args(0) = go.get_handle ().as_octave_value ();
    feval ("__gnuplot_drawnow__", args);
  }

  void print_figure (const graphics_object& go, const std::string& term,
                     const std::string& file, bool mono,
                     const std::string& debug_file) const
  {
    octave_value_list args;
    if (! debug_file.empty ())
      args(4) = debug_file;
    args(3) = mono;
    args(2) = file;
    args(1) = term;
    args(0) = go.get_handle ().as_octave_value ();
    feval ("__gnuplot_drawnow__", args);
  }

  Matrix get_canvas_size (const graphics_handle&) const
  {
    Matrix sz (1, 2, 0.0);
    return sz;
  }

  double get_screen_resolution (void) const
  { return 72.0; }

  Matrix get_screen_size (void) const
  { return Matrix (1, 2, 0.0); }

  void close (void)
  {
    if (toolkit_loaded)
      {
        munlock ("__init_gnuplot__");

        gtk_manager::unload_toolkit ("gnuplot");

        toolkit_loaded = false;
      }
  }

private:

  void send_quit (const octave_value& pstream) const
  {
    if (! pstream.is_empty ())
      {
        octave_value_list args;
        Matrix fids = pstream.matrix_value ();

        Ffputs (ovl (fids(0), "\nquit;\n"));

        Ffflush (ovl (fids(0)));
        Fpclose (ovl (fids(0)));

        if (fids.numel () > 1)
          {
            Fpclose (ovl (fids(1)));

            if (fids.numel () > 2)
              Fwaitpid (ovl (fids(2)));
          }
      }
  }
};

static bool
have_gnuplot_binary (void)
{
  const std::string exeext = std::string (OCTAVE_CONF_EXEEXT);
  const std::string path = octave_env::getenv ("PATH");

  octave_value_list tmp = feval ("gnuplot_binary", octave_value_list ());
  std::string gnuplot_binary = tmp(0).string_value ();

  string_vector args (gnuplot_binary);
  std::string gnuplot_path = search_path_for_file (path, args);

  file_stat fs (gnuplot_path);

  if (! fs.exists () && ! exeext.empty ())
    {
      args[0] += exeext;

      gnuplot_path = search_path_for_file (path, args);

      fs = file_stat (gnuplot_path);
    }

  return fs.exists ();
}

// Initialize the gnuplot graphics toolkit.

DEFUN_DLD (__init_gnuplot__, , , "")
{
  octave_value retval;

  if (! have_gnuplot_binary ())
    error ("__init_gnuplot__: the gnuplot program is not available, see 'gnuplot_binary'");
  else if (! toolkit_loaded)
    {
      mlock ();

      graphics_toolkit tk (new gnuplot_graphics_toolkit ());
      gtk_manager::load_toolkit (tk);

      toolkit_loaded = true;
    }

  return retval;
}

DEFUN_DLD (__have_gnuplot__, , ,
           "-*- texinfo -*-\n\
@deftypefn {Loadable Function} {@var{gnuplot_available} =} __have_gnuplot__ ()\n\
Undocumented internal function.\n\
@end deftypefn")
{
  octave_value retval;

  retval = have_gnuplot_binary ();

  return retval;
}