/*
 *                 Sun Public License Notice
 * 
 * The contents of this file are subject to the Sun Public License
 * Version 1.0 (the "License"). You may not use this file except in
 * compliance with the License. A copy of the License is available at
 * http://www.sun.com/
 * 
 * The Original Code is NetBeans. The Initial Developer of the Original
 * Code is Sun Microsystems, Inc. Portions Copyright 1997-2000 Sun
 * Microsystems, Inc. All Rights Reserved.
 */

package org.openide.nodes;

import java.awt.datatransfer.*;
import java.awt.dnd.DnDConstants;
import java.io.IOException;
import java.text.MessageFormat;

import org.openide.util.datatransfer.*;

/** Class that contains specific datatransfer flavors and methods to work with
* nodes. There are flavors to allow a node
* to be copied or cut, and to decide its paste types.
* 
This is a dummy utility class--no instances are possible.
*
* @author Jaroslav Tulach
*/
public abstract class NodeTransfer extends Object {
    private NodeTransfer() {}

    /** Constants for drag-n-drop operations.
    * Are exactly the same as constants
    * in {@link DnDConstants}.
    */
    public static final int DND_NONE = DnDConstants.ACTION_NONE;
    public static final int DND_COPY = DnDConstants.ACTION_COPY;
    public static final int DND_MOVE = DnDConstants.ACTION_MOVE;
    public static final int DND_COPY_OR_MOVE = DnDConstants.ACTION_COPY | DnDConstants.ACTION_MOVE;
    public static final int DND_LINK = DnDConstants.ACTION_LINK;
    public static final int DND_REFERENCE = DnDConstants.ACTION_LINK;

    /** Constant indicating copying to the clipboard.
    * Equal to {@link #DND_COPY}, because
    * copy to clipboard and d'n'd copy should be the same.
    */
    public static final int CLIPBOARD_COPY = DND_COPY;

    /** Constant indicating cutting to the clipboard.
    */
    public static final int CLIPBOARD_CUT = 0x04;

    /** Generic mask for copying nodes (do not destroy the original).
    * Equal to {@link #CLIPBOARD_COPY} or {@link #DND_COPY}.
    */
    public static final int COPY = CLIPBOARD_COPY | DND_COPY;

    /** Generic mask for moving nodes (destroy the original).
    * Equal to {@link #CLIPBOARD_CUT} or {@link #DND_MOVE}.
    */
    public static final int MOVE = CLIPBOARD_CUT | DND_MOVE;



    /** Flavor for representation class {@link NodeTransfer.Paste}.
    * Provides methods for obtaining a set of {@link PasteType}s when
    * the target node is known.
    */
    private static final DataFlavor nodePasteFlavor = new DataFlavor (
                "application/x-java-openide-nodepaste;class=org.openide.nodes.Node", // NOI18N
                Node.getString ("LBL_nodePasteFlavor")
            );

    /** message format to create and parse the mimetype
    */
    private static MessageFormat dndMimeType = new MessageFormat (
                "application/x-java-openide-nodednd;class=org.openide.nodes.Node;mask={0}" // NOI18N
            );

    /** Creates data flavor for given mask of dnd actions.
    * @param actions any mask of dnd constants DND_* and CLIPBOARD_*
    */
    private static DataFlavor createDndFlavor (int actions) {
        try {
            return new DataFlavor (dndMimeType.format (new Object[] { new Integer (actions) }));
        } catch (ClassNotFoundException ex) {
            throw new InternalError ();
        }
    }

    /** Creates transferable that represents a node operation, such as cut-to-clipboard.
    * The transferable will be recognizable by {@link #node}, {@link #nodes}, and {@link #cookie}.
    *
    * @param n the node to create a transferable for
    * @param actions the action performed on the node
    * @return the transferable 
    */
    public static ExTransferable.Single transferable (final Node n, int actions) {
        return new ExTransferable.Single (createDndFlavor (actions)) {
                   public Object getData () {
                       return n;
                   }
               };
    }


    /** Obtain a node from a transferable.
    * Probes the transferable in case it includes a flavor corresponding
    * to a node operation (which you must specify a mask for).
    *
    * @param t transferable
    * @param action one of the DND_* or CLIPBOARD_* constants
    * @return the node or null
    */
    public static Node node (Transferable t, int action) {
        DataFlavor[] flavors = t.getTransferDataFlavors ();
        if (flavors == null) {
            return null;
        }
        int len = flavors.length;

