from flask import Flask, render_template, request, jsonify, session
from stockfish import Stockfish # Assurez-vous que le chemin est correct si besoin
import chess # python-chess

app = Flask(__name__)
app.secret_key = 'super_secret_key_for_session' # Important pour les sessions

# Pour simplifier, une instance globale. Pour une prod, gérer par session/jeu.
# Assurez-vous que le binaire stockfish est dans votre PATH ou spécifiez le chemin.
try:
    stockfish_path = "/usr/games/stockfish" # chemin vers votre binaire
    stockfish = Stockfish(path=stockfish_path, parameters={"Threads": 2, "Hash": 128})
except Exception as e:
    print(f"Erreur à l'initialisation de Stockfish: {e}")
    print("Veuillez vérifier que Stockfish est installé et accessible via le PATH, ou spécifiez le chemin correct.")
    # Vous pourriez vouloir quitter l'application ou avoir un mode dégradé.
    stockfish = None


@app.route('/')
def index():
    return render_template('index.html')

@app.route('/new_game', methods=['POST'])
def new_game():
    if not stockfish:
        return jsonify({"error": "Stockfish non initialisé"}), 500
        
    data = request.json
    mode = data.get('mode', 'human') # 'ai' or 'human'
    
    initial_fen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
    session['fen'] = initial_fen
    session['mode'] = mode
    session['turn'] = 'w' # White's turn
    session['history'] = []
    
    stockfish.set_fen_position(initial_fen)
    
    # python-chess board (optionnel mais recommandé)
    session['board_pgn'] = chess.Board().fen() # Stocker le FEN pour reconstruire

    return jsonify({
        "fen": initial_fen,
        "turn": session['turn'],
        "message": "Nouvelle partie commencée."
    })

@app.route('/move', methods=['POST'])
def handle_move():
    if not stockfish:
        return jsonify({"error": "Stockfish non initialisé"}), 500

    if 'fen' not in session:
        return jsonify({"error": "Aucune partie en cours. Commencez une nouvelle partie."}), 400

    data = request.json
    move_uci = data.get('move') # e.g., "e2e4"

    # Reconstruire l'état du board python-chess (si utilisé)
    board = chess.Board(session['fen'])
    
    # Validation du tour
    current_player_color = 'w' if board.turn == chess.WHITE else 'b'
    if session['turn'] != current_player_color:
         return jsonify({"error": "Pas votre tour.", "fen": session['fen'], "turn": session['turn']}), 400

    try:
        move_obj = board.parse_uci(move_uci)
    except ValueError:
        return jsonify({"error": "Format de coup invalide.", "fen": session['fen'], "turn": session['turn']}), 400


    if not stockfish.is_move_correct(move_uci) or move_obj not in board.legal_moves:
        return jsonify({"error": "Coup illégal.", "fen": session['fen'], "turn": session['turn']}), 400

    # Appliquer le coup humain
    stockfish.make_moves_from_current_position([move_uci])
    board.push(move_obj)
    session['fen'] = stockfish.get_fen_position() # ou board.fen()
    session['history'].append(move_uci)
    session['turn'] = 'b' if current_player_color == 'w' else 'w'
    
    ai_move_uci = None
    game_status = "En cours"

    if board.is_checkmate():
        game_status = f"Mat! {'Les Blancs' if board.turn == chess.BLACK else 'Les Noirs'} gagnent."
    elif board.is_stalemate() or board.is_insufficient_material() or board.is_seventyfive_moves() or board.is_fivefold_repetition():
        game_status = "Pat!"
        
    # Mode IA
    if session['mode'] == 'ai' and game_status == "En cours" and ( (board.turn == chess.BLACK and current_player_color == 'w') or \
                                                                    (board.turn == chess.WHITE and current_player_color == 'b') ) : # Tour de l'IA
        # S'assurer que stockfish a la bonne position si on utilise board.fen()
        stockfish.set_fen_position(board.fen()) 
        ai_move_uci = stockfish.get_best_move_time(1000) # 1 seconde de réflexion
        if ai_move_uci:
            ai_move_obj = board.parse_uci(ai_move_uci)
            stockfish.make_moves_from_current_position([ai_move_uci]) # Stockfish est déjà à jour
            board.push(ai_move_obj)
            session['fen'] = stockfish.get_fen_position() # ou board.fen()
            session['history'].append(ai_move_uci)
            session['turn'] = 'w' if session['turn'] == 'b' else 'b'

            if board.is_checkmate():
                 game_status = f"Mat! {'Les Blancs' if board.turn == chess.BLACK else 'Les Noirs'} gagnent."
            elif board.is_stalemate() or board.is_insufficient_material() or board.is_seventyfive_moves() or board.is_fivefold_repetition():
                game_status = "Pat!"
        else: # Si l'IA ne retourne pas de coup (ce qui peut arriver si elle est matée/patée)
            if board.is_checkmate():
                 game_status = f"Mat! {'Les Blancs' if board.turn == chess.BLACK else 'Les Noirs'} gagnent."
            elif board.is_stalemate():
                game_status = "Pat!"


    return jsonify({
        "fen": session['fen'],
        "turn": session['turn'],
        "last_move_human": move_uci,
        "last_move_ai": ai_move_uci,
        "game_status": game_status,
        "history": session['history']
    })

if __name__ == '__main__':
    app.run(debug=True)