import importlib
from dataclasses import dataclass

@dataclass(frozen=True, slots=True)
class SnakeRegistration:
  module: str
  version: str

SNAKE_REGISTRATIONS = {
  "TemplateSnake": SnakeRegistration("snakes.core.template", "1.0.0"),
  "ApexBattleSnake": SnakeRegistration("snakes.strategies.apex", "1.0.0"),
  "PrismBattleSnake_GPT_5_6_Sol": SnakeRegistration(
    "snakes.strategies.prism", "1.3.0"
  ),
  "DummSnake": SnakeRegistration("snakes.legacy.DummSnake", "1.0.0"),
  "LogicSnake": SnakeRegistration("snakes.legacy.LogicSnake", "1.1.0"),
  "MasterSnake": SnakeRegistration("snakes.legacy.MasterSnake", "1.2.0"),
  "BetterMasterSnake": SnakeRegistration("snakes.legacy.BetterMasterSnake", "1.3.0"),
  "BestBattleSnake": SnakeRegistration("snakes.legacy.BestBattleSnake", "2.6.0"),
  "TrainedBattleSnake": SnakeRegistration(
    "snakes.legacy.TrainedBattleSnake", "0.1.0"
  ),
  "UltimateBattleSnake": SnakeRegistration(
    "snakes.legacy.UltimateBattleSnake", "4.5.0"
  ),
  "SupremeBattleSnake_ClaudeOpus4_6": SnakeRegistration(
    "snakes.legacy.SupremeBattleSnake_ClaudeOpus4_6",
    "1.0.0",
  ),
}

# Backward-compatible public version map.
SNAKE_REGISTRY = {
  name: registration.version for name, registration in SNAKE_REGISTRATIONS.items()
}

DEFAULT_SNAKE_CONFIG = {
  "apiversion": "1",
  "author": "",
  "color": "#888888",
  "head": "default",
  "tail": "default",
}


def build_snake(selected_snake: str):
  registration = SNAKE_REGISTRATIONS.get(selected_snake)
  if registration is None:
    raise ValueError(f"Unknown snake: {selected_snake}")

  snake_module = importlib.import_module(registration.module)
  snake_class = getattr(snake_module, selected_snake)
  return snake_class()

def get_snake_version(selected_snake: str) -> str | None:
  registration = SNAKE_REGISTRATIONS.get(selected_snake)
  return registration.version if registration is not None else None


class SnakeBuilder:
  @classmethod
  def build(self, selected_snake: str):
    return build_snake(selected_snake)

  @classmethod
  def get_version(self, selected_snake: str) -> str | None:
    return get_snake_version(selected_snake)