IOS + Swift, How to redirect to iTunes purchase page

I'm making an app that we could play preview and purchase song from iTunes. Let's say I have song title named "Test Song" on "First" album from artist named "John". What I need to do is, when I tap button "Buy This Song On iTunes" it open iTunes and directly go to song page where we can purchase this song, how can I do that?

I've seen this method on app called Shazam.