/**
 * Copyright 2010 JogAmp Community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and should not be interpreted as representing official policies, either expressed
 * or implied, of JogAmp Community.
 */
package jogamp.graph.math;

import java.util.ArrayList;

import com.jogamp.graph.geom.Vertex;

public class VectorFloatUtil {

	public static final int CW = -1;
	public static final int CCW = 1;
	public static final int COLLINEAR = 0;

	/** compute the dot product of two points
	 * @param vec1 vector 1
	 * @param vec2 vector 2
	 * @return the dot product as float
	 */
	public static float dot(float[] vec1, float[] vec2)
	{
		return (vec1[0]*vec2[0] + vec1[1]*vec2[1] + vec1[2]*vec2[2]);
	}
	/** Normalize a vector
	 * @param vector input vector
	 * @return normalized vector
	 */
	public static float[] normalize(float[] vector)
	{
		float[] newVector = new float[3];

		float d = MathFloat.sqrt(vector[0]*vector[0] + vector[1]*vector[1] + vector[2]*vector[2]);
		if(d> 0.0f)
		{
			newVector[0] = vector[0]/d;
			newVector[1] = vector[1]/d;
			newVector[2] = vector[2]/d;
		}
		return newVector;
	}

	/** Scales a vector by param
	 * @param vector input vector
	 * @param scale constant to scale by
	 * @return scaled vector
	 */
	public static float[] scale(float[] vector, float scale)
	{
		float[] newVector = new float[3];

		newVector[0] = vector[0]*scale;
		newVector[1] = vector[1]*scale;
		newVector[2] = vector[2]*scale;
		return newVector;
	}
	
	/** Adds to vectors
	 * @param v1 vector 1
	 * @param v2 vector 2
	 * @return v1 + v2
	 */
	public static float[] vectorAdd(float[] v1, float[] v2)
	{
		float[] newVector = new float[3];

		newVector[0] = v1[0] + v2[0];
		newVector[1] = v1[1] + v2[1];
		newVector[2] = v1[2] + v2[2];
		return newVector;
	}

	/** cross product vec1 x vec2
	 * @param vec1 vector 1
	 * @param vec2 vecttor 2
	 * @return the resulting vector
	 */
	public static float[] cross(float[] vec1, float[] vec2)
	{
		float[] out = new float[3];

		out[0] = vec2[2]*vec1[1] - vec2[1]*vec1[2];
		out[1] = vec2[0]*vec1[2] - vec2[2]*vec1[0];
		out[2] = vec2[1]*vec1[0] - vec2[0]*vec1[1];

		return out;
	}

	/** Column Matrix Vector multiplication
	 * @param colMatrix column matrix (4x4)
	 * @param vec vector(x,y,z)
	 * @return result new float[3] 
	 */
	public static float[] colMatrixVectorMult(float[] colMatrix, float[] vec)
	{
		float[] out = new float[3];

		out[0] = vec[0]*colMatrix[0] + vec[1]*colMatrix[4] + vec[2]*colMatrix[8] + colMatrix[12]; 
		out[1] = vec[0]*colMatrix[1] + vec[1]*colMatrix[5] + vec[2]*colMatrix[9] + colMatrix[13]; 
		out[2] = vec[0]*colMatrix[2] + vec[1]*colMatrix[6] + vec[2]*colMatrix[10] + colMatrix[14]; 

		return out;
	}
	
	/** Matrix Vector multiplication
	 * @param rawMatrix column matrix (4x4)
	 * @param vec vector(x,y,z)
	 * @return result new float[3] 
	 */
	public static float[] rowMatrixVectorMult(float[] rawMatrix, float[] vec)
	{
		float[] out = new float[3];

		out[0] = vec[0]*rawMatrix[0] + vec[1]*rawMatrix[1] + vec[2]*rawMatrix[2] + rawMatrix[3]; 
		out[1] = vec[0]*rawMatrix[4] + vec[1]*rawMatrix[5] + vec[2]*rawMatrix[6] + rawMatrix[7]; 
		out[2] = vec[0]*rawMatrix[8] + vec[1]*rawMatrix[9] + vec[2]*rawMatrix[10] + rawMatrix[11]; 

		return out;
	}
	
	/** Calculate the midpoint of two values
	 * @param p1 first value
	 * @param p2 second vale
	 * @return midpoint
	 */
	public static float mid(float p1, float p2)
	{
		return (p1+p2)/2.0f;
	}
	/** Calculate the midpoint of two points
	 * @param p1 first point
	 * @param p2 second point
	 * @return midpoint
	 */
	public static float[] mid(float[] p1, float[] p2)
	{
		float[] midPoint = new float[3];
		midPoint[0] = (p1[0] + p2[0])/2.0f;
		midPoint[1] = (p1[1] + p2[1])/2.0f;
		midPoint[2] = (p1[2] + p2[2])/2.0f;

