package causation.lab;

import javax.swing.*;
import java.awt.*;
import java.util.StringTokenizer;

/**
 * This class displays a set of independencies for a particular 
 * hypothesis.
 *
 * @see	IndepInternalFrame
 * @see	DSeparationFacts
 * @version	0.9	Aug 18, 1999
 * @author	David Danks
 */

public class HypIndepDisplay extends JComponent {

/////////////////// Static Class Variables ///////////////////
	private static final String TITLE_START = "Hypothesis";
	private static final Color LABEL = new Color(102, 102, 102);
	private static final Color BACKGROUND = Color.white;
	private static final Font FONT = new Font("Dialog", Font.BOLD, 12);
	private static final Insets MARGIN = new Insets(10, 10, 10, 10);
	private static final int BORDER_WIDTH = 2;
	private static final int SPACE = 4;
	private static final int INSET = 4;	// constants for drawing the
	private static final int CENTER = 5;	// independence symbol
	private static final int BASE = 2*INSET+CENTER;
	private static final int DROP = 7;
	private static final String NO_INDEPS_STRING = "No independencies.";

/////////////////// Instance Variables ///////////////////
	private Image im;
	private DSeparationFacts dsep;
	private String title;

/////////////////// Constructors ///////////////////
/**
 * This creates a HypIndepDisplay with given Image and DSeparationFacts,
 * and with the title "Hypothesis".
 * @param	display		The Image to display
 * @param	dsepFacts	The DSeparationFacts to display
 */
	public HypIndepDisplay(Image display, DSeparationFacts dsepFacts) {
		this(display, dsepFacts, -1);
	}
/**
 * This creates a HypIndepDisplay with given Image and DSeparationFacts,
 * and with the title "Hypothesis #<code>count</code>".
 * @param	display		The Image to display
 * @param	dsepFacts	The DSeparationFacts to display
 * @param	count			The hypothesis number (for the title)
 */
	public HypIndepDisplay(Image display, DSeparationFacts dsepFacts,
		int count) {
		im = display;
		dsep = dsepFacts;
		if (count < 0) title = TITLE_START;
		else title = TITLE_START+" #"+String.valueOf(count);
		setFont(FONT);
	}
	
/////////////////// Instance Methods ///////////////////
/**
 * @return	The preferred size of this HypIndepDisplay
 */
	public Dimension getPreferredSize() {
		FontMetrics fm = getFontMetrics(getFont());
		int width = 0; int height = 0;
		// account for text
		width = Math.max(width, fm.stringWidth(title));
		height += fm.getHeight();
		// account for image
		width = Math.max(width, im.getWidth(this));
		height += im.getHeight(this);
		// account for line
		
		// account for facts
		String[] facts = dsep.getDSepFacts();
		if (facts.length == 0) {
			height += fm.getHeight();
			width = Math.max(width, fm.stringWidth(NO_INDEPS_STRING));
		}
		else {
			height += (facts.length+1)*fm.getHeight();
			for (int i=0; i<facts.length; i++) {
// this isn't quite right, but we add 10 as a fudge factor
			width = Math.max(width, 
				fm.stringWidth(facts[i])+BASE+2*SPACE+10);
			}
		}

		// account for margin
		width += MARGIN.left+MARGIN.right;
		width += MARGIN.top+MARGIN.bottom;
		return new Dimension(width, height);
	}
/**
 * @return	The minimum size of the HypIndepDisplay (=preferred size)
 */	
	public Dimension getMinimumSize() { return getPreferredSize(); }

/**
 * Changes the hypothesis number for the title.
 * @param	count	The new hypothesis number
 */
	public void setNumber(int count) {
		if (count < 0) title = TITLE_START;
		else title = TITLE_START+" #"+String.valueOf(count);
		if (isShowing()) repaint();
	}
/**
 * @return	<code>true</code>, since we paint the background
 */
	public boolean isOpaque() { return true; }
/**
 * Does the painting of the display.
 * @param	g	The Graphics context in which to paint the HypIndepDisplay
 */
	public void paintComponent(Graphics g) {
		FontMetrics fm = getFontMetrics(getFont());
		g.setColor(BACKGROUND);
		g.fillRect(0, 0, getWidth(), getHeight());
		g.setColor(LABEL);
		// draw the label
		int xInset = (getWidth()-fm.stringWidth(title))/2;
		g.drawString(title, xInset, MARGIN.top+fm.getAscent());
		// draw the image
		xInset = (getWidth()-im.getWidth(this))/2;
		g.drawImage(im, xInset, MARGIN.top+fm.getHeight(), this);
		// draw a dividing line

		int yOffset = MARGIN.top+fm.getHeight()+im.getHeight(this);

		// draw the facts
		String[] facts = dsep.getDSepFacts();
		if (facts.length == 0) {
			g.drawString(NO_INDEPS_STRING, MARGIN.left, 
				yOffset+fm.getAscent());
			return;
		}
		for (int i=0; i<facts.length; i++) {
			StringTokenizer st = new StringTokenizer(facts[i], "|");
			// first variable
			String token = st.nextToken();
			g.drawString(token, MARGIN.left, yOffset+fm.getHeight());
			int xOffset = MARGIN.left+fm.stringWidth(token)+SPACE;
			// independence symbol
			g.drawLine(xOffset, yOffset+fm.getHeight(),	// draw base
				xOffset+BASE, yOffset+fm.getHeight());
			g.drawLine(xOffset+INSET, yOffset+DROP,		// and left line
				xOffset+INSET, yOffset+fm.getHeight());
			g.drawLine(xOffset+INSET+CENTER, yOffset+DROP,	// and right line
				xOffset+INSET+CENTER, yOffset+fm.getHeight());
			xOffset += BASE+SPACE;
			// second variable
			token = st.nextToken();
			g.drawString(token, xOffset, yOffset+fm.getHeight());
			xOffset += fm.stringWidth(token)+SPACE;
			// conditioning set, if there is one
			if (st.hasMoreTokens()) {
				token = st.nextToken();
				StringTokenizer con = new StringTokenizer(token, ",");
				token = "| ";
				while (con.hasMoreTokens()) token += con.nextToken()+", ";
				token = token.substring(0, token.length()-2);
				g.drawString(token, xOffset, yOffset+fm.getHeight());
			}
			yOffset += fm.getHeight();
		}
		
		// draw a border around the outside
		for (int i=0; i<BORDER_WIDTH; i++) {
			g.drawRect(i, i, getWidth()-2*i, getHeight()-2*i);
		}
	}
}