Dragon Egg Harvester

local sensor = peripheral.wrap('right')

local isMoving
local isStart = true
local isEnd

--0.0, y=-3.0, z=1.0

function init()
    while true do
        while not placeCobbleStone() do
            sleep(3)
        end
        checkFuel()
        moveToEgg()
        turtle.dig()
        returnToBase()
        transferEgg()
        sleep(5)
    end
end

function placeCobbleStone()
    if ( turtle.getItemCount(1) > 0 and turtle.getItemDetail(1).name == 'minecraft:cobblestone' ) then
        turtle.select(1)
        return turtle.place()
    else
        error("No Cobblestone")
    end
end

function transferEgg()
    if ( turtle.getItemCount(2) > 0 and turtle.getItemDetail(2).name == 'minecraft:dragon_egg' ) then
        turtle.select(2)
        turtle.dropDown()
    else
        error('what the $!@#, there is no egg?!')
    end
end

function checkFuel()
    if turtle.getFuelLevel() <= 5 then
        turtle.select(16)
        turtle.refuel(1)
        turtle.select(1)
    end
end

function moveToEgg()
    isMoving = true
    turtle.up()
    turtle.forward()
    turtle.forward()
    turtle.forward()
    isMoving = false
    isStart = false
    isEnd = true
end

function returnToBase()
    isMoving = true
    turtle.back()
    turtle.back()
    turtle.back()
    turtle.down()
    isMoving = false
    isEnd = false
    isStart = true
end

init()