The change of light from the value of the logical blockstate

I want to make a block that works like a redstone lamp:

when the logical blockstate LIT = true, return the light 15

else the logical blockstate LIT = false, return the light 0

public class LargeKeroseneLanternBlock extends Block {

    public static final IntegerProperty POWER = IntegerProperty.create("power", 0, 15);
    public static final ToIntFunction<BlockState> LIGHT = $$0 -> $$0.getValue(POWER);
    public LargeKeroseneLanternBlock() {

        super(BlockBehaviour.Properties.of().sound(SoundType.METAL).strength(3f).lightLevel(LIGHT).requiresCorrectToolForDrops());

        this.registerDefaultState(this.stateDefinition.any().setValue(POWER, 0));
    }

I use the ToIntFunction to set the light level to the block, but how can I do this in the case of a logical blockstate LIT (like a redstone lamp).

Can anyone help me with this?