local curX = 0
	local curY = 0
	local curZ = 0
	local curO = 1

	orientations = {
		NORTH = 1,
		EAST = 2,
		SOUTH = 3,
		WEST = 4
	}

	directions = {
		FORWARD = 1,
		UP = 2,
		DOWN = 3
	}

	function init(x, y, z, o)
		curX = x
		curY = y
		curZ = z
		curO = o
	end

	function getPosition()
		local res = {}
		res["x"] = curX
		res["y"] = curY
		res["z"] = curZ
		res["o"] = curO
		return res
	end

	function move(dir, canDig)
		local moveResult = false

		if(dir == directions.FORWARD) then
			--print("Moving forward.")
			if(turtle.detect()) then
				moveResult = turtle.dig()
			end
			moveResult = turtle.forward()
		end

		if(dir == directions.UP) then
			--print("Moving up.")
			if(turtle.detectUp()) then
				moveResult = turtle.digUp()
			end
			moveResult = turtle.up()
		end

		if(dir == directions.DOWN) then
			--print("Moving down.")
			if(turtle.detectDown()) then
				moveResult = turtle.digDown()
			end
			moveResult = turtle.down()
		end

		if(moveResult) then
			handleMove(dir)
		end
	end

	function moveTo(dest)
		local moveAmt = 0
		if(curY < dest.y) then
			moveAmt = dest.y - curY
			print("Moving up " .. moveAmt .. " blocks")
			for i=1,moveAmt,1 do move(directions.UP, true) end
		end

		if(curY > dest.y) then
			moveAmt = curY - dest.y
			print("Moving down " .. moveAmt .. " blocks")
			for i=1,moveAmt,1 do move(directions.DOWN, true) end
		end

		if(curX < dest.x) then
			setOrientation(orientations.EAST)
			moveAmt = dest.x - curX
			print("Moving east " .. moveAmt .. " blocks")