How do P and S Rank work?

[Pebble14 #RestEasyHarambe]

I have a vague idea of how it works, S i imagine you would probably need to get everything in a level, toppings, secrets, etc. Is S forfeit if you get hit at all during this? Also is P rank just the exact same but keep your combo throughout the entire level. If anyone who's gotten these ranks can clear this up for me that'd be cool

[Josephi]

You can get hit and still get an S or P rank. Getting hit only makes the combo bar go down, but if you don't get points fast enough your combo will end. Also you don't need everything for an S rank, just need a high enough score. I got one in John Gutter even though I missed 2 secrets.