package examples;

/**
 * Terms of use:  You may use or modify this code for CSE132 assignments, but
 * you must provide full documentation according to CSE132 documentation standards.
 * 
 * @author Ken Goldman, March 2006
 */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;

public class EditableTree extends JTree {
	private static final long serialVersionUID = 1L;
	static final int OFFSET = 5;
	static final Cursor USUAL_CURSOR =
		Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR);
	static final Cursor ACCEPT_CURSOR = createCursor("accept32x32.gif",16,0);
	static final Cursor REJECT_CURSOR = createCursor("reject32x32.gif",16,0);
	static final Font FONT = new Font("helvetica", Font.BOLD, 18);
	
	static Cursor createCursor(String filename, int x, int y) {
		Image img = (new ImageIcon(filename)).getImage();
		return Toolkit.getDefaultToolkit().createCustomCursor(img,new Point(x,y),filename);
	}
	
	public EditableTree(MutableTreeNode root) {
		super(root);
		setFont(FONT);
		new TreeEditor(this);
	}
		
	static class TreeEditor extends MouseAdapter implements MouseMotionListener {
		JTree tree;
		DefaultTreeModel model;
		TreePath mouseSelection, dropTarget;
		JLabel draggingFeedback = new JLabel("");
		JPopupMenu popup;
		AbstractAction cut;
		
		TreeEditor(JTree tree) {
			this.tree = tree;
			model = (DefaultTreeModel) tree.getModel();
			tree.addMouseListener(this);
			tree.addMouseMotionListener(this);
			draggingFeedback.setVisible(false);
			draggingFeedback.setFont(tree.getFont());
			tree.add(draggingFeedback);
			tree.setEditable(true);  // allows node names to be edited within the tree
		}
		


		public void mousePressed(MouseEvent me) {
			if (handlePopupTrigger(me))
				return;
			Point p = me.getPoint();
			mouseSelection = tree.getPathForLocation(p.x,p.y);
			if (mouseSelection != null) {
				draggingFeedback.setText(mouseSelection.getLastPathComponent().toString());
				draggingFeedback.setLocation(p.x+OFFSET,p.y);
				draggingFeedback.setVisible(true);
				draggingFeedback.setSize(draggingFeedback.getPreferredSize());
			}
		}

		public void mouseDragged(MouseEvent me) {
			if (draggingFeedback.isVisible()) {
				Point p = me.getPoint();
				dropTarget  = tree.getPathForLocation(p.x,p.y);
				draggingFeedback.setLocation(p.x+OFFSET,p.y);
				if (isDropLegal()) {
					tree.setCursor(ACCEPT_CURSOR);
					draggingFeedback.setForeground(Color.GREEN);
				} else {
					tree.setCursor(REJECT_CURSOR);
					draggingFeedback.setForeground(Color.RED);
				}
			}
		}
		
		public void mouseReleased(MouseEvent me) {
			draggingFeedback.setVisible(false);
			tree.setCursor(USUAL_CURSOR);
			if (handlePopupTrigger(me) || mouseSelection == null)
				return;
			if (isDropLegal()) {
				Node src = (Node) mouseSelection.getLastPathComponent();
				model.removeNodeFromParent(src);
				Node dest = (Node) dropTarget.getLastPathComponent();
				model.insertNodeInto(src, dest, dest.getChildCount());
				
				//tree.expandPath(dropTarget);
				//tree.scrollPathToVisible(new TreePath(src.getPath()));
				tree.setSelectionPath(new TreePath(src.getPath()));
			}
			mouseSelection = null;
		}
		
		public boolean isDropLegal() {
			return mouseSelection != null && dropTarget != null &&
			// don't drop on self (makes no sense, would create a cycle)
				dropTarget != mouseSelection &&
			// don't drop on a descendant (would create a cycle or sever the tree)
				!mouseSelection.isDescendant(dropTarget) &&
			// don't drop on the immediate parent (since already there)
				!mouseSelection.getParentPath().equals(dropTarget);
		}

		public void mouseMoved(MouseEvent arg0) { }
		
		boolean handlePopupTrigger(MouseEvent me) {
			if (me.isPopupTrigger()) {			
				Point p = me.getPoint();
				mouseSelection = tree.getPathForLocation(p.x,p.y);
				if (mouseSelection != null) {
					showPopup(p.x,p.y);
				}
				return true;
			}
			return false;
		}
		
		void showPopup(int x, int y) {
			if (popup == null) {
				popup = new JPopupMenu();
				popup.add(new AbstractAction("new") {
					public void actionPerformed(ActionEvent ae) {
						Node src = (Node) mouseSelection.getLastPathComponent();
						Node child = new Node("new",src);
						model.insertNodeInto(child, src, src.getChildCount()-1);
						tree.setSelectionPath(new TreePath(child.getPath()));
					}
				});
				popup.add(cut = new AbstractAction("cut") {
					public void actionPerformed(ActionEvent ae) {
						Node src = (Node) mouseSelection.getLastPathComponent();
						if (src.getParent() != null)
							model.removeNodeFromParent(src);	
					}		
				});
			}
			cut.setEnabled(((Node) mouseSelection.getLastPathComponent()).getParent() != null);
			popup.show(tree,x,y);
		}
	}
	
	public static void main(String[] args) {
		Node root = new Node("root",null);
		new Node("aa", new Node("a",root));
		new Node("bb", new Node("b",root));
		final JTree tree = new EditableTree(root);
		tree.setEditable(true);
		JFrame f = new JFrame("MyTree");
		f.add(new JScrollPane(tree));
		f.pack();
		f.setVisible(true);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
	
	static class Node extends DefaultMutableTreeNode {
		public Node(Object contents, Node parent) {
			super(contents);
			if (parent != null) {
				parent.add(this);
				setParent(parent);
			}
		}
		
		public void setUserObject(Object x) {
			super.setUserObject(x);
			System.out.println("Node name changed to " + x);
		}
	}
}