// Linear Regression by Exner Enterprises, C.1997-99
// November 4, 1999
// Author: Nicholas Exner
// http://www.uiuc.edu/ph/www/exner
// Free to redistribute/publish/modify pending that
// the above comments are retained.

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import java.util.*;

public class Line2 extends Applet {
	Image offscreenImage;
	Graphics h;
	int appSizeX, appSizeY;
	Vector objVect;
	Spread window;

   public void init(){
	appSizeX=this.size().width;
	appSizeY=this.size().height;
	setBackground(Color.white);
	LinePoint.loadImages(this);

	offscreenImage = createImage(appSizeX, appSizeY);
	h = offscreenImage.getGraphics();

      window = new Spread(h);
      window.resize(136,285);
      Point d = location();
      window.move((d.x+400),d.y);
      window.hide();
	
	objVect = new Vector();
	objVect.addElement(new LinePoint(window));
	objVect.addElement(new ExnerSlideBar(364,123));
	repaint();
   }

   public void paint(Graphics g) {
  	  Enumeration e = objVect.elements();
	  while(e.hasMoreElements()) {
	   ShowableObject c = (ShowableObject)e.nextElement();		
	   c.show(h);
	  }
	g.drawImage(offscreenImage,0,0,this);
   }

  public boolean mouseDown(Event evt, int x, int y) {
	System.out.println("x: "+(x)+"y: "+(y));		// Debug position
  	  Enumeration e = objVect.elements();
	  while(e.hasMoreElements()) {
	   ShowableObject c = (ShowableObject)e.nextElement();		
	   c.setMousePoint(x,y);
	  }
	if (x > 589&& x < 617)
		if (y> 185 && y <206)
		      window.show();

	if (x > 319&& x < 472)
		if (y> 143 && y <169)
			ShowableObject.drawBlue= true;
	if (x>=355 && x <=434) 
		if (y>=173 && y < 198) {
			window.hide();
			for (int i=0; i < 12; i++) {
				CellMatrix.cellArray[0][i].putValue("");
				CellMatrix.cellArray[1][i].putValue("");
			}
		}

	window.repaint();

	repaint();
	return true;
  }

   public boolean mouseUp(Event evt, int x, int y) {
	return true;
   }

   public boolean mouseDrag(Event evt, int x, int y) {
  	Enumeration e = objVect.elements();
	while(e.hasMoreElements()) {
	   	ShowableObject c = (ShowableObject)e.nextElement();		   		c.mouseDrag(x,y);
	}
	repaint();
	return true;
   }

   public void update(Graphics g) {
	paint(g);
   }
} // End class Line2
/////////////////// ShowableObject Class ////////////////////////////
class ShowableObject extends Applet {
	static boolean drawBlue=false;

	public void show (Graphics g) {
		return;
	}
	public void keyPress(Event evt, int key) {
		return;
	}
   	public void mouseDrag(int x, int y) {
		return;
   	}

     	public void setMousePoint(int x ,int y) {
		return;
   	}

}


/////////////  New Line Stuff Class //////////
class LinePoint extends ShowableObject {
	int maxPoints=50, xspots[], yspots[];
 	int currspots = 0, spotX=0, spotY=0, prevX=0, prevY=0;
	double m=0, b=0, m2=0, averagex=0, averagey=0;
	int lastx=0, lasty=0;
	static Image backImg,barImg;
	boolean notMoveMode=true;
	Spread window;
	boolean paintLine;

	public LinePoint(Spread window2) {	// Constructor for class
		xspots = new int[maxPoints];
		yspots = new int[maxPoints];
		window=window2;
		resetGraph();
	}

	public static void loadImages(Applet parent) {
		backImg = parent.getImage(parent.getCodeBase(),"back.jpg");
		barImg = parent.getImage(parent.getCodeBase(),"bar.jpg");
	}

	public void setMousePoint(int x, int y) {
		if (x>=25 && x <=175){
			if (y>=20 && y<=170)
				addspot(x-25,y-20);
				if (notMoveMode)
					m2=0;
		} else {
			if (x>=355 && x <=434) 
				if (y>=173 && y < 198)
					resetGraph();
		}
	}

	public void addspot(int x, int y) {
	   if (notMoveMode) {
		if (!paintLine && currspots<maxPoints) {
			xspots[currspots]=x;
			yspots[currspots]=y;
//Experimental
if (currspots < 50) {
	CellMatrix.cellArray[0][currspots].putValue(Double.toString(1+(x*2.0/30)));
	CellMatrix.cellArray[1][currspots].putValue(Double.toString(10+(y*(-2.0)/30)));
}
if (currspots >= 12) {
      window.resize(136,10+(currspots*25));
}
			currspots++;
		}
		prevX=x;
		prevY=y;
	   }
	}

	public void resetGraph() {
		paintLine = false;
		for (int i=0; i< maxPoints; i++) {
			xspots[i]=0;
			yspots[i]=0;
		}
	      window.resize(136,285);
		currspots=0;
		averagex=0;
		averagey=0;
		ShowableObject.drawBlue= false;
		notMoveMode=true;
	}

    private boolean calculateRegression() { 
        // Verify that at least two points have been clicked.
        int n = currspots; 
        if (n < 2) 
            return false;

