package mygraphs;

import java.awt.*;
import java.util.*;

class GraphPanel extends Panel {
	Vector		items = new Vector();	// This is same as items in panel - store here too for convenience
	Vector		colors = new Vector();
	Vector		itsYMaxs = new Vector();
	float	[]	ySlopes = null;
	boolean	negativeY = false, autoScale = false, oneMax = true;
	Image		offScrImage = null;
	boolean	offScrUpToDate = false;
	int			scaleInset = 5;
	
	GraphPanel() {}
	
	public void addItem(GraphableData obj, Color col) {
		items.addElement(obj);
		colors.addElement(col);
		if(oneMax && itsYMaxs.size() > 0) itsYMaxs.addElement(itsYMaxs.elementAt(0));
		else itsYMaxs.addElement(new Float(1.0));
		updateSlopes();
	}
	
	// Override this for graphs that store data points
	public void getNewTimepoint() {
		repaint();
	}
	
	// Override this to paint the graph
	public void paint(Graphics g) {
		paintOffscreen();
		if(offScrUpToDate) g.drawImage(offScrImage, 0, 0, this);
	}

	private void paintOffscreen() {
		Rectangle area = getBounds();
		if(offScrImage == null || offScrImage.getWidth(this) != area.width ||
					offScrImage.getHeight(this) != area.height) {
			offScrImage = createImage(area.width, area.height);
			offScrUpToDate = false;
		}
		
		if(offScrUpToDate) return;
		
		Graphics og = offScrImage.getGraphics();
		og.setColor(Color.white);
		og.fillRect(0, 0, area.width, area.height);
		
		plotGraph(og);
		og.dispose();
	}
	
	public void plotGraph(Graphics g) {}	// Override for each type of graph
	
	public void update(Graphics g) {	// Gets rid of erase to white blink
		paint(g);
	}

	public void setSize(Dimension d) {
		super.setSize(d);
		updateSlopes();
	}
	public void setBounds(int x, int y, int width, int height) {
		super.setBounds(x, y, width, height);
		updateSlopes();
	}

	public void updateSlopes() {
		int		index;
		float	max;
		
		if(ySlopes == null || ySlopes.length != itsYMaxs.size())
			ySlopes = new float[itsYMaxs.size()];

		Dimension area = getSize();
		Enumeration elem = itsYMaxs.elements();
		index = 0;
		while(elem.hasMoreElements()) {
			max = ((Float)elem.nextElement()).floatValue();
			if(negativeY) ySlopes[index] = ((float)(area.height - scaleInset * 2) / (max * 2));
			else ySlopes[index] = ((float)(area.height - scaleInset * 2) / max);
			index++;
		}
		offScrUpToDate = false;
		getParent().repaint();
	}

	public boolean 	getAutoscale() { return autoScale; }
	public void		setAutoscale(boolean auto_scale) { autoScale = auto_scale; }

	public void setYScale(float max) {
		if(max <= 0) return;	// Maybe need to throw an exception ?
		for(int index = 0; index < itsYMaxs.size(); index++) {
			itsYMaxs.setElementAt(new Float(max), index);
		}
		updateSlopes();
	}
	
	public void setYScale(float max, int index_num) {
		if(max <= 0) return;	// Maybe need to throw an exception ?
		if(oneMax) { setYScale(max); return; }
		
		if(index_num >= itsYMaxs.size()) return;	// Also an exception here ?
		itsYMaxs.setElementAt(new Float(max), index_num);
		updateSlopes();
	}
	
	public void setYScale(float max, GraphableData obj) {
		int index = 0;
		while(index < itsYMaxs.size() && obj != items.elementAt(index))
			index++;
		if(index < itsYMaxs.size()) setYScale(max, index);
	}

	public synchronized Dimension getMinimumSize() {
		return(new Dimension(50, 50));
	}
	
	public synchronized Dimension getPreferredSize() {
		return(new Dimension(1000, 1000));
	}
}