import random
from copy import deepcopy
from math import inf

from utilities.constants import GREEN, WHITE


class MiniMax():

    def AI(self, board, depth, maxPlayer, gameManager):
        if depth == 0 or board.winner() is not None:
            return board.scoreOfTheBoard(), board

        if maxPlayer:
            maxEval = -inf
            bestMove = None
            for move in self.getAllMoves(board, maxPlayer):
                evaluation = self.AI(move, depth - 1, False, gameManager)[0]
                maxEval = max(maxEval, evaluation)
                if maxEval > evaluation:
                    bestMove = move
                if maxEval == evaluation:
                    bestMove = bestMove if random.choice([True, False]) else move
            return maxEval, bestMove
        else:
            minEval = inf
            bestMove = None
            colour = WHITE if gameManager.turn == GREEN else GREEN
            for move in self.getAllMoves(board, colour):
                evaluation = self.AI(move, depth - 1, True, gameManager)[0]
                minEval = min(minEval, evaluation)
                if minEval < evaluation:
                    bestMove = move
                if minEval == evaluation:
                    bestMove = bestMove if random.choice([True, False]) else move

            return minEval, bestMove

    def _simulateMove(self, piece, move, board, skip):
        board.move(piece, move[0], move[1])
        if skip:
            board.remove(skip)

        return board

    def getAllMoves(self, board, colour):
        moves = []

        for piece in board.getAllPieces(colour):
            validMoves = board.getValidMoves(piece)
            for move, skip in validMoves.items():
                tempBoard = deepcopy(board)
                tempPiece = tempBoard.getPiece(piece.row, piece.col)
                newBoard = self._simulateMove(tempPiece, move, tempBoard, skip)
                moves.append(newBoard)
        return moves