		return midPoint;
	}
	/** Compute the norm of a vector
	 * @param vec vector
	 * @return vorm
	 */
	public static float norm(float[] vec)
	{
		return MathFloat.sqrt(vec[0]*vec[0] + vec[1]*vec[1] + vec[2]*vec[2]);
	}
	/** Compute distance between 2 points
	 * @param p0 a ref point on the line
	 * @param vec vector representing the direction of the line
	 * @param point the point to compute the relative distance of
	 * @return distance float
	 */
	public static float computeLength(float[] p0, float[] point)
	{
		float[] w = new float[]{point[0]-p0[0],point[1]-p0[1],point[2]-p0[2]};

		float distance = MathFloat.sqrt(w[0]*w[0] + w[1]*w[1] + w[2]*w[2]);

		return distance;
	}

	/**Check equality of 2 vec3 vectors
	 * @param v1 vertex 1
	 * @param v2 vertex 2
	 * @return
	 */
	public static boolean checkEquality(float[] v1, float[] v2)
	{
		if(Float.compare(v1[0], v2[0]) == 0 
				&& Float.compare(v1[1] , v2[1]) == 0
				&& Float.compare(v1[2], v2[2]) == 0 )
			return true;
		return false;
	}

	/** Compute the determinant of 3 vectors
	 * @param a vector 1
	 * @param b vector 2
	 * @param c vector 3
	 * @return the determinant value
	 */
	public static float computeDeterminant(float[] a, float[] b, float[] c)
	{
		float area = a[0]*b[1]*c[2] + a[1]*b[2]*c[0] + a[2]*b[0]*c[1] - a[0]*b[2]*c[1] - a[1]*b[0]*c[2] - a[2]*b[1]*c[0];
		return area;
	}

	/** Check if three vertices are colliniear
	 * @param v1 vertex 1
	 * @param v2 vertex 2
	 * @param v3 vertex 3
	 * @return true if collinear, false otherwise
	 */
	public static boolean checkCollinear(float[] v1, float[] v2, float[] v3)
	{
		return (computeDeterminant(v1, v2, v3) == VectorFloatUtil.COLLINEAR);
	}

	/** Compute Vector
	 * @param v1 vertex 1
	 * @param v2 vertex2 2
	 * @return Vector V1V2
	 */
	public static float[] computeVector(float[] v1, float[] v2)
	{
		float[] vector = new float[3];
		vector[0] = v2[0] - v1[0];
		vector[1] = v2[1] - v1[1];
		vector[2] = v2[2] - v1[2];
		return vector;
	}

	/** Check if vertices in triangle circumcircle
	 * @param a triangle vertex 1
	 * @param b triangle vertex 2
	 * @param c triangle vertex 3
	 * @param d vertex in question
	 * @return true if the vertex d is inside the circle defined by the 
	 * vertices a, b, c. from paper by Guibas and Stolfi (1985).
	 */
	public static boolean inCircle(Vertex a, Vertex b, Vertex c, Vertex d){
		return (a.getX() * a.getX() + a.getY() * a.getY()) * triArea(b, c, d) -
		(b.getX() * b.getX() + b.getY() * b.getY()) * triArea(a, c, d) +
		(c.getX() * c.getX() + c.getY() * c.getY()) * triArea(a, b, d) -
		(d.getX() * d.getX() + d.getY() * d.getY()) * triArea(a, b, c) > 0;
	}

	/** Computes oriented area of a triangle
	 * @param a first vertex
	 * @param b second vertex
	 * @param c third vertex
	 * @return compute twice the area of the oriented triangle (a,b,c), the area
	 * is positive if the triangle is oriented counterclockwise.
	 */
	public static float triArea(Vertex a, Vertex b, Vertex c){
		return (b.getX() - a.getX()) * (c.getY() - a.getY()) - (b.getY() - a.getY())*(c.getX() - a.getX());
	}

	/** Check if points are in ccw order
	 * @param a first vertex
	 * @param b second vertex
	 * @param c third vertex
	 * @return true if the points a,b,c are in a ccw order
	 */
	public static boolean ccw(Vertex a, Vertex b, Vertex c){
		return triArea(a,b,c) > 0;
	}

	/** Computes the area of a list of vertices to check if ccw
	 * @param vertices
	 * @return positve area if ccw else negative area value
	 */
	public static float area(ArrayList<Vertex> vertices) {
		int n = vertices.size();
		float area = 0.0f;
		for (int p = n - 1, q = 0; q < n; p = q++)
		{
			float[] pCoord = vertices.get(p).getCoord();
			float[] qCoord = vertices.get(q).getCoord();
			area += pCoord[0] * qCoord[1] - qCoord[0] * pCoord[1];
		}
		return area;
	}
}