/**
 * @file Vector.java
 * @brief
 *    File containing the Vector class, a helper class for the
 *    vector based evaluation system
 * 
 * @author  Christos Choutouridis   8997 cchoutou@ece.auth.gr
 * @author  Konstantina Tsechelidou 8445 konstsec@ece.auth.gr
 */

package gr.auth.ee.dsproject.node;

/**
 * @class Vector
 * @brief
 *    A helper class to represent vectors in the Maze
 */
public class Vector {
   public int x, y; // the coordinate alternative to vector representation
   
   /**
    * @brief   the plain constructor makes a zero vector
    */
   public Vector () {
      x = y = 0;
   }

   /**
    * @brief
    *    Makes a vector from x,y coordinates of two points in Maze
    * @param p1x  Point 1 x coordinate
    * @param p1y  Point 1 y coordinate
    * @param p2x  Point 2 x coordinate
    * @param p2y  Point 2 y coordinate
    */
   public Vector (int p1x, int p1y, int p2x, int p2y) {
      x = p2x - p1x;
      y = p2y - p1y;
   }

   /*
    * ========== setters =========
    */
   public int setX (int x) { return (this.x = x); }   // set x
   public int setY (int y) { return (this.y = y); }   // set y

   /**
    * @brief
    *    The Euclidean norm of the vector
    * @return  the norm
    */
   public double norm () {
      return Math.sqrt (x*x + y*y);
   }

   /**
    * @brief
    *    The dot product of the vector with another vector
    * @param a The 2nd vector of the product
    * @return  the dot product value
    */
   public double dot (Vector a) {
      return (a.x*this.x + a.y*this.y);
   }

   /**
    * @brief
    *    A static version of dot product of 2 vectors
    * @param a    Vector a
    * @param b    Vector b
    * @return  The dot product of a and b
    */
   public static double dot (Vector a, Vector b) {
      return (a.x*b.x + a.y*b.y);
   }
}