1 files changed, 34 insertions, 4 deletions

diff --git a/src/ch/epfl/maze/physical/ProbabilisticAnimal.java b/src/ch/epfl/maze/physical/ProbabilisticAnimal.java
index f62fea1..c4d4f2a 100644
--- a/src/ch/epfl/maze/physical/ProbabilisticAnimal.java
+++ b/src/ch/epfl/maze/physical/ProbabilisticAnimal.java
@@ -3,37 +3,67 @@ package ch.epfl.maze.physical;
 import ch.epfl.maze.util.Direction;
 import ch.epfl.maze.util.Vector2D;
 
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Random;
+import java.util.stream.Collectors;
 
 /**
  * A probabilistic animal that use a random component in its decision making process.
  *
  * @author Pacien TRAN-GIRARD
  */
-
 abstract public class ProbabilisticAnimal extends Animal {
 
     private final Random randomSource;
+    private Direction currentDirection;
 
     /**
      * Constructs a probabilistic animal with a starting position
      *
      * @param position Starting position of the probabilistic animal in the labyrinth
      */
-
     public ProbabilisticAnimal(Vector2D position) {
         super(position); // no pun intended
         this.randomSource = new Random();
+        this.currentDirection = Direction.NONE;
+    }
+
+    /**
+     * Excludes the origin direction for choices.
+     *
+     * @param choices An array of choices
+     * @return An array of smart choices
+     */
+    protected Direction[] excludeOrigin(Direction[] choices) {
+        return (new ArrayList<>(Arrays.asList(choices)))
+                .stream()
+                .filter(dir -> !dir.isOpposite(this.currentDirection))
+                .collect(Collectors.toList())
+                .toArray(new Direction[0]);
     }
 
     /**
-     * Moves according to a <i>random walk</i>.
+     * Returns a random Direction from the given choices.
+     *
+     * @param choices An array of Direction
+     * @return A random Direction taken from the given choices
      */
+    protected Direction getRandomDirection(Direction[] choices) {
+        return choices[randomSource.nextInt(choices.length)];
+    }
 
+    /**
+     * Moves according to an improved version of a <i>random walk</i> : the
+     * probabilistic animal does not directly retrace its steps if not forced.
+     */
     @Override
     public Direction move(Direction[] choices) {
         if (choices.length == 0) return Direction.NONE;
-        return choices[randomSource.nextInt(choices.length)];
+
+        Direction[] smartChoices = choices.length > 1 ? this.excludeOrigin(choices) : choices;
+        this.currentDirection = this.getRandomDirection(smartChoices);
+        return this.currentDirection;
     }
 
 }