Write a program that calculates purchase price for movie tickets using swift. It should not be a full-blown mobile app; it can be a simple class or collection of methods invokable by your test suite. We'll provide you with some requirements, test-cases, and even a sample interface - all you have to do is give us some software.

The Base Admission Rate cover movies to be viewed on a regular weekday (see "Special Movie Day" below), in 2D, with a length of <= 120 minutes, viewed from the main seating area (there is also a balcony seating area, which is much fancier).