import java.awt.*;
import java.applet.*;

public class Bohr extends Applet implements Runnable{
	Thread moveThread;
	private static final int MOVEPAUSE = 50;
	public Image offScreenImage;
	mycan thecanvas;
	public boolean myGo = false;
	public int ni=2;

	public void start()  {
		if(myGo) {
			if(moveThread == null){
				moveThread = new Thread(this);
				moveThread.start();
			}
		}
	}
	
	public void stop()  {
		if(moveThread != null){
			moveThread.stop();
			try {
				moveThread.join();
			}
			catch (InterruptedException e) { }
		}
		moveThread=null;
	}
		
	public void run() {
		while (true){
			try {
				moveThread.sleep(MOVEPAUSE);
			}catch(InterruptedException e) {
			}
			thecanvas.repaint();
		}
	}
	
	public void init() {
		super.init();
		offScreenImage = createImage(450,350);
		thecanvas = new mycan(this,offScreenImage);

		//{{INIT_CONTROLS
		setLayout(null);
		resize(500,350);
		panel1 = new java.awt.Panel();
		panel1.setLayout(new GridLayout(0,1,0,0));
		panel1.reshape(450,0,50,350);
		add(panel1);
		Group1 = new CheckboxGroup();
		radioButton1 = new java.awt.Checkbox("1", Group1, false);
		radioButton1.reshape(0,0,50,50);
		radioButton1.setBackground(Color.white);
		panel1.add(radioButton1);
		radioButton2 = new java.awt.Checkbox("2", Group1, true);
		radioButton2.reshape(0,50,50,50);
		radioButton2.setBackground(Color.white);
		panel1.add(radioButton2);
		radioButton3 = new java.awt.Checkbox("3", Group1, false);
		radioButton3.reshape(0,100,50,50);
		radioButton3.setBackground(Color.white);
		panel1.add(radioButton3);
		radioButton4 = new java.awt.Checkbox("4", Group1, false);
		radioButton4.reshape(0,150,50,50);
		radioButton4.setBackground(Color.white);
		panel1.add(radioButton4);
		radioButton5 = new java.awt.Checkbox("5", Group1, false);
		radioButton5.reshape(0,200,50,50);
		radioButton5.setBackground(Color.white);
		panel1.add(radioButton5);
		radioButton6 = new java.awt.Checkbox("6", Group1, false);
		radioButton6.reshape(0,250,50,50);
		radioButton6.setBackground(Color.white);
		panel1.add(radioButton6);
		radioButton7 = new java.awt.Checkbox("7", Group1, false);
		radioButton7.reshape(0,300,50,50);
		radioButton7.setBackground(Color.white);
		panel1.add(radioButton7);
		//}}
		
		add("Center",thecanvas);
	}

	public boolean handleEvent(Event event) {
		if (event.target == radioButton1 && event.id == Event.ACTION_EVENT){
			ni = 1;
			thecanvas.repaint();
		}
		if (event.target == radioButton2 && event.id == Event.ACTION_EVENT){
			ni = 2;
			thecanvas.repaint();
		}
		if (event.target == radioButton3 && event.id == Event.ACTION_EVENT){
			ni = 3;
			thecanvas.repaint();
		}
		if (event.target == radioButton4 && event.id == Event.ACTION_EVENT){
			ni = 4;
			thecanvas.repaint();
		}
		if (event.target == radioButton5 && event.id == Event.ACTION_EVENT){
			ni = 5;
			thecanvas.repaint();
		}
		if (event.target == radioButton6 && event.id == Event.ACTION_EVENT){
			ni = 6;
			thecanvas.repaint();
		}
		if (event.target == radioButton7 && event.id == Event.ACTION_EVENT){
			ni = 7;
			thecanvas.repaint();
		}
		return super.handleEvent(event);
	}
	
