class User(Base):
    __tablename__ = "users"
    __table_args__ = {'mysql_engine': "InnoDB", 'mysql_charset': "utf8"}

    id = Column(Integer, primary_key=True)
    username = Column(Unicode(50), unique=True, nullable=False)
    first_name = Column(Unicode(20), default=u"")
    last_name = Column(Unicode(20), default=u"")
    _password = Column("password", Unicode(100), nullable=False)
    enabled = Column(Boolean, nullable=False, default=True)
    is_staff = Column(Boolean, nullable=False, default=False)
    role_id = Column(
        Integer,
        ForeignKey("roles.id", ondelete="CASCADE"),
        nullable=False
    )

    role = relationship(Role, backref="users")
    _role_slug = None

    def has_role(self, *args):
        return bool(self.role_slug in args)

    @property
    def name_and_role(self):
        return self.name + " - " + self.role.name

    @property
    def name(self):
        return "%s %s" % (self.first_name, self.last_name)

    @property
    def password(self):
        return self._password

    @property
    def role_slug(self):
        if not self._role_slug:
            self._role_slug = self.role.name
        return self._role_slug

    @password.setter
    def password(self, password):
        if not isinstance(password, (str, unicode, basestring)):
            raise Exception('Invalid type. Password must be a string.')

        hashed_password = password

        if isinstance(password, unicode):
            password_8bit = password.encode('UTF-8')
        else:
            password_8bit = password

        salt = sha1()
        salt.update(os.urandom(60))
        hash = sha1()
        hash.update(password_8bit + salt.hexdigest())
        hashed_password = salt.hexdigest() + hash.hexdigest()

        if not isinstance(hashed_password, unicode):
            hashed_password = hashed_password.decode('UTF-8')

        self._password = hashed_password

    def validate_password(self, password):
        hashed_pass = sha1()
        hashed_pass.update(password + self._password[:40])
        return self._password[40:] == hashed_pass.hexdigest()