MJZ LUA simple Tunneling x4

--{program="Tunneler",version="1.1",date="19.10.2021"}
---------------------------------------
-- Arguements and Arg Checking
local tArgs = { ... }
if #tArgs ~= 1 then
    print( "Usage: tunnel <length>" )
    return
end
local length = tonumber( tArgs[1] )
if length < 1 then
    print( "Tunnel length must be positive" )
    return
end

-- Collected block number / Increaser
local collected = 0
local function collect()
    collected = collected + 1
    if math.fmod(collected, 25) == 0 then
        print( "Mined "..collected.." blocks." )
    end
end

-- Digging functions
local function tryDig()
    while turtle.dig() do
        collect()
        if not turtle.detect() then
            return true
        end
    end
    return not turtle.detect()
end

local function tryDigUp()
    while turtle.digUp() do
        collect()
        if not turtle.detectUp() then
            return true
        end
    end
    return not turtle.detectUp()
end

-- Functions for dropping off items into a chest from slot 1.
local function depositChest()
    turtle.up()
    turtle.turnRight()
    turtle.forward()
    turtle.select(1)
    turtle.placeDown()
    for slot=2,16 do
        turtle.select(slot)
        turtle.dropDown(turtle.getItemCount(slot))
    end
    turtle.select(1)
end

local function previousState()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.forward()
    turtle.down()
    turtle.turnRight()
end

local function checkSpace()
    local space = 0
    for slot=2,16 do
        space = space + turtle.getItemSpace(slot)
    end
    if space == 0 then
        depositChest()
        previousState()
        return false
    else
        return true
    end
end

-- Main Program for digging the tunnel
write( "Tunnelling 4 block high" )
for n=1,length do
    write(".")
    turtle.select(2)
    turtle.placeDown()
    if not checkSpace() then break end
    tryDigUp()
    turtle.turnLeft()
    tryDig()
    turtle.up()
    tryDig()
    tryDigUp()
    turtle.up()
    tryDig()
    tryDigUp()
    turtle.up()
    tryDig()
    turtle.turnRight()
    turtle.turnRight()
    tryDig()
    turtle.down()
    tryDig()
    turtle.down()
    tryDig()
    turtle.down()
    tryDig()
    turtle.turnLeft()

    if n<length then
        tryDig()
        if not turtle.forward() then
            print( "Aborting Tunnel." )
            break
        end
    else
        print( "Tunnel complete." )
    end
end