local modname = minetest.get_current_modname()

local level_max = minetest.registered_items[modname .. ":leaves"].level_max

blockgame.register_abm({
	label = "make unsupported leaves fall",
	nodenames = {
		modname .. ":leaves_alive",
		modname .. ":leaves_growing",
	},
	interval = 5,
	chance = 4,
	action = function (pos, node)
		local is_supported = false

		blockgame.flood_fill(pos, function (pos, distance)
			local nodename = minetest.get_node(pos).name

			if blockgame.item_matches(nodename, {"group:supports_leaves"}) then
				is_supported = true
				return false
			end

			if blockgame.item_matches(nodename, {"group:extends_leaves_support"}) then
				return true
			end
		end, 3)

		if not is_supported then
			local level = math.random(1, level_max)
			minetest.set_node(pos, {name = modname .. ":leaves_" .. level})
			minetest.check_for_falling(pos)
			-- TODO: send out event here that makes nearby leaves check if they're unsupported as well?
		end
	end,
})