Snow

local SLEEP_BETWEEN_DIG = 0.5
local SLEEP_MAIN_LOOP_WAIT = 30
local SLEEP_MAIN_LOOP_ACTIVE = 1
local SNOW_PER_LOOP = 32
local TURTLE_INVENTORY_SIZE = 16
local SNOW_STACK_SIZE = 16


function garbage_all()
    local i = TURTLE_INVENTORY_SIZE

    while i > 0 do
        turtle.select(i)
        turtle.drop()
        i = i - 1
    end
end

function select_item(item)
    local slot = 1

    while slot <= TURTLE_INVENTORY_SIZE do
        local data = turtle.getItemDetail(slot)
        if data and data.name == item then
            turtle.select(slot)
            return true
        end
        slot = slot + 1
    end
    return false
end

function is_full()
    local slot
    local data
    local empty

    slot = TURTLE_INVENTORY_SIZE
    empty = 0
    while slot > 0 do
        data = turtle.getItemDetail(slot)
        if not data then
            empty = empty + 1
        end
        slot = slot - 1
    end
    return empty < (SNOW_PER_LOOP / SNOW_STACK_SIZE)
end

function dig_snow()
    local i

    i = 0
    while i < SNOW_PER_LOOP do
        turtle.dig()
        sleep(SLEEP_BETWEEN_DIG)
        i = i + 1
    end
end

function drop_to_chest()
    while select_item('minecraft:snowball') and turtle.dropDown() do end
    return select_item('minecraft:snowball')
end

function core()
    while true do
        if not is_full() then
            dig_snow()
        elseif not select_item('minecraft:snowball') then
            garbage_all()
        end
        if not drop_to_chest() then
            sleep(SLEEP_MAIN_LOOP_WAIT)
        else
            sleep(SLEEP_MAIN_LOOP_ACTIVE)
        end
    end
end

core()