////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011-2020 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 "GLCanvas.h"
#include "gl-select.h"

#include "gl-render.h"
#include "gl2ps-print.h"
#include "graphics.h"
#include "interpreter.h"

namespace QtHandles
{
#if defined (HAVE_QOPENGLWIDGET)
#  define OCTAVE_QT_OPENGL_WIDGET_FORMAT_ARGS
#else
#  if defined (Q_OS_WIN32)
#    define OCTAVE_QT_OPENGL_WIDGET_FORMAT_ARGS         \
  QGLFormat (QGL::SampleBuffers | QGL::AlphaChannel     \
             | QGL::IndirectRendering),
#  else
#    define OCTAVE_QT_OPENGL_WIDGET_FORMAT_ARGS \
  QGLFormat (QGL::SampleBuffers | QGL::AlphaChannel),
#  endif
#endif

  GLCanvas::GLCanvas (octave::base_qobject& oct_qobj,
                      octave::interpreter& interp,
                      const graphics_handle& gh, QWidget *xparent)
    : OCTAVE_QT_OPENGL_WIDGET (OCTAVE_QT_OPENGL_WIDGET_FORMAT_ARGS xparent),
      Canvas (oct_qobj, interp, gh), m_glfcns (), m_renderer (m_glfcns)
  {
    setFocusPolicy (Qt::ClickFocus);
    setFocus ();
  }

  GLCanvas::~GLCanvas (void)
  { }

  void
  GLCanvas::initializeGL (void)
  {
    m_glfcns.init ();
  }

  void
  GLCanvas::draw (const graphics_handle& gh)
  {
    gh_manager& gh_mgr = m_interpreter.get_gh_manager ();

    octave::autolock guard  (gh_mgr.graphics_lock ());

    graphics_object go = gh_mgr.get_object (gh);

    if (go)
      {
        graphics_object fig = go.get_ancestor ("figure");
        double dpr = fig.get ("__device_pixel_ratio__").double_value ();
        m_renderer.set_viewport (dpr * width (), dpr * height ());
        m_renderer.set_device_pixel_ratio (dpr);
        m_renderer.draw (go);
      }
  }

  uint8NDArray
  GLCanvas::do_getPixels (const graphics_handle& gh)
  {
    uint8NDArray retval;

    gh_manager& gh_mgr = m_interpreter.get_gh_manager ();

    graphics_object go = gh_mgr.get_object (gh);

    if (go && go.isa ("figure"))
      {
        Matrix pos = go.get ("position").matrix_value ();
        double dpr = go.get ("__device_pixel_ratio__").double_value ();
        pos(2) *= dpr;
        pos(3) *= dpr;

        // Make sure we have a valid current context
        if (! begin_rendering ())
          return retval;

        // When the figure is not visible or its size is frozen for printing,
        // we use a framebuffer object to make sure we are rendering on a
        // suitably large frame.
        if (go.get ("visible").string_value () == "off"
            || go.get ("__printing__").string_value () == "on")
          {
            OCTAVE_QT_OPENGL_FBO
            fbo (pos(2), pos(3),
                 OCTAVE_QT_OPENGL_FBO::Attachment::Depth);

            fbo.bind ();

            m_renderer.set_viewport (pos(2), pos(3));
            m_renderer.set_device_pixel_ratio (dpr);
            m_renderer.draw (go);
            retval = m_renderer.get_pixels (pos(2), pos(3));

            fbo.release ();
          }
        else
          {
            m_renderer.set_viewport (pos(2), pos(3));
            m_renderer.set_device_pixel_ratio (dpr);
            m_renderer.draw (go);
            retval = m_renderer.get_pixels (pos(2), pos(3));
          }

        end_rendering ();
      }

    return retval;
  }

  void
  GLCanvas::do_print (const QString& file_cmd, const QString& term,
                      const graphics_handle& handle)
  {
    gh_manager& gh_mgr = m_interpreter.get_gh_manager ();

    octave::autolock guard  (gh_mgr.graphics_lock ());

    graphics_object go = gh_mgr.get_object (handle);

    if (go.valid_object ())
      {
        graphics_object fig (go.get_ancestor ("figure"));

