////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011-2022 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/>.
//
////////////////////////////////////////////////////////////////////////

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

#include "interpreter-qobject.h"
#include "octave-qobject.h"
#include "qt-application.h"
#include "qt-interpreter-events.h"

#include "graphics-init.h"
#include "input.h"
#include "interpreter.h"

OCTAVE_BEGIN_NAMESPACE(octave)

interpreter_qobject::interpreter_qobject (base_qobject& oct_qobj)
: QObject (), m_octave_qobj (oct_qobj), m_interpreter (nullptr)
{ }

void interpreter_qobject::execute (void)
{
  // The Octave application context owns the interpreter.

  qt_application& app_context = m_octave_qobj.app_context ();

  interpreter& interp = app_context.create_interpreter ();

  event_manager& evmgr = interp.get_event_manager ();

  evmgr.connect_link (m_octave_qobj.get_qt_interpreter_events ());
  evmgr.install_qt_event_handlers (m_octave_qobj.get_qt_interpreter_events ());
  evmgr.enable ();

  int exit_status = 0;

  try
    {
      // Final initialization.

      interp.initialize ();

      if (app_context.start_gui_p ()
          && ! m_octave_qobj.experimental_terminal_widget ())
        {
          input_system& input_sys = interp.get_input_system ();

          input_sys.PS1 (">> ");
          input_sys.PS2 ("");
        }

      if (interp.initialized ())
        {
          // The interpreter should be completely ready at this point so let
          // the GUI know.

          m_interpreter = &interp;

          emit ready ();

          graphics_init (interp, m_octave_qobj);

          // Start executing commands in the command window.

          exit_status = interp.execute ();
        }
    }
  catch (const exit_exception& xe)
    {
      exit_status = xe.exit_status ();
    }

  // FIXME: The following comment doesn't seem to make sense now.

  // Signal that the interpreter is done executing code in the
  // main REPL, from script files, or command line eval arguments.
  // By using a signal here, we give the GUI a chance to process
  // any pending events, then signal that it is safe to shutdown
  // the interpreter.  Our notification here allows the GUI to
  // insert the request to shutdown the interpreter in the event
  // queue after any other pending signals.  The application
  // context owns the interpreter and will be responsible for
  // deleting it later, when the application object destructor is
  // executed.

  emit shutdown_finished (exit_status);
}

void interpreter_qobject::interpreter_event (const fcn_callback& fcn)
{
  if (! m_interpreter)
    return;

  event_manager& evmgr = m_interpreter->get_event_manager ();

  evmgr.post_event (fcn);
}

void interpreter_qobject::interpreter_event (const meth_callback& meth)
{
  if (! m_interpreter)
    return;

  event_manager& evmgr = m_interpreter->get_event_manager ();

  evmgr.post_event (meth);
}

void interpreter_qobject::interrupt (void)
{
  if (! m_interpreter)
    return;

  // The following is a direct function call across threads.
  // We need to ensure that it uses thread-safe functions.

  m_interpreter->interrupt ();
}

void interpreter_qobject::pause (void)
{
  // FIXME: Should we make this action work with the old terminal
  // widget?

  if (m_octave_qobj.experimental_terminal_widget ())
    {
      if (! m_interpreter)
        return;

      // The following is a direct function call across threads.
      // We need to ensure that it uses thread-safe functions.

      m_interpreter->pause ();
    }
}

void interpreter_qobject::stop (void)
{
  // FIXME: Should we make this action work with the old terminal
  // widget?

  if (m_octave_qobj.experimental_terminal_widget ())
    {
      if (! m_interpreter)
        return;

      // The following is a direct function call across threads.
      // We need to ensure that it uses thread-safe functions.

      m_interpreter->stop ();
    }
}

void interpreter_qobject::resume (void)
{
  // FIXME: Should we make this action work with the old terminal
  // widget?

  if (m_octave_qobj.experimental_terminal_widget ())
    {
      // FIXME: This action should only be available when the
      // interpreter is paused.

      interpreter_event
        ([=] (interpreter& interp)
        {
          // INTERPRETER THREAD

          interp.resume ();
        });
    }
}

qt_interpreter_events *interpreter_qobject::qt_link (void)
{
  return m_octave_qobj.qt_link ();
}

OCTAVE_END_NAMESPACE(octave)