xdecor.box = {
	slab_y = function(height, shift)
		return {
			-0.5,
			-0.5 + (shift or 0),
			-0.5,
			 0.5,
			-0.5 + height + (shift or 0),
			 0.5
		}
	end,
	slab_z = function(depth)
		return {-0.5, -0.5, -0.5 + depth, 0.5, 0.5, 0.5}
	end,
	bar_y = function(radius)
		return {-radius, -0.5, -radius, radius, 0.5, radius}
	end,
	cuboid = function(radius_x, radius_y, radius_z)
		return {-radius_x, -radius_y, -radius_z, radius_x, radius_y, radius_z}
	end
}

xdecor.nodebox = {
	regular = {type = "regular"},
	null = {
		type = "fixed", fixed = {0,0,0,0,0,0}
	}
}

xdecor.pixelbox = function(size, boxes)
	local fixed = {}
	for _, box in ipairs(boxes) do
		-- `unpack` has been changed to `table.unpack` in newest Lua versions.
		local x, y, z, w, h, l = unpack(box)
		fixed[#fixed + 1] = {
			(x / size) - 0.5,
			(y / size) - 0.5,
			(z / size) - 0.5,
			((x + w) / size) - 0.5,
			((y + h) / size) - 0.5,
			((z + l) / size) - 0.5
		}
	end

	return {type = "fixed", fixed = fixed}
end

local mt = {}

mt.__index = function(table, key)
	local ref = xdecor.box[key]
	local ref_type = type(ref)

	if ref_type == "function" then
		return function(...)
			return {type = "fixed", fixed = ref(...)}
		end
	elseif ref_type == "table" then
		return {type = "fixed", fixed = ref}
	elseif ref_type == "nil" then
		error(key .. "could not be found among nodebox presets and functions")
	end

	error("unexpected datatype " .. tostring(type(ref)) .. " while looking for " .. key)
end

setmetatable(xdecor.nodebox, mt)
