import javax.swing.*;
import java.awt.*;

public class Triangles extends JApplet {

    double perimeter;  
    double area;   
    double base;   
    double height; 
    double length; 
    String  triType;

    public void init() {

	String input;

        // type of triangle to be computed
        triType = JOptionPane.showInputDialog(  "Enter the type of triangle" +
						"(R, E, I)" );
	triType = triType.toUpperCase();
                 
	if ( triType.equals("E") )  // equilateral triangle
	{
	    input = JOptionPane.showInputDialog(  "Enter length of the equilateral triangle " );
	    length = Double.parseDouble( input );
	    height = (Math.sqrt(3) / 2) * length;
		
	    if ( length <= 0 )
		JOptionPane.showMessageDialog( null, 
				 "error, please enter value greater than 0" );

	    else {
		area = length / 2 * height;
		perimeter = length * 3;
		/*JOptionPane.showMessageDialog( null,  "Area = " +
		                               area + "\n" + 
					       "Perimeter = " +
					       perimeter );
		*/
	    }
	}	
	else if ( triType.equals("R") ) {   // right triangle
	    input = JOptionPane.showInputDialog(  "Enter the length of one" +
		    " non-hypotenuse side of the right triangle."  );
	    base = Double.parseDouble( input );
	    input = JOptionPane.showInputDialog(  "Enter the length of the other" +
		    " non-hypotenuse side of the right triangle."  );
	    height = Double.parseDouble( input );

	    if ( base<=0 || height<=0 )
		JOptionPane.showMessageDialog( null, 
				 "error, please enter values greater than 0" );
	    else {
		area = base / 2 * height;
		perimeter = height + base + Math.sqrt(height*height+ base*base);
		/*JOptionPane.showMessageDialog( null,  "Area = " +
					       area + "\n" + 
					       "Perimeter = " +
					       perimeter );
		*/
	    }
	}
	
	else if ( triType.equals("I") ) {   // isosceles triangle
	    input = JOptionPane.showInputDialog(  "Enter the length of the" +
		    " base of the isoceles triangle."  );
	    base = Double.parseDouble( input );
	    input = JOptionPane.showInputDialog(  "Enter the length of the other" +
		    " side of the isoceles triangle."  );
	    length = Double.parseDouble( input );

	    height = Math.sqrt(length * length - (base * base / 4));
		
	    if (base > (length + length))
		JOptionPane.showMessageDialog( null, 
					       "error:  the base must be less"+
					       " than the sum of the sides"  );
	    else if (length <= 0 || base <=0)
		JOptionPane.showMessageDialog( null, 
				 "error, please enter values greater than 0" );
	    else {
		area = base / 2 * height;
		perimeter = length + length + base;
		/*JOptionPane.showMessageDialog( null,  "Area = " +
					       area + "\n" + 
					       "Perimeter = " +
					       perimeter );
		*/
	    }
	}	   

	else
	    JOptionPane.showMessageDialog( null, 
					   "sorry:  Only R, E, or I" );
    }


    public void paint( Graphics g ) {
	super.paint( g );

	g.drawString( "Area = " + area, 10, 100 );
	g.drawString( "Perimeter = " + perimeter, 10, 200 );

	//optional
	//draw the triangle
	int iBase = (int)base;
	int iHeight = (int)height;
	int iLength = (int)length;

	if ( triType.equals("R") ) {
	    g.drawLine( 300, 300, 300, 300+iBase );
	    g.drawLine( 300, 300+iBase, 300+iHeight, 300+iBase );
	    g.drawLine( 300, 300, 300+iHeight, 300+iBase );
	}
	else if ( triType.equals("E") ) {
	    g.drawLine( 300, 300, 300, 300+iLength );
	    double angle = Math.toRadians(30); //30 degrees "down"
	    int x2 = (int)(Math.cos(angle)*length+300);
	    int y2 = (int)(Math.sin(angle)*length+300);
	    g.drawLine( 300, 300, x2, y2 );
	    g.drawLine( 300, 300+iLength, x2, y2 );
	}
	else if ( triType.equals("I") ) {
	    g.drawLine( 300, 300, 300+iBase, 300 );
	    //double angle = Math.toRadians(30);
	    double theta = Math.asin(height/length);
	    int x2 = (int)(Math.cos(-theta)*length+300);
	    int y2 = (int)(Math.sin(-theta)*length+300);
	    g.drawLine( 300, 300, x2, y2 );
	    g.drawLine( 300+iBase, 300, x2, y2 );
	}
    }
}

/* w/out trig:
Right: (x,y)
  up:  (x,y-s1)
  right:(x+s2,y)

Iso:    (x,y)
  up:   (x+b/2,y-h)
  right:(x+b,y)

Equi (special case of Iso, b=s)
      (x,y)
 up:  (x+s/2,y-h)
right:(x+s,y)

*/