//
// "$Id: fl_dnd_win32.cxx,v 1.12 2004/07/19 23:33:05 laza2000 Exp $"
//
// Drag & Drop code for the Fast Light Tool Kit (FLTK).
// This is code for dragging *out* of the application. Code for dragging
// into the application is in win32.cxx
//
// Copyright 1998-2003 by Bill Spitzak and others.
//
// 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, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems to "fltk-bugs@fltk.org

// I believe this was written by Matthias Melcher, correct?

#include <fltk/events.h>
#include <fltk/Window.h>
#include <fltk/x.h>

// All of the following code requires GCC 3.x or a non-GNU compiler...
#if !defined(__GNUC__) || __GNUC__ >= 3

#include <ole2.h>
#include <shellapi.h>

HANDLE fl_global_selection(int clipboard);
HANDLE fl_global_selection_ansi(int clipboard);

// this class is needed to allow FLTK apps to be a DnD source
class FLDropSource : public IDropSource
{
  DWORD m_cRefCount;
public:
  FLDropSource() { m_cRefCount = 0; }
  HRESULT STDMETHODCALLTYPE QueryInterface( REFIID riid, LPVOID *ppvObject ) {
    if (IID_IUnknown==riid || IID_IDropSource==riid)
    {
      *ppvObject=this;
      ((LPUNKNOWN)*ppvObject)->AddRef();
      return S_OK;
    }
    *ppvObject = NULL;
    return E_NOINTERFACE;
  }
  ULONG STDMETHODCALLTYPE AddRef() { return ++m_cRefCount; }
  ULONG STDMETHODCALLTYPE Release() {
    long nTemp;
    nTemp = --m_cRefCount;
    if(nTemp==0)
      delete this;
    return nTemp;
  }
  STDMETHODIMP GiveFeedback( ULONG ) { return DRAGDROP_S_USEDEFAULTCURSORS; }
  STDMETHODIMP QueryContinueDrag( BOOL esc, DWORD keyState ) { 
    if ( esc ) 
      return DRAGDROP_S_CANCEL;
    if ( !(keyState & MK_LBUTTON) ) 
      return DRAGDROP_S_DROP;
    return S_OK;
  }
};

/*
 * this is the actual object that FLTK can drop somewhere
 * - the implementation is minimal, but it should work with all decent Win32 drop targets
 */
class FLDataObject : public IDataObject
{
  DWORD m_cRefCount;
public:
  FLDataObject() { m_cRefCount = 1; }
  HRESULT STDMETHODCALLTYPE QueryInterface( REFIID riid, LPVOID *ppvObject ) {
    if (IID_IUnknown==riid || IID_IDataObject==riid)
    {
      *ppvObject=this;
      ((LPUNKNOWN)*ppvObject)->AddRef();
      return S_OK;
    }
    *ppvObject = NULL;
    return E_NOINTERFACE;
  }
  ULONG STDMETHODCALLTYPE AddRef() { return ++m_cRefCount; }
  ULONG STDMETHODCALLTYPE Release() {
    long nTemp;
    nTemp = --m_cRefCount;
    if(nTemp==0)
      delete this;
    return nTemp;
  }
  // GetData currently allows ASCII text through Global Memory only
  HRESULT STDMETHODCALLTYPE GetData( FORMATETC *pformatetcIn, STGMEDIUM *pmedium ) {
    if ((pformatetcIn->dwAspect & DVASPECT_CONTENT) &&
        (pformatetcIn->tymed & TYMED_HGLOBAL) &&
        (pformatetcIn->cfFormat == CF_UNICODETEXT))
    {
      pmedium->tymed	      = TYMED_HGLOBAL;
      pmedium->hGlobal	      = fl_global_selection(0);
      pmedium->pUnkForRelease = NULL;
      return S_OK;
    }
    if ((pformatetcIn->dwAspect & DVASPECT_CONTENT) &&
        (pformatetcIn->tymed & TYMED_HGLOBAL) &&
        (pformatetcIn->cfFormat == CF_TEXT))
    {
      pmedium->tymed	      = TYMED_HGLOBAL;
      pmedium->hGlobal	      = fl_global_selection_ansi(0);
      pmedium->pUnkForRelease = NULL;
      return S_OK;
    }
    return DV_E_FORMATETC;
  }
  HRESULT STDMETHODCALLTYPE QueryGetData( FORMATETC *pformatetc )
  {
    if ((pformatetc->dwAspect & DVASPECT_CONTENT) &&
        (pformatetc->tymed & TYMED_HGLOBAL) &&
        ((pformatetc->cfFormat == CF_UNICODETEXT) || (pformatetc->cfFormat == CF_TEXT)) )
      return S_OK;
    return DV_E_FORMATETC;	
  }  
  // all the following methods are not really needed for a DnD object
  HRESULT STDMETHODCALLTYPE GetDataHere( FORMATETC *pformatetcIn, STGMEDIUM *pmedium) { return E_NOTIMPL; }
  HRESULT STDMETHODCALLTYPE GetCanonicalFormatEtc( FORMATETC *in, FORMATETC *out) { return E_NOTIMPL; }
  HRESULT STDMETHODCALLTYPE SetData( FORMATETC *pformatetc, STGMEDIUM *pmedium, BOOL fRelease) { return E_NOTIMPL; }
  HRESULT STDMETHODCALLTYPE EnumFormatEtc( DWORD dir, IEnumFORMATETC **ppenumFormatEtc) { return E_NOTIMPL; }
  HRESULT STDMETHODCALLTYPE DAdvise( FORMATETC *pformatetc, DWORD advf,
      IAdviseSink *pAdvSink, DWORD *pdwConnection) { return E_NOTIMPL; }
  HRESULT STDMETHODCALLTYPE DUnadvise( DWORD dwConnection) { return E_NOTIMPL; }
  HRESULT STDMETHODCALLTYPE EnumDAdvise( IEnumSTATDATA **ppenumAdvise) { return E_NOTIMPL; }
};


/*
 * drag and drop whatever is in the cut-copy-paste buffer
 * - create a selection first using: 
 *     copy(const char *stuff, int len, 0)
 */
bool fltk::dnd()
{
  DWORD dropEffect;
  ReleaseCapture();

  FLDataObject *fdo = new FLDataObject;
  fdo->AddRef();
  FLDropSource *fds = new FLDropSource;
  fds->AddRef();

  HRESULT ret = DoDragDrop( fdo, fds, DROPEFFECT_MOVE|DROPEFFECT_LINK|DROPEFFECT_COPY, &dropEffect );

  fdo->Release();
  fds->Release();

  // Windows handled the mouse release, remember that:
  fltk::pushed_ = 0;
  fltk::e_state &= ~fltk::ANY_BUTTON;

  return ret==DRAGDROP_S_DROP; // or DD_S_CANCEL
}
#else
bool fltk::dnd()
{
  // Always indicate DnD failed when using GCC < 3...
  return false;
}
#endif // !__GNUC__ || __GNUC__ >= 3


//
// End of "$Id: fl_dnd_win32.cxx,v 1.12 2004/07/19 23:33:05 laza2000 Exp $".
//