import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseEvent;




public class DBCanvas extends DoubleBuffer {
    
    // colors
    private Color highl, line, point, curve, bg, text;
    
    
    private MyPoint[] ver; // kontrolne body
    private MyPoint s, f;
    private int selected = -1, drag = -1; // index vybrateho kontrolneho bodu

    private int i = 2, max = 20; // pocet kontrolnych bodov (zaciname od dva kvoli fantomovym bodom a uzavretej krivke), velkost pola
    private float delta,s1,s2,s3,s4;
    
    // beta-splain prmenne
    public float beta1,beta2;
    public boolean joined, fantom, lines, points;
    
      
   
    public DBCanvas(int w, int h){
        
        super(w,h);
        ver = new MyPoint[max];
        s = new MyPoint(-1,-1);
        ver[0] = new MyPoint(-1,-1);
        f = new MyPoint(-1,-1);
        joined = false;
        fantom = false;
        lines = false;
        points = false;
        // farby
        highl = new Color(246, 255, 195);
        line = new Color(196,196,196);
        curve = new Color(24,186,00);
        bg = new Color(255,255,255);
        text = new Color(70,70,70);
        point = new Color(120,120,120);
        // beta hodnoty
        beta1 = 1;
        beta2 = 0;
    }
    
    
    public void delete_curve(){
        max = 20;
        i = 2;
        ver = new MyPoint[20];
    }

   private void beta_splain(Graphics g){
        g.setColor(curve);
        delta=2*beta1*beta1*beta1 + 4*beta1*beta1 + 4*beta1 + beta2 + 2;
        int jMin, jMax;
                    
        if(!joined){ // fantomove vrcholy 
            ver[1] = new MyPoint(ver[2].X+((ver[2].X-ver[3].X)/(beta1*beta1*beta1)),
                                ver[2].Y+((ver[2].Y-ver[3].Y)/(beta1*beta1*beta1)));
            ver[i] = new MyPoint(((beta1*beta1*beta1)*(ver[i-1].X-ver[i-2].X))+ver[i-1].X,
                                ((beta1*beta1*beta1)*(ver[i-1].Y-ver[i-2].Y))+ver[i-1].Y);
            jMin =3; jMax = i;
        }
        else
        {
            ver[0] = new MyPoint(ver[i-2]);
            ver[1] = new MyPoint(ver[i-1]);
            ver[i] = new MyPoint(ver[2]);
            ver[i+1] = new MyPoint(ver[3]);
            jMin =2; jMax = i+1;
        }
        
  s.setXY(-1, -1);
  for (int j=jMin;j<jMax;j++){     
       float u=0;
  
       while (u<1) {
            s1=(u*u*u*(-2)*beta1*beta1*beta1 +
                u*u*6*beta1*beta1*beta1 +
                u*(-6)*beta1*beta1*beta1 +
                2*beta1*beta1*beta1)/delta;  // (-2 u^3 b1^3)+(6 u^2 b1^3) - (6 u b1^3) + (2 b1^3) /d
            s2=(u*u*u*2*(beta1*beta1*beta1 + beta1*beta1 + beta1 + beta2) +
                u*u*(-3)*(2*beta1*beta1*beta1 + 2*beta1*beta1 + beta2) +
                u*6*beta1*(beta1*beta1 - 1) +
                4*beta1*beta1 + 
                4*beta1 + 
                beta2)/delta; // (2u^2 (b1^3 + b1^2 + b1 + b2)) - (3u^2 (2b1^3 + 2b1^2 + b2))
                                                //+(6u b1 (b1^2 - 1)) + ( 4b1^2 + 4b1 + b2 ) / d
            s3=(u*u*u*(-2)*(beta1*beta1 + beta1 + beta2 + 1) +
                u*u*3*(2*beta1*beta1 + beta2) +
                u*6*beta1 +
                2)/delta;       // (-2u^3 (b1^2 + b1 + b2 + 1) + (3u^2 (2b1^2 + b2) + (6u b1 + 2) /d
            s4=(u*u*u*2)/delta; // (2 u^3)/d 
    
            f.setXY(s1*ver[j-2].X + s2*ver[j-1].X + s3*ver[j].X + s4*ver[j+1].X,
                    s1*ver[j-2].Y + s2*ver[j-1].Y + s3*ver[j].Y + s4*ver[j+1].Y);
    
            if((s.X != -1) || (s.Y != -1 ))
                g.drawLine( Math.round(s.X) , Math.round(s.Y), Math.round(f.X) , Math.round(f.Y) );
   
            s.X=f.X;
            s.Y=f.Y;

            u+=0.01;
       } 
  }
}    
    
    private void checkArray(){
        
        if(i+1 >= max-1){
            max += 10;
            MyPoint[] pom = new MyPoint[max];
            for(int j=0;j<i;j++)
                pom[j] = new MyPoint(ver[j]);
            ver = pom;
        }
    }
    
    private int select(int x, int y, int limit){
        
        for(int j=2;j<i;j++)
            if(limit*limit>((x-ver[j].X)*(x-ver[j].X)+(y-ver[j].Y)*(y-ver[j].Y))) return j;
        return -1;
    }
    
