added class constants.py with class Constants

and bfs.py with class Node

src/constants.py

@@ -0,0 +1,11 @@
+class Constants:
+    """ Class to represent all constants for the app """
+
+    def __init__(self):
+        self.move = "move"
+        self.up = "up"
+        self.down = "down"
+        self.right = "right"
+        self.left = "left"
+        self.rotate_right = "rotate_right"
+        self.rotate_left = "rotate_left"

src/utils/bfs.py

@@ -0,0 +1,64 @@
+from constants import Constants as c
+
+class Node:
+    def __init__(self, current_x, current_y, agent_direction, action=None, parent=None):
+        self.current_x = current_x
+        self.current_y = current_y
+        self.action = action
+        self.parent = parent
+        self.agent_direction = agent_direction
+
+    def successor(self):
+        x = self.current_x
+        y = self.current_y
+        neighbours = []
+
+        if x < 9:  # right neighbour
+            if self.agent_direction == c.right:
+                actions = c.move
+            elif self.agent_direction == c.left:
+                actions = [c.rotate_right, c.rotate_right, c.move]
+            elif self.agent_direction == c.up:
+                actions = [c.rotate_right, c.move]
+            elif self.agent_direction == c.down:
+                actions = [c.rotate_left, c.move]
+
+            neighbours.append((actions, (x + 1, y), c.right))
+
+        if x > 0:  # left neighbour
+            if self.agent_direction == c.right:
+                actions = [c.rotate_left, c.rotate_left, c.move]
+            elif self.agent_direction == c.left:
+                actions = c.move
+            elif self.agent_direction == c.up:
+                actions = [c.rotate_left, c.move]
+            elif self.agent_direction == c.down:
+                actions = [c.rotate_right, c.move]
+
+            neighbours.append((actions, (x - 1, y), c.left))
+
+        if y > 0:  # upper neighbour
+            if self.agent_direction == c.right:
+                actions = [c.rotate_left, c.move]
+            elif self.agent_direction == c.left:
+                actions = [c.rotate_right, c.move]
+            elif self.agent_direction == c.up:
+                actions = c.move
+            elif self.agent_direction == c.down:
+                actions = [c.rotate_left, c.rotate_left, c.move]
+
+            neighbours.append((actions, (x, y - 1), c.up))
+
+        if y < 9:  # down neighbour
+            if self.agent_direction == c.right:
+                actions = [c.rotate_right, c.move]
+            elif self.agent_direction == c.left:
+                actions = [c.rotate_left, c.move]
+            elif self.agent_direction == c.up:
+                actions = [c.rotate_left, c.rotate_left, c.move]
+            elif self.agent_direction == c.down:
+                actions = c.move
+
+            neighbours.append((actions, (x, y + 1), c.down))
+
+        return neighbours