// Copyright (C) 2010, Guy Barrand. All rights reserved.
// See the file tools.license for terms.

#ifndef tools_Xt_OpenGLArea
#define tools_Xt_OpenGLArea

#include <X11/IntrinsicP.h>
#include <X11/CoreP.h>
#include <X11/CompositeP.h>
#include <X11/StringDefs.h>

#include <GL/glx.h>

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

namespace tools {
namespace Xt {

///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////

typedef struct _OpenGLAreaClassRec* OpenGLAreaWidgetClass;
typedef struct _OpenGLAreaRec* OpenGLAreaWidget;

typedef struct {
 int reason;
 XEvent* event;
} XoAnyCallbackStruct;

#define XoNdoubleBufferOn "doubleBufferOn"
#define XoNpaintCallback  "paintCallback"
#define XoNeventCallback  "eventCallback"

#define XoCR_PAINT 1
#define XoCR_EVENT 2

///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////

typedef struct {
  void* extension;
} OpenGLAreaClassPart;

typedef struct _OpenGLAreaClassRec {
  CoreClassPart core_class;
  CompositeClassPart composite_class;
  OpenGLAreaClassPart openGLArea_class;
} OpenGLAreaClassRec;

typedef struct {
  Boolean doubleBufferOn;
  XtCallbackList paintCallback;
  XtCallbackList eventCallback;
  Visual* visual;
  Boolean installColormap;
  GLXContext glContext;
} OpenGLAreaPart;

typedef struct _OpenGLAreaRec {
  CorePart core;
  CompositePart composite;
  OpenGLAreaPart openGLArea;
} OpenGLAreaRec;

///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////

class OpenGLArea {
public:
  static void paint(Widget a_this) {
    if(!XtIsRealized(a_this)) return;
    if(make_current(a_this)==1) {
      XoAnyCallbackStruct value;
      value.reason = XoCR_PAINT;
      value.event = 0;
      ::XtCallCallbacks(a_this,XoNpaintCallback,(XtPointer)&value);
      ::glXSwapBuffers(XtDisplay(a_this),XtWindow(a_this));
      ::glXMakeCurrent(XtDisplay(a_this),None,NULL);
    }
  }
protected:
  static void initialize_class(void) {}

  static void initialize_widget(Widget a_request,Widget a_this,ArgList,Cardinal*) {
    if(a_request->core.width<=0)  a_this->core.width  = 100;
    if(a_request->core.height<=0) a_this->core.height = 100;

#ifdef OPENGLAREA_DEBUG
    ::printf ("debug : OpenGLArea : InitializeWidget : %s\n",::XtName(a_this));
#endif

    OpenGLAreaPart& athis = _athis(a_this);
    athis.visual          = CopyFromParent;
    athis.installColormap = False;
    athis.glContext       = NULL;

    Display* display;
    Screen* screen;
    int iscreen;
    XVisualInfo* vinfo;
    display = XtDisplay(a_this);
    screen = XtScreen(a_this);
    iscreen = XScreenNumberOfScreen(screen);
  
   {int error,event;
    if(::glXQueryExtension(display,&error,&event)==0) {
      CWarn ("X server does not have OpenGL extensions.\n");
    }}
  
    if(athis.doubleBufferOn==True) {
      int atbs_1[] = {
        GLX_RGBA,
        GLX_RED_SIZE,   1,
        GLX_GREEN_SIZE, 1,
        GLX_BLUE_SIZE,  1,
        GLX_ALPHA_SIZE, 1,
        GLX_DEPTH_SIZE, 1,
        GLX_DOUBLEBUFFER,
        None
      };
      vinfo = ::glXChooseVisual  (display,iscreen,atbs_1);
      if(vinfo==NULL) { //GLX_ALPHA_SIZE : problem with Xming. Try without it.
        int atbs_2[] = {
          GLX_RGBA,
          GLX_RED_SIZE,   1,
          GLX_GREEN_SIZE, 1,
          GLX_BLUE_SIZE,  1,
          GLX_DEPTH_SIZE, 1,
          GLX_DOUBLEBUFFER,
          None
        };
        vinfo = ::glXChooseVisual  (display,iscreen,atbs_2);
      }
    } else {
      int atbs_1[] = {
        GLX_RGBA,
        GLX_RED_SIZE,   1,
        GLX_GREEN_SIZE, 1,
        GLX_BLUE_SIZE,  1,
        GLX_ALPHA_SIZE, 1,
        GLX_DEPTH_SIZE, 1,
        None
      };
      vinfo = ::glXChooseVisual  (display,iscreen,atbs_1);
      if(vinfo==NULL) { //GLX_ALPHA_SIZE : problem with Xming. Try without it.
        int atbs_2[] = {
          GLX_RGBA,
          GLX_RED_SIZE,   1,
          GLX_GREEN_SIZE, 1,
          GLX_BLUE_SIZE,  1,
          GLX_DEPTH_SIZE, 1,
          None
        };
        vinfo = ::glXChooseVisual  (display,iscreen,atbs_2);
      }
    }
  
