Temperature Datapack

I want to make a temperature datapack for a cold world. I want the player to take damage (the same type of damage as with the new snow block) if they don't wear a certain type of armor (for example, leather, or maybe an armor trim—I still need to decide) or if they don't stay near a heat source (like a lit furnace, a campfire, or a magma block, for example). How could I do it?