Sugarcane

-- Sugarcane Harvesting
-- By fenthis

depth = 15
width = 15
delay = 120 -- Delay in seconds between runs


total_count = 0


function do_left_or_right(dir)
    if dir then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
end

function is_odd(n)
    return ((n % 2) == 1)
end

function try_n(times)
    for i = 1, times do
        act.try()
    end
end

function harvest()
    -- Into first square
    turtle.up()
    act.try()

    -- Loop through the field.
    for r = 1,width do
        for x = 1,depth do
            turtle.digDown()
            if x ~= depth then
                act.try()
            end
        end

        if (r ~= width) then
            do_left_or_right(is_odd(r))
            act.try()
            do_left_or_right(is_odd(r))
        end
    end

    -- Return
    if not is_odd(width) then
        act.try()
    else
        -- In case it's regrown
        turtle.up()
        turtle.turnLeft()
        turtle.turnLeft()
        try_n(depth)
        turtle.down()
    end
    turtle.turnLeft()
    try_n(width - 1)
    turtle.down()

    -- Ok, chest time
    turtle.turnRight()
    count = 0
    for i = 1, 16 do
        items = turtle.getItemCount(i)
        count = count + items
        if items > 0 then
            turtle.select(i)
            turtle.drop()
        end
    end
    total_count = total_count + count
    turtle.turnLeft()
    turtle.turnLeft()

    print("Harvest complete, collected " .. count .. " items for a total of " ..
        total_count .. " with " .. turtle.getFuelLevel() .. " fuel remaining.")
end

-- Do something
print("Running with a delay of " .. delay .. " seconds. Press Q to quit.")
while true do
    -- First, go for it.
    harvest()

    -- Then wait
    os.startTimer(delay)
    repeat
        e, a1 = os.pullEvent()
        if e == "char" and (a1 == "Q" or a1 == "q") then
            print("Quitting!")
            return
        end
    until e == "timer"
end