/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program 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 program 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 this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file ghost/intern/GHOST_DropTargetWin32.h
 *  \ingroup GHOST
 */

#ifndef __GHOST_DROPTARGETWIN32_H__
#define __GHOST_DROPTARGETWIN32_H__

#include <string.h>
#include <GHOST_Types.h>
#include "GHOST_WindowWin32.h"
#include "GHOST_SystemWin32.h"

class GHOST_DropTargetWin32 : public IDropTarget
{
public:
	/* IUnknownd implementation.
	 * Enables clients to get pointers to other interfaces on a given object 
	 * through the QueryInterface method, and manage the existence of the object
	 * through the AddRef and Release methods. All other COM interfaces are 
	 * inherited, directly or indirectly, from IUnknown. Therefore, the three 
	 * methods in IUnknown are the first entries in the VTable for every interface. 
	 */
	HRESULT __stdcall QueryInterface(REFIID riid, void **ppvObj);
	ULONG __stdcall AddRef(void);
	ULONG __stdcall Release(void);

	/* IDropTarget implementation
	 * + The IDropTarget interface is one of the interfaces you implement to
	 *   provide drag-and-drop operations in your application. It contains methods
	 *   used in any application that can be a target for data during a
	 *   drag-and-drop operation. A drop-target application is responsible for:
	 * 
	 *  - Determining the effect of the drop on the target application.
	 *  - Incorporating any valid dropped data when the drop occurs.
	 *  - Communicating target feedback to the source so the source application
	 *	  can provide appropriate visual feedback such as setting the cursor.
	 *  - Implementing drag scrolling.
	 *  - Registering and revoking its application windows as drop targets.
	 * 
	 * The IDropTarget interface contains methods that handle all these 
	 * responsibilities except registering and revoking the application window 
	 * as a drop target, for which you must call the RegisterDragDrop and the 
	 * RevokeDragDrop functions.
	 */
	
	HRESULT __stdcall DragEnter(IDataObject *pDataObject, DWORD grfKeyState, POINTL pt, DWORD *pdwEffect);
	HRESULT __stdcall DragOver(DWORD grfKeyState, POINTL pt, DWORD *pdwEffect);
	HRESULT __stdcall DragLeave(void);
	HRESULT __stdcall Drop(IDataObject *pDataObject, DWORD grfKeyState, POINTL pt, DWORD *pdwEffect);

	/**
	 * Constructor
	 * With the modifier keys, we want to distinguish left and right keys.
	 * Sometimes this is not possible (Windows ME for instance). Then, we want
	 * events generated for both keys.
	 * \param window	The window to register as drop target.
	 * \param system	The associated system.
	 */
	GHOST_DropTargetWin32(GHOST_WindowWin32 *window, GHOST_SystemWin32 *system);

	/**
	 * Destructor
	 * Do NOT destroy directly. Use Release() instead to make COM happy.
	 */
	~GHOST_DropTargetWin32();

private:

	/* Internal helper functions */

	/**
	 * Base the effect on those allowed by the dropsource.
	 * \param dwAllowed Drop sources allowed drop effect.
	 * \return The allowed drop effect.
	 */
	DWORD allowedDropEffect(DWORD dwAllowed);

	/**
	 * Query DataObject for the data types it supports.
	 * \param pDataObject Pointer to the DataObject.
	 * \return GHOST data type.
	 */
	GHOST_TDragnDropTypes getGhostType(IDataObject *pDataObject);

	/**
	 * Get data to pass in event.
	 * It checks the type and calls specific functions for each type.
	 * \param pDataObject Pointer to the DataObject.
	 * \return Pointer to data.
	 */
	void *getGhostData(IDataObject *pDataObject);

	/**
	 * Allocate data as file array to pass in event.
	 * \param pDataObject Pointer to the DataObject.
	 * \return Pointer to data.
	 */
	void *getDropDataAsFilenames(IDataObject *pDataObject);

	/**
	 * Allocate data as string to pass in event.
	 * \param pDataObject Pointer to the DataObject.
	 * \return Pointer to data.
	 */
	void *getDropDataAsString(IDataObject *pDataObject);

	/**
	 * Convert Unicode to ANSI, replacing unconvertable chars with '?'.
	 * The ANSI codepage is the system default codepage, 
	 * and can change from system to system.
	 * \param in LPCWSTR.
	 * \param out char *. Is set to NULL on failure.
	 * \return 0 on failure. Else the size of the string including '\0'.
	 */
	int WideCharToANSI(LPCWSTR in, char * &out);

	/* Private member variables */
	/* COM reference count. */
	LONG m_cRef;
	/* Handle of the associated window. */
	HWND m_hWnd;
	/* The associated GHOST_WindowWin32. */
	GHOST_WindowWin32 *m_window;
	/* The System. */
	GHOST_SystemWin32 *m_system;
	/* Data type of the dragged object */
	GHOST_TDragnDropTypes m_draggedObjectType;

#ifdef WITH_CXX_GUARDEDALLOC
	MEM_CXX_CLASS_ALLOC_FUNCS("GHOST:GHOST_DropTargetWin32")
#endif
};

#endif  // __GHOST_DROPTARGETWIN32_H__