	//{{DECLARE_CONTROLS
	java.awt.Panel panel1;
	java.awt.Checkbox radioButton1;
	CheckboxGroup Group1;
	java.awt.Checkbox radioButton2;
	java.awt.Checkbox radioButton3;
	java.awt.Checkbox radioButton4;
	java.awt.Checkbox radioButton5;
	java.awt.Checkbox radioButton6;
	java.awt.Checkbox radioButton7;
	//}}

}
class mycan extends java.awt.Canvas
{
	Image offScreenImage;
	Bohr a;
	public double r0 = 7;
	public int ex, ey, xf = 0, yf = 0, nf = 0;
	public int xnuc = 40, ynuc = 110;
	
	public mycan(Bohr myApplet, Image myImage) {
		offScreenImage = myImage;
		a = myApplet;
		resize(450,350);
		repaint();
	}

	public void update(Graphics g){
		Graphics offg = offScreenImage.getGraphics();
		paint(offg);
		g.drawImage(offScreenImage, 0, 0, this);
	}
		
	public void paint(Graphics g){
		g.setColor(Color.white);
		g.fillRect(0,0,450,350);
		drawNucleus(xnuc,ynuc,g);
		g.setColor(Color.gray);
		for (int i = 1; i<9; i++) {
			drawOrbit(xnuc,ynuc,(int)(r0*i*i),g);
		}
		// output area for spectral lines
		g.setColor(Color.darkGray);
		g.fillRect(16,16,408,38);
		g.setColor(Color.blue);
		g.drawRect(18,18,404,34);
		g.setColor(Color.black);
		g.fillRect(20,20,400,30);
		g.setFont(new Font("TimesRoman", Font.PLAIN, 12));
		g.drawString("0",15,13);
		g.drawString("1",215,13);
		g.drawString("2 10   m",410,13);
		g.drawString("-6",431,9);
		// location of spectral lines (1 pixel = 5 nm)
		g.setColor(Color.gray);
		for (int i=1; i<5; i++){
			for (int j=i+1; j<5*i; j++){
				int lam5 = (int)(0.2/(0.01097*(1/(double)(i*i) - 1/(double)(j*j))));
				if (lam5 < 400) g.drawLine(lam5+20,30,lam5+20,40);
			}
		}
		// output area for energies
		g.setColor(Color.pink);
		g.fillRect(36,150,40,199);
		g.setColor(Color.black);
		g.drawRect(36,150,40,199);
		// energies: 0 at 160, 1 eV = 12 pixels
		g.setFont(new Font("TimesRoman", Font.PLAIN, 12));
		g.drawString("E (eV)",16,145);
		g.drawString("0",25,163);
		g.drawLine(36,160,76,160);
		g.drawString("-15",15,343);
		g.setColor(Color.gray);
		for (int i=1; i<20; i++){
			int E = 160+(int)(12*13.6/(i*i));
			g.drawLine(47,E,65,E);
		}
		g.setColor(Color.red);
		int Ei = 160+(int)(12*13.6/(a.ni*a.ni));
		g.drawLine(41,Ei,71,Ei);		
		ey = ynuc;
		ex = xnuc + (int)(r0*a.ni*a.ni);
		drawElectron(ex, ey, g);
		if (nf > a.ni){
			g.setColor(Color.yellow);
			drawArrow(g, xf, yf, ex, ey);
			g.setColor(Color.blue);
			g.fillOval(xf-3,yf-3,7,7);
			int Ef = 160+(int)(12*13.6/(nf*nf));
			g.drawLine(41,Ef,71,Ef);		
			double lambda = 1.0/(0.01097*(1/(double)(a.ni*a.ni) - 1/(double)(nf*nf)));
			g.setFont(new Font("TimesRoman", Font.PLAIN, 18));
			g.drawString(" = "+outString(""+lambda,5)+" nm",330,70);
			g.drawLine(328,69,322,59);  // paint letter lambda
			g.drawLine(322,69,325,64);
			g.drawLine(80,340,86,340);  // paint letter Delta
			g.drawLine(80,340,83,330);
			g.drawLine(86,340,83,330);
			double deltaE = 13.6*(1/(double)(a.ni*a.ni) - 1/(double)(nf*nf));
			g.drawString("E = "+outString(""+deltaE,4)+" eV",88,341);
			int lam5 = (int)(lambda/5.0);
			if (lam5 < 400) {
				// choose color according to spectrum (white outside the visible)
				g.setColor(Color.white);
				if (lambda > 400) g.setColor(Color.magenta);
				if (lambda > 430) g.setColor(Color.blue);
				if (lambda > 480) g.setColor(Color.green);
				if (lambda > 560) g.setColor(Color.yellow);
				if (lambda > 610) g.setColor(Color.orange);
				if (lambda > 650) g.setColor(Color.red);
				if (lambda > 710) g.setColor(Color.white);
				g.fillRect(lam5+19,26,3,18);
				g.drawLine(56, Ef+1, 56, Ei);
				g.drawLine(54, Ei-5, 56, Ei);
				g.drawLine(58, Ei-5, 56, Ei);
			}
		}
	}
	public void drawOrbit(int x, int y, int r, Graphics g){
		g.drawOval(x-r,y-r,2*r,2*r);
	}
	
