local function clamp(val, min_val, max_val)
    return math.min(math.max(val, min_val), max_val)
end

core.register_chatcommand(
    "wolfvision",
    {
        privs = { interact = true },
        func = function(player_name, params)
            local p = core.get_player_by_name(player_name)
            if not p then
                return
            end

            local words = string.split(params, " ")
            local saturation, light = 1.0, nil
            if words[1] then
                saturation = tonumber(words[1]) or 1.0
                saturation = clamp(saturation, -2.0, 2.0)
            end
            if words[2] then
                light = tonumber(words[2])
                if light then
                    light = clamp(light, 0.0, 1.0)
                end
            end

            p:set_lighting({saturation = saturation})
            p:override_day_night_ratio(light)

            return true, string.format("set: saturation=%s, light=%s %s", dump(saturation), dump(light), ".")
        end,
    }
)