        // Make sure we have a valid current context
        if (! begin_rendering ())
          error ("print: no valid OpenGL offscreen context");

        try
          {
            if (fig.get ("visible").string_value () == "on")
              octave::gl2ps_print (m_glfcns, fig, file_cmd.toStdString (),
                                   term.toStdString ());
            else
              {
                // When the figure is not visible, we use a framebuffer object
                // to make sure we are rendering on a suitably large frame.
                Matrix pos = fig.get ("position").matrix_value ();
                double dpr = fig.get ("__device_pixel_ratio__").double_value ();
                pos(2) *= dpr;
                pos(3) *= dpr;

                OCTAVE_QT_OPENGL_FBO
                  fbo (pos(2), pos(3),
                       OCTAVE_QT_OPENGL_FBO::Attachment::Depth);

                fbo.bind ();

                octave::gl2ps_print (m_glfcns, fig, file_cmd.toStdString (),
                                     term.toStdString ());

                fbo.release ();
              }
          }
        catch (octave::execution_exception& ee)
          {
            emit interpreter_event
              ([ee] (void)
               {
                 // INTERPRETER THREAD

                 throw ee;
               });
          }

        end_rendering ();
      }
  }

  graphics_object
  GLCanvas::selectFromAxes (const graphics_object& ax, const QPoint& pt)
  {
    makeCurrent ();

    if (ax)
      {
        octave::opengl_selector s (m_glfcns);

        s.set_viewport (width (), height ());
        return s.select (ax, pt.x (), height () - pt.y (),
                         octave::select_ignore_hittest);
      }

    return graphics_object ();
  }

  void
  GLCanvas::drawZoomBox (const QPoint& p1, const QPoint& p2)
  {
    Matrix overlaycolor (3, 1);
    overlaycolor(0) = 0.45;
    overlaycolor(1) = 0.62;
    overlaycolor(2) = 0.81;
    double overlayalpha = 0.1;
    Matrix bordercolor = overlaycolor;
    double borderalpha = 0.9;
    double borderwidth = 1.5;

    m_renderer.draw_zoom_box (width (), height (),
                              p1.x (), p1.y (), p2.x (), p2.y (),
                              overlaycolor, overlayalpha,
                              bordercolor, borderalpha, borderwidth);
  }

  void
  GLCanvas::paintGL (void)
  {
    canvasPaintEvent ();
  }

  void
  GLCanvas::mouseDoubleClickEvent (QMouseEvent *xevent)
  {
    canvasMouseDoubleClickEvent (xevent);
  }

  void
  GLCanvas::mouseMoveEvent (QMouseEvent *xevent)
  {
    canvasMouseMoveEvent (xevent);
  }

  void
  GLCanvas::mousePressEvent (QMouseEvent *xevent)
  {
    canvasMousePressEvent (xevent);
  }

  void
  GLCanvas::mouseReleaseEvent (QMouseEvent *xevent)
  {
    canvasMouseReleaseEvent (xevent);
  }

  void
  GLCanvas::wheelEvent (QWheelEvent *xevent)
  {
    canvasWheelEvent (xevent);
  }

  void
  GLCanvas::keyPressEvent (QKeyEvent *xevent)
  {
    if (! canvasKeyPressEvent (xevent))
      OCTAVE_QT_OPENGL_WIDGET::keyPressEvent (xevent);
  }

  void
  GLCanvas::keyReleaseEvent (QKeyEvent *xevent)
  {
    if (! canvasKeyReleaseEvent (xevent))
      OCTAVE_QT_OPENGL_WIDGET::keyReleaseEvent (xevent);
  }

  bool
  GLCanvas::begin_rendering (void)
  {
    bool retval = true;

    if (! isValid ())
      {
#  if defined (HAVE_QT_OFFSCREEN)
        static bool os_ctx_ok = true;
        if (os_ctx_ok && ! m_os_context.isValid ())
          {
            // Try to initialize offscreen context
            m_os_surface.create ();
            if (! m_os_context.create ())
              {
                os_ctx_ok = false;
                return false;
              }
          }

        retval = m_os_context.makeCurrent (&m_os_surface);
#  else
        retval = false;
#  endif
      }
    else
      makeCurrent ();

    return retval;
  }

  void
  GLCanvas::end_rendering (void)
  {
    doneCurrent ();
  }
}
