// StarFieldView.java
// Author: P Gray
// starfield for displaying financial data

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;
import java.util.Enumeration;



class StarFieldView extends Panel	{
	private Point axisOrigin;
	private int width, height;
	private double scale;
	private SourceDomain sourceDomain;
	private double cacheX[], cacheY[];
	private int selected;

	public StarFieldView(SourceDomain sourceDomain, double scale) {
		setSize(new Dimension(100,100));
		// initialise origin to midpoint of panel
		axisOrigin = new Point();
		// initialise scale
		this.scale = scale;
		// initialise data
		this.sourceDomain = sourceDomain;
		int dataSize = sourceDomain.dataSize();
		cacheX = new double[dataSize];
		cacheY = new double[dataSize];
		loadData(0,1);
		selected = -1;
	}

	public void paint(Graphics g)	{
		Vector coords;
		double x, y;
		// get panel dimensions
		height = getSize().height;
		width = getSize().width;
		// set axis to center
		axisOrigin.setX(width / 2);
		axisOrigin.setY(height / 2);
		// draw the axes
		g.setColor(Color.blue);
		g.drawLine(0,axisOrigin.getY(),width,axisOrigin.getY());
		g.drawLine(axisOrigin.getX(),0,axisOrigin.getX(),height);
		// draw all the elements except the selected one
		for (int i = 0; i < sourceDomain.dataSize(); i++) {
			if (i != selected)	{
				g.setColor(Color.red);
				g.fillOval(axisOrigin.getX() + (int)(cacheX[i]*scale) - 2, axisOrigin.getY() - (int)(cacheY[i]*scale) - 2, 4, 4);
				}
		}
		// do selected item last so it isn't obscured
		if (selected >=0)  {
			g.setColor(Color.green);
			g.fillOval(axisOrigin.getX() + (int)(cacheX[selected]*scale) - 2, axisOrigin.getY() - (int)(cacheY[selected]*scale) - 2, 4, 4);
			}
	}


	void loadData(int xAxisField, int yAxisField)	{
   		for (int i = 0; i < sourceDomain.dataSize(); i++) {
   			cacheX[i] = sourceDomain.fieldAsReal(i,xAxisField);
   			cacheY[i] = sourceDomain.fieldAsReal(i,yAxisField);
   		}
   		repaint();
	}

	// accessing methods
	public SourceDomain sourceDomain()	{
		return sourceDomain;
	}

	// updating methods
	public void itemSelected(int pos) {
		selected = pos;
		repaint();
	}

	public void update(int pos)	{
		selected = pos;
		repaint();
	}

	public void setScale(double val)	{
		scale = val;
		repaint();
	}


} // end StarFieldPanel