import random

import chess
import chess.engine

ENGINE_A = "./engines/chessV0"
ENGINE_B = "./engines/chessV1"

POSITIONS_FILE = "positions.txt"
MAX_GAMES = 100


class UCIEngine:
    def __init__(self, path, name, depth):
        self.name = name
        self.depth = depth

        print(f"Starting {name}: {path}")

        self.engine = chess.engine.SimpleEngine.popen_uci(path)

        print(f"{name} ready")

    def get_move(self, board):
        result = self.engine.play(board, chess.engine.Limit(depth=self.depth))
        return result.move

    def quit(self):
        self.engine.quit()


def play_game(engine_white, engine_black, fen, game_number):
    board = chess.Board(fen)

    print("\n" + "=" * 60)
    print(f"GAME {game_number}")
    print("=" * 60)

    print("Starting FEN:")
    print(fen)

    move_number = 1

    while not board.is_game_over() and move_number <= 200:
        if board.turn == chess.WHITE:
            engine = engine_white
            color = "White"
        else:
            engine = engine_black
            color = "Black"

        move = engine.get_move(board)

        print(f"{move_number}. {color} ({engine.name}) plays {move}")

        board.push(move)

        if board.turn == chess.WHITE:
            move_number += 1

    result = board.result()

    print("Game finished:", result)
    print("Moves played:", board.fullmove_number)

    return result


def main():
    depth = int(input("Search depth: "))

    with open(POSITIONS_FILE) as f:
        positions = [line.strip() for line in f if line.strip()]

    random.shuffle(positions)

    engine_a = UCIEngine(ENGINE_A, "chessV0", depth)

    engine_b = UCIEngine(ENGINE_B, "chessV1", depth)

    results = {"chessV0 wins": 0, "chessV1 wins": 0, "draws": 0}

    try:
        for i, fen in enumerate(positions[:MAX_GAMES], 1):
            # alternate colors
            if i % 2 == 0:
                white = engine_a
                black = engine_b
                a_color = chess.BLACK
            else:
                white = engine_b
                black = engine_a
                a_color = chess.WHITE

            result = play_game(white, black, fen, i)

            if result == "1-0":
                if a_color == chess.WHITE:
                    results["chessV0 wins"] += 1
                else:
                    results["chessV1 wins"] += 1

            elif result == "0-1":
                if a_color == chess.BLACK:
                    results["chessV0 wins"] += 1
                else:
                    results["chessV1 wins"] += 1

            else:
                results["draws"] += 1

            print("\nCurrent score:")
            print(results)

    finally:
        engine_a.quit()
        engine_b.quit()

    print("\n" + "=" * 60)
    print("FINAL RESULTS")
    print("=" * 60)

    print(results)


if __name__ == "__main__":
    main()