import random
try:
    import chess
except ImportError:
    chess = None
from .base import Job

class ChessPuzzleJob(Job):
    def get_name(self):
        return "SACHOVE ULOHY"

    def print_body(self, p):
        if chess is None:
            p.text("CHYBA: Neni nainstalovana knihovna 'chess'.\n")
            p.text("Spust: pip install chess\n\n")
            return
        
        fen, instruction, solution = self.generate_puzzle()
        
        p.text(f"{instruction}\n\n")
        self.print_board(p, fen)
        p.text("\n")
        
        p.text("Legenda: K=Kral, Q=Dama, R=Vez\n")
        p.text("         B=Strelec, N=Jezdec, P=Pesec\n")
        p.text("         (Velka=Bily, mala=Cerny)\n\n")

        p.text("Reseni (naskenuj):\n")
        p.qr(solution, size=6, native=True)

    def generate_puzzle(self):
        """
        Simulates a random game until a 'Mate in 1' situation arises.
        """
        while True:
            board = chess.Board()
            # Play up to 120 ply (60 moves)
            for _ in range(120):
                if board.is_game_over():
                    break
                
                legal_moves = list(board.legal_moves)
                random.shuffle(legal_moves)
                
                # Check if any move leads to immediate checkmate
                for move in legal_moves:
                    board.push(move)
                    if board.is_checkmate():
                        # Found a puzzle!
                        board.pop() # Revert to state before mate
                        board.pop()
                        solution = board.san(move)
                        turn = "Bily" if board.turn == chess.WHITE else "Cerny"
                        return board.fen(), f"{turn} na tahu. Mat jednim tahem.", solution
                    board.pop()
                
                # No mate found, play a random move to progress the game
                if legal_moves:
                    board.push(random.choice(legal_moves))
                else:
                    break

    def print_board(self, p, fen):
        board_str = fen.split(' ')[0]
        rows = board_str.split('/')
        
        # Center the board
        p.set(align='center')
        
        # Top border
        p.text("  +-----------------+\n")
        
        for i, row in enumerate(rows):
            rank = 8 - i
            line = f"{rank} | "
            for char in row:
                if char.isdigit():
                    count = int(char)
                    line += ". " * count
                else:
                    line += f"{char} "
            line += "|\n"
            p.text(line)
            
        p.text("  +-----------------+\n")
        p.text("    a b c d e f g h\n")
        p.set(align='left')