/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     
 * Port to the D programming language:
 *     Jacob Carlborg <doob@me.com>
 *******************************************************************************/
module dwt.dnd.DND;

import dwt.dwthelper.utils;

 
import dwt.DWT;
import dwt.DWTError;
import dwt.DWTException;

/**
 *
 * Class DND contains all the constants used in defining a 
 * DragSource or a DropTarget.
 *
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class DND {
    
    /**
     * The transfer mechanism for data that is being cut
     * and then pasted or copied and then pasted (value is 1).
     * 
     * @see Clipboard
     * 
     * @since 3.1
     */
    public const static int CLIPBOARD = 1 << 0;
    
    /**
     * The transfer mechanism for clients that use the selection 
     * mechanism (value is 2).
     * 
     * @see Clipboard
     *
     * @since 3.1
     */
    public const static int SELECTION_CLIPBOARD = 1 << 1;

    /**
     * Drag and Drop Operation: no drag/drop operation performed
     * (value is 0).
     */
    public const static int DROP_NONE = 0;
    
    /**
     * Drag and Drop Operation: a copy of the data in the drag source is 
     * added to the drop target (value is 1 &lt;&lt; 0).
     */
    public const static int DROP_COPY = 1 << 0;
    
    /**
     * Drag and Drop Operation: a copy of the data is added to the drop target and 
     * the original data is removed from the drag source (value is 1 &lt;&lt; 1).
     */
    public const static int DROP_MOVE = 1 << 1;
    
    /**
     * Drag and Drop Operation: the drop target makes a link to the data in 
     * the drag source (value is 1 &lt;&lt; 2).
     */
    public const static int DROP_LINK = 1 << 2;
    
    /**
     * Drag and Drop Operation: the drop target moves the data and the drag source removes 
     * any references to the data and updates its display.  This is not available on all platforms
     * and is only used when a non-DWT application is the drop target.  In this case, the DWT 
     * drag source is informed in the dragFinished event that the drop target has moved the data.
     * (value is 1 &lt;&lt; 3).
     * 
     * @see DragSourceListener#dragFinished
     */
    public const static int DROP_TARGET_MOVE = 1 << 3;
    
    /**
     * Drag and Drop Operation: During a dragEnter event or a dragOperationChanged, if no modifier keys
     * are pressed, the operation is set to DROP_DEFAULT.  The application can choose what the default 
     * operation should be by setting a new value in the operation field.  If no value is choosen, the
     * default operation for the platform will be selected (value is 1 &lt;&lt; 4).
     * 
     * @see DropTargetListener#dragEnter
     * @see DropTargetListener#dragOperationChanged
     * @since 2.0 
     */
    public const static int DROP_DEFAULT = 1 << 4;
    
    /**
     * DragSource Event: the drop has successfully completed or has been terminated (such as hitting 
     * the ESC key); perform cleanup such as removing data on a move operation (value is 2000).
     */
    public static const int DragEnd     = 2000;
    
    /**
     * DragSource Event: the data to be dropped is required from the drag source (value is 2001).
     */
    public static const int DragSetData = 2001;
    
    /**
     * DropTarget Event: the cursor has entered the drop target boundaries (value is 2002).
     */
    public static const int DragEnter   = 2002;
    
    /**
     * DropTarget Event: the cursor has left the drop target boundaries OR the drop
     * operation has been cancelled (such as by hitting ECS) OR the drop is about to 
     * happen (user has released the mouse button over this target) (value is 2003).
     */
    public static const int DragLeave   = 2003;
    
    /**
     * DropTarget Event: the cursor is over the drop target (value is 2004).
     */
    public static const int DragOver    = 2004;
    
    /**
     * DropTarget Event: the operation being performed has changed usually due to the user 
     * changing the selected modifier keys while dragging (value is 2005).
     */
    public static const int DragOperationChanged = 2005;
    
    /**
     * DropTarget Event: the data has been dropped (value is 2006).
     */
    public static const int Drop = 2006;
    
    /**
     * DropTarget Event: the drop target is given a last chance to modify the drop (value is 2007).
     */
    public static const int DropAccept  = 2007;
    
    /**
     * DragSource Event: a drag is about to begin (value is 2008).
     */
    public static const int DragStart = 2008;

    /**
     * DropTarget drag under effect: No effect is shown (value is 0).
     */
    public static const int FEEDBACK_NONE = 0;
    
    /**
     * DropTarget drag under effect: The item under the cursor is selected; applies to tables
     * and trees (value is 1).
     */
    public static const int FEEDBACK_SELECT = 1;
    
    /**
     * DropTarget drag under effect: An insertion mark is shown before the item under the cursor; applies to 
     * trees (value is 2).
     */
    public static const int FEEDBACK_INSERT_BEFORE = 2;
    
    /**
     * DropTarget drag under effect:An insertion mark is shown after the item under the cursor; applies to
     * trees (value is 4).
     */ 
    public static const int FEEDBACK_INSERT_AFTER = 4;
    
