[CC} dig

if not turtle then
    printError( "Requires a Turtle" )
    return
end

local tArgs = { ... }
if #tArgs ~= 1 then
    print( "Usage: dig <length>" )
    return
end

-- Mine in a quarry pattern until we hit something we can't dig
local length = tonumber( tArgs[1] )

if length < 1 then
    print( "Dig length must be positive" )
    return
end

local function refuel()
    local fuelLevel = turtle.getFuelLevel()
    if fuelLevel == "unlimited" or fuelLevel > 0 then
        return
    end

    local function tryRefuel()
        for n=1,16 do
            if turtle.getItemCount(n) > 0 then
                turtle.select(n)
                if turtle.refuel(1) then
                    turtle.select(1)
                    return true
                end
            end
        end
        turtle.select(1)
        return false
    end

    if not tryRefuel() then
        print( "Add more fuel to continue." )
        while not tryRefuel() do
            os.pullEvent( "turtle_inventory" )
        end
        print( "Resuming Tunnel Facing." )
    end
end

local function tryDig()
    while turtle.detect() do
        if turtle.dig() then
            sleep(0.5)
        else
            return false
        end
    end
    return true
end

local function tryForward()
    refuel()
    while not turtle.forward() do
        if turtle.detect() then
            if not tryDig() then
                return false
            end
        elseif turtle.attack() then
        else
            sleep( 0.5 )
        end
    end
    return true
end

for n=1,length do
    tryForward()

    if n<length then
        tryDig()
        if not tryForward() then
            print( "Aborting digging." )
            break
        end
    else
        print( "Digging complete." )
    end

end