        String subtype = "x-java-openide-nodednd"; // NOI18N
        String primary = "application"; // NOI18N
        String mask = "mask"; // NOI18N

        for (int i = 0; i < len; i++) {
            DataFlavor df = flavors[i];
            if (
                df.getSubType ().equals (subtype) &&
                df.getPrimaryType ().equals (primary)
            ) {
                try {
                    int m = Integer.valueOf (df.getParameter (mask)).intValue ();
                    if ((m & action) != 0) {
                        // found the node
                        return (Node)t.getTransferData (df);
                    }
                } catch (NumberFormatException nfe) {
                    maybeReportException (nfe);
                } catch (ClassCastException cce) {
                    maybeReportException (cce);
                } catch (IOException ioe) {
                    maybeReportException (ioe);
                } catch (UnsupportedFlavorException ufe) {
                    maybeReportException (ufe);
                }
            }
        }

        return null;
    }

    /** Obtain a list of nodes from a transferable.
    * If there is only a single node in the transferable, this will just return a singleton
    * array like {@link #node}.
    * If there is a {@link ExTransferable#multiFlavor multiple transfer} (of at least one element),
    * each element of which
    * contains a node, then an array of these will be returned.
    * If neither of these things is true, null will be returned.
    * 
This is a convenience method intended for those who wish to specially support pastes
    * of multiple nodes at once. (By default, {@link org.openide.explorer.ExplorerActions} will
    * fallback to presenting each component of a multiple-item transferable separately when checking for paste
    * types on a target node, so if you have only one paste type and it makes no difference whether all of the nodes
    * are pasted together or separately, you can just use {@link #node}.)
    * 
If you wish to test for cookies, you should do so manually
    * according to your specific logic.
    * @param t the transferable to probe
    * @param action a DnD or clipboard constant
    * @return a non-empty array of nodes, or null
    */
    public static Node[] nodes (Transferable t, int action) {
        try {
            if (t.isDataFlavorSupported (ExTransferable.multiFlavor)) {
                MultiTransferObject mto = (MultiTransferObject) t.getTransferData (ExTransferable.multiFlavor);
                int count = mto.getCount ();
                Node[] ns = new Node[count];
                boolean ok = true;
                for (int i = 0; i < count; i++) {
                    Node n = node (mto.getTransferableAt (i), action);
                    if (n == null) {
                        ok = false;
                        break;
                    } else {
                        ns[i] = n;
                    }
                }
                if (ok && count > 0) return ns;
            } else {
                Node n = node (t, action);
                if (n != null) return new Node[] { n };
            }
        } catch (ClassCastException cce) {
            maybeReportException (cce);
        } catch (IOException ioe) {
            maybeReportException (ioe);
        } catch (UnsupportedFlavorException ufe) {
            maybeReportException (ufe);
        }
        return null;
    }

    /** Obtain a cookie instance from the copied node in a transferable.
    * 

    * First of all it checks whether the given transferable contains
    * a node and then asks for the cookie.
    * 
If you wish to specially support multiple-node transfers, please use {@link #nodes}
    * and manually check for the desired combination of cookies.
    *
    * @param t transferable to check in
    * @param cookie cookie representation class to look for
    * @param action the action which was used to store the node 
    *
    * @return cookie or null if it does not exist
    */
    public static Node.Cookie cookie (Transferable t, int action, Class cookie) {
        Node n = node (t, action);
        return n == null ? null : n.getCookie (cookie);
    }

    /** Creates transfer object that is used to carry an intelligent
    * paste source through transferable or clipboard.
    * {@link #findPaste} can retrieve it.
    * @param paste the intelligent source of paste types
    * @return the transferable
    */
    public static ExTransferable.Single createPaste (final Paste paste) {
        return new ExTransferable.Single (nodePasteFlavor) {
                   public Object getData () {
                       return paste;
                   }
               };
    }

    /** Find an intelligent source of paste types in a transferable.
    * Note that {@link AbstractNode#createPasteTypes} looks for this
    * by default, so cut/copied nodes may specify how they may be pasted
    * to some external node target.
    * @param t the transferable to test
    * @return the intelligent source or null if none is in the transferable
    */
    public static Paste findPaste (Transferable t) {
        try {
            if (t.isDataFlavorSupported (nodePasteFlavor)) {
                return (Paste)t.getTransferData (nodePasteFlavor);
            }
        } catch (ClassCastException cce) {
            maybeReportException (cce);
        } catch (IOException ioe) {
            maybeReportException (ioe);
        } catch (UnsupportedFlavorException ufe) {
            maybeReportException (ufe);
        }
        return null;
    }

    /** Print a stack trace if debugging is on.
    * Used for exceptions that could occur when probing transferables,
    * which should not interrupt the probing with an error, but
    * indicate a bug elsewhere and should be reported somehow.
    * @param e the exception
    */
    private static void maybeReportException (Exception e) {
        org.openide.ErrorManager.getDefault().notify(org.openide.ErrorManager.INFORMATIONAL, e);
        // else do nothing
    }

    /** An intelligent source of paste types (ways how to paste)
    * for a target node.
    * 

    * Each node should check for this
    * type in a paste operation to allow anyone to insert something
    * into it.
    * 

    * Sample example of implementation of {@link Node#getPasteTypes}:
    * 
    *   public PasteType[] getPasteTypes (Transferable t) {
    *     NodeTransfer.Paste p = (NodeTransfer.Paste)t.getTransferData (
    *       NodeTransfer.nodePasteFlavor
    *     );
    *     return p.types (this);
    *   }
    * 
    */
    public interface Paste {
        /** Method that checks the type of target node and can
        * decide which paste types it supports.
        *
        * @param target the target node
        * @return array of paste types that are valid for such a target node
        */
        public PasteType[] types (Node target);
    }

}