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package com.javafx.experiments.utils3d.geom;

/**
 * The <code>Point2D</code> class defines a point representing a location
 * in {@code (x,y)} coordinate space.
 * <p>
 */
public class Point2D {
    /**
     * The X coordinate of this <code>Point2D</code>.
     */
    public float x;

    /**
     * The Y coordinate of this <code>Point2D</code>.
     */
    public float y;

    /**
     * Constructs and initializes a <code>Point2D</code> with
     * coordinates (0,&nbsp;0).
     */
    public Point2D() { }

    /**
     * Constructs and initializes a <code>Point2D</code> with 
     * the specified coordinates.
     *
     * @param x the X coordinate of the newly
     *          constructed <code>Point2D</code>
     * @param y the Y coordinate of the newly
     *          constructed <code>Point2D</code>
     */
    public Point2D(float x, float y) {
        this.x = x;
        this.y = y;
    }

    /**
     * Sets the location of this <code>Point2D</code> to the 
     * specified <code>float</code> coordinates.
     *
     * @param x the new X coordinate of this {@code Point2D}
     * @param y the new Y coordinate of this {@code Point2D}
     */
    public void setLocation(float x, float y) {
        this.x = x;
        this.y = y;
    }

    /**
     * Sets the location of this <code>Point2D</code> to the same
     * coordinates as the specified <code>Point2D</code> object.
     * @param p the specified <code>Point2D</code> to which to set
     * this <code>Point2D</code>
     */
    public void setLocation(Point2D p) {
        setLocation(p.x, p.y);
    }

    /**
     * Returns the square of the distance between two points.
     *
     * @param x1 the X coordinate of the first specified point
     * @param y1 the Y coordinate of the first specified point
     * @param x2 the X coordinate of the second specified point
     * @param y2 the Y coordinate of the second specified point
     * @return the square of the distance between the two
     * sets of specified coordinates.
     */
    public static float distanceSq(float x1, float y1, float x2, float y2) {
        x1 -= x2;
        y1 -= y2;
        return (x1 * x1 + y1 * y1);
    }

    /**
     * Returns the distance between two points.
     *
     * @param x1 the X coordinate of the first specified point
     * @param y1 the Y coordinate of the first specified point
     * @param x2 the X coordinate of the second specified point
     * @param y2 the Y coordinate of the second specified point
     * @return the distance between the two sets of specified
     * coordinates.
     */
    public static float distance(float x1, float y1, float x2, float y2) {
        x1 -= x2;
        y1 -= y2;
        return (float) Math.sqrt(x1 * x1 + y1 * y1);
    }

    /**
     * Returns the square of the distance from this 
     * <code>Point2D</code> to a specified point.
     *
     * @param px the X coordinate of the specified point to be measured
     *           against this <code>Point2D</code>
     * @param py the Y coordinate of the specified point to be measured
     *           against this <code>Point2D</code>
     * @return the square of the distance between this
     * <code>Point2D</code> and the specified point.
     */
    public float distanceSq(float px, float py) {
        px -= x;
        py -= y;
        return (px * px + py * py);
    }

    /**
     * Returns the square of the distance from this 
     * <code>Point2D</code> to a specified <code>Point2D</code>.
     *
     * @param pt the specified point to be measured
     *           against this <code>Point2D</code>
     * @return the square of the distance between this
     * <code>Point2D</code> to a specified <code>Point2D</code>.
     */
    public float distanceSq(Point2D pt) {
        float px = pt.x - this.x;
        float py = pt.y - this.y;
        return (px * px + py * py);
    }

    /**
     * Returns the distance from this <code>Point2D</code> to 
     * a specified point.
     *
     * @param px the X coordinate of the specified point to be measured
     *           against this <code>Point2D</code>
     * @param py the Y coordinate of the specified point to be measured
     *           against this <code>Point2D</code>
     * @return the distance between this <code>Point2D</code>
     * and a specified point.
     */
    public float distance(float px, float py) {
        px -= x;
        py -= y;
        return (float) Math.sqrt(px * px + py * py);
    }

    /**
     * Returns the distance from this <code>Point2D</code> to a
     * specified <code>Point2D</code>.
     *
     * @param pt the specified point to be measured
     *           against this <code>Point2D</code>
     * @return the distance between this <code>Point2D</code> and
     * the specified <code>Point2D</code>.
     */
    public float distance(Point2D pt) {
        float px = pt.x - this.x;
        float py = pt.y - this.y;
        return (float) Math.sqrt(px * px + py * py);
    }

    /**
     * Returns the hashcode for this <code>Point2D</code>.
     * @return      a hash code for this <code>Point2D</code>.
     */
    public int hashCode() {
        int bits = Float.floatToIntBits(x);
        bits ^= Float.floatToIntBits(y) * 31;
        return bits;
    }

    /**
     * Determines whether or not two points are equal. Two instances of
     * <code>Point2D</code> are equal if the values of their 
     * <code>x</code> and <code>y</code> member fields, representing
     * their position in the coordinate space, are the same.
     * @param obj an object to be compared with this <code>Point2D</code>
     * @return <code>true</code> if the object to be compared is
     *         an instance of <code>Point2D</code> and has
     *         the same values; <code>false</code> otherwise.
     */
    public boolean equals(Object obj) {
        if (obj == this) return true;
        if (obj instanceof Point2D) {
            Point2D p2d = (Point2D) obj;
            return (x == p2d.x) && (y == p2d.y);
        }
        return false;
    }
    
    /**
     * Returns a <code>String</code> that represents the value 
     * of this <code>Point2D</code>.
     * @return a string representation of this <code>Point2D</code>.
     */
    public String toString() {
        return "Point2D["+x+", "+y+"]";
    }    
}