niceBridge

local tArgs = { ... }

if #tArgs ~= 1 then
    print( "Usage: bridge <length>" )
    return
end

-- Initial Fueling
turtle.refuel(1)

-- variable to tell main function when to stop
local o = 1
j = 2
-- Function to get the fuel level of the robot as a number
fcount = function()
        return turtle.getFuelLevel()
end

-- Move forward, Fuel Check and Refuel function. also places down block for every movement.
forwardCheck = function(num)
		for i=1,num do
			if not turtle.detectDown() then
				findSlot()
				turtle.placeDown()
			end

			while not turtle.forward() do
				turtle.dig()
				turtle.attack()
				turtle.attackUp()
				if fcount() < 1 then
                	turtle.select(1)
                	print ("Attempting to eat my fuel...")
                	if turtle.getItemCount(1) < 1 then
                    	print ("I am out of fuel...")
                    	o = 0
                	end
                	turtle.refuel(1)
					turtle.select(j)
        		end
			turtle.digUp()
			end
		end

		findSlot()

        if fcount() < 1 then
                turtle.select(1)
                print ("Attempting to eat my fuel...")
                if turtle.getItemCount(1) < 1 then
                    print ("I am out of fuel...")
                    o = 0
                end
                turtle.refuel(1)
				turtle.select(j)
        end
end

--Finds an inventory slot with a block that is not slot 1
findSlot = function()
	while turtle.getItemCount(j) == 0 do
		if j < 16 then
			j = j+1
		else
			print("Out of blocks")
		end
	end
	turtle.select(j)
end

placeBehind = function()
	turtle.turnLeft()
	turtle.turnLeft()
	findSlot()
	turtle.place()
	turtle.turnRight()
	turtle.turnRight()
end

rightBridge = function(i)
	turtle.turnRight()
	findSlot()
	turtle.placeUp()
	forwardCheck(1)
	placeBehind()
	forwardCheck(3)
	findSlot()
	turtle.placeUp()
	turtle.turnLeft()
	forwardCheck(1)
	placeBehind()
end

leftBridge = function(i)
	turtle.turnLeft()
	forwardCheck(1)
	placeBehind()
	forwardCheck(3)
	turtle.turnRight()
	forwardCheck(1)
	placeBehind()
end

--First line of bridge to establish pattern
initLine = function()
	turtle.turnLeft()
	forwardCheck(2)
	turtle.placeUp()
	turtle.turnRight()
	turtle.turnRight()
	forwardCheck(1)
	placeBehind()
	forwardCheck(3)
	turtle.placeUp()
	turtle.turnLeft()
	forwardCheck(1)
	placeBehind()
end

niceBridge = function(length)
	initLine()
	for i=1,(length-1)/2 do
		leftBridge()
		rightBridge()
	end
	turtle.turnLeft()
	turtle.forward()
	turtle.turnLeft()
	for i=1,length do
		turtle.forward()
	end
end

niceBridge(tonumber(tArgs[1]))