    if(vinfo==NULL) {
      CWarn ("Can't choose a visual.\n");
    } else {
      a_this->core.depth = vinfo->depth;
      athis.visual = vinfo->visual;
      if( (vinfo->depth ==DefaultDepth (display,iscreen))  &&
          (vinfo->visual==DefaultVisual(display,iscreen)) ) {
        a_this->core.colormap = XDefaultColormap (display,iscreen);
        athis.installColormap = False;
      } else {
        a_this->core.colormap =
  	XCreateColormap (display,XRootWindow(display,iscreen),vinfo->visual, AllocNone);
        athis.installColormap = True;
      }  
      if(a_this->core.colormap==0L) {
        CWarn ("Can't get/create a X colormap.\n");
      }  
      athis.glContext = ::glXCreateContext (display,vinfo,NULL,GL_TRUE);
      if(athis.glContext==NULL) {
        athis.glContext = ::glXCreateContext (display,vinfo,NULL,GL_FALSE);
        if(athis.glContext==NULL) {
          CWarn ("Can't create a GLX context.\n");
        }
      }
      ::XFree(vinfo);
    }

    ::XtAddEventHandler
       (a_this,ButtonPressMask|ButtonReleaseMask|ButtonMotionMask|KeyPressMask|KeyReleaseMask,0,event_handler,NULL);

#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : InitializeWidget : end\n");
#endif
  }

  static void realize_widget(Widget a_this,XtValueMask* a_mask,XSetWindowAttributes* a_watbs) {
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : realize_widget : %s\n",XtName(a_this));
#endif

    // Have to create window ourselves due to OpenGL that compells it's visual.
    // In principle colormap is correctly set in a_watbsy.
  
    OpenGLAreaPart& athis = _athis(a_this);
    
    ::XtCreateWindow(a_this,(unsigned int)InputOutput,athis.visual,*a_mask,a_watbs);
  
    // Call the Realize procedure (XtInheritRealize) :
    if(widget_class()->core_class.superclass->core_class.realize!=NULL)
      (widget_class()->core_class.superclass->core_class.realize)(a_this, a_mask, a_watbs);
  
    // If window is delete, all seems ok :
    if(athis.installColormap==True) install_colormap(a_this);
  
    //make_current(a_this);
  
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : realize_widget : end\n");
#endif
  }

  static void destroy_widget(Widget a_this) {
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : destroy_widget : begin\n");
#endif
    OpenGLAreaPart& athis = _athis(a_this);
    if(athis.installColormap==True) {
      uninstall_colormap (a_this);
      athis.installColormap    = False;
      ::XFreeColormap(XtDisplay(a_this),a_this->core.colormap);
    }
    if(athis.glContext!=NULL) {
      ::glXMakeCurrent(XtDisplay(a_this),None,NULL);
      ::glXDestroyContext(XtDisplay(a_this),athis.glContext);
      athis.glContext = NULL;
    }
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : destroy_widget : end\n");
#endif
  }

  static Boolean set_values(Widget a_current,Widget,Widget a_this,ArgList,Cardinal*) {
    OpenGLAreaPart& athis = _athis(a_this);
    if(athis.doubleBufferOn != ((OpenGLAreaWidget)a_current)->openGLArea.doubleBufferOn) {
      // Can't change buffering here if X window is created.
      // With OpenGL, buffering fix parameter of the X window.
      // Buffering must be choosen before the execution of the
      // Realize method that create the window.
      if(XtIsRealized(a_this) && (athis.installColormap==True)) {
        CWarn("Can't change buffering after \"realization\" of the widget.\n");
        athis.doubleBufferOn = ((OpenGLAreaWidget)a_current)->openGLArea.doubleBufferOn;
      }
    }
    return False;
  }
  
  static void change_widget_size(Widget a_this) {
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : change_widget_size : %s\n",XtName(a_this));
#endif

