////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2007-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// 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
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

/*

To initialize:

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

*/

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include <string>

#include "dMatrix.h"
#include "file-stat.h"
#include "oct-env.h"

#include "build-env.h"
#include "builtin-defun-decls.h"
#include "defun-dld.h"
#include "error.h"
#include "graphics.h"
#include "interpreter-private.h"
#include "interpreter.h"
#include "ov.h"
#include "ovl.h"
#include "parse.h"
#include "utils.h"
#include "variables.h"

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

class gnuplot_graphics_toolkit : public octave::base_graphics_toolkit
{
public:
  gnuplot_graphics_toolkit (octave::interpreter& interp)
    : octave::base_graphics_toolkit ("gnuplot"), m_interpreter (interp) { }

  ~gnuplot_graphics_toolkit (void) = default;

  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_graphicssmoothing (false);
              }
            break;
          }
      }
  }

  void redraw_figure (const graphics_object& go) const
  {
    static bool drawnow_executing = false;

    // Prevent recursion
    if (! drawnow_executing)
      {
        octave::unwind_protect frame;
        frame.protect_var (drawnow_executing);

        drawnow_executing = true;
        octave_value_list args;
        args(0) = go.get_handle ().as_octave_value ();
        octave::feval ("__gnuplot_drawnow__", args);
      }
  }

  void print_figure (const graphics_object& go, const std::string& term,
                     const std::string& file,
                     const std::string& debug_file) const
  {
    octave_value_list args;
    if (! debug_file.empty ())
      args(3) = debug_file;
    args(2) = file;
    args(1) = term;
    args(0) = go.get_handle ().as_octave_value ();
    octave::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 (m_interpreter.mislocked ("__init_gnuplot__"))
      m_interpreter.munlock ("__init_gnuplot__");
  }

private:

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

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

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

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

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

  octave::interpreter& m_interpreter;
};

static bool
have_gnuplot_binary (void)
{
  const std::string exeext = octave::build_env::EXEEXT;
  const std::string path = octave::sys::env::getenv ("PATH");
  bool retval = false;

  try
    {
      octave_value_list tmp
        = octave::feval ("gnuplot_binary", octave_value_list ());

      if (tmp(0).is_string () && ! tmp(0).isempty ())
        {
          std::string gnuplot_binary = tmp(0).string_value ();

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

          octave::sys::file_stat fs (gnuplot_path);

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

              gnuplot_path = octave::search_path_for_file (path, args);

              fs = octave::sys::file_stat (gnuplot_path);
            }

          retval = fs.exists ();
        }
    }
  catch (octave::execution_exception&)
    {
      octave::interpreter& interp
        = octave::__get_interpreter__ ("have_gnuplot_binary");

      interp.recover_from_exception ();
    }

  return retval;
}

// Initialize the gnuplot graphics toolkit.

DEFMETHOD_DLD (__init_gnuplot__, interp, , ,
               doc: /* -*- texinfo -*-
@deftypefn {} {} __init_gnuplot__ ()
Undocumented internal function.
@end deftypefn */)
{
  if (! have_gnuplot_binary ())
    error ("__init_gnuplot__: the gnuplot program is not available, see 'gnuplot_binary'");
  else if (! interp.mislocked ("__init_gnuplot__"))
    {
      octave::gtk_manager& gtk_mgr = interp.get_gtk_manager ();

      octave::graphics_toolkit tk (new gnuplot_graphics_toolkit (interp));
      gtk_mgr.load_toolkit (tk);

      interp.mlock ();
    }

  return octave_value_list ();
}

DEFUN_DLD (__have_gnuplot__, , ,
           doc: /* -*- texinfo -*-
@deftypefn {} {@var{gnuplot_available} =} __have_gnuplot__ ()
Undocumented internal function.
@end deftypefn */)
{
  return ovl (have_gnuplot_binary ());
}

/*
## No test needed for internal helper function.
%!assert (1)
*/
