Lazyweb request

I want a Firefox extension with the following specs:

• When Firefox is opened, I am asked whether I want a timed session
• If I say yes, then I enter the time limit for my session
• When the limit expires, a window pops up asking me if I want X more minutes, where X is a value that I set (like a snooze alarm)

We can call this FocusFox and I completely give my idea to you if you implement it.