    // Call the Resize procedure (XtInheritResize) :
    if(widget_class()->core_class.superclass->core_class.resize!=NULL)
      (widget_class()->core_class.superclass->core_class.resize)(a_this);
  
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : change_widget_size : end\n");
#endif
}

  static void draw_widget(Widget  a_this,XEvent* a_event,Region a_region) {
#ifdef OPENGLAREA_DEBUG
    printf("debug : OpenGLArea : draw_widget : %s\n",XtName(a_this));
#endif

    if(widget_class()->core_class.superclass->core_class.expose!=NULL)
      (widget_class()->core_class.superclass->core_class.expose)(a_this,a_event,a_region);

    if(make_current(a_this)==1) {
#ifdef OPENGLAREA_DEBUG
      printf("debug : OpenGLArea : draw_widget : %s : make_current ok : call paintCallback...\n",XtName(a_this));
#endif
      XoAnyCallbackStruct value;
      value.reason = XoCR_PAINT;
      value.event = a_event;
      ::XtCallCallbacks(a_this,XoNpaintCallback,(XtPointer)&value);
      ::glXSwapBuffers(XtDisplay(a_this),XtWindow(a_this));
      ::glXMakeCurrent(XtDisplay(a_this),None,NULL);
    }
  
#ifdef OPENGLAREA_DEBUG
  printf("debug : OpenGLArea : draw_widget : end\n");
#endif
  }

protected:
  static OpenGLAreaPart& _athis(Widget a_this) {return *(&(((OpenGLAreaWidget)a_this)->openGLArea));}
  static void CWarn(const char* a_msg) {
    ::printf("%s",a_msg);
  }
  static void CWarnF(const char* a_format,...) {
    va_list args;
    va_start(args,a_format);
    ::vprintf(a_format,args);
    va_end(args);
  }
  static int make_current(Widget a_this) {
    if(!XtIsRealized(a_this)) return 0;
    OpenGLAreaPart& athis = _athis(a_this);
    if(athis.glContext==NULL) return 0;
    return (int)::glXMakeCurrent(XtDisplay(a_this),XtWindow(a_this),athis.glContext);
  }

  static void event_handler(Widget a_this,XtPointer,XEvent* a_event ,Boolean*) {
    XoAnyCallbackStruct value;
    value.reason = XoCR_EVENT;
    value.event = a_event;
    ::XtCallCallbacks(a_this,XoNeventCallback,(XtPointer)&value);
  }

  static void install_colormap(Widget a_this) {
    // From Mesa/widgets/GLwDrawingArea.c/post_colormap routine.
    // Could use also XtSetWMColormapWindows.
    if( !XtIsWidget(a_this) || !XtIsRealized(a_this) ) return;
    Widget shell = get_shell(a_this);
    if(shell==NULL) return;
    Display* display = XtDisplay (a_this);
    Window wthis   = XtWindow  (a_this);
    Window wshell  = XtWindow  (shell);
    Window*           ws = NULL;
    int               wn = 0;
    ::XGetWMColormapWindows (display,wshell, &ws, &wn);
    // Check if colormap of this is a colormap of a Window in list :
    XWindowAttributes watbs;
    XGetWindowAttributes  (display,wthis,&watbs);
    Colormap cmapthis = watbs.colormap;
    int found                 = -1;
    for(int count=0;count<wn;count++) {
      Colormap             cmap;
      XGetWindowAttributes (display,ws[count],&watbs);
      cmap                 = watbs.colormap;
      if(cmap==cmapthis) {
        ::XFree (ws);
        return;
      }
      if(ws[count]==wshell) {
        found = count;
      }
    }
    // Have to add window of this in list :
    if(wn==0) {
      if(ws!=NULL) ::XFree(ws);
      ws = (Window*)::malloc( 2 * sizeof(Window));
    } else {
      ws = (Window*)::realloc(ws,(wn + 2) * sizeof(Window));
    }
    if(ws==NULL) return;
    if(found==-1) {
      // Window of shell not in list :
      ws[wn] = wthis; wn++;
      ws[wn] = wshell;wn++;
    } else {
      ws[found] = wthis;
      ws[wn]    = wshell; wn++;  // Shell must be last.
    }
    if (::XSetWMColormapWindows(display,wshell, ws, wn)==0) {
      CWarnF ("install_colormap: can't install colormap of %s in %s.\n",XtName(a_this),XtName(shell));
    }
    ::free(ws);
  }

