How Does Tiny Metal Scoring Work?

[Makar | 1,950]

Does anyone know exactly how the scoring works to get bronze silver and gold medals? I’ve tried searching the internet but really can’t find much. It seems opposite of advance wars. No bonus points for finishing a map quickly. It seems like exploration and healing your units and capturing buildings give you points. You lose points per unit on the field each turn and also lose points if your opponent captures one of your buildings. 

What I’m most confused about is it seems like the scores you need to get increase if you retry a level to get a better score? I’ve just started playing but I swear that just happened. If anyone can clear anything up that'd be amazing. 

I will make a proper guide if I fully learn the scoring system.