snake-python/snakes/TemplateSnake.py

import random

class TemplateSnake:
  def __init__(self):
    self.history = []

  def clear_history(self):
    self.history = []

  def add_to_history(self, data:dict):
    self.history.append(data)

  def get_history(self):
    return self.history

  def add_calculations(self, calculations:dict):
    self.calculations.append(calculations)

  def choose_move(self, game_data:dict):
    self.calculations = []
    self.eat_the_snake_overwrite = False

    self.board_width = game_data['board']['width']
    self.board_height = game_data['board']['height']

    self.my_snake = game_data['you']
    self.other_snakes = [ x for x in game_data['board']['snakes'] if x["id"] != self.my_snake["id"] ]

    self.my_head = self.my_snake['head']
    self.my_body = self.my_snake["body"]
    self.game_type = game_data['game']["ruleset"]["name"]

    self.find_safe_positions()
    moves = list(self.safe_positions.keys())
    if len(moves) > 0:
      move = random.choice(moves)
    else:
      print("No safe positions left - Going to Die")
      move = None

    self.add_to_history({"turn": game_data["turn"], "data": self.calculations})
    return move if move else "up"

  def get_possible_moves(self, snake_head):
    return {
      "up": {
        "x": snake_head["x"],
        "y": snake_head["y"] + 1
      },
      "down": {
        "x": snake_head["x"],
        "y": snake_head["y"] - 1
      },
      "left": {
        "x": snake_head["x"] - 1,
        "y": snake_head["y"]
      },
      "right": {
        "x": snake_head["x"] + 1,
        "y": snake_head["y"]
      }
    }

  def get_snake_body_without_snake_tail(self, snake:list[dict]):
    if len(set((pos["x"], pos["y"]) for pos in snake)) < 3:
      return snake

    snake.pop()
    return snake

  def avoid_my_body(self) -> list:
    """
    my_body: List of dictionaries of x/y coordinates for every segment of a Battlesnake.
            e.g. [ {"x": 0, "y": 0}, {"x": 1, "y": 0}, {"x": 2, "y": 0} ]
    possible_moves: List of strings. Moves to pick from.
            e.g. ["up", "down", "left", "right"]

    return: The list of remaining possible_moves, with the 'neck' direction removed
    """
    remove = []
    for direction, location in self.safe_positions.items():
      if location in self.my_body:
        remove.append(direction)

    for direction in remove:
      del self.safe_positions[direction]

    self.add_calculations({"function": "avoid_my_body", "my_body": self.my_body, "safe_positions": self.safe_positions})

  def avoid_walls(self):
    remove = []
    for direction, location in list(self.safe_positions.items()):
      x_out_range = (location["x"] < 0 or location["x"] == self.board_width)
      y_out_range = (location["y"] < 0 or location["y"] == self.board_height)
      if x_out_range or y_out_range:
        remove.append(direction)

    for direction in remove:
      del self.safe_positions[direction]

    self.add_calculations({"function": "avoid_walls", "board_width": self.board_width, "board_height": self.board_height, "safe_positions": self.safe_positions})

  def avoid_snakes(self):
    remove = []
    for snake in self.other_snakes:
      for direction, location in self.safe_positions.items():
        #if self.game_type == "constrictor":
          if location in snake["body"]:
            remove.append(direction)
        #else:
        #  if location in self.get_snake_body_without_snake_tail(snake["body"]):
        #    remove.append(direction)

    remove = set(remove)
    for direction in remove:
      del self.safe_positions[direction]

    self.add_calculations({"function": "avoid_snakes", "other_snakes": self.other_snakes, "safe_positions": self.safe_positions})

  def avoid_get_eaten_by_other_snakes(self):
    remove = []
    no_way_out = {}
    for snake in self.other_snakes:
      for direction, location in self.safe_positions.items():
        if len(self.safe_positions) > 1:
          #TODO: Avoid Draw when heads are by the food
          if snake["length"] < self.my_snake["length"] and location in [{"x": v["x"], "y": v["y"]} for k, v in self.get_possible_moves(snake["head"]).items()]:
            self.eat_the_snake_overwrite = True
            self.kill_the_snake = direction
          #TODO: Check if snake on the way to the food here and only remove this pos
          elif location in [{"x": v["x"], "y": v["y"]} for k, v in self.get_possible_moves(snake["head"]).items()]:
            no_way_out[direction] = location
            remove.append(direction)

    remove = set(remove)
    for direction in remove:
      del self.safe_positions[direction]

    if len(self.safe_positions) == 0:
      self.safe_positions = no_way_out

    self.add_calculations({"function": "avoid_get_eaten_by_other_snakes", "other_snakes": self.other_snakes, "safe_positions": self.safe_positions})

  def find_safe_positions(self):
    self.safe_positions = self.get_possible_moves(self.my_head)
    self.add_calculations({"function": "get_possible_moves", "safe_positions": self.safe_positions})

    self.avoid_my_body()
    self.avoid_walls()
    self.avoid_snakes()
    self.avoid_get_eaten_by_other_snakes()