import javax.swing.*;

import se.chalmers.cs.gf.linearize.Linearizer;

public class NodeView extends JLabel {

        private static NodeTransferHandler nodeHandler 
            = new NodeTransferHandler();
        private static DragMouseAdapter nodeMouseListener
            = new DragMouseAdapter();

        private Node node;

        private Linearizer linearizer;

        public NodeView(Node node, Linearizer linearizer) {
                this.node = node;
                this.linearizer = linearizer;
                setTransferHandler(nodeHandler);
                addMouseListener(nodeMouseListener);
        }

        public Node getNode() {
                return node;
        }

        public boolean canAttach(Node child) {
                return getAttachPos(child) != -1;
        }

        /**
         *  Get the first free position of the same type as the given node.
         *  If there is no free slot, the first slot of the right type
         *  is returned. If there is no slot of the right type,
         *  -1 is returned.
         */
        public int getAttachPos(Node child) {
                for (int pos = 0; pos < node.getArity(); pos++)
                        if (node.isFree(pos) && node.canAttach(pos, child))
                                return pos;
                for (int pos = 0; pos < node.getArity(); pos++)
                        if (node.canAttach(pos, child))
                                return pos;
                return -1;
        }

        /**
         *  Attach a node as a child of our node, if possible.
         *  The first free slot of the right type is taken.
         *  If there is no free slot, the child in the first
         *  free slot of the right type is removed.
         *  FIXME: we should detach the removed child into a 
         *  separate node.
         *  @return true if the node could be added, false otherwise.
         */
        public boolean attachNode(Node child) {
                // FIXME: make sure we are not trying to attach a node to itself
                // or its own children.

                int pos = getAttachPos(child);
                if (pos != -1) {
                        Node oldChild = node.attachChild(pos, child);
                        if (oldChild != null) {
                                // FIXME: detach oldChild to a separate view
                        }
                        updateText();
                        return true;
                }
                return false;
        }

        public void updateText() {
                setText(node.getFun() + ": " + node.getText(linearizer));
        }

}