ComputerCraft Farming

shell.run("clear")
print("== MATIX'S FARMING SCRIPT ==\nThanks for using Matix's farming script.\n\nLogs:")

Directions = {
    LEFT = 0,
    RIGHT = 1
}

-- Checks the fuel and refills the turtle
function CheckFuel()
    if turtle.getFuelLevel() < 2 then
        if turtle.getItemCount(1) > 0 then
            print("INFO: Refilling")
            turtle.select(1)
            turtle.refuel(1)
        else
            print("WARN: OUT OF FUEL! Need fuel refill in first slot.")
            -- loop and wait for refuel
            repeat
                sleep(1)
            until turtle.getItemCount(1) > 0
        end
    end
end

-- Till the block below the turtle
function TillBelow()
    if not turtle.detectDown() then
        turtle.digDown()
    end
end

function PickupItems()
    turtle.select(2)
    turtle.suckDown()
end

local notifiedAboutEmptyCrops = false
-- Place and farm crops
function PlaceAndFarm()
    BlockDetected, BlockData = turtle.inspectDown()
    if BlockDetected then
        if BlockData.state.age == 7 then
            turtle.select(2)
            turtle.digDown()
            sleep(0.2)
        end
    end
    if not turtle.detectDown() then
        if turtle.getItemCount(2) > 0 then
            notifiedAboutEmptyCrops = false
            turtle.select(2)
            turtle.placeDown()
        else
            if not notifiedAboutEmptyCrops then
                notifiedAboutEmptyCrops = true
                print("WARN: NO SEEDS OR CROPS in slot 2 of turtle inventory.")
            end
        end
    end
end

-- Check if block is above turtle. If a block is above the turtle, then it assumes it is a chest.
function PlaceItemsInChest()
    if turtle.detectUp() then
        print("INFO: Placing items in chest")
        for slot = 3, 16 do
            turtle.select(slot)
            turtle.dropUp()
        end
    end
end

local lastDirection = Directions.RIGHT
-- Checks the turtles position and moves it
function PerformMovement()
    if turtle.detect() then
        if lastDirection == Directions.RIGHT then
            lastDirection = Directions.LEFT
            turtle.turnLeft()
            if not turtle.detect() then
                turtle.forward()
                turtle.turnLeft()
            else
                turtle.turnLeft()
                turtle.turnLeft()
                turtle.forward()
                turtle.turnRight()
                lastDirection = Directions.RIGHT
            end
        else
            lastDirection = Directions.RIGHT
            turtle.turnRight()
            if not turtle.detect() then
                turtle.forward()
                turtle.turnRight()
            else
                turtle.turnRight()
                turtle.turnRight()
                turtle.forward()
                turtle.turnLeft()
                lastDirection = Directions.LEFT
            end
        end
    else
        turtle.forward()
    end
end

print("INFO: Starting main loop...")
-- Main loop
repeat
    CheckFuel()
    TillBelow()
    PlaceAndFarm()
    PickupItems()
    PlaceItemsInChest()
    PerformMovement()
until false

print("ERROR: Farming script ended natrually. THIS SHOULD NOT HAPPEN!")