local tArgs = { ... }
if #tArgs ~= 2 then
    print( "Usage: tunnel <length> <number>" )
    return
end

local length = tonumber( tArgs[1] )
local num = tonumber( tArgs[2] )

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

if num < 1 then
    print( "Tunnel number 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
                    return true
                end
            end
        end
        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." )
    end
end

local function digForward()
    while turtle.detect() do
        turtle.dig()
    end
end

local function digUp()
    while turtle.detectUp() do
        turtle.digUp()
    end
end

local function digDown()
    while turtle.detectDown() do
            turtle.digDown()
    end
end

local function forward()
    refuel()
    while not turtle.forward() do
        digForward()
        turtle.attack()
        sleep( 0.1 )
    end
end

local function up()
    refuel()
    while not turtle.up() do
        digUp()
        turtle.attackUp()
        sleep( 0.1 )
    end
end

local function down()
    refuel()
    while not turtle.down() do
        digDown()
        turtle.attackDown()
        sleep( 0.1 )
    end
end

local function move()
    turtle.select(1)
    turtle.placeDown()
    forward()
    up()
    down()
end

print( "Tunnelling..." )

for r=1,num do
    for n=1,length do
        turtle.select(1)
        turtle.placeDown()

        forward()

        if math.fmod(n, 10) == 0 then
            turtle.turnLeft()
            turtle.turnLeft()

            turtle.select(2)
            turtle.place()

            turtle.turnLeft()
            turtle.turnLeft()
        end

        up()

        if math.fmod(n, 3) == 0 then
            turtle.turnLeft()

            forward()
            forward()
            forward()
            forward()

            turtle.turnLeft()
            turtle.turnLeft()

            forward()
            forward()
            forward()
            forward()

            forward()
            forward()
            forward()
            forward()

            turtle.turnLeft()
            turtle.turnLeft()

            forward()
            forward()
            forward()
            forward()

            turtle.turnRight()
        end

        down()
    end

    if math.fmod(r, 2) == 0 then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end

    move()
    move()
    move()
    move()
    move()
    move()
    move()
    move()
    move()
    move()
    move()

    if math.fmod(r, 2) == 0 then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end
end

print( "Tunnel complete." )
print( "Mined "..collected.." items total." )