-- * useful functions

-- Digs in front, moves forward and digs up and down
function digForward()
	-- digs until the front is clear
	while turtle.detect() do
	    turtle.dig()
	end

	turtle.forward()

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

	turtle.digDown()

end

-- * Complex tasks to perform

-- Simple 3 block height tunnel with turn around
function SimpleTunnel(len)
	for i=1,2 do
		-- loop for digging
		for x=1,len do
		   digForward()

		   -- TODO: empt inventory from time to time
		   -- TODO: Output progress only every 10 blocks
		   write("Progress: "..x.."/"..len)
		end
		-- turn around before going back
		if i == 1 then
			-- turn
			turtle.turnRight()
			-- dig 2
			digForward()
			digForward()
			digForward()

			-- turn
			turtle.turnRight()
		end
	end

end


-- turtleMine
-- TODO: determine task by command
local arg = {...}
SimpleTunnel(arg[1])