import java.util.*;
import java.awt.*;
import java.lang.*;

public class Sphere implements Item
{
	private int centerx, centery, centerz;
	private double radius;
	private World world;
	private Color baseColor;
	
	public Sphere()
	{
		centerx = centery = centerz = 0;
		radius = 50.0;
	}
	public Sphere(World w)
	{
		centerx = centery = centerz = 0;
		radius = 50.0;
		world = w;
	}
	public Sphere(int cx, int cy, int cz, double r)
	{
		centerx = cx;
		centery = cy;
		centerz = cz;
		radius = r;
	}
	public Sphere(int cx, int cy, int cz, double r, World w)
	{
		centerx = cx;
		centery = cy;
		centerz = cz;
		radius = r;
		world = w;
	}
	public Sphere(long seed, World w)
	{
		Random random = new Random(seed);

		baseColor = new Color(random.nextFloat(), 
			random.nextFloat(), random.nextFloat());
	
		centerx = random.nextInt() % 200;
		centery = random.nextInt() % 150;
		centerz = random.nextInt() % 50 - 50;
		
		radius = (random.nextDouble() + random.nextDouble() + random.nextDouble()) * 32.0;
	
		world = w;
	}
	public Sphere(long seed, World w, int width, int height)
	{
		Random random = new Random(seed);

		baseColor = new Color(random.nextFloat(), 
			random.nextFloat(), random.nextFloat());
	
		centerx = random.nextInt() % width/2;
		centery = random.nextInt() % height/2;
		centerz = random.nextInt() % 50 - 50;
		
		radius = (random.nextDouble() + random.nextDouble() + random.nextDouble()) * 32.0;
	
		world = w;
	}

	public void setWorld(World w)
	{
		world = w;
	}

	public boolean contains(int x, int y)
	{
		double distance = Math.sqrt((double) (x-centerx)*(x-centerx) 
									       + (y-centery)*(y-centery));
		return (distance <= radius);
	}
	
	public boolean almostContains(int x, int y)
	{
		double distance = Math.sqrt((double) (x-centerx)*(x-centerx) 
									       + (y-centery)*(y-centery));
		return (distance-1.0 <= radius);
	}

	public String toString()
	{
		String str = "Sphere: ";
		str = str + "center = " + centerx + ", " + centery + ", " + centerz 
			      + "; radius = " + radius + "; color = " + baseColor;
		return str;
	}
	
	public double zIntersectCalc(int x, int y, boolean VERBOSE) throws ItemException
	{
		// Note that this algorithm returns only the greater of two intersections.
		
		if (!almostContains(x, y))
		{
			throw new ItemException("Use contains before trying zIntersect!");
		}
		
		// else if (!contains(x, y))
		// {
			
		// }
		
		double xsq = (double)(x-centerx)*(x-centerx);
		double ysq = (double)(y-centery)*(y-centery);
		
		double zret = (radius * radius) - (xsq + ysq);
		if (zret < 0)
		{
			System.out.println("r^2 - x^2 - y^2 = " + zret + ". Using zero");
			zret = centerz;
		}	
		else
			zret = centerz + Math.sqrt(zret);
		return zret;
		
	}
	
	public double zIntersectVerbose(int x, int y) throws ItemException
	{
		return zIntersectCalc(x, y, true);
	}
	public double zIntersect(int x, int y) throws ItemException
	{
		return zIntersectCalc(x, y, false);
	}

	public Color getNiftyColorAt(int x, int y, double z)
	{
		double x_y = (double) ((x-centerx) - (y-centery));
		double x_z = (double) ((x-centerx) - (z-centerz));
		double y_z = (double) ((y-centery) - (z-centerz));
		
		double r = x_y / (4.0 * radius) + .5;
		double g = x_z / (4.0 * radius) + .5;
		double b = y_z / (4.0 * radius) + .5;

		//	double r = ((x_y > 0) ? x_y : -x_y);
		//	r /= (2.0 * radius);
		//	r = 1.0 - r;
		//	double g = ((x_z > 0) ? x_z : -x_z);
		//	g /= (2.0 * radius);
		//	g = 1.0 - g;
		//	double b = ((y_z > 0) ? y_z : -y_z);
		//	b /= (2.0 * radius);
		//	b = 1.0 - b;

		return new Color((float) r, (float) g, (float) b);

		//	double r = Math.abs(x-centerx)/radius;
		//	double g = Math.abs(y-centery)/radius;
		//	double b = Math.abs(z-centerz)/radius;
		//	return new Color((float) r, (float) g, (float) b);
		//	return baseColor;
	}

	public Color getColorAt(int x, int y, double z)
	{
		XYZVector V, L, H, N;
		double r, g, b;
		double a, d, s;
	
		V = new XYZVector(0.0, 0.0, 1.0);
		
		//	L = new XYZVector((double) world.lightx, (double) world.lighty, (double) world.lightz, 
		//					  (double) x, (double) y, z);

		N = new XYZVector((double) centerx, (double) centery, (double) centerz,
						  (double) x, (double) y, z);		
		L = new XYZVector((double) x, (double) y, z,
						  (double) world.lightx, (double) world.lighty, (double) world.lightz);
						  
		V.normalize();
		L.normalize();
		N.normalize();
		H = XYZVector.plus(L, V);
		H.normalize();
		
		d = XYZVector.dotProduct(N, L);
		if (d<0) d = 0;
		
		a = world.kambient;
		d *= world.kdiffuse;
		
		s = XYZVector.dotProduct(N, H);
		if (s < 0)
			s = 0;
		else
			s = world.kspecular * Math.pow(s, world.specularExponent);
		
		r = (double) baseColor.getRed() / 255.0;
		g = (double) baseColor.getGreen() / 255.0;
		b = (double) baseColor.getBlue() / 255.0;
		
		r *= (a + d); if (r > 1.0) r = 1.0;
		g *= (a + d); if (g > 1.0) g = 1.0;
		b *= (a + d); if (b > 1.0) b = 1.0;
		
		r = s + r*(1-s);
		g = s + g*(1-s);
		b = s + b*(1-s);
		
		return new Color((float) r, (float) g, (float) b);
	}	

	public Color getColorAt(double x, double y, double z)
	{
		return baseColor;
	}

	public double maxZ() throws ItemException
	{
		return (double) centerz + radius;
	}
	
	public void translate(int dx, int dy, int dz)
	{
		centerx += dx;
		centery += dy;
		centerz += dz;		
	}	

}