    private void addVertex(int x, int y){
        
       checkArray();
       ver[i] = new MyPoint(x,y);

       i++;
    }

    private void deleteVertex(int index){
        
       if(ver[index] != null){
           ver[index] = null;
       }
       tidyUpVertex();
       this.i--;
    }  
    
   private void tidyUpVertex(){
        
        for(int j=0;j<this.i;j++){
            if(ver[j]==null){
                if((j+1<this.i) && (ver[j+1]!=null)){
                    ver[j] = ver[j+1];
                    ver[j+1] = null;
                }
            }
        }
    }
    
    
     private void clrScr(Graphics g){
        g.setColor(bg);
        g.fillRect(0, 0, WIDTH, HEIGHT);
    }
    
    @Override
    public void paintBuffer(Graphics g){
       
       
       int jMin = 2, jMax = i; 
        
       clrScr(g);
       
       if(i>3 && fantom){
                jMin = 1;
                jMax = i+1;
           }
              
       for(int j=jMin;j<jMax;j++){
           if(ver[j]!=null){
                if(lines && (j+1<jMax) && (ver[j+1]!= null)) {
                    g.setColor(line);
                    g.drawLine(Math.round(ver[j].X), Math.round(ver[j].Y), Math.round(ver[j+1].X), Math.round(ver[j+1].Y));
                }
                g.setColor(bg);
                g.fillOval((int)ver[j].X-2, (int)ver[j].Y-2, 5, 5);
                g.setColor(point);
                g.drawOval((int)ver[j].X-2, (int)ver[j].Y-2, 5, 5);
                if(j>1 && j<i && points){
                    g.drawRect(Math.round(ver[j].X)+5, Math.round(ver[j].Y), 16+(j>11?8:0), 16);
                    g.drawString("V"+(j-2), Math.round(ver[j].X)+7, Math.round(ver[j].Y)+12);                    
                }
           }
       }
       
       if(i>3){
           beta_splain(g);
       }
       
       if(fantom && i>3){
            g.setColor(highl);
            g.fillRect(Math.round(ver[i].X)+5, Math.round(ver[i].Y), 75, 16);
            g.fillRect(Math.round(ver[1].X)+5, Math.round(ver[1].Y), 62, 16);
            g.setColor(text);
            g.drawRect(Math.round(ver[i].X)+5, Math.round(ver[i].Y), 75, 16);
            g.drawRect(Math.round(ver[1].X)+5, Math.round(ver[1].Y), 62, 16);
            g.drawString("fantom V-1", Math.round(ver[1].X)+7, Math.round(ver[1].Y)+12);                    
            g.drawString("fantom V"+(i-2), Math.round(ver[i].X)+7, Math.round(ver[i].Y)+12);                    
       }
       
       if((selected > 0) && (selected < i) && (ver[selected]!= null)){
           g.setColor(highl);
              g.fillOval((int)ver[selected].X-2, (int)ver[selected].Y-2, 5, 5);
       }else
       if((drag > 0) && (drag < i) && (ver[drag]!= null)){
           g.setColor(highl);
           g.fillOval(Math.round(ver[drag].X)-2, Math.round(ver[drag].Y-2), 5, 5);
           g.fillRect(Math.round(ver[drag].X)+5, Math.round(ver[drag].Y), 75, 16);
           g.setColor(text);
           g.drawRect(Math.round(ver[drag].X)+5, Math.round(ver[drag].Y), 75, 16);
           g.drawString("drag to move", Math.round(ver[drag].X)+7, Math.round(ver[drag].Y)+12);
       }
    }
    
  
    @Override
    public void onMouseDown(MouseEvent e){
        
        int x = e.getX(), y = e.getY();
        
       // if((x>0) && (x<WIDTH) && (y>0) && (y<HEIGHT))
            selected = select(x,y,10);
        repaint();
    }
    
    @Override
    public void onMouseDrag(MouseEvent e){
        
        int x = e.getX(), y = e.getY();
        
        if((selected >= 0) && (ver[selected]!= null)){
            ver[selected].X = x;//>0?(x<WIDTH?x:WIDTH-1):1;
            ver[selected].Y = y;//>0?(y<WIDTH?y:HEIGHT-1):1;
        }
        repaint();
    }
    
    @Override
    public void onMouseUp(MouseEvent e){
        
        int x = e.getX(), y = e.getY();
        
        if((selected<0) && (e.getButton() == MouseEvent.BUTTON1))// && 
                //(x>0) && (x<WIDTH) && (y>0) && (y<HEIGHT))
            addVertex(x, y);
        else if((selected >= 0) && (e.getButton() == MouseEvent.BUTTON3))
            deleteVertex(selected);
        if(e.getButton() == MouseEvent.BUTTON2) 
            points = !points;
        selected = -1;
        repaint();
    }
    
    @Override
    public void onMouseMove(MouseEvent e){
        drag = select(e.getX(),e.getY(),10);
        repaint();
    }
    
}