// -*- c-basic-offset: 4 -*-
/** @file GLViewer.cpp
 *
 *  @author James Legg
 *  @author Darko Makreshanski
 *
 *  This 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 2 of the License, or (at your option) any later version.
 *
 *  This software 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public
 *  License along with this software. If not, see
 *  <http://www.gnu.org/licenses/>.
 *
 */

#include "panoinc_WX.h"
#include "base_wx/wxutils.h"

#include "panoinc.h"
#include "hugin_config.h"
#if defined HAVE_EPOXY && HAVE_EPOXY
#include <epoxy/gl.h>
#ifdef __WXMSW__
#include <epoxy/wgl.h>
#endif
#else
#include <GL/glew.h>
#endif
#include <base_wx/platform.h>
#include <wx/settings.h>
#include <wx/dcclient.h>
#include <wx/event.h>

#include "GLViewer.h"
#include "GLRenderer.h"
#include "TextureManager.h"
#include "MeshManager.h"
#include "ToolHelper.h"
#include "GLPreviewFrame.h"
#include "hugin/huginApp.h"

#if !defined HAVE_EPOXY || !HAVE_EPOXY
bool GLViewer::initialised_glew=false;
#endif
ViewState * GLViewer::m_view_state = NULL;
size_t GLViewer::m_view_state_observer = 0;

BEGIN_EVENT_TABLE(GLViewer, wxGLCanvas)
    EVT_PAINT (GLViewer::RedrawE)
    EVT_SIZE  (GLViewer::Resized)
    EVT_ERASE_BACKGROUND(GLViewer::OnEraseBackground)
    // mouse motion
    EVT_MOTION (GLViewer::MouseMotion)
    // mouse entered or left the preview
    EVT_ENTER_WINDOW(GLViewer::MouseEnter)
    EVT_LEAVE_WINDOW(GLViewer::MouseLeave)
    // mouse buttons
    EVT_MOUSEWHEEL(GLViewer::MouseWheel)
    EVT_MOUSE_EVENTS(GLViewer::MouseButtons)
    // keyboard events
    EVT_KEY_DOWN(GLViewer::KeyDown)
    EVT_KEY_UP(GLViewer::KeyUp)
END_EVENT_TABLE()


GLViewer::GLViewer(
            wxWindow* parent, 
            HuginBase::Panorama &pano, 
            int args[], 
            GLPreviewFrame *frame_in,
            wxGLContext * shared_context
            ) :
          wxGLCanvas(parent, wxID_ANY, args, wxDefaultPosition, wxDefaultSize,
                     0, wxT("GLPreviewCanvas"), wxNullPalette)
{
    /* create OpenGL context... */
    m_glContext = new wxGLContext(this, shared_context);
  
    m_renderer = 0;
    m_visualization_state = 0;
    
    m_pano = &pano;

    frame = frame_in;

    m_background_color = frame->GetPreviewBackgroundColor();
    
    started_creation = false;
    redrawing = false;
    m_toolsInitialized = false;

    active = true;
}

GLViewer::~GLViewer()
{
    if (m_renderer)
    {
      delete m_tool_helper;
      delete m_renderer;
      delete m_visualization_state;
      // because m_view_state is a static member variable we need to check
      // if other class has already deleted it
      --m_view_state_observer;
      if (m_view_state_observer == 0)
      {
        delete m_view_state;
        m_view_state=NULL;
      }
    }
    delete m_glContext;
}

void GLViewer::SetUpContext()
{
    // set the context
    DEBUG_INFO("Setting rendering context...");
    Show();
    m_glContext->SetCurrent(*this);
    DEBUG_INFO("...got a rendering context.");
    if (!started_creation)
    {
        // It appears we are setting up for the first time.
        started_creation = true;
        
