// AddKGon.java
// Command to add a regular k-gon to the drawing.

// Written by Scot Drysdale to
// use for VoronoiTool

import java.awt.Point;
import java.awt.geom.Point2D;
import javax.swing.JOptionPane;

public class AddKGon extends Command {
	private PointShape center = null;	// starting point for polygon
	  
	// When the mouse is clicked the first time, record the original point.
	// Each successive click create a new segment until get back to original
	// point.
	public void executeClick(Point p, Drawing dwg)
	{
		if(center == null)		// Starting a polygon?
		{
			center = new PointShape(p);
			dwg.setTempShape(center);
		}
		else
		{	// Get a point on the circle and create the polygon
			createKGon(center, Math.sqrt(center.euclideanSq(p)), dwg);
			center = null;
		}
	}
	
	public static void createKGon(PointShape center, double radius, Drawing dwg)
	{
		int sides = -1;
		
		// Get the number of sides from a dialog box
		String input = JOptionPane.showInputDialog("Enter number of sides (> 2):");
		while(input != null && sides < 3)
		{
			try
			{
				sides = Integer.parseInt(input);
			}
			catch (NumberFormatException exception) 
			{
				JOptionPane.showMessageDialog(null, "Invalid integer");
				sides = -1;
			}
			
			if(sides < 3)
				input = JOptionPane.showInputDialog("Re-enter number of sides (> 2):");
		}
		
		if(input == null)   // Cancel command selected?
		{
			dwg.setTempShape(null);
			return;		
		}
		
		PointShape pOrig = new PointShape(
				new Point2D.Double(center.getX() + radius, center.getY()));
		PointShape last = pOrig;
		
		double arc = 2*Math.PI/sides;
//		double length = arc*radius;    // remove later - not exact
//		double angle = Math.PI/2; // remove later
//		double alpha = arc; // Remove later
		
		// for common centers
//		double newLength = length*1.01;
//		double cDist = 2*length*(newLength/length)/(Math.pow(newLength/length, 2) - 1);
//		PointShape currentO = new PointShape(
//				new Point2D.Double(last.getX(), last.getY() + length));
//		dwg.add(new Segment(last, currentO));
//		last = currentO;
//		length = newLength;
//		cDist += length;  // Shift center by the length to make new point origin
		
		for(int j = 1; j < sides; j++)
		{
			double alpha = j * arc;
//		    arc *= 1.01; // REMOVE later
			PointShape current = new PointShape(
					new Point2D.Double(center.getX() + radius*Math.cos(alpha), 
							           center.getY() + radius*Math.sin(alpha))); 
			
/*			// Fixed angle and length ratios
//			length *= 1.001;
			length += arc*radius/sides;
		    PointShape current = new PointShape(
					new Point2D.Double(last.getX() + length*Math.cos(angle), 
							           last.getY() + length*Math.sin(angle))); */
			
/*			// Straight line with constant length ratios
//			length *= 1.01;
			length += arc*radius/sides;
		    PointShape current = new PointShape(
					new Point2D.Double(last.getX(), last.getY() + length));
*/
			
			// Straight line with same centers
/*		    PointShape current = new PointShape(
					new Point2D.Double(last.getX(), last.getY() + length));
			dwg.add(new Segment(last, current)); 
			newLength = length * Math.sqrt(2*newLength/cDist + 1);
			length = newLength;
			cDist = cDist + length;
*/
			
			// Shared by all
			dwg.add(new Segment(last, current)); 
			last = current;
//			angle += arc; 
//			alpha += arc; // REMOVE later
		} 
		
		dwg.add(new Segment(last, pOrig));
		dwg.setTempShape(null);
	}
}