I am writing a rogue-like 'zombie' management game. The game map will be similar to Prison Architect. A top-down 50 X 50 grid.

I want to implemented a day night cycle and during the night I would like the player to be able to position lights.

I would like to be able to lighten and dark to whole map to display the day and night cycle.

Then lights would be a circle of light blocked by game entities such as walls, players, trees etc.

How would I achieve and what is the standard way of achieving this?