	public void drawElectron(int x, int y, Graphics g){
		g.setColor(Color.red);
		g.fillOval(x-3,y-3,7,7);
	}
	
	
	public void drawNucleus(int x, int y, Graphics g){
		g.setColor(Color.green);
		g.fillOval(x-3,y-3,7,7);
	}
	
	public String outString(String inString, int l){    // returns the first l chars of string
		int ls = (int)Math.min(inString.length(),l);
		return inString.substring(0,ls);
	}
	
	public boolean handleEvent(Event event) {
		if (event.target == this && event.id == Event.MOUSE_DOWN) {
			xf = 0;
			yf = 0;
			nf = 0;
			int cx = event.x;
			int cy = event.y;
			int dist = (int)(Math.sqrt((cx-xnuc)*(cx-xnuc) + (cy-ynuc)*(cy-ynuc)));
			for (int i = a.ni+1; i<10; i++){
				if (Math.abs((int)(r0*i*i)-dist) < 4) {
					xf = cx;
					yf = cy;
					nf = i;
				}
			}
			//System.out.println("cx,cy "+cx+" "+cy+" xf,yf "+xf+" "+yf);
			//System.out.println("a.ni "+a.ni+" dist "+dist);
			repaint();
			return true;
		}
		return super.handleEvent(event);
	}
	
	public void drawArrow(Graphics g, int tailX, int tailY, int headX, int headY) {
	    double theta = Math.atan( (double)(tailY-headY)/(tailX-headX) );
	    if((tailX-headX)>=0) theta+= Math.PI;
	    int w1=10/2, w2=20/2, w3=30/2;
	    double s = Math.sin(theta);
	    double c = Math.cos(theta);	    
	    int sw1 = (int)(s*w1);
	    int sw2 = (int)(s*w2);
	    int sw3 = (int)(s*w3);
	    int cw1 = (int)(c*w1);
	    int cw2 = (int)(c*w2);
	    int cw3 = (int)(c*w3);
	    int[] exes = {tailX-sw1, headX-cw3-sw1, headX-cw3-sw2, headX, headX-cw3+sw2, headX-cw3+sw1, tailX+sw1, tailX-sw1};
	    int[] whys = {tailY+cw1, headY-sw3+cw1, headY-sw3+cw2, headY, headY-sw3-cw2, headY-sw3-cw1, tailY-cw1, tailY+cw1};
	    Polygon arrow = new Polygon(exes, whys, 8);
	    g.fillPolygon(arrow); 
	    g.setColor(Color.gray);
	    g.drawPolygon(arrow);   
	}	
}