  static void uninstall_colormap(Widget a_this) {
    if( !XtIsWidget(a_this) || !XtIsRealized(a_this) ) return;
    Widget shell = get_shell (a_this);
    if(shell==NULL) return;
    Display* display = XtDisplay (a_this);
    Window wthis     = XtWindow  (a_this);
    Window wshell    = XtWindow  (shell);
    Window*           ws  = NULL;
    int               wn  = 0;
    ::XGetWMColormapWindows (display,wshell, &ws, &wn);
    if( (wn==0) || (ws==NULL) ) return;
    Window* nws = (Window*)::malloc( wn  * sizeof(Window));
    if(nws==NULL) {
      ::XFree (ws);
      return;
    }
    int nwn = 0;
    for(int count=0;count<wn;count++) {
      if(ws[count]!=wthis) {
        nws[nwn] = ws[count];
        nwn++;
      }
    }
    if(wn!=nwn) {
      if (::XSetWMColormapWindows(display,wshell, nws, nwn)==0) {
        CWarnF("uninstall_colormap: can't install colormap of %s in %s.\n",XtName(a_this),XtName(shell));
      }
    }
    ::XFree (ws);
    ::free (nws);
  }
  
  static Widget get_shell(Widget a_this) {
    Widget widget = a_this;
    while(1) {
      if(widget==NULL) return NULL;
      if(XtIsShell(widget)) return widget;
      widget = XtParent(widget);
    }
  }

public:
  static WidgetClass widget_class() {
    static XtResource s_resources [] = {
      {(String)XoNdoubleBufferOn,(String)"DoubleBufferOn",XtRBoolean,sizeof(Boolean),
       XtOffset(OpenGLAreaWidget,openGLArea.doubleBufferOn),XtRImmediate,(XtPointer)True},
      {(String)XoNpaintCallback,XtCCallback,XtRCallback,sizeof(XtCallbackList),
       XtOffset(OpenGLAreaWidget,openGLArea.paintCallback),XtRImmediate,(XtPointer)NULL},
      {(String)XoNeventCallback,XtCCallback,XtRCallback,sizeof(XtCallbackList),
       XtOffset(OpenGLAreaWidget,openGLArea.eventCallback),XtRImmediate,(XtPointer)NULL}
    };

    static OpenGLAreaClassRec s_openGLAreaClassRec = {
      // Core Class Part :
      {
        (WidgetClass) &compositeClassRec, // pointer to superclass ClassRec   
        (String)"OpenGLArea",             // widget resource class name       
        sizeof(OpenGLAreaRec),           // size in bytes of widget record   
        initialize_class,                // class_initialize                 
        NULL,                            // dynamic initialization           
        FALSE,                           // has class been initialized?      
        initialize_widget,               // initialize                       
        NULL,                            // notify that initialize called    
        realize_widget,                  // XCreateWindow for widget         
        NULL,                            // widget semantics name to proc mapWidget
        0,                               // number of entries in actions     
        s_resources,                     // resources for subclass fields    
        XtNumber(s_resources),           // number of entries in resources   
        NULLQUARK,                       // resource class quarkified        
        TRUE,                            // compress MotionNotify for widget 
        TRUE,                            // compress Expose events for widget
        TRUE,                            // compress enter and leave events  
        TRUE,                            // select for VisibilityNotify      
        destroy_widget,                  // free data for subclass pointers  
        change_widget_size,              // geom manager changed widget size 
        draw_widget,                     // rediplay window                  
        set_values,                      // set subclass resource values     
        NULL,                            // notify that SetValues called    
        XtInheritSetValuesAlmost,        // SetValues got "Almost" geo reply
        NULL,                            // notify that get_values called    
        XtInheritAcceptFocus,            // assign input focus to widget     
        XtVersion,                       // version of intrinsics used       
        NULL,                            // list of callback offsets         
        XtInheritTranslations,           // translations                     
        XtInheritQueryGeometry,          // return preferred geometry        
        XtInheritDisplayAccelerator,     // display your accelerator         
        NULL                             // pointer to extension record      
      },
      // Composite Class Part :
      {
        XtInheritGeometryManager,   // geometry manager for children   
        XtInheritChangeManaged,     // change managed state of child   
        XtInheritInsertChild,       // physically add child to parent  
        XtInheritDeleteChild,       // physically remove child             
        NULL                        // pointer to extension record     
      },
      // OpenGLArea :
      {
        NULL
      }
    };
    return (WidgetClass)&s_openGLAreaClassRec;
  }
};

}}

#endif