import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class Threevector {

	private double xcoord, ycoord, zcoord; // Private data members

	// Default constructor
	Threevector()
	{
		xcoord = 0.0;
		ycoord = 0.0;
		zcoord = 0.0;
	}
	// Cartesian constructor
	Threevector(double x, double y, double z)
	{
		xcoord = x;
		ycoord = y;
		zcoord = z;
	}
	// Vector duplication constructor
	Threevector(Threevector v)
	{
		xcoord = v.getX();
		ycoord = v.getY();
		zcoord = v.getZ();
	}
	// Spherical polar constructor
	//Example call: Threevector v1 = new Threevector(1,2,3,Type.d); - d for degrees, r for radians
	Threevector(double r, double theta, double phi, Type type)
	{
		switch (type){
		case d:	
			xcoord = r*Math.sin(Math.toRadians(theta))*Math.cos(Math.toRadians(phi));
			ycoord = r*Math.sin(Math.toRadians(theta))*Math.sin(Math.toRadians(phi));
			zcoord = r*Math.cos(Math.toRadians(theta));
		case r:	
			xcoord = r*Math.sin(theta)*Math.cos(phi);
			ycoord = r*Math.sin(theta)*Math.sin(phi);
			zcoord = r*Math.cos(theta);
		default:
			System.out.println("ERROR: Units of angle undefined, please select 'd' for degrees or 'r' for radians.");
		}
	}

	// Methods to print out contents to screen and file
	public void print()
	{
		System.out.println(xcoord + "\t" + ycoord + "\t" + zcoord);
	}
	public void printtoFile()
	{
		String filename = "output_3vector.txt";
		try
		{
			PrintWriter out = new PrintWriter(new FileWriter(filename));
			out.println(xcoord + "\t" + ycoord + "\t" + zcoord);
			out.close();
		}
		catch(IOException e)
		{
			System.out.println("Unable to open file " + filename);
		}

	}

	//Methods to return the cartesian coordinates of the vector
	public double getX()
	{
		return xcoord;
	}

	public double getY()
	{
		return ycoord;
	}

	public double getZ()
	{
		return zcoord;
	}

	//Methods to return spherical polar coordinate angles of the vector
	//Example call: v1.getTheta(Type.d); - d for degrees, r for radians
	public double getTheta(Type type)
	{
		switch (type){
		case d:	
			return Math.toDegrees(Math.acos(zcoord/mag3()));	
		case r:	
			return Math.acos(zcoord/mag3());			
		default:
			System.out.println("ERROR: Units of angle undefined, please select 'd' for degrees or 'r' for radians.");			
			return 0;
		}
	}

	//Example call: v1.getPhi(Type.d); - d for degrees, r for radians
	public double getPhi(Type type)
	{
		switch (type){
		case d:	
			return Math.toDegrees(Math.atan(ycoord/xcoord));
		case r:	
			return Math.atan2(ycoord,xcoord);	//do not use atan, must take into account range of input variables				
		default:
			System.out.println("ERROR: Units of angle undefined, please select 'd' for degrees or 'r' for radians.");			
			return 0;
		}
	}

	//Method to return the square of the vector
	public double square3()
	{
		return xcoord*xcoord + ycoord*ycoord + zcoord*zcoord;
	}

	//Method to return the magnitude of the vector
	public double mag3()
	{	
		return Math.sqrt(square3());
	}

	//Methods to alter cartesian values of coordinates
	public void setX(double x_new)
	{
		xcoord = x_new;
	}
	public void setY(double y_new)
	{
		ycoord = y_new;
	}
	public void setZ(double z_new)
	{
		zcoord = z_new;
	}

	//Method to calculate the dot product of two vectors
	public double dot(Threevector v_other)
	{
		return v_other.getX()*xcoord + v_other.getY()*ycoord + v_other.getZ()*zcoord;
	}

	//Method to calculate the cross product of two vectors
	public Threevector cross(Threevector v_other)
	{
		return new Threevector(ycoord*v_other.getZ() - zcoord*v_other.getY(),zcoord*v_other.getX() - xcoord*v_other.getZ(),xcoord*v_other.getY() - ycoord*v_other.getX());
	}

	//Method to scale a vector
	public void scale(double scale)
	{
		xcoord *= scale;
		ycoord *= scale;
		zcoord *= scale;

	}
	//Methods to combine vectors
	public Threevector add(Threevector v_other)
	{
		return new Threevector(v_other.getX() + xcoord,v_other.getY() + ycoord,v_other.getZ() + zcoord);

	}
	public void increment(Threevector v_other)
	{
		xcoord += v_other.getX();
		ycoord += v_other.getY();
		zcoord += v_other.getZ();
	}
	public Threevector subtract(Threevector v_other)
	{
		return new Threevector(xcoord - v_other.getX(),ycoord - v_other.getY(),zcoord - v_other.getZ());

	}	
};