from django.contrib.auth.backends import BaseBackend
from .models import Usuarios


class CustomAuthBackend(BaseBackend):
    def authenticate(self, request, username=None, password=None, **kwargs):
        if not username or password is None:
            return None
        try:
            # Buscar al usuario en la base de datos usando `username`
            user = Usuarios.objects.get(username=username)
        except Usuarios.DoesNotExist:
            return None

        if user.check_password(password):
            return user

        # Compatibilidad con contraseñas antiguas guardadas en texto plano: se migran a hash al ingresar
        if user.password and user.password == password:
            user.set_password(password)
            user.save(update_fields=["password"])
            return user
        return None

    def get_user(self, user_id):
        try:
            return Usuarios.objects.get(pk=user_id)
        except Usuarios.DoesNotExist:
            return None