Does anyone know how much mastery you get when playing a game?

I was thinking, if I made up the system, I would want it to be something like this, where you get points based on what happened in the game.

+5 for completing a game. +1 for each enemy turret destroyed by your team if you lose the game. +12 if your team wins the game. +1 for each turret your team still had standing if you win the game. +1 for each dragon slain by your team. +1 for each baron your team got. +(20-your team's deaths)/5 if your team has under 20 deaths. +0.5 per kill +0.5 per assist -1 per death +(Minutes the game lasted)/10

And I'd really hope it'd be heavily objective-oriented like this so that people that want to get mastery quickly would really want to try to get objectives rather than a little more kda. And of course, something that encourages players to still play the game well rather than something that would make people play the game really badly trying to earn more mastery points. I've also heard that you get points even if you didn't do well, but you get a lot more points a lot faster if you play well, so these numbers were made with that in mind. But of course this isn't how it really works. Does anyone know how the system really works?