////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011-2023 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"

OCTAVE_BEGIN_NAMESPACE(octave)

  GLWidget::GLWidget (Canvas &parent_canvas)
    : QOpenGLWidget (&parent_canvas), m_parent_canvas (parent_canvas),
      m_glfcns (), m_renderer (m_glfcns)
  {
    setFocusPolicy (Qt::ClickFocus);
    setFocus ();
  }

  GLWidget::~GLWidget (void) { }

  void
  GLWidget::initializeGL (void)
  {
    // The qopengl_functions object (part of Octave, not Qt) is just
    // wrapper around QOpenGLFunctions_1_1.  Does initialization really
    // need to be deferred until initializeGL is called?

    m_glfcns.init ();

    // All other resources we need are currently (supposed to be)
    // managed by the QOpenGLWidget object so there is else nothing to
    // do here.  If we used custom shader programs, then we would need
    // to initialize them here.
  }

  void
  GLWidget::draw (graphics_object go)
  {
    if (go)
      {
        begin_rendering ();

        unwind_action reset_current ([=] () { end_rendering (); });

        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
  GLWidget::do_getPixels (graphics_object go)
  {
    uint8NDArray retval;

    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;

        begin_rendering ();

        unwind_action reset_current ([=] () { end_rendering (); });

        // 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")
          {
            QOpenGLFramebufferObject
              fbo (pos(2), pos(3),
                   QOpenGLFramebufferObject::Attachment::Depth);

            fbo.bind ();

            unwind_action release_fbo ([&] () { fbo.release (); });

            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));
          }
        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));
          }
      }

    return retval;
  }

  void
  GLWidget::do_print (const QString& file_cmd, const QString& term,
                      graphics_object go)
  {
    if (go.valid_object ())
      {
        begin_rendering ();

        unwind_action reset_current ([=] () { end_rendering (); });

        graphics_object fig (go.get_ancestor ("figure"));

        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;

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

            fbo.bind ();

            unwind_action release_fbo ([&] () { fbo.release (); });

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

  graphics_object
  GLWidget::selectFromAxes (const graphics_object& ax, const QPoint& pt)
  {
    if (ax)
      {
        begin_rendering ();

        unwind_action reset_current ([=] () { end_rendering (); });

        octave::opengl_selector s (m_glfcns);

        s.set_viewport (width (), height ());

        graphics_object go = s.select (ax, pt.x (), height () - pt.y (),
                                       octave::select_ignore_hittest);

        doneCurrent ();
      }

    return graphics_object ();
  }

  void
  GLWidget::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
  GLWidget::paintGL (void)
  {
    m_parent_canvas.canvasPaintEvent ();
  }

  void
  GLWidget::mouseDoubleClickEvent (QMouseEvent *xevent)
  {
    m_parent_canvas.canvasMouseDoubleClickEvent (xevent);
  }

  void
  GLWidget::mouseMoveEvent (QMouseEvent *xevent)
  {
    m_parent_canvas.canvasMouseMoveEvent (xevent);
  }

  void
  GLWidget::mousePressEvent (QMouseEvent *xevent)
  {
    m_parent_canvas.canvasMousePressEvent (xevent);
  }

  void
  GLWidget::mouseReleaseEvent (QMouseEvent *xevent)
  {
    m_parent_canvas.canvasMouseReleaseEvent (xevent);
  }

  void
  GLWidget::wheelEvent (QWheelEvent *xevent)
  {
    m_parent_canvas.canvasWheelEvent (xevent);
  }

  void
  GLWidget::keyPressEvent (QKeyEvent *xevent)
  {
    if (! m_parent_canvas.canvasKeyPressEvent (xevent))
      QOpenGLWidget::keyPressEvent (xevent);
  }

  void
  GLWidget::keyReleaseEvent (QKeyEvent *xevent)
  {
    if (! m_parent_canvas.canvasKeyReleaseEvent (xevent))
      QOpenGLWidget::keyReleaseEvent (xevent);
  }

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

    if (! isValid ())
      {
        // FIXME: Is this really the right way to manager offscreen
        // rendering for printing?

        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
      makeCurrent ();

    return retval;
  }

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

  GLCanvas::GLCanvas (octave::interpreter& interp,
                      const graphics_handle& gh, QWidget *parent)
    : Canvas (interp, gh, parent), m_glwidget (new GLWidget (*this))
  { }

  GLCanvas::~GLCanvas (void)
  {
    delete m_glwidget;
  }

  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);

    m_glwidget->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);

    return m_glwidget->do_getPixels (go);
  }

  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);

    try
      {
        m_glwidget->do_print (file_cmd, term, go);
      }
    catch (octave::execution_exception& ee)
      {
        emit interpreter_event
          ([=] (void)
          {
            // INTERPRETER THREAD
            throw ee;
          });
      }
  }

  graphics_object
  GLCanvas::selectFromAxes (const graphics_object& ax, const QPoint& pt)
  {
    return m_glwidget->selectFromAxes (ax, pt);
  }

  void
  GLCanvas::drawZoomBox (const QPoint& p1, const QPoint& p2)
  {
    m_glwidget->drawZoomBox (p1, p2);
  }

  bool
  GLCanvas::begin_rendering (void)
  {
    return m_glwidget->begin_rendering ();
  }

  void
  GLCanvas::end_rendering (void)
  {
    m_glwidget->end_rendering ();
  }

OCTAVE_END_NAMESPACE(octave)