import java.awt.*;

import java.lang.*;



public class Xrayb extends java.applet.Applet {
	int X0=10,Y0=350,H=300,W=450;

	int MAXATOMS = 5;

	final int HRange=5,KRange=5;

	int x[] = new int[MAXATOMS+1];

	int y[] = new int[MAXATOMS+1];

	int highlight[] = new int[MAXATOMS+1];
	int xtest,ytest;
	int current=1;

	final int nk=(2*HRange+1)*(2*KRange+1);

	double h[] = new double[nk+1];

	double k[] = new double[nk+1];
	double Ire[] = new double[nk+1];
	double Iim[] = new double[nk+1];
	double Itestre[] = new double[nk+1];
	double Itestim[] = new double[nk+1];
	double Intensity[] = new double[nk+1];
	double testIntensity[] = new double[nk+1];
	boolean 	highlighted = false;
	boolean	isTestAtom = false;
	boolean	newDiffPattern = false;


	TextField xpos,ypos,message;



	public void init() {

	

		for (int n = 1;n<=MAXATOMS;n++) {

			x[n] = 0;

			y[n] = 0;

			highlight[n] = 0;
			}

		for (int f=1;f<=nk;f++) {

			h[f] = (f-1)/(2*HRange+1) - HRange;

			k[f] = (f-1)%(2*KRange+1) - KRange;

			Intensity[f] = 0;

			}

	

		setLayout(new FlowLayout() );

		

		xpos = new TextField(String.valueOf(0),3);

		ypos = new TextField(String.valueOf(0),3);

		message = new TextField("",25);



		add(new Label("x:"));

		add(xpos);

		add(new Label("y:"));

		add(ypos);

		add(message);

		add(new Button("Xray"));

		add(new Button("Restart"));
		add(new Button("New Xray"));
		add(new Button("Accept"));
		add(new Button("Reject"));

		}//End init

	

	void restart(){

		current = 1;
		removeTestAtom();
		highlighted = false;
		isTestAtom = false;
		newDiffPattern = false;


		for (int n = 1;n<=MAXATOMS;n++) {

			x[n] = 0;

			y[n] = 0;
			highlight[n] = 0;

			}

		for (int f=1;f<=nk;f++) {

			Intensity[f] = 0;

			testIntensity[f] = 0;
			}

		repaint();

		}



	public boolean action(Event e, Object arg) {

		if (e.target instanceof Button) {

			String command = (String)arg;

			if (command.equals("Xray")) {

				diffract();

				}

			if (command.equals("Restart")) {

				restart();

				}
			if (command.equals("New Xray")) {
				newDiffract();
				newDiffPattern = true;
				}
			if (command.equals("Accept")) {
				updateDiffractionPattern();
				newDiffPattern = false;
				}
			if (command.equals("Reject")) {
				newDiffPattern = false;
				}
			repaint();

			}

		return true;

		}//End action



	public boolean mouseDown (Event e, int xin, int yin) {

		if (current<=MAXATOMS) {

			if (xin>=X0&&xin<=450&&yin>=Y0-H&&yin<=Y0) {

				x[current] = -X0+xin;

				xpos.setText(String.valueOf(x[current]));

				y[current] = Y0-yin;

				ypos.setText(String.valueOf(y[current]));

				current++;

				message.setText("");

				}

			else {

				message.setText("Click on the blue area");

				}

			}

		else {

			message.setText("All spots entered - now highlighting");

			if (highlighted == false && isTestAtom == false) {
				for (int i = 1;i<=MAXATOMS;i++)
					highlight[i] = 0;
				boolean found = locateAtom(xin,yin);
				if (found == true) {
					removeTestAtom();
					highlighted = true;
					}
				}
			else if (highlighted == true && isTestAtom == false) {
					addTestAtom(xin,yin);
					isTestAtom = true;
					}
			else if (highlighted == true && isTestAtom == true) {
				int highAtom = 0;
				for (int i = 1;i<=MAXATOMS;i++)
					if (highlight[i] == 1)
						highAtom = i;
				removeTestAtom();
				boolean found = locateAtom(xin,yin);
				if (found == true) {
					highlight[highAtom] = 0 ;
					highlighted = true;
					}
				else {
					addTestAtom(xin,yin);
					}
				}
			}
		

		repaint();

		return true;

		}//End mouseDown

	void addTestAtom(int xin , int yin) {
		xtest=xin-X0;
		ytest=Y0-yin;
		}

	void removeTestAtom() {
		xtest = 0;
		ytest = 0;
		}

	boolean locateAtom(int xin, int yin){
		int found = 0;
		int xspot = xin-X0;
		int yspot = Y0-yin;

		for (int i=1; i<=MAXATOMS; i++) {
			for (int ii=-5;ii<=5;ii++)
				for (int jj=-5;jj<=5;jj++)
					if(x[i]+ii==xspot&&y[i]+jj==yspot) {
						highlight[i] = 1;
						System.out.println("Spot #"+i+"x = "+xin+"y = "+yin);
						found = 1;
						}
					}
		if (found == 0) return false;
			else return true;
		}
		

	void diffract() {

		double arg;

		double xmid[] = new double[nk+1];

		double ymid[] = new double[nk+1];

	  	int n,f;



		for(n=1;n<=MAXATOMS;n++) {

			xmid[n] = (double)(x[n])/450;

			ymid[n] = (double)(y[n])/300;

