package rescuecore2.misc.geometry;

import rescuecore2.misc.geometry.spatialindex.Indexable;
import rescuecore2.misc.geometry.spatialindex.PointRegion;
import rescuecore2.misc.geometry.spatialindex.Region;

/**
   A point in 2D space. Points are immutable.
 */
public class Point2D implements Indexable {
    private double x;
    private double y;
    private PointRegion region;

    /**
       Create a new Point2D.
       @param x The x coordinate.
       @param y The y coordinate.
     */
    public Point2D(double x, double y) {
        this.x = x;
        this.y = y;
        region = null;
    }

    /**
       Get the X coordinate.
       @return The X coordinate.
     */
    public double getX() {
        return x;
    }

    /**
       Get the Y coordinate.
       @return The Y coordinate.
     */
    public double getY() {
        return y;
    }

    /**
       Create a new Point2D that is a translation of this point.
       @param dx The x translation.
       @param dy The y translation.
       @return A new Point2D.
     */
    public Point2D translate(double dx, double dy) {
        return new Point2D(x + dx, y + dy);
    }

    /**
       Create a vector by subtracting a point from this point.
       @param p The Point2D to subtract from this one.
       @return A new Vector2D that represents the vector from the other point to this one.
     */
    public Vector2D minus(Point2D p) {
        return new Vector2D(this.x - p.x, this.y - p.y);
    }

    /**
       Create a Point2D by adding a vector to this point.
       @param v The Vector2D to add.
       @return A new Point2D.
     */
    public Point2D plus(Vector2D v) {
        return new Point2D(this.x + v.getX(), this.y + v.getY());
    }

    @Override
    public boolean equals(Object o) {
        if (!(o instanceof Point2D)) {
            return false;
        }
        return this.x == ((Point2D)o).x && this.y == ((Point2D)o).y;
    }

    @Override
    public int hashCode() {
        return new Double(x).hashCode() ^ new Double(y).hashCode();
    }

    @Override
    public String toString() {
        return x + " , " + y;
    }

    @Override
    public Region getBoundingRegion() {
        if (region == null) {
            region = new PointRegion(x, y);
        }
        return region;
    }
}