package brsVisitor;

import brs.*;
import javax.swing.*;
import java.awt.*;

/**
 * This class acts as an MVC view adapter for a BiTree to display the tree on a JComponent.    The JComponent is assumed to have a null layout.
 * The display process clears the JComponent of all other components and then lays out JLabels on it where each label's text is the String representation
 * of a node's data.   Note:  If a JScrollPane is used to hold the JComponent, it must be validated after running showTree() method.
 * @dependency brsVisitor.BRSDisplayAdapter$RowColIdx uses
 */
public class BRSDisplayAdapter
{
        /**
	 * The offset from the top in pixels of the entire display.
	 */
	private int rowOffset = 0;
        /**
	 * The offset from the left in pixels of the entire display.
	 */
	private int colOffset = 0;
        /**
	 * The width of the label to make.
	 */
	private int labelWidth = 100;
        /**
	 * The height of the label to make.
	 */
	private int labelHeight = 30;
        /**
	 * The maximum depth, in rows, of the tree to be displayed.   This quantitiy is calculated each  time the tree is displayed.
	 */
	private int maxDepth = 0;
       /**
	 * The JComponent upon which the BiTree is to be shown.
	 */
	private JComponent container;

        /**
	 * An anonymous inner class IBRSAlgo that is used to traverse the BiTree, calling the showData() method at every non-null node.
	 */
	private IVisitor displayVisitor = new IVisitor() {

            public Object emptyCase(BiTree host, Object param)
            {
              return (null);
            }

            public final Object nonEmptyCase(BiTree host, Object param)
            {
              showData( host.getRootDat(), (RowColIdx) param);
              host.getLeftSubTree().execute(this, ((RowColIdx) param).nextLeft());
              host.getRightSubTree().execute(this,((RowColIdx) param).nextRight());
              return(null);
            }

        };
	private BRSGetMaxDepthVisitor getMaxDepthVisitor = new BRSGetMaxDepthVisitor();

        /**
	 * This class is a "carrier" class that holds the row and column index for a node in a BiTree.   The rows are numbered from 0 at the first row.
	 * The columns are numbered from 0 from the left.    This class is also a factory for the RowColIdx needed for the left and right sub-trees
	 * of the present node.   This is a private inner class of BRSDisplayAdapter.
	 */
	class RowColIdx
        {
            /**
            * The stored column index.
            */
            int colIdx;
            int rowIdx;
            /**
            * Constructor for the class.
            * @param rowIdx The row index
            * @param colIdx The column index
            */
            public RowColIdx(int rowIdx, int colIdx)
            {
              this.rowIdx = rowIdx;
              this.colIdx = colIdx;
            }

            /**
            * Accessor method for the row index.
            * @return
            */
            int getRowIdx()
            {
              return rowIdx;
            }

            /**
            * Accessor method for the row index.
            * @return
            */
            int getColIdx()
            {
              return colIdx;
            }

            /**
            * Factory method for the RowColIdx instance needed for the left sub-tree.   The new (row, col) indices are (row+1, 2*col)
            * @return A new RowColIdx instance
            */
            RowColIdx nextLeft()
            {
                  return new RowColIdx(rowIdx+1,colIdx*2);
            }
            /**
            * Factory method for the RowColIdx instance needed for the left sub-tree.   The new (row, col) indices are (row+1, 2*col+1)
            * @return A new RowColIdx instance
            */
            RowColIdx nextRight()
            {
                return new RowColIdx(rowIdx+1,colIdx*2+1);
            }
        }

        /**
	 * Constructor for the class that defaults the label width x height  to 100 x 30
	 * @param container The JComponent to display the BiTree on.
	 * @param rowOffset The vertical offset of the display in pixels.
	 * @param colOffset The horizontal offset of the display in pixels.
	 */
	private BRSDisplayAdapter(JComponent container, int rowOffset, int colOffset)
        {
          this.container = container;
          this.rowOffset = rowOffset;
          this.colOffset = colOffset;
        }

        /**
	 * Constructor for the class that also allows the label width and height to be specified..
	 * @param container The JComponent to display the BiTree on.
	 * @param rowOffset The vertical offset of the display in pixels.
	 * @param colOffset The horizontal offset of the display in pixels.
	 * @param labelWidth The width of the labels
	 * @param labelHeight The hieght of the labels.
	 */
	public BRSDisplayAdapter(JComponent container, int rowOffset, int colOffset, int labelWidth, int labelHeight)
        {
          this(container, rowOffset, colOffset);
          this.labelWidth = labelWidth;
          this.labelHeight = labelHeight;
        }

        /**
	 * Calculates the bounds of the label for a node, given its row and column index.
	 * @param rowColIdx The row and column index of the node.
	 * @return A bounds Rectangle object.
	 */
	private Rectangle getBounds(RowColIdx rowColIdx)
        {
          int row = rowOffset + rowColIdx.getRowIdx()*labelHeight;
          int col = colOffset + (
                      (labelWidth*(1<<(maxDepth-1)))     // = total width
                      *(2*rowColIdx.getColIdx()+1)/(1<<(rowColIdx.getRowIdx()+1)) // = fractional center position
                    ) - labelWidth/2;  // = label width compensation

          return new Rectangle(col, row,labelWidth, labelHeight);
        }

        /**
	 * Creates a JLabel whose text is the String representation of the supplied data.   The bounds of
	 * the label are calculated from the supplied RowColIdx.
	 * @param data The data to be displayed.
	 * @param rowColIdx The row and column index of the data's node.
	 */
	private void showData(Object data, RowColIdx rowColIdx)
        {
          JLabel label = new JLabel();
          label.setHorizontalAlignment(SwingConstants.CENTER);
          label.setText(data.toString());
          label.setBounds(getBounds(rowColIdx));
          container.add(label);
        }

       /**
	 * Displays a BiTree on a JComponent by clearing the JComponent of all other components and then laying out a JLabel for every non-null node of the tree.
	 * @param tree
	 */
	public void displayTree(BiTree tree)
        {
            container.removeAll();
            maxDepth = ((Integer)tree.execute(getMaxDepthVisitor,null)).intValue();
            container.setPreferredSize(   // to get scroll bars to work properly.
                          new Dimension(colOffset+(1<<(maxDepth-1))*labelWidth,
                                        rowOffset+maxDepth*labelHeight));
            tree.execute(displayVisitor, new RowColIdx(0,0));
            container.validate();
        }


}