#if defined HAVE_EPOXY && HAVE_EPOXY
        // check the openGL capabilities.
        if (!(epoxy_gl_version() > 11 && epoxy_has_gl_extension("GL_ARB_multitexture")))
        {
            started_creation = false;
            wxConfigBase::Get()->Write(wxT("DisableOpenGL"), 1l);
            wxConfigBase::Get()->Flush();
            DEBUG_ERROR("Sorry, OpenGL 1.1 + GL_ARB_multitexture extension required.");
            frame->Close();
            wxMessageBox(_("Sorry, the fast preview window requires a system which supports OpenGL version 1.1 with the GL_ARB_multitexture extension.\nThe fast preview cannot be opened.\n\nHugin has been configured to start without fast preview.\nPlease restart Hugin."), _("Error"), wxOK | wxICON_ERROR);
            return;
        }
#else
        if (!initialised_glew)
        {
            // initialise the glew library, if not done it before.
            GLenum error_state = glewInit();
            initialised_glew = true;
            if (error_state != GLEW_OK)
            {
                // glewInit failed
                started_creation=false;
                DEBUG_ERROR("Error initialising GLEW: "
                        << glewGetErrorString(error_state) << ".");
                frame->Close();
                wxMessageBox(_("Error initializing GLEW\nFast preview window can not be opened."),_("Error"), wxOK | wxICON_ERROR);
                return;
            }
        }
        // check the openGL capabilities.
        if (!(GLEW_VERSION_1_1 && GLEW_ARB_multitexture))
        {
            started_creation=false;
            wxConfigBase::Get()->Write(wxT("DisableOpenGL"), 1l);
            wxConfigBase::Get()->Flush();
            DEBUG_ERROR("Sorry, OpenGL 1.1 + GL_ARB_multitexture extension required.");
            frame->Close();
            wxMessageBox(_("Sorry, the fast preview window requires a system which supports OpenGL version 1.1 with the GL_ARB_multitexture extension.\nThe fast preview cannot be opened.\n\nHugin has been configured to start without fast preview.\nPlease restart Hugin."),_("Error"), wxOK | wxICON_ERROR);
            return;
        }
#endif

        setUp();
#ifdef __WXGTK__
        if(this==frame->getPreview())
        {
            frame->getOverview()->setUp();
        }
        else
        {
            frame->getPreview()->setUp();
        };
#endif
    }
}

void GLPreview::setUp()
{
    DEBUG_DEBUG("Preview Setup");
    if (m_toolsInitialized)
    {
        return;
    };
    m_toolsInitialized = true;
    // we need something to store the state of the view and control updates
    if (!m_view_state)
    {
        GLint countMultiTexture;
        glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB,&countMultiTexture);
        m_view_state = new ViewState(m_pano, countMultiTexture>1);
    }
    ++m_view_state_observer;
    m_visualization_state = new VisualizationState(m_pano, m_view_state, this, RefreshWrapper, this, (PreviewMeshManager*) NULL);
    //Start the tools going:
    PreviewToolHelper *helper = new PreviewToolHelper(m_pano, m_visualization_state, frame);
    m_tool_helper = static_cast<ToolHelper*>(helper);
    frame->MakePreviewTools(helper);
    // now make a renderer
    m_renderer =  new GLPreviewRenderer(m_pano, m_view_state->GetTextureManager(),
                                 m_visualization_state->GetMeshManager(),
                                 m_visualization_state, helper, m_background_color);
}

GLOverview::~GLOverview()
{
    if (m_renderer)
    {
        if (m_renderer == plane_m_renderer)
        {
            delete panosphere_m_tool_helper;
            delete panosphere_m_renderer;
            delete panosphere_m_visualization_state;
        }
        else
        {
            delete plane_m_tool_helper;
            delete plane_m_renderer;
            delete plane_m_visualization_state;
        };
    };
}

void GLOverview::setUp()
{
    DEBUG_DEBUG("Overview Setup");
    if (m_toolsInitialized)
    {
        return;
    };
    m_toolsInitialized = true;
    // we need something to store the state of the view and control updates
    if (!m_view_state)
    {
        GLint countMultiTexture;
        glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB,&countMultiTexture);
        m_view_state = new ViewState(m_pano, countMultiTexture>1);
    }
    ++m_view_state_observer;

    panosphere_m_visualization_state = new PanosphereOverviewVisualizationState(m_pano, m_view_state, this, RefreshWrapper, this);
    plane_m_visualization_state = new PlaneOverviewVisualizationState(m_pano, m_view_state, this, RefreshWrapper, this);

    m_visualization_state = panosphere_m_visualization_state;