    /**
     * DropTarget drag under effect: The widget is scrolled up or down to allow the user to drop on items that 
     * are not currently visible;  applies to tables and trees (value is 8).
     */ 
    public static const int FEEDBACK_SCROLL = 8;
    
    /**
     * DropTarget drag under effect: The item currently under the cursor is expanded to allow the user to 
     * select a drop target from a sub item; applies to trees (value is 16).
     */ 
    public static const int FEEDBACK_EXPAND = 16;

    /**
     * Error code: drag source can not be initialized (value is 2000).
     */
    public static const int ERROR_CANNOT_INIT_DRAG = 2000;
    
    /**
     * Error code: drop target cannot be initialized (value is 2001).
     */
    public static const int ERROR_CANNOT_INIT_DROP = 2001;
    
    /**
     * Error code: Data can not be set on system clipboard (value is 2002).
     */
    public static const int ERROR_CANNOT_SET_CLIPBOARD = 2002;
    
    /**
     * Error code: Data does not have correct format for type (value is 2003).
     * @since 3.1
     */
    public static const int ERROR_INVALID_DATA = 2003;
    
    /**
     * DropTarget Key: The string constant for looking up the drop target 
     * for a control using <code>getData(String)</code>. When a drop target 
     * is created for a control, it is stored as a property in the control 
     * using <code>setData(String, Object)</code>.
     * 
     * @since 3.4
     */
    public static const String DROP_TARGET_KEY = "DropTarget"; //$NON-NLS-1$
    
    /**
     * DragSource Key: The string constant for looking up the drag source 
     * for a control using <code>getData(String)</code>. When a drag source 
     * is created for a control, it is stored as a property in the control 
     * using <code>setData(String, Object)</code>.
     * 
     * @since 3.4
     */
    public static const String DRAG_SOURCE_KEY = "DragSource"; //$NON-NLS-1$

    static const String INIT_DRAG_MESSAGE = "Cannot initialize Drag"; //$NON-NLS-1$
    static const String INIT_DROP_MESSAGE = "Cannot initialize Drop"; //$NON-NLS-1$
    static const String CANNOT_SET_CLIPBOARD_MESSAGE = "Cannot set data in clipboard"; //$NON-NLS-1$
    static const String INVALID_DATA_MESSAGE = "Data does not have correct format for type"; //$NON-NLS-1$

/**
 * Throws an appropriate exception based on the passed in error code.
 *
 * @param code the DND error code
 */
public static void error (int code) {
    error (code, 0);
}

/**
 * Throws an appropriate exception based on the passed in error code.
 * The <code>hresult</code> argument should be either 0, or the
 * platform specific error code.
 * <p>
 * In DND, errors are reported by throwing one of three exceptions:
 * <dl>
 * <dd>java.lang.IllegalArgumentException</dd>
 * <dt>thrown whenever one of the API methods is invoked with an illegal argument</dt>
 * <dd>dwt.DWTException (extends java.lang.RuntimeException)</dd>
 * <dt>thrown whenever a recoverable error happens internally in DWT</dt>
 * <dd>dwt.DWTError (extends java.lang.Error)</dd>
 * <dt>thrown whenever a <b>non-recoverable</b> error happens internally in DWT</dt>
 * </dl>
 * This method provides the logic which maps between error codes
 * and one of the above exceptions.
 * </p>
 *
 * @param code the DND error code.
 * @param hresult the platform specific error code.
 *
 * @see DWTError
 * @see DWTException
 * @see IllegalArgumentException
 */
public static void error (int code, int hresult) {      
    switch (code) {     
        /* OS Failure/Limit (fatal, may occur only on some platforms) */
        case DND.ERROR_CANNOT_INIT_DRAG:{
            String msg = DND.INIT_DRAG_MESSAGE;
            if (hresult !is 0) msg ~= " result = "~Integer.toString(hresult); //$NON-NLS-1$
            throw new DWTError (code, msg);
        }
        case DND.ERROR_CANNOT_INIT_DROP:{
            String msg = DND.INIT_DROP_MESSAGE;
            if (hresult !is 0) msg ~= " result = "~Integer.toString(hresult); //$NON-NLS-1$
            throw new DWTError (code, msg);
        }
        case DND.ERROR_CANNOT_SET_CLIPBOARD:{
            String msg = DND.CANNOT_SET_CLIPBOARD_MESSAGE;
            if (hresult !is 0) msg ~= " result = "~Integer.toString(hresult); //$NON-NLS-1$
            throw new DWTError (code, msg);
        }
        case DND.ERROR_INVALID_DATA:{
            String msg = DND.INVALID_DATA_MESSAGE;
            if (hresult !is 0) msg ~= " result = "~Integer.toString(hresult); //$NON-NLS-1$
            throw new DWTException (code, msg);
        }
        
        default:
    }
            
    /* Unknown/Undefined Error */
    DWT.error(code);
}

}