Digger Tunnel Turtle for Minecraft

--Own Tunnel Turtle same size 2X3 but with feature bring items in chest, set torches and refill the border with cobble stone

length = 100
torchPl = 5
torchCounter = 0
layerCounter = 0

function layerDig()
    leftLayer()
    refillCopple()
    rightLayer()
    refillCopple()
    checkItemsAndGoEmpty()

end

function leftLayer()
    Dig()
    ForwardDown()
    checkLeftBorder()
    DigUp()
    MoveUppest()
    checkFrontBorder()
    turn180()
    Dig()
    ForwardUp()
    DigDown()
    MoveLowest()
    Dig()
    ForwardDown()
    checkFrontBorder()
    DigUp()
    MoveUppest()
    checkFrontBorder()
    layerCounter = layerCounter + 1
    placeTorch()
    turtle.turnLeft()
end

function rightLayer()
    Dig()
    ForwardUp()
    checkRightBorder()
    DigDown()
    MoveLowest()
    checkFrontBorder()
    turn180()
    Dig()
    ForwardDown()
    DigUp()
    MoveUppest()
    Dig()
    ForwardUp()
    checkFrontBorder()
    placeTorch()
    DigDown()
    MoveLowest()
    checkFrontBorder()
    layerCounter = layerCounter + 1
    turtle.turnRight()
end

function Dig()
    while turtle.detect() do
        turtle.dig()
        sleep(0.4)
    end
end

function DigUp()
    while turtle.detectUp() do
        turtle.digUp()
        sleep(0.4)
    end
end

function DigDown()
    while turtle.detectDown() do
        turtle.digDown()
        sleep(0.4)
    end
end

function BackToChest()
    turn180()
    for i=1, layerCounter, 1 do
        Dig()
        turtle.forward()
    end
    Drop()
    turn180()
end

function BackToLayer()
    for i=1, layerCounter, 1 do
        Dig()
        turtle.forward()
    end
end

function Drop()
    for i=1, 14, 1 do
        turtle.select(i)
        turtle.drop(64)
    end
end

function ForwardDown()
    turtle.forward()
    if(turtle.detectDown() == false) then
        turtle.select(15)
        turtle.placeDown()
    end
end

function ForwardUp()
    turtle.forward()
    if(turtle.detectUp() == false) then
        turtle.select(15)
        turtle.placeUp()
    end
end

function MoveUppest()
    turtle.up()
    if(turtle.detectUp() == false) then
        turtle.select(15)
        turtle.placeUp()
    end
end

function MoveLowest()
    turtle.down()
    if(turtle.detectDown() == false) then
        turtle.select(15)
        turtle.placeDown()
    end
end

function turn180()
    turtle.turnLeft()
    turtle.turnLeft()
end

function checkLeftBorder()
    turtle.turnLeft()
    checkFrontBorder()
end

function checkRightBorder()
    turtle.turnRight()
    checkFrontBorder()
end

function checkFrontBorder()
    if(turtle.detect() == false) then
        turtle.select(15)
        turtle.place()
    end
end

function placeTorch()
    if(torchCounter == torchPl) then
        turn180()
        turtle.forward()
        turtle.select(16)
        turtle.place()
        torchCounter = 0
        turn180()
        turtle.forward()
    else
        torchCounter = torchCounter + 1
    end
end

function checkItemsAndGoEmpty()
    haveToEmpty = 1

    for i = 1, 14, 1 do
        if (turtle.getItemCount(i) == 0) then
            haveToEmpty = 0
        end
    end

    if (haveToEmpty == 1) then
        BackToChest()
        BackToLayer()
    end
end

function refillCopple()
    local cnt = turtle.getItemCount(15)
    if cnt < 8 then
        for i=1, 15, 1 do
            turtle.select(i)
            local comp = turtle.compareTo(16)
            if comp == true then
                turtle.transferTo(16)
            end
        end
    end
end

function start()
    local input = 1
    shell.run("clear")
    while input == 1 do
        term.setCursorPos(1,1)
        print("Menu:")
        print("=======================================")
        term.setCursorPos(1,3)
        term.clearLine()
        print("Length of the tunnel: "..length)
        term.clearLine()
        term.setCursorPos(1,5)
        term.clearLine()
        print("Enter [S] for start or [C] for change settings - [Q] quit:")
        term.clearLine()

        local inputstring = read()

        if inputstring == 'S' or inputstring == 's' then
            if checkStartConditions() == 1 then
                run()
            end
        elseif inputstring == 'C' or inputstring == 'c' then
            setting()
        elseif inputstring == 'Q' or inputstring == 'q' then
            input = 0
            shell.run("clear")
        else
            term.setCursorPos(1,10)
            term.clear()
            print("Invalid Input")
        end
    end
end

function checkStartConditions()
    term.setCursorPos(1,10)
    term.clear()
    local retValue = 1
    local torchCount = turtle.getItemCount(16)
    local cobbleCount = turtle.getItemCount(15)
    if torchCount == 0 then
        print("No torches found!")
        retValue = 0
    else
        print("Number of found torches: "..torchCount)
    end

    if cobbleCount == 0 then
        print("No cobble stone found!")
        retValue = 0
    else
        print("Number of found cobble stone: "..cobbleCount)
    end

    if retValue == 0 then
        print("Start conditions not correct - please fill torches in slot 16 and cobblestone in slot 15")
        return 0
    else
        return 1
    end
end

function setting()
    local setting = 1
    local invalidCounter = 0
    shell.run("clear")
    while setting == 1 do
        term.setCursorPos(1,1)
        print("Setting:")
        print("=======================================")
        term.setCursorPos(1,3)
        term.clearLine()
        print("Actual using tunnel length: "..length)
        term.setCursorPos(1,5)
        term.clearLine()
        print("Enter the new length of the tunnel:")
        local inputstring = read()

        if(tonumber(inputstring) ~= nil) then
            length = tonumber(inputstring)
            setting = 0
        else
            term.setCursorPos(1,10)
            term.clear()
            print("Invalid Input")
            invalidCounter = invalidCounter + 1
        end

        if invalidCounter == 3 then
            setting = 0
        end
    end
    shell.run("clear")
end

function run()
    for i=1, length / 2, 1 do
        layerDig()
    end

    BackToChest()
end

start()