        // Method of least squares...
        double sumx  = 0.0; 
        double sumxx = 0.0; 
        double sumy  = 0.0; 
        double sumxy = 0.0; 

		for(int i=0; i < currspots; i++){
			sumx+=(xspots[i]+0.0);
			sumy+=(yspots[i]+0.0);
			sumxx+=((xspots[i]+0.0)*(xspots[i]));
			sumxy+=((xspots[i]+0.0)*(yspots[i]));
		}

        double den = sumxx - sumx * sumx / n;
	  if (den != 0) 
	        m = (sumxy - sumx * sumy / n ) / den; 
	  else 
		  m = 3.14/2.0;
        b = (sumy - m * sumx) /n; 
	  averagex=(sumx/n);
	  averagey=(sumy/n);
        return true; 
    }

    public int figureFit() {
	int fit;
	if (Math.abs(m) < 1){
		double y2 = -m2*(averagex-150)+averagey;
		double y1 = -m*(averagex-150)+averagey;
		fit = (int)Math.abs(y2-y1);
	} else {
		double x2 = (averagey+20)/m2+averagex;
		double x1 = (averagey+20)/m+averagex;
		fit = (int)Math.abs(x2-x1);
	}
	if (fit > 125)
		fit=125;
	return fit;
    }

	public void show( Graphics g) {
		g.drawImage(backImg,0,0,this);
		showLine(g);

	if (currspots > 1)
		g.drawImage(barImg,198,167-figureFit(),this);

        drawStripImage(g, backImg,20,172,165,30);  // Top Numbers
        drawStripImage(g, backImg,20,0,165,20);	   // Bottom Numbers
        drawStripImage(g, backImg,192,168,42,45); // Bulb

		// Show Spots
		g.setColor(Color.blue);
		for (int i=0; i < currspots; i++) {
			g.fillOval(xspots[i]-2+25,yspots[i]+20-2,4,4);
		}
	} // End Show

	public void showLine( Graphics g) {
		g.setColor(Color.blue);

        // Plot a straight line through the points.
        if (calculateRegression()) { 
		int xright = 150;
		if (ShowableObject.drawBlue)
	            g.drawLine(25, (int)b+20, xright+25, 20+(int)(m * xright + (b))); 

		g.setColor(Color.red);
		//Midpoint to side
		g.drawLine((int)averagex+25, (int)averagey+20, xright+25, 		20+(int)averagey+(int)(-m2*(averagex-xright))); 

		// left to midpoint
		g.drawLine((int)averagex+25, (int)averagey+20, 25, 20+(int)averagey+(int)(-		m2*(averagex))); 

		g.drawString("y = "+cutDouble(-m2)+"x + "+ 			cutDouble2(averagey+(m2*averagex)),510,80);


		if (ShowableObject.drawBlue) {
			g.setColor(Color.blue);
			g.drawString("y = "+cutDouble(-m)+"x + "+
				cutDouble2(averagey+(m*averagex)),510,180);
		}
        } 
	} // End showLine

	public double cutDouble(double value) {
		int dog;
		dog = (int)(value*1000);
		return dog/1000.0;
	}

	public double cutDouble2(double value) {
		int dog;
		value= (value*2.0)/30.0;
		dog = (int)(value*10);
		return dog/10.0;
	}
	public void mouseDrag(int x, int y) {
	   if (notMoveMode) {
		if (x > lastx) {	
			m2+=incrementUp();
			if (m2 > 15 || m2 < -15) {
				System.out.println("Change signs.");
				m2 = -m2+2;
			}
		} 
		if (x < lastx) {
			m2-=incrementUp();
			if (m2 > 15 || m2 < -15) {
				System.out.println("Change signs.");
				m2 = -m2-2;
			}
		}
	   }
		System.out.println("Slope m: "+m+" Slope m2:" + m2);
		lastx = x;
		lasty = y;
	}

	public double incrementUp() {
		double increment=.1;

		if (m2 < 1  && m2 > -1)
			increment=.1;
		
		if (m2 > 3 || m2 < -3)
			increment=1;

		return increment;
	}

public void drawStripImage(Graphics g, Image imagePtr,int drawX, int drawY,int width, int length) {
     Graphics subArea = g.create(drawX, drawY, width, length);
     int stripX = drawX; //(imageNum-1)*imageWidth;
     int stripY = drawY; //0;
     subArea.drawImage(imagePtr, -stripX, -stripY, this);
     subArea.dispose();
}

} // End Class


/////////////////// ExnerSlideBar Class ///////////////////////////////
class ExnerSlideBar extends ShowableObject {
	private int xPos=0,yPos=0,width=50,valuePos=0;
	private boolean selected=false;

public ExnerSlideBar() {
	valuePos = width/2;
}

public ExnerSlideBar(int x, int y){
	xPos=x;
	yPos=y;
	valuePos = width/2;
}
   public void show(Graphics g){
	g.setColor(Color.white);
	g.fillRect(xPos,yPos+1,width,2);  	   // x line
	g.setColor(Color.black);
	g.drawRect(xPos,yPos+1,width,2); 	   // x line

	g.setColor(Color.white);
	g.fill3DRect(xPos+valuePos,yPos-4,6,12,true);  // value line
   }

   public int getValue() {
	return (valuePos*2);
	//System.out.println("ValuePos= "+valuePos+".");
   }

   public void reset() {
	valuePos = width/2;
   }

   public void setMousePoint(int x, int y) {
		if (x>=(xPos+valuePos) && x <=(xPos+valuePos+6)) {
			if (y>=(yPos-4) && y<=(yPos+8)) {
				selected=true;				
			}
		}
		return;
   }

   public void unsetMousePoint(int x, int y) {
		selected=false;
   }

   public void mouseDrag(int x, int y) {
	if (selected) {
	   if (y >= (yPos-5) && y <= (yPos+9)) {
		if (x >= (xPos+width))
			valuePos=width;
		if (x <= xPos)
			valuePos= 0;
		if (x < (xPos+width) && x > xPos)
			valuePos=Math.abs(xPos-x);
	    }
	}
   }
} // End Class ExnerSlideBar