mapgen_rivers = {}

if minetest.get_mapgen_setting("mg_name") ~= "singlenode" then
	minetest.set_mapgen_setting("mg_name", "singlenode", true)
	minetest.log("warning", "[mapgen_rivers] Mapgen set to singlenode")
end

local modpath = minetest.get_modpath(minetest.get_current_modname())
dofile(modpath .. '/settings.lua')

local sfile = io.open(minetest.get_worldpath() .. '/river_data/size')
if sfile then
	sfile:close()
else
	dofile(modpath .. '/pregenerate.lua')
	collectgarbage()
end

mapgen_rivers.use_mapgen_thread = minetest.settings:get_bool("mapgen_rivers_use_mapgen_thread")
mapgen_rivers.thread = 'main'
if mapgen_rivers.use_mapgen_thread then
	if minetest.register_mapgen_dofile then
		minetest.register_mapgen_dofile(modpath .. '/mapgen.lua')
	else
		minetest.log("warning", "[mapgen_rivers] Mapgen thread not available on this Minetest version.")
		mapgen_rivers.use_mapgen_thread = false
	end
end

if not mapgen_rivers.use_mapgen_thread then
	dofile(modpath .. '/mapgen.lua')
end

-- Setup a metatable to load grid on request if not present
local mt = {
	__index = function(_, field)
		if field == 'grid' then
			dofile(modpath .. '/load_grid.lua')
			return mapgen_rivers.grid
		end
	end,
}
setmetatable(mapgen_rivers, mt)