/*
This is a modified DND 1.0 library which does not depend on Xt
event handling.
Modifications Copyright (c) 1997 Oliver Graf <ograf@fga.de>

Original DND lib
Copyright (C) 1996 César Crusius

This file is part of the DND Library.  This library is free
software; you can redistribute it and/or modify it under the terms of
the GNU Library General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version.  This library 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 Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/* #define DEBUG */

#include "offix.h"
#include <X11/cursorfont.h>
#include <X11/Xatom.h>
#include <X11/Xmu/WinUtil.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

/* Local variables */
static Display		*dpy;		/* current display		*/
static int		DragPrecision;	/* minimum dx,dy to start drag	*/
static int		Dragging;	/* Drag state flag		*/
static int		DataOK;		/* Non-zero if data registered	*/
static Atom		DndProtocol;	/* ClientMessage identifier	*/
static Atom		DndSelection;	/* For the data transfers	*/
static Atom             OldDndProtocol; /* Version 0 atom               */
static Atom             OldDndSelection;/* Version 0 atom               */
static Atom		WM_STATE;	/* Needed for icon stuff	*/
static Window		Target;		/* Drop window			*/
static Widget		MainWidget;	/* Main widget of application	*/
static int		DataType;	/* Current drag data type	*/
static int		RootFlag;	/* Non-zero if dropped on root	*/
static XColor	        Black,White;    /* For the cursors              */

/*=========================================================================
 * Data for the standard Dnd cursors
 *=========================================================================*/
#include "offix-cursors.h"

/*=============================================================== CursorData
 * CursorData contains all the data for the cursors bitmaps
 *==========================================================================*/
typedef struct
{
  int	Width,Height;
  unsigned char	*ImageData,*MaskData;
  int	HotSpotX,HotSpotY;
  Pixmap	ImagePixmap,MaskPixmap;
  Cursor	CursorID;
} CursorData;

static CursorData DndCursor[DndEND]={
  { 0,0,NULL,NULL,0,0,0 },
  { grey_width,	grey_height,grey_bits,grey_mask_bits,
    grey_x_hot,grey_y_hot},
  { file_width,file_height,file_bits,file_mask_bits,
    file_x_hot,file_y_hot},
  { files_width,files_height,files_bits,files_mask_bits,
    files_x_hot,files_y_hot},
  { text_width,text_height,text_bits,text_mask_bits,
    text_x_hot,text_y_hot },
  { dir_width,dir_height,dir_bits,dir_mask_bits,
    dir_x_hot,dir_y_hot },
  { link_width,link_height,link_bits,link_mask_bits,
    link_x_hot,link_y_hot},
  { app_width,app_height,app_bits,app_mask_bits,
    app_x_hot,app_y_hot },
  { url_width,url_height,url_bits,url_mask_bits,
    url_x_hot,url_y_hot },
  { mime_width,mime_height,mime_bits,mime_mask_bits,
    mime_x_hot,mime_y_hot }
};

/* Local prototypes */
int DndIsDragging(void);
void DndStartAction(Widget widget,
		    XtPointer data,
		    XEvent *event,
		    Boolean *p);
void DndPropertyHandler(Widget widget,
			XtPointer data,
			XEvent *event,
			Boolean *p);

/*======================================================== DndHandleDragging
 * Takes care of the drag and drop process. Wait until the pointer had moved
 * a little. Then takes control over the pointer until the buttons are
 * released. After that send a Drag And Drop ClientMessage event. Returns
 * non-zero if a drop did take place.
 *===========================================================================*/
int
DndHandleDragging(Widget widget,XEvent *event)
{
  XEvent Event;
  Window root	= RootWindowOfScreen(XtScreenOfObject(widget));
  XtAppContext app= XtWidgetToApplicationContext(widget);
  Window  DispatchWindow;
  int DropX,DropY;

  if(Dragging) return 0;

  XUngrabPointer(dpy,CurrentTime);
  /* Take control over the pointer */
  XGrabPointer(dpy,root,False,
	       ButtonMotionMask|ButtonPressMask|ButtonReleaseMask,
	       GrabModeSync,GrabModeAsync,root,
	       DndCursor[DataType].CursorID,
	       CurrentTime);

  /* Wait for button release */
  Dragging=1; RootFlag=0;
  while(Dragging)
    {
      XAllowEvents(dpy,SyncPointer,CurrentTime);
      XtAppNextEvent(app,&Event);
      switch(Event.type)
	{
	case ButtonRelease:
	  if(Event.xbutton.subwindow)
	    RootFlag=0;
	  else
	    RootFlag=1;
	  Dragging=0;
	  break;
	default:
	  XtDispatchEvent(&Event);
	  break;
	}
    }
  DataOK=0;
  /* Now release the pointer */
  XUngrabPointer(dpy,CurrentTime);
  /* Try to guess if the drop occurred in the root window */
  if(!RootFlag)
    {
      Target=XmuClientWindow(dpy,Event.xbutton.subwindow);
      if (Target==Event.xbutton.subwindow)
	DispatchWindow=Target;
      else
	DispatchWindow=PointerWindow;
    }
  else
    Target=DispatchWindow=XtWindow(MainWidget);