			//System.out.println("xm = "+xmid[n]+"ym = "+ymid[n]);

			}

		for(f=1;f<=nk;f++) {

			Ire[f] = Iim[f] = 0;

			for(n=1;n<=MAXATOMS;n++) {			

				arg = (double)( 2*3.14159*( h[f]*xmid[n]+k[f]*ymid[n] ) );

				Ire[f] += (double)(Math.cos(arg));

				Iim[f] += (double)(Math.sin(arg)); 

				Intensity[f] = Ire[f]*Ire[f]+Iim[f]*Iim[f];

				}

			}

		}//End diffract

	void newDiffract() {
		double argnew,argold;//,vol=0;
		double xold=0,yold=0,xnew=0,ynew=0;
	  	int n,f;

		for(n=1;n<=MAXATOMS;n++) {
			if (highlight[n] == 1) {
				xold = (double)(x[n])/450;
				yold = (double)(y[n])/300;
				xnew = (double)(xtest)/450;
				ynew = (double)(ytest)/300;
				//System.out.println("xm = "+xmid[n]+"ym = "+ymid[n]);
				}
			}

		for(f=1;f<=nk;f++) {
			argold = (double)( 2*3.14159*( h[f]*xold+k[f]*yold ) );
			argnew = (double)( 2*3.14159*( h[f]*xnew+k[f]*ynew ) );
			Itestre[f] = Ire[f]+(double)((Math.cos(argnew)-Math.cos(argold)) );
			Itestim[f] = Iim[f]+(double)((Math.sin(argnew)-Math.sin(argold)) ); 
			testIntensity[f] = Itestre[f]*Itestre[f]+Itestim[f]*Itestim[f];
			}
		}//End newDiffract

	void	updateDiffractionPattern() {
		for (int n=1;n<=MAXATOMS;n++) {
			if (highlight[n] == 1) {
				System.out.print("Atom # "+n+" updated from "+x[n]+", "+y[n]);
				x[n] = xtest;
				y[n] = ytest;
				removeTestAtom();
				System.out.println(" to "+x[n]+", "+y[n]);
				}
			}
		for (int f=1;f<=nk;f++) {
			Ire[f] = Itestre[f];
			Iim[f] = Itestim[f];
			Intensity[f] = testIntensity[f];
			Itestre[f] = Itestim[f] = testIntensity[f] = 0;
			}
		}//End updateDiffractionPattern


	public void paint(Graphics g) {

		int xdraw,ydraw;

		int kxdraw[] = new int[nk+1];

		int kydraw[] = new int[nk+1];
		int kxndraw[] = new int[nk+1];
		int kyndraw[] = new int[nk+1];
		

		//Set up Atomic box and Frequency domain

		g.setColor(Color.blue);

		g.fillRect(X0,Y0-H,W,H);

		g.setColor(Color.cyan);

		g.fillRect(10,400,450,50);

		

		//Add coordinate axes

		g.setColor(Color.black);

		g.drawLine(X0,Y0-H,X0,Y0);

		g.drawLine(X0,Y0,X0+W,Y0);

		g.drawLine(10,400,10,450);

		g.drawLine(10,450,460,450);

	

		//Add atoms to the field

		for (int n=1;n<=MAXATOMS;n++) {
			if(x[n]!=0&&y[n]!=0) {
				if (highlight[n] == 0)	g.setColor(Color.red);
				else if (highlight[n] == 1) g.setColor(Color.orange);
				xdraw = X0+x[n];

				ydraw = Y0-y[n];

				g.fillOval(xdraw-5,ydraw-5,10,10);

				}	

			}


		//Add the test spot, if necessary
		if(xtest!=0&&ytest!=0) {
			g.setColor(Color.white);
			xdraw = X0+xtest;
			ydraw = Y0-ytest;
			g.fillOval(xdraw-5,ydraw-5,10,10);
			}		


		//Add the frequency components

		for (int f=1;f<=nk;f++) {	

			kxdraw[f] = (int)(10+3.75*f);

			kydraw[f] = (int)((450-2.5*Intensity[f]));

			}
		g.setColor(Color.black);

		for (int f=1;f<=nk-1;f++) {
			g.drawLine(kxdraw[f],kydraw[f],kxdraw[f+1],kydraw[f+1]);

			}

		if(newDiffPattern == true) {
			for (int f=1;f<=nk;f++) {	
				kxdraw[f] = (int)(10+3.75*f);
				kydraw[f] = (int)((450-2.5*testIntensity[f]));
				}
			g.setColor(Color.red);
			for (int f=1;f<=nk-1;f++) {
				g.drawLine(kxdraw[f],kydraw[f],kxdraw[f+1],kydraw[f+1]);
				}
			}

		}//End paint

	}