local NODE_YOUNG = "young"

nature = {}

local function set_young_node(pos)
    local meta = minetest.env:get_meta(pos)

    meta:set_string(NODE_YOUNG, "true")
    minetest.after(5,
	function(pos)
	    local meta = minetest.env:get_meta(pos)
	    meta:set_string(NODE_YOUNG, "false")
	end,
    pos)
end

local function is_not_young(pos)
    local meta = minetest.env:get_meta(pos)

    local young = meta:get_string(NODE_YOUNG)
    return young ~= "true"
end

function nature:grow_node(pos, nodename)
    if pos ~= nil then
	local light_enough = minetest.env:get_node_light(pos, nil)
		>= MINIMUM_GROWTH_LIGHT 

	if is_not_young(pos) and light_enough then
	    minetest.env:remove_node(pos)
	    minetest.env:add_node(pos, { name = nodename })
	    set_young_node(pos)

	    minetest.log("info", nodename .. " has grown at " .. pos.x .. ","
		.. pos.y .. "," .. pos.z)
	end
    end
end

function nature:is_near_water(pos)
    return minetest.env:find_node_near(pos, DISTANCE_FROM_WATER,
	    { "default:water_source" }) ~= nil or DISTANCE_FROM_WATER == -1
end