/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2020 iText Group NV
 * Authors: Kevin Day, Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
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 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
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 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
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 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
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 */
package com.itextpdf.text.pdf.parser;

import java.util.Arrays;

/**
 * Represents a vector (i.e. a point in space).  This class is completely
 * unrelated to the {@link java.util.Vector} class in the standard JRE.
 * <br><br>
 * For many PDF related operations, the z coordinate is specified as 1
 * This is to support the coordinate transformation calculations.  If it
 * helps, just think of all PDF drawing operations as occurring in a single plane
 * with z=1.
 */
public class Vector {
    /** index of the X coordinate */
    public static final int I1 = 0;
    /** index of the Y coordinate */
    public static final int I2 = 1;
    /** index of the Z coordinate */
    public static final int I3 = 2;

    /** the values inside the vector */
    private final float[] vals = new float[]{
            0,0,0
    };

    /**
     * Creates a new Vector
     * @param x the X coordinate
     * @param y the Y coordinate
     * @param z the Z coordinate
     */
    public Vector(final float x, final float y, final float z) {
        vals[I1] = x;
        vals[I2] = y;
        vals[I3] = z;
    }

    /**
     * Gets the value from a coordinate of the vector
     * @param index the index of the value to get (I1, I2 or I3)
     * @return a coordinate value
     */
    public float get(final int index){
        return vals[index];
    }

    /**
     * Computes the cross product of this vector and the specified matrix
     * @param by the matrix to cross this vector with
     * @return the result of the cross product
     */
    public Vector cross(final Matrix by){

        float x = vals[I1]*by.get(Matrix.I11) + vals[I2]*by.get(Matrix.I21) + vals[I3]*by.get(Matrix.I31);
        float y = vals[I1]*by.get(Matrix.I12) + vals[I2]*by.get(Matrix.I22) + vals[I3]*by.get(Matrix.I32);
        float z = vals[I1]*by.get(Matrix.I13) + vals[I2]*by.get(Matrix.I23) + vals[I3]*by.get(Matrix.I33);

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

    /**
     * Computes the difference between this vector and the specified vector
     * @param v the vector to subtract from this one
     * @return the results of the subtraction
     */
    public Vector subtract(final Vector v){
        float x = vals[I1] - v.vals[I1];
        float y = vals[I2] - v.vals[I2];
        float z = vals[I3] - v.vals[I3];

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

    /**
     * Computes the cross product of this vector and the specified vector
     * @param with the vector to cross this vector with
     * @return the cross product
     */
    public Vector cross(final Vector with){
        float x = vals[I2]*with.vals[I3] - vals[I3]*with.vals[I2];
        float y = vals[I3]*with.vals[I1] - vals[I1]*with.vals[I3];
        float z = vals[I1]*with.vals[I2] - vals[I2]*with.vals[I1];

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

    /**
     * Normalizes the vector (i.e. returns the unit vector in the same orientation as this vector)
     * @return the unit vector
     * @since 5.0.1
     */
    public Vector normalize(){
        float l = this.length();
        float x = vals[I1]/l;
        float y = vals[I2]/l;
        float z = vals[I3]/l;
        return new Vector(x, y, z);
    }

    /**
     * Multiplies the vector by a scalar
     * @param by the scalar to multiply by
     * @return the result of the scalar multiplication
     * @since 5.0.1
     */
    public Vector multiply(final float by){
        float x = vals[I1] * by;
        float y = vals[I2] * by;
        float z = vals[I3] * by;
        return new Vector(x, y, z);
    }

    /**
     * Computes the dot product of this vector with the specified vector
     * @param with the vector to dot product this vector with
     * @return the dot product
     */
    public float dot(final Vector with){
        return vals[I1]*with.vals[I1] + vals[I2]*with.vals[I2] + vals[I3]*with.vals[I3];
    }

    /**
     * Computes the length of this vector
     * <br>
     * <b>Note:</b> If you are working with raw vectors from PDF, be careful -
     * the Z axis will generally be set to 1.  If you want to compute the
     * length of a vector, subtract it from the origin first (this will set
     * the Z axis to 0).
     * <br>
     * For example:
     * <code>aVector.subtract(originVector).length();</code>
     *
     * @return the length of this vector
     */
    public float length(){
        return (float)Math.sqrt(lengthSquared());
    }

    /**
     * Computes the length squared of this vector.
     *
     * The square of the length is less expensive to compute, and is often
     * useful without taking the square root.
     * <br><br>
     * <b>Note:</b> See the important note under {@link Vector#length()}
     *
     * @return the square of the length of the vector
     */
    public float lengthSquared(){
        return vals[I1]*vals[I1] + vals[I2]*vals[I2] + vals[I3]*vals[I3];
    }

    /**
     * @see java.lang.Object#toString()
     */
    @Override
	public String toString() {
        return vals[I1]+","+vals[I2]+","+vals[I3];
    }
   /**
    * Calculates the hashcode using the values.
    * @since 5.0.6
    */
    @Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + Arrays.hashCode(vals);
		return result;
	}
    /*
     * (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
	@Override
	public boolean equals(final Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj == null) {
			return false;
		}
		if (getClass() != obj.getClass()) {
			return false;
		}
		Vector other = (Vector) obj;
		if (!Arrays.equals(vals, other.vals)) {
			return false;
		}
		return true;
	}

}
