import os
import time
import shutil
import hashlib
from datetime import datetime
from files import FILES

CHECK_INTERVAL = 60  # segundos

def sha256sum(path):
    """Devuelve el hash SHA256 del fichero."""
    h = hashlib.sha256()
    with open(path, "rb") as f:
        for chunk in iter(lambda: f.read(4096), b""):
            h.update(chunk)
    return h.hexdigest()

def ensure_backup_dir(file_path):
    """Crea backup/<nombre_sin_ext>/ si no existe."""
    file_name = os.path.basename(file_path)
    name, _ = os.path.splitext(file_name)
    backup_dir = os.path.join("backup", name)
    os.makedirs(backup_dir, exist_ok=True)
    return backup_dir

def get_latest_backup(file_path):
    """Devuelve la ruta del backup más reciente o None si no hay."""
    backup_dir = ensure_backup_dir(file_path)
    files = sorted(os.listdir(backup_dir), reverse=True)
    if not files:
        return None
    return os.path.join(backup_dir, files[0])

def backup_file(file_path):
    """Crea una copia con timestamp."""
    backup_dir = ensure_backup_dir(file_path)
    file_name = os.path.basename(file_path)
    name, ext = os.path.splitext(file_name)
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    dest = os.path.join(backup_dir, f"{name}_{timestamp}{ext}")
    shutil.copy2(file_path, dest)
    print(f"[BACKUP] Copia creada: {dest}")

def process_file(file_path):
    """Comprueba si hay cambios y crea backup si es necesario."""
    if not os.path.isfile(file_path):
        print(f"[WARN] No existe: {file_path}")
        return

    latest = get_latest_backup(file_path)

    if latest is None:
        print(f"[INIT] No hay copia previa de {file_path}, creando primera copia...")
        backup_file(file_path)
        return

    # Comparamos hashes
    current_hash = sha256sum(file_path)
    latest_hash = sha256sum(latest)

    if current_hash != latest_hash:
        print(f"[CHANGE] Detectado cambio en {file_path}, creando nueva copia...")
        backup_file(file_path)
    else:
        print(f"[OK] Sin cambios en {file_path}")

def main():
    print("Iniciando watcher de saves...")

    while True:
        for f in FILES:
            process_file(f)
        time.sleep(CHECK_INTERVAL)

if __name__ == "__main__":
    main()