import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;



public class nagelpnt extends Applet implements MouseListener, MouseMotionListener{
    int p1x, p1y, p2x, p2y, p3x, p3y, pick, cnt ;
    
    public void init() {
	addMouseListener(this);
        addMouseMotionListener(this);
	setBackground(Color.white);
        resize(300,300);
        Font font = new java.awt.Font("TimesRoman", Font.PLAIN, 12);
        cnt =0;
        p1x=150;
        p1y=20;
        p2x=30;
        p2y=220;
        p3x=240;
        p3y=280;        
        pick =0;
	setFont(font);
    }
    public void paint(Graphics g) {

	double v1x = p2x-p1x;
	double v1y = p2y-p1y;
	double v2x = p3x-p2x;
	double v2y = p3y-p2y;
	double v3x = p3x-p1x;
	double v3y = p3y-p1y;
        double l1 = Math.sqrt(v1x*v1x+v1y*v1y);
        double l2 = Math.sqrt(v2x*v2x+v2y*v2y);
        double l3 = Math.sqrt(v3x*v3x+v3y*v3y);
        double dim = 2;
        double h1x = dim*v1y/l1; 
        double h1y = -dim*v1x/l1;
        double h2x = dim*v2y/l2; 
        double h2y = -dim*v2x/l2;
        double h3x = dim*v3y/l3; 
        double h3y = -dim*v3x/l3;
        g.setColor(Color.green);
        Polygon pg1=new Polygon();
        pg1.addPoint(p1x-(int)h1x,p1y-(int)h1y);
        pg1.addPoint(p1x+(int)h1x,p1y+(int)h1y);   
        pg1.addPoint(p2x+(int)h1x,p2y+(int)h1y);    
        pg1.addPoint(p2x-(int)h1x,p2y-(int)h1y);
        g.fillPolygon(pg1);
        Polygon pg2 =new Polygon();
        pg2.addPoint(p2x-(int)h2x,p2y-(int)h2y);
        pg2.addPoint(p2x+(int)h2x,p2y+(int)h2y);   
        pg2.addPoint(p3x+(int)h2x,p3y+(int)h2y);    
        pg2.addPoint(p3x-(int)h2x,p3y-(int)h2y);
        g.fillPolygon(pg2);
        Polygon pg3 =new Polygon();
        pg3.addPoint(p1x-(int)h3x,p1y-(int)h3y);
        pg3.addPoint(p1x+(int)h3x,p1y+(int)h3y);   
        pg3.addPoint(p3x+(int)h3x,p3y+(int)h3y);    
        pg3.addPoint(p3x-(int)h3x,p3y-(int)h3y);
        g.fillPolygon(pg3);
        g.setColor(Color.blue);
        g.fillOval(p1x-4,p1y-4,8,8);
        g.fillOval(p2x-4,p2y-4,8,8);
        g.fillOval(p3x-4,p3y-4,8,8);
        g.setColor(Color.orange);
        g.fillOval(p1x-2,p1y-2,4,4);
        g.fillOval(p2x-2,p2y-2,4,4);
        g.fillOval(p3x-2,p3y-2,4,4);
        g.setColor(Color.green);
        if (cnt > 0){
            g.setColor(Color.red);

            double L1 = Math.sqrt(v1x*v1x+v1y*v1y);
            double L2 = Math.sqrt(v2x*v2x+v2y*v2y);
            double L3 = Math.sqrt(v3x*v3x+v3y*v3y);
            double h  = (L1+L2+L3)/2;
            double q1x = p2x+(h-L1)*v2x/L2;
            double q1y = p1y+v1y+(h-L1)*v2y/L2;
            double q2x = p1x+(h-L1)*v3x/L3;
            double q2y = p1y+(h-L1)*v3y/L3;
            double q3x = p1x+(h-L3)*v1x/L1;
            double q3y = p1y+(h-L3)*v1y/L1;
            double V1x = q1x-p1x;
            double V1y = q1y-p1y;
            double V2x = q2x-p2x;
            double V2y = q2y-p2y;
            double V3x = q3x-p3x;
            double V3y = q3y-p3y;
            double m1 = V1y*p1x-V1x*p1y;
            double m2 = V2y*p2x-V2x*p2y;
            double m3 = V3y*p3x-V3x*p3y;
            double DET = -V1y*V2x+V1x*V2y;
             double nx = (-V2x*m1+V1x*m2)/DET;
             double ny = (-V2y*m1+V1y*m2)/DET;
            if(V1x == 0){
                g.drawLine((int)(m1/V1y),0,(int)(m1/V1y),300);}
            else{
		g.drawLine(0,(int)(-m1/V1x),300,(int)(-(m1-300*V1y)/V1x));}
            if(V2x == 0){
                g.drawLine((int)(m2/V2y),0,(int)(m2/V2y),300);}
            else{
		g.drawLine(0,(int)(-m2/V2x),300,(int)(-(m2-300*V2y)/V2x));}
            if(V3x == 0){
                g.drawLine((int)(m3/V3y),0,(int)(m3/V3y),300);}
            else{
		g.drawLine(0,(int)(-m3/V3x),300,(int)(-(m3-300*V3y)/V3x));}
            if (cnt >1){
	     if(DET != 0){
	     g.setColor(Color.blue);
	     g.fillOval((int)nx-4,(int)ny-4,8,8);
	     g.setColor(Color.orange);
	     g.fillOval((int)nx-2,(int)ny-2,4,4);
             g.setColor(Color.gray);
             g.drawString("Nagelpunkten",(int)nx+15,(int)ny+5);}}}
    }

    public void mousePressed(MouseEvent e) {
	double bestdist = 8;
	int x = e.getX();
	int y = e.getY();
	double dist1 = (p1x - x) * (p1x - x) + (p1y - y) * (p1y - y);
	double dist2 = (p2x - x) * (p2x - x) + (p2y - y) * (p2y - y);
	double dist3 = (p3x - x) * (p3x - x) + (p3y - y) * (p3y - y);
	    if (dist1 < bestdist) {
		pick = 1;}
            else{
                if (dist2 < bestdist){
		    pick =2;}
		else{
                    if (dist3 < bestdist){
			pick=3;}
                    else{
                        pick =0;}}}
	    if(pick==0){
		cnt=(cnt+1)%3;
                play(getCodeBase(),"audio/ding.au");
                repaint();}
    }

    public void mouseReleased(MouseEvent e) {
    }
    public void mouseEntered(MouseEvent e) {
    }

    public void mouseExited(MouseEvent e) {
    }

    public void mouseClicked(MouseEvent e) {
    }
    public void mouseMoved(MouseEvent e) {
    }
    public void mouseDragged(MouseEvent e) {
	int x= e.getX();
        int y= e.getY();
        if(pick==1){
	    p1x=x;
            p1y=y;
        }
        if(pick==2){
	    p2x=x;
            p2y=y;
        }
        if(pick==3){
	    p3x=x;
            p3y=y;
        }
        repaint();
    }


}