You probably want to look at one of the DateTime modules on CPAN for this. I would recommend DateTime. It's a bit hefty to read, but it has everything you need, plus the documentation is really good.

As for testing the menus ... You have 5 valid states. Either you're in a valid state or you're not. Test for the five valid states using if-elsif, and else for your invalid states. Something like:

if ( --VALID STATE 1, 0000--) {
    # Do something here
}
elsif ( --VALID STATE 2, 1000--) {
    # Do something here
}
elsif ( -- And so on for your 5 valid states) {
}
else {
    # This is where your 11 INVALID states drop down.
    # Does it really matter *which* invalid state it is?
}
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If you need more help, please don't hesitate to ask for clarification.