Automated Turtle Harvesting

--@author thor12022
local fieldSize = 8
local isOdd = math.ceil(fieldSize/2) ~= (fieldSize/2)
-- It goes forever
while true do
    -- if we need more fuel for this pass
    --TODO update for odd
    if (isOdd and turtle.getFuelLevel() < ((fieldSize * fieldSize) + 2*fieldSize)) or (turtle.getFuelLevel() < ((fieldSize * fieldSize) + fieldSize)) then
        turtle.suckUp()
        turtle.refuel()
    end
    -- face outward
    turtle.turnLeft()
    turtle.turnLeft()
    -- loop over the rows
    local turnRight = true
    for x = 1,fieldSize,1 do
        -- loop over the columns (except the last one)
        for y = 1,fieldSize - 1,1 do
            turtle.digDown()
            turtle.placeDown()
            turtle.forward()
        end
        -- harvest the last one
        turtle.digDown()
        turtle.placeDown()
        -- all but the last row
        if x ~= fieldSize then
            -- turn right or left and change column
            if turnRight == true then
                turtle.turnRight()
                turtle.forward()
                turtle.turnRight()
                turnRight = false
            else
                turtle.turnLeft()
                turtle.forward()
                turtle.turnLeft()
                turnRight = true
            end
        end
    end

    -- face the starting point
    turtle.turnRight()
    -- go back over the row if there was an odd size
    if isOdd then
        turtle.turnRight()
        for back = 1,(fieldSize-1),1 do
            turtle.forward()
        end
        turtle.turnRight()
    end
    -- go back down the column
    for back = 1,(fieldSize-1),1 do
        turtle.forward()
    end
    -- face the chest
    turtle.turnLeft()
    --empty everything into the chest
    for slot = 1,16,1 do
        turtle.select(slot)
        -- we keep trying to dump inventory
        while turtle.getItemCount(slot) ~= 0 do
            if not turtle.drop() then
                -- if the target inventory was full, we'll try it again later
                os.sleep(10)
            end
        end
    end
    -- reset to the starting conditions
    turtle.select(1)
    -- go again in 45 minutes
    os.sleep(2400)
end