package RayTracing;

public class Cylinder {

    private Vector center;
    private Float length;
    private Float rad;
    private Vector rotation;
    private Integer matIndex;

    private Vector noraml;


    public Cylinder() {
        this.normal = null;
    }

    public Vector getCenter() {
        return center;
    }
    public void setCenter(Vector center) {
        this.center = center;
    }
    public Float getLength() {
        return length;
    }
    public void setLength(Float length) {
        this.length = length;
    }
    public Float getRad() {
        return rad;
    }
    public void setRad(Float rad) {
        this.rad = rad;
    }
    public Vector getRotation() {
        return rotation;
    }
    public void setRotation(Vector rotation) {
        this.rotation = rotation;
    }
    public Integer getMatIndex() {
        return matIndex;
    }
    public void setMatIndex(Integer matIndex) {
        this.matIndex = matIndex;
    }

    public double getHitDistance(Ray ray) {

        //STEP 1
        //rotation

        Vector norm = new Vector(0,0,1);
        norm = norm.rotate(this.rotation);


        //STEP 2
        Vector s = norm.scale((this.length)/2);
        Vector cUp = this.center.add(s);
        Vector cDown = this.center.minus(s);

        //STEP 3
        Vector axis = (cUp.minus(cDown));
        Vector v1 = axis.multiply(ray.dir);
        Vector v2 = axis.multiply(ray.p0).add(cDown.multiply(cUp));

        double a = v1.normSquared();
        double b = 2 * ( v1.dot(v2));
        double c = v2.normSquared()  - (Math.pow(this.rad * this.length, 2));

        double dis = (Math.pow(b, 2) - 4 * a * c);

        if (dis < 0)
            return -1;

        double n1 = -1;
        double n2 = -1;

        if (dis == 0)
            n1 = (-b/(2*a));

        else {
            n1 = (-b + dis) / (2 * a);
            n2 = (-b - dis) / (2 * a);
        }

        double minN = -1;
        if (n1 > 0 && n2 > 0)
            minN = Math.min(n1, n2);
        else if (n1 > 0 && n2 < 0)
                minN = n1;
        else if (n1 < 0 && n2 > 0)
                minN = n2;


        Vector x0 = new Vector(ray.p0.getX() + minN*ray.dir.getX(), ray.p0.getY() + minN*ray.dir.getY(), ray.p0.getZ() + minN*ray.dir.getZ());
        Vector movement = x0.minus(cDown).dot(norm);
        Vector x0OnAxis = new Vector(cDown.getX() + movement * norm.getX(), cDown.getY() + movement * norm.getY(), cDown.getZ() + movement * norm.getZ());
        normal = x0.minus(x0OnAxis);

        Plane upPlane = new Plane(axis, axis.dot(cUp));
        Plane downPlane = new Plane(axis, axis.dot(cDown));

        double planeHit = -1;

        double h1 = upPlane.getHitDistance(ray);
        double hittingPointUp = new Vector(ray.p0.getX() + h1*ray.dir.getX(), ray.p0.getY() + h1*ray.dir.getY(), ray.p0.getZ() + h1*ray.dir.getZ());

        if(cUp.minus(hittingPointUp).normSquared() <= r*r)
            planeHit = h1;

        double h2 = downPlane.getHitDistance(ray);
        double hittingPointDown = new Vector(ray.p0.getX() + h2*ray.dir.getX(), ray.p0.getY() + h2*ray.dir.getY(), ray.p0.getZ() +  h2*ray.dir.getZ());
        if(cDown.minus(hittingPointDoown).normSquared() <= r*r && (planeHit < 0 || planeHit > h2))
            planeHit = h2;


        if(minN < 0 && planeHit < 0)
            return -1;

        if(minN > 0 && planeHit > 0) {
            if(minN < planeHit) {
                return minN;
            }
            this.normal = axis;
            return planeHit;
        }

        if(planeHit > 0) {
            this.normal = axis;
            return planeHit;
        }
        return minN;
    }

    public Vector getNormalAtSurfacePoint(Vector intersection) {
        return this.normal;
    }

    public Vector rotateX(Vector vector){
        Vector a = new Vector(1,0,0);
        Vector b = new Vector(0,Math.cos(Math.toRadians(rotation.getX())),-Math.sin(Math.toRadians(rotation.getX())));
        Vector c = new Vector (0,Math.sin(Math.toRadians(rotation.getX())),Math.cos(Math.toRadians(rotation.getX())));

        double x = a.dot(vector);
        double y = b.dot(vector);
        double z = c.dot(vector);

        return new Vector(x,y,z);
    }


    public Vector rotateY(Vector vector){
        Vector a = new Vector(Math.cos(Math.toRadians(rotation.getY())),0,Math.sin(Math.toRadians(rotation.getY())));
        Vector b = new Vector(0,1,0);
        Vector c = new Vector (-Math.sin(Math.toRadians(rotation.getY())),0,Math.cos(Math.toRadians(rotation.getY())));

        double x = a.dot(vector);
        double y = b.dot(vector);
        double z = c.dot(vector);

        return new Vector(x,y,z);
    }

    public Vector rotateZ(Vector vector){
        Vector a = new Vector(Math.cos(Math.toRadians(rotation.getZ())),-Math.sin(Math.toRadians(rotation.getZ())),0);
        Vector b = new Vector(Math.sin(Math.toRadians(rotation.getZ())),Math.cos(Math.toRadians(rotation.getZ())),0);
        Vector c = new Vector (0,0,1);

        double x = a.dot(vector);
        double y = b.dot(vector);
        double z = c.dot(vector);

        return new Vector(x,y,z);
    }

}