import random

from scipy.stats import binom

from engine import LiarsDiceEngine, Bid


class BotAi:
    def ai_turn(self, game_state: LiarsDiceEngine) -> Bid | None:
        bid = game_state.current_bid or Bid(die_face=1, num_dice=0)

        # Challenge a bid if we deem it sufficiently unlikely, based on the statistical odds of the bid being true. Do
        # not hardcode a value to avoid the AI always reacting in a predetermined manner.
        if (
            self.calculate_odds(game_state, bid.die_face, bid.num_dice)
            < random.uniform(0.1, 0.5)
        ):
            return None

        max_confidence = 0
        max_confidence_bids = []

        for d in range(bid.die_face, 7):
            for n in range(1, game_state.num_all_dice):
                if (d == bid.die_face and n > bid.num_dice) or d > bid.die_face:
                    confidence = self.calculate_odds(game_state, d, n)
                    if confidence == max_confidence:
                        max_confidence_bids.append(Bid(d, n))
                    elif confidence > max_confidence:
                        max_confidence = confidence
                        max_confidence_bids = [Bid(d, n)]

        return random.choice(max_confidence_bids) if max_confidence_bids else None

    @staticmethod
    def calculate_odds(game_state: LiarsDiceEngine, die_face: int, num_values: int) -> float:
        num_minimum_needed_values = (
            num_values - game_state.dice[game_state.active_player_index][die_face] - 1
        )
        die_face_probability = 2.0 / 6 if game_state.wild_ones_variant else 1.0 / 6

        return binom.sf(
            k=num_minimum_needed_values,
            n=game_state.num_opponent_dice,
            p=die_face_probability,
        )