blockgame.vector = blockgame.vector or {}
local api = blockgame.vector

api.horizontal_directions = {
	west = vector.new(-1, 0, 0),
	east = vector.new(1, 0, 0),
	south = vector.new(0, 0, -1),
	north = vector.new(0, 0, 1),
}
api.sides = api.horizontal_directions

api.directions = {
	west = vector.new(-1, 0, 0),
	east = vector.new(1, 0, 0),
	down = vector.new(0, -1, 0),
	up = vector.new(0, 1, 0),
	south = vector.new(0, 0, -1),
	north = vector.new(0, 0, 1),
}
api.dirs = api.directions

local function get_keys (tab)
	local keyset = {}
	local n = 0
	for key, value in pairs(tab) do
		n = n + 1
		keyset[n] = key
	end
	return keyset
end

local function random_element (tab)
	local keys = get_keys(tab)
	return tab[keys[math.random(#keys)]]
end

function api.random_dir ()
	return random_element(api.dirs)
end

function api.random_side ()
	return random_element(api.sides)
end

function api.get_below (pos)
	return pos + api.dirs.down
end