import java.awt.*;
import java.applet.*;
import java.util.*;
import java.awt.event.*;
import java.lang.String;




public class RectPerim extends Applet {  
	Graphics offScreenG;
	Image offScreenImg, backImg;
	boolean redraw = true;
	int X, Y, traceCount = 0, setLineOfConstraint = -1;
	int constraintX, constraintY;
	int xTracePoints[] = new int[1000], yTracePoints[] = new int[1000];
	int width, length, heldPerimWidth, heldPerimLength, heldAreaWidth, heldAreaLength;
	int pastLength, pastWidth;
	float area, perimeter, slope, tempLength, tempWidth, shownLength, shownWidth;
	Font f = new Font("Times New Roman", Font.BOLD, 20);
	Checkbox Area;
	Checkbox Perimeter;
	Checkbox Constraint;
	Checkbox Trace;
	
	public void init() {
		backImg = getImage(getCodeBase(),"back.jpg");
		offScreenImg = createImage(this.size().width, this.size().height);
		offScreenG = offScreenImg.getGraphics();
		repaint();
	
		Area = new Checkbox("Set Area");
		add(Area);
		Perimeter = new Checkbox("Set Perimeter");
		add(Perimeter);
		Constraint = new Checkbox("Line of Constraint");
		add(Constraint);
		Trace = new Checkbox("Trace");
		add(Trace);
	}

	public void paint (Graphics g){
		if (redraw){
			offScreenG.drawImage(backImg,0,0,this);
			show(offScreenG);
			g.setFont(f);
			g.drawImage(offScreenImg,0,0,this);
			if ((width > 0 && width < 40) || (length > 0 && length < 40))
				g.setColor(Color.red);
			else
				g.setColor(Color.black);
			g.drawString("Area: " + roundValue(area),30,40);
			g.drawString("Perimeter: " + roundValue(perimeter),30,68);
			g.drawString("Width: " + roundValue(shownWidth), 230, 40);
			g.drawString("Length: " + roundValue(shownLength), 230, 68);
		}
	}

	public float roundValue (float x){
		float y = x*1000;
		y = (int)y;
		y = (float)y/1000;
		return y;
	}


	public void update (Graphics g) {
		paint(g);
	}

	public boolean mouseDown(Event evt, int x, int y){
		System.out.println("X: " + x + "Y: " + y);
		if (Constraint.getState()){
			if (setLineOfConstraint == -1){
				setLineOfConstraint = 0;
				constraintX = x;
				constraintY = y;
			}
			repaint();
		}
	
		down(x,y);
		repaint();
		
		return true;
	}

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

	public void down(int x, int y){
		X = x;
		Y = y;
		setLengthAndWidth();
		setAreaAndPerimeter();
		if (Trace.getState()){
			if (traceCount < 1000){
				xTracePoints[traceCount] = width + 20;
				yTracePoints[traceCount] = 380 - length;
				traceCount++;
			}
		}
	}	

	public void drag(int x, int y){
		X = x;
		Y = y;
		setLengthAndWidth();
		setAreaAndPerimeter();
		if (Trace.getState()){
			if (traceCount < 1000){
				xTracePoints[traceCount] = width + 20;
				yTracePoints[traceCount] = 380 - length;
				traceCount++;
			}
		}
		repaint();
	}

	public void setLengthAndWidth(){
		redraw = true;
		if (X>=20 && X<=380)
			width = X-20;
		else if (X<20)
			width = 0;
		else 
			width = 360;

		if (Y>=100 && Y<=380)
			length = 380-Y;
		else if (Y>380)
			length = 0;
		else{
			Y=100;
			length = 280;
		}

		if(Area.getState()){
			float temp = (float)heldAreaWidth/width;
			float tempLength = (float)heldAreaLength * temp;
			length = (int)tempLength;
			if (length > 280){
				length = 280;
				width = heldAreaWidth*heldAreaLength/length;
			}
			if (Constraint.getState())
				redraw = false;
		}

		if(Perimeter.getState()){
			int temp = heldPerimWidth - width;
			length = heldPerimLength + temp;
			if (length > 280){
				length = 280;
				width = (heldPerimLength + heldPerimWidth) - length; 
			}
			if (length < 0){
				length = 0;
			}
			if (Area.getState()){
				if (length != heldAreaWidth || width != heldAreaLength)
					if (length != heldAreaLength || width != heldAreaWidth){
						redraw = false;
						length = pastLength;
						width = pastWidth;
					}
			}
			if (Constraint.getState())
				redraw = false;
		}

		if (Constraint.getState()){
			
			slope = (380 - (float)constraintY)/((float)constraintX - 20);
			tempLength = slope * width;
			length = (int)tempLength;

			if (length > 280){
				length = 280;
				tempWidth = length/slope;
				width = (int)tempWidth;
			}
		}
			

		if(length == 0 || width == 0){
			length = 0;
			width = 0;
			if (Perimeter.getState() || Area.getState()){
				redraw = false;
				length = pastLength;
				width = pastWidth;
			}
		}	

		shownWidth = (float)width/40;
		shownLength = (float)length/40;

		pastLength = length;
		pastWidth = width;
	}

	public void setAreaAndPerimeter(){
		perimeter = (2*(shownWidth + shownLength));
		area = shownWidth*shownLength;
		if (Area.getState()){
			area = (float)heldAreaLength*(float)heldAreaWidth/1600;
			shownLength = area/shownWidth;
			perimeter = 2*(shownWidth + shownLength);
		}
	}

	public void show(Graphics offScreenG){
		if (setLineOfConstraint == 0){
			if (constraintX < 60 || constraintY > 340)
				offScreenG.setColor(Color.red);
			else
				offScreenG.setColor(Color.black);

			offScreenG.drawLine(20, 380, constraintX, constraintY);
			setLineOfConstraint = -2;
		}	

		else{
			if (width < 40 || length < 40)
				offScreenG.setColor(Color.red);
			else
				offScreenG.setColor(Color.black);
			if (width != 0 && length != 0){
				offScreenG.drawRect(20,380 - length,width,length);
				offScreenG.drawRect(21,381 - length,width-2,length-2);
				offScreenG.drawRect(22,382 - length,width-4,length-4);
				if (Constraint.getState())
					offScreenG.drawLine(20, 380, constraintX, constraintY);
			}
		}

		
		if(Trace.getState()){
			for(int i = 0; i < traceCount; i++)
				offScreenG.drawLine(xTracePoints[i],yTracePoints[i],xTracePoints[i],yTracePoints[i]);
		}
	}

	public boolean action(Event evt, Object arg) {
		 if(evt.target == Perimeter){
			heldPerimWidth = width;
			heldPerimLength = length;
		}

		if(evt.target == Area){
			heldAreaWidth = width;
			heldAreaLength = length;
		}	

		if(evt.target == Trace){
			if (Trace.getState())
				for(int i = 0; i < xTracePoints.length; i++){
					traceCount = 0;
				}  
		}

		if(evt.target == Constraint)
			setLineOfConstraint = -1;

		return true;
	}			

	public Insets insets() {
		return new Insets(410, 0, 0, 0);
	}
}