  /* Now build the event structure */
  DropX=Event.xbutton.x_root;
  DropY=Event.xbutton.y_root;
  Event.xclient.type		= ClientMessage;
  Event.xclient.display		= dpy;
  Event.xclient.message_type	= DndProtocol;
  Event.xclient.format		= 32;
  Event.xclient.window		= Target;
  Event.xclient.data.l[0]      	= DataType;
  Event.xclient.data.l[1]      	= (long)event->xbutton.state;
  Event.xclient.data.l[2]      	= (long)XtWindow(widget);
  Event.xclient.data.l[3]      	= DropX + 65536L*(long)DropY;
  Event.xclient.data.l[4]      	= 1;

  /* Send the drop message */
  XSendEvent(dpy,DispatchWindow,True,NoEventMask,&Event);
  /* Send an old style version of the message just in case */
  Event.xclient.message_type = OldDndProtocol;
  XSendEvent(dpy,DispatchWindow,True,NoEventMask,&Event);

#ifdef DEBUG
  fprintf(stderr,"ClientMessage sent to 0x%x(0x%x).\n",
	  DispatchWindow,Target);
  fprintf(stderr,"The drop coordinates are (%d,%d).\n",DropX,DropY);
#endif

  return 1;
}

/*=============================================================== DndIsIcon
 * Return non-zero if the application is iconic (widget=toplevel)
 *========================================================================*/
int
DndIsIcon(Widget widget)
{
    Atom JunkAtom;
    int JunkInt;
    unsigned long WinState,JunkLong;
    unsigned char *Property;

    XGetWindowProperty(dpy,XtWindow(widget),WM_STATE,
		       0L,2L,False,AnyPropertyType,
		       &JunkAtom,&JunkInt,&WinState,&JunkLong,
		       &Property);
    WinState=(unsigned long)(*((long*)Property));
    return (WinState==3);
}

/*============================================================ DndInitialize
 * Must be called anywhere before the top level widget creation and the
 * main loop. Initialize global variables and bind the DndDispatch function
 * to the top level widget. Creates the cursors to be used in drag actions.
 *=========================================================================*/
void
DndInitialize(Widget shell)
{
    int	 screen,i;
    Colormap colormap;
    Window	 root;

    dpy	= XtDisplayOfObject(shell);
    screen	= DefaultScreen(dpy);
    colormap= DefaultColormap(dpy,screen);
    root	= DefaultRootWindow(dpy);


    Black.pixel=BlackPixel(dpy,screen);
    White.pixel=WhitePixel(dpy,screen);
    XQueryColor(dpy,colormap,&Black);
    XQueryColor(dpy,colormap,&White);

    for(i=1;i!=DndEND;i++)
    {
	DndCursor[i].ImagePixmap=
	    XCreateBitmapFromData(dpy,root,
				  (char *) DndCursor[i].ImageData,
				  DndCursor[i].Width,
				  DndCursor[i].Height);
	DndCursor[i].MaskPixmap=
	    XCreateBitmapFromData(dpy,root,
				  (char *) DndCursor[i].MaskData,
				  DndCursor[i].Width,
				  DndCursor[i].Height);
	DndCursor[i].CursorID=
	    XCreatePixmapCursor(dpy,DndCursor[i].ImagePixmap,
				DndCursor[i].MaskPixmap,
				&Black,&White,
				DndCursor[i].HotSpotX,
				DndCursor[i].HotSpotY);
    }

    DndCursor[0].CursorID=XCreateFontCursor(dpy,XC_question_arrow);

    /* These two are for older versions */
    OldDndProtocol=XInternAtom(dpy,"DndProtocol",FALSE);
    OldDndSelection=XInternAtom(dpy,"DndSelection",FALSE);
    /* Now the correct stuff */
    DndProtocol=XInternAtom(dpy,"_DND_PROTOCOL",FALSE);
    DndSelection=XInternAtom(dpy,"_DND_SELECTION",FALSE);

    WM_STATE=XInternAtom(dpy,"WM_STATE",True);
    Dragging=0;
    DragPrecision=10;
    RootFlag=0;
    MainWidget=shell;
}

int
DndIsDragging(void)
{
  return Dragging;
}

/*================================================================= DndSetData
 * Updates the selection data.
 *===========================================================================*/
void
DndSetData(int Type,unsigned char *Data,unsigned long Size)
{
  Window root = DefaultRootWindow(dpy);
  int AuxSize;
  unsigned char *AuxData;
  unsigned long BackSize=Size;

  if (DataOK) return;

  /* Set the data type -- allow any type */
  DataType = Type;

  /* Set the data */
  AuxData = Data;
  AuxSize = ( Size <= INT_MAX ? (int)Size : INT_MAX );
  XChangeProperty(dpy,root,DndSelection,XA_STRING,8,
		  PropModeReplace,Data,AuxSize);
  for(Size-=(unsigned long)AuxSize;Size;Size-=(unsigned long)AuxSize)
    {
      Data+=AuxSize;
      AuxSize = ( (Size<=(INT_MAX)) ? (int)Size : (INT_MAX) );
	XChangeProperty(dpy,root,DndSelection,XA_STRING,8,
			PropModeAppend,Data,AuxSize);
    }

