-- Tunnel Digging Script for CC: Tweaked
-- Digs a 3x3 tunnel for a specified distance, with auto-refueling.

-- Function to refuel if needed
local function refuelIfNeeded()
    if turtle.getFuelLevel() < 10 then
        print("Low fuel! Attempting to refuel...")
        for i = 1, 16 do
            turtle.select(i)
            if turtle.refuel(0) then -- Check if the item can refuel
                turtle.refuel()
                print("Refueled with item in slot " .. i)
                break
            end
        end
        if turtle.getFuelLevel() < 10 then
            print("Out of fuel! Please add fuel to the turtle.")
            while turtle.getFuelLevel() < 10 do
                sleep(1)
            end
        end
    end
end

-- Function to dig a 3x3 section
local function dig3x3()
    -- Dig the bottom row
    turtle.dig()
    turtle.forward()
    turtle.digDown()

    -- Dig middle and upper rows
    for _ = 1, 2 do
        turtle.digUp()
        turtle.up()
        turtle.dig()
        turtle.forward()
    end

    -- Return to the bottom layer
    for _ = 1, 2 do
        turtle.back()
        turtle.down()
    end
end

-- Main function to dig the tunnel
local function digTunnel(length)
    for i = 1, length do
        print("Digging segment " .. i .. " of " .. length)
        refuelIfNeeded()
        dig3x3()
    end
    print("Tunnel completed!")
end

-- Get user input for tunnel length
print("Enter the tunnel length:")
local length = tonumber(read())

if length and length > 0 then
    digTunnel(length)
else
    print("Invalid input! Please enter a positive number.")
end