Initial commit

retro_gamer/examples/beast/agents/beast.py

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+from retro_gamer.examples.beast.helpers import add, distance, get_occupant
+from random import random, choice
+
+class Beast:
+    """A beast that hunts the player."""
+    character = "H"
+    color = "red"
+    probability_of_moving = 0.03
+    probability_of_random_move = 0.2
+    deadly = True
+
+    def __init__(self, position):
+        self.position = position
+
+    def handle_push(self, vector, game):
+        future_position = add(self.position, vector)
+        on_board = game.on_board(future_position)
+        obstacle = get_occupant(game, future_position)
+        if obstacle or not on_board:
+            self.die(game)
+            return True
+        else:
+            return False
+
+    def play_turn(self, game):
+        if self.should_move():
+            possible_moves = []
+            for position in self.get_adjacent_positions():
+                if game.is_empty(position) and game.on_board(position):
+                    possible_moves.append(position)
+            if possible_moves:
+                if self.should_move_randomly():
+                    self.position = choice(possible_moves)
+                else:
+                    self.position = self.choose_best_move(possible_moves, game)
+            player = game.get_agent_by_name("player")
+            if player and player.position == self.position:
+                player.die(game)
+
+    def get_adjacent_positions(self):
+        """Returns all eight adjacent positions, including diagonals."""
+        positions = []
+        for i in [-1, 0, 1]:
+            for j in [-1, 0, 1]:
+                if i or j:
+                    positions.append(add(self.position, (i, j)))
+        return positions
+
+    def should_move(self):
+        return random() < self.probability_of_moving
+
+    def should_move_randomly(self):
+        return random() < self.probability_of_random_move
+
+    def choose_best_move(self, possible_moves, game):
+        player = game.get_agent_by_name("player")
+        move_distances = [[distance(player.position, move), move] for move in possible_moves]
+        shortest_distance, best_move = sorted(move_distances)[0]
+        return best_move
+
+    def die(self, game):
+        game.remove_agent(self)
+        game.num_beasts -= 1
+        game.state['beasts_killed'] += 1
+        if game.num_beasts == 0:
+            game.state["message"] = "You win!"
+            game.end()