  /* Set the data for old DND version */
  Size = BackSize;
  AuxData = Data;
  AuxSize = ( Size <= INT_MAX ? (int)Size : INT_MAX );
  XChangeProperty(dpy,root,OldDndSelection,XA_STRING,8,
		  PropModeReplace,Data,AuxSize);
  for(Size-=(unsigned long)AuxSize;Size;Size-=(unsigned long)AuxSize)
    {
      Data+=AuxSize;
      AuxSize = ( (Size<=(INT_MAX)) ? (int)Size : (INT_MAX) );
      XChangeProperty(dpy,root,OldDndSelection,XA_STRING,8,
		      PropModeAppend,Data,AuxSize);
    }

  /* Everything is now ok */
  DataOK=1;
}

/*================================================================== DndGetData
 * Return a pointer to the current data. See HOWTO for more details.
 *===========================================================================*/
void
DndGetData(XEvent *event, unsigned char **Data,unsigned long *Size)
{
  Window root	= DefaultRootWindow(dpy);

  Atom ActualType,ActualDndSelection;
  int	ActualFormat;
  unsigned long RemainingBytes;

  ActualDndSelection=(DndProtocolVersion(event) == 0L ?
		      OldDndSelection :
		      DndSelection );

  XGetWindowProperty(dpy,root,ActualDndSelection,
		     0L,1000000L,
		     FALSE,AnyPropertyType,
		     &ActualType,&ActualFormat,
		     Size,&RemainingBytes,
		     Data);
}

/*================================== DndDataType DndDragButtons DndSourceWidget
 *
 * Return information about the Dnd event received. If a non-dnd event is
 * passed, the function DndDataType returns DndNotDnd, and the others
 * return zero.
 *===========================================================================*/
int
DndDataType(XEvent *event)
{
  int Type;

  if(!DndIsDropMessage(event)) return DndNotDnd;
  Type=(int)(event->xclient.data.l[0]);
  if(Type>=DndEND) Type=DndUnknown;
  return Type;
}

int
DndDragButtons(XEvent *event)
{
  if(!DndIsDropMessage(event)) return 0;
  return (int)(event->xclient.data.l[1]);
}

Window
DndSourceWindow(XEvent *event)
{
  if(!DndIsDropMessage(event)) return 0;
  if(DndProtocolVersion(event)<__DragAndDropH__)
    /* We will try to do something about it, but nothing is certain */
    return XtWindow((Widget)(event->xclient.data.l[2]));
  return (Window)(event->xclient.data.l[2]);
}

void
DndDropRootCoordinates(XEvent *event,int *x,int *y)
{
  if(!DndIsDropMessage(event))
    {
      *x=0; *y=0;
      return;
    }

  /* If it is an old protocol version we try to get the coordinates
     using the current pointer position. Of course, the pointer may have
     moved since the drop, but there's nothing we can do about it.
  */
  if(DndProtocolVersion(event)<1L)
    {
      Window root_return,child_return;
      int win_x_return,win_y_return;
      unsigned int mask_return;

      XQueryPointer(dpy,DefaultRootWindow(dpy),
		    &root_return,&child_return,x,y,
		    &win_x_return,&win_y_return,&mask_return);
      return;
    }
  /* Thanks god you are using a decent protocol version */
  *x=(int)((long)(event->xclient.data.l[3]) & 0xffff);
  *y=(int)((long)(event->xclient.data.l[3])/65536);
}

void
DndDropCoordinates(Widget widget,XEvent *event,int *x,int *y)
{
  int root_x,root_y;
  Window child_return;

  DndDropRootCoordinates(event,&root_x,&root_y);
  XTranslateCoordinates(dpy,DefaultRootWindow(dpy),
			XtWindow(widget),
			root_x,root_y,
			x,y,
			&child_return);
}

long
DndProtocolVersion(XEvent *event)
{
  if(!DndIsDropMessage(event)) return -1L;
  return event->xclient.data.l[4];
}

int
DndIsDropMessage(XEvent *event)
{
  if(event->xclient.type != ClientMessage) return 0;
  if(event->xclient.message_type == OldDndProtocol &&
     event->xclient.data.l[4]==0) return 1;
  if(event->xclient.message_type == DndProtocol) return 1;
  return 0;
}

void
DndChangeCursor(int Type,int width,int height,char *image,char *mask,
		int hot_x,int hot_y)
{
  DndCursor[Type].ImagePixmap=
    XCreateBitmapFromData(dpy,DefaultRootWindow(dpy),
			  image,width,height);
  DndCursor[Type].MaskPixmap=
    XCreateBitmapFromData(dpy,DefaultRootWindow(dpy),
			  mask,width,height);
  DndCursor[Type].CursorID=
    XCreatePixmapCursor(dpy,DndCursor[Type].ImagePixmap,
			DndCursor[Type].MaskPixmap,
			&Black,&White,
			hot_x,hot_y);
}