Computercraft Cow Farm Turtle

-- Constants
requiredWheat = 48
requiredFuel = 500
waitTime = 6*60 -- Seconds between breed cycles

fuelDirection = "right"
wheatDirection = "up"

--  Breeds the cows with Wheat
function breed()
    -- Power the water in the farm
    redstonePulse()

    -- Wait for cows
    os.sleep(1)

    -- Place wheat
    for i=1,200,1 do
        turtle.place()
    end

    -- Turn off water
    redstonePulse()

end

-- Fires a 2 tick pulse of redstone on the left and right of the turtle
function redstonePulse()
    redstone.setOutput("left", true)
    redstone.setOutput("right", true)
    os.sleep(0.2)
    redstone.setOutput("left", false)
    redstone.setOutput("right", false)
end

-- Select the next slot
function selectNext()
    if turtle.getSelectedSlot() == 16 then
        turtle.select(1)
    else
        turtle.select(turtle.getSelectedSlot()+1)
    end
end

-- Go through all the stations and perform a breed cycle
function breedCycle()
    turtle.select(1)
    print("Starting breed cycle")

    -- Check fuel
    if turtle.getFuelLevel() < requiredFuel then
        getFuel(fuelDirection)
    end
    if turtle.getItemCount() < requiredWheat then
        getWheat(wheatDirection)
    end

    turtle.forward()
    turtle.forward()
    turtle.forward()

    turtle.turnRight()
    turtle.forward()
    breed()
    turtle.turnLeft()
    turtle.turnLeft()

    turtle.forward()
    turtle.forward()
    breed()
    turtle.back()
    turtle.turnRight()

    turtle.forward()
    turtle.forward()
    turtle.forward()
    turtle.forward()

    turtle.turnRight()
    turtle.forward()
    breed()
    turtle.turnLeft()
    turtle.turnLeft()

    turtle.forward()
    turtle.forward()
    breed()
    turtle.back()
    turtle.turnRight()

    for i=1,7,1 do
        turtle.back()
    end
end

function getFuel(direction)
    print("Refueling")
    turtle.select(16)
    local success = false
    local alreadyComplained = false;

    -- Face chest
    if direction=="left" then
        turtle.turnLeft()
    end
    if direction=="right" then
        turtle.turnRight()
    end

    while not success do
        os.queueEvent("randomEvent")
        os.pullEvent()
        -- Get the fuel
        if direction=="down" then
                turtle.suckDown()
            end
        if direction=="up" then
            turtle.suckUp()
        end
        if direction=="left" then
            turtle.suck()
        end
        if direction=="right" then
            turtle.suck()
        end

        -- Attempt refuel
        turtle.refuel()
        success = turtle.getFuelLevel() >= requiredFuel

        -- Place item back in chest if bucket
        if direction=="down" then
                turtle.dropDown()
            end
        if direction=="up" then
            turtle.dropUp()
        end
        if direction=="left" or direction=="right" then
            turtle.drop()
        end

        -- Complain if unsuccessfull
        if not success and not alreadyComplained then
            print("Not enough fuel. Please place fuel in chest.")
            alreadyComplained = true
        end
    end

    turtle.select(1)
    print("Fuel at "..string.format(turtle.getFuelLevel()).."/"..string.format(requiredFuel))

    -- Face forward
    if direction=="left" then
        turtle.turnRight()
    end
    if direction=="right" then
        turtle.turnLeft()
    end

end

function getWheat(direction)
    print("Obtaining wheat")
    local success = false
    local alreadyComplained = false
    turtle.select(1)
    local numWheat = turtle.getItemSpace()

    -- Face chest
    if direction=="left" then
        turtle.turnLeft()
    end
    if direction=="right" then
        turtle.turnRight()
    end

    while not success do
        os.queueEvent("randomEvent")
        os.pullEvent()
        -- Get the wheat
        if direction=="down" then
            turtle.suckDown(numWheat)
        end
        if direction=="up" then
            turtle.suckUp(numWheat)
        end
        if direction=="left" then
            turtle.suck(numWheat)
        end
        if direction=="right" then
            turtle.suck(numWheat)
        end

        -- See if I have enough
        success = turtle.getItemCount() >= requiredWheat

        -- Complain if unsuccessfull
        if not success and not alreadyComplained then
            print("Not enough wheat. Please place "..requiredWheat-turtle.getItemCount().." wheat in the chest.")
            alreadyComplained = true
        end
    end

    -- Face forward
    if direction=="left" then
        turtle.turnRight()
    end
    if direction=="right" then
        turtle.turnLeft()
    end

    print("Wheat obtained")
end

-- Main loop
function main()
    while true do
        breedCycle()
        os.sleep(waitTime)
    end
end


main()