    //Start the tools going:
    panosphere_m_tool_helper = new PanosphereOverviewToolHelper(m_pano, panosphere_m_visualization_state, frame);
    frame->MakePanosphereOverviewTools(panosphere_m_tool_helper);

    plane_m_tool_helper = new PlaneOverviewToolHelper(m_pano, plane_m_visualization_state, frame);
    frame->MakePlaneOverviewTools(plane_m_tool_helper);

    // now make a renderer
    panosphere_m_renderer =  new GLPanosphereOverviewRenderer(m_pano, m_view_state->GetTextureManager(),
                                 panosphere_m_visualization_state->GetMeshManager(),
                                 panosphere_m_visualization_state, panosphere_m_tool_helper, m_background_color);
    plane_m_renderer =  new GLPlaneOverviewRenderer(m_pano, m_view_state->GetTextureManager(),
                                 plane_m_visualization_state->GetMeshManager(),
                                 plane_m_visualization_state, plane_m_tool_helper, m_background_color);
                                 
    switch(mode) {
        case PANOSPHERE_OUTSIDE:
        case PANOSPHERE_INSIDE:
            m_visualization_state = panosphere_m_visualization_state;
            m_tool_helper = panosphere_m_tool_helper;
            m_renderer = panosphere_m_renderer;
            panosphere_m_visualization_state->setInsideView(mode == PANOSPHERE_INSIDE);
            break;
        case PLANE:
            m_visualization_state = plane_m_visualization_state;
            m_tool_helper = plane_m_tool_helper;
            m_renderer = plane_m_renderer;
            break;
    }
}

void GLViewer::SetPhotometricCorrect(bool state)
{
    m_view_state->GetTextureManager()->SetPhotometricCorrect(state);
    Refresh();
}

void GLViewer::SetLayoutMode(bool state)
{
    m_visualization_state->GetMeshManager()->SetLayoutMode(state);
    Refresh();
}

void GLViewer::SetLayoutScale(double scale)
{
    m_visualization_state->GetMeshManager()->SetLayoutScale(scale);
    Refresh();
}

void GLOverview::SetLayoutMode(bool state)
{
    panosphere_m_visualization_state->GetMeshManager()->SetLayoutMode(state);
    plane_m_visualization_state->GetMeshManager()->SetLayoutMode(state);
    Refresh();
}

void GLOverview::SetLayoutScale(double scale)
{
    panosphere_m_visualization_state->GetMeshManager()->SetLayoutScale(scale*MeshManager::PanosphereOverviewMeshInfo::scale_diff);
    plane_m_visualization_state->GetMeshManager()->SetLayoutScale(scale);
    Refresh();
}


void GLViewer::RedrawE(wxPaintEvent& e)
{
    if (!IsActive()) {
        return;
    }
    
    //TODO: CanResize specific to a viewer?
    DEBUG_DEBUG("REDRAW_E");
    if(!IsShown()) return;
    // don't redraw during a redraw.
    if (!(frame->CanResize())) {
        DEBUG_DEBUG("RESIZE IN REDRAW");
        frame->ContinueResize();
        return;
    }
        
    if (!redrawing)
    {
        DEBUG_DEBUG("REDRAW_E IN");
        redrawing = true;
        SetUpContext();
        Redraw();
        redrawing = false;
    }
    DEBUG_DEBUG("END OF REDRAW_E");
}

void GLViewer::RefreshWrapper(void * obj)
{
    DEBUG_DEBUG("REFRESH WRAPPER");
    GLViewer* self = static_cast<GLViewer*>(obj);
    self->Refresh();
}

void GLViewer::Resized(wxSizeEvent& e)
{

    if (!IsActive()) {
        return;
    }

    DEBUG_DEBUG("RESIZED_OUT");
   
    if (frame->CanResize()) {
        DEBUG_DEBUG("RESIZED_IN");
        if(!IsShown()) return;
        // if we have a render at this point, tell it the new size.
        DEBUG_DEBUG("RESIZED_IN_SHOWN");
        if (m_renderer)
        {
          DEBUG_DEBUG("RESIZED_IN_RENDERER");
          wxSize clientSize = GetClientSize();
#if defined __WXGTK3__ || defined __WXOSX__
          m_scale = GetContentScaleFactor();
          clientSize *= m_scale;
#endif
          SetUpContext();
          offset = m_renderer->Resize(clientSize.GetWidth(), clientSize.GetHeight());
          Redraw();
        };
    }
}

void GLViewer::Redraw()
{
    // get the renderer to redraw the OpenGL stuff
    if(!m_renderer) return;
    // don't redraw if we are in middle of a pending change of the panorama object
    if(m_pano->hasPendingChanges()) return;
    DEBUG_INFO("Rendering.");
    
