oop = require("oop/oop")

function BankAccount(cls)
    cls.setattr(cls, "owner", nil, cls.visibility.PUBLIC)
    cls.setattr(cls, "balance", nil, cls.visibility.PUBLIC)
    cls.setattr(cls, "pin", nil, cls.visibility.PROTECTED)
    cls.setattr(cls, "token", nil, cls.visibility.PRIVATE)

    cls.method("deposit", function(this, amount)
        this.balance = this.balance + amount
        print("deposit:", amount, "balance:", this.balance)
    end, cls.visibility.PUBLIC)

    cls.method("withdraw", function(this, amount, pin)
        if pin ~= this.pin then
            print("bad pin")
            return
        end
        this.balance = this.balance - amount
        print("withdraw:", amount, "balance:", this.balance)
    end, cls.visibility.PUBLIC)

    cls.method("audit", function(this)
        print("audit:", this.owner, "balance:", this.balance)
    end, cls.visibility.PROTECTED)

    cls.method("rotate_token", function(this)
        this.token = "t-" .. tostring(os.time())
        print("token rotated")
    end, cls.visibility.PRIVATE)

    function cls.__init(this, owner, pin)
        this.owner = owner
        this.balance = 0
        this.pin = pin
        this.token = "t-" .. tostring(os.time())
    end
end

function PremiumAccount(cls)
    cls.inherit(BankAccount)

    function cls.monthly_bonus(this)
        this.deposit(25)
        this.audit()
    end
end

local acct = oop.new(BankAccount, "Kim", 1234)
acct.deposit(100)
acct.withdraw(30, 1234)

local vip = oop.new(PremiumAccount, "Sam", 9999)
vip.monthly_bonus()

local ok, err = pcall(function()
    vip.rotate_token()
end)
print("rotate_token from outside:", ok, err)