Miner Turtle

--------- Variables ----------
chest = 14
torch = 15
fuel = 16
maxFuel = 100

--------- Functions ----------
function checkFuel()
    print(turtle.getFuelLevel())
    if  turtle.getFuelLevel() < 1 then
        print('Refueling')
        refuel()
    end
end

function refuel()
    turtle.select(16)
    while turtle.getItemCount(fuel) > 0 and turtle.getFuelLevel() < maxFuel do
        turtle.refuel(1)
    end
end

function forward()
    checkFuel()
    while not turtle.forward() do
        turtle.dig()
    end
end

function clearBlocks()
    while turtle.detectUp() or turtle.detectDown() do
        turtle.digUp()
        turtle.digDown()
    end
end

function left()
    turtle.turnLeft()
    turtle.dig()
    forward()
end

function turnAround()
    turtle.turnLeft()
    turtle.turnLeft()
end

function right()
    turtle.turnRight()
    turtle.dig()
    forward()
end

function isFull()
    for i = 1,16 do
        if turtle.getItemCount(i) == 0 then
            return false
        end
    end
  return true
end

function returnHome()
    turnAround()
    turtle.select(chest)
    while not turtle.compare() do
        forward()
    end
    for i=1, 12, 1 do
        turtle.select(i)
        turtle.drop()
    end
    turnAround()
    while not turtle.detect() do
        forward()
    end
end

function dropOffCheck()
    if isFull() then
        returnHome()
    end
end

function placeTorch()
    turtle.turnRight()
    turtle.select(torch)
    turtle.place()
    turtle.turnLeft()
end



--------- Execution ----------
lastTorch = 6
while true do
    dropOffCheck()
    if lastTorch > 5 then
        placeTorch()
        lastTorch=0
    end
    forward()
    clearBlocks()
    left()
    clearBlocks()
    turnAround()
    forward()
    forward()
    clearBlocks()
    turnAround()
    forward()
    turtle.turnRight()
    lastTorch = lastTorch+1
end