    // we should use the window background colour outside the panorama
    // FIXME shouldn't this work on textured backrounds?
#if defined __WXMAC__ && wxCHECK_VERSION(3,1,0) 
    wxColour col(128,128,128);
#else
    wxColour col = wxSystemSettings::GetColour(wxSYS_COLOUR_BTNFACE);
#endif
    m_renderer->SetBackground(col.Red(), col.Green(), col.Blue());
    if (m_visualization_state->RequireRecalculateViewport())
    {
        // resize the viewport in case the panorama dimensions have changed.
        wxSize clientSize = GetClientSize();
#if defined __WXGTK3__ || defined __WXOSX__
        m_scale = GetContentScaleFactor();
        clientSize *= m_scale;
#endif
        offset = m_renderer->Resize(clientSize.GetWidth(), clientSize.GetHeight());
    }
    m_visualization_state->DoUpdates();
    m_renderer->Redraw();
    glFlush();
    SwapBuffers();
    // tell the view state we did all the updates and redrew.
    m_visualization_state->FinishedDraw();
    DEBUG_INFO("Finished Rendering.");
}

void GLViewer::OnEraseBackground(wxEraseEvent& e)
{
    // Do nothing, to avoid flashing on MSW
}

void GLViewer::MouseMotion(wxMouseEvent& e)
{
    if(m_renderer)
        m_tool_helper->MouseMoved(hugin_utils::roundi(e.m_x * m_scale - offset.x),
                              hugin_utils::roundi(e.m_y * m_scale - offset.y), e);
}

void GLViewer::MouseEnter(wxMouseEvent & e)
{
    if(m_renderer)
        m_tool_helper->MouseEnter(hugin_utils::roundi(e.m_x * m_scale - offset.x),
                              hugin_utils::roundi(e.m_y * m_scale - offset.y), e);
}

void GLViewer::MouseLeave(wxMouseEvent & e)
{
    if(m_renderer)
        m_tool_helper->MouseLeave();
}

void GLViewer::MouseButtons(wxMouseEvent& e)
{
    if(m_renderer) {
        //disregard non button events
        if (e.IsButton()) {
            m_tool_helper->MouseButtonEvent(e);
        }
    }
#ifdef __WXMSW__
    //use normal mouse button processing of GLCanvas 
    //otherwise the mouse wheel is not working
    e.Skip();
#endif
}

void GLViewer::MouseWheel(wxMouseEvent& e)
{
    if(m_renderer) {
        m_tool_helper->MouseWheelEvent(e);
    }
}


void GLViewer::KeyDown(wxKeyEvent& e)
{
    if(m_renderer)
        m_tool_helper->KeypressEvent(e.GetKeyCode(), e.GetModifiers(), true);
}

void GLViewer::KeyUp(wxKeyEvent& e)
{
    if(m_renderer)
        m_tool_helper->KeypressEvent(e.GetKeyCode(), e.GetModifiers(), false);
}

void GLViewer::MarkToolsDirty()
{
    m_tool_helper->MarkDirty();
}

void GLViewer::SetViewerBackground(wxColour col)
{
    this->m_background_color = col;
    if(m_renderer)
        m_renderer->SetPreviewBackgroundColor(col);
}

void GLOverview::SetMode(OverviewMode mode)
{
    this->mode = mode;
    if (panosphere_m_renderer != 0 && plane_m_renderer != 0) {
        switch(mode) {
            case PANOSPHERE_OUTSIDE:
            case PANOSPHERE_INSIDE:
                m_visualization_state = panosphere_m_visualization_state;
                m_tool_helper = panosphere_m_tool_helper;
                m_renderer = panosphere_m_renderer;
                panosphere_m_visualization_state->setInsideView(mode == PANOSPHERE_INSIDE);
                break;
            case PLANE:
                m_visualization_state = plane_m_visualization_state;
                m_tool_helper = plane_m_tool_helper;
                m_renderer = plane_m_renderer;
                break;
        }
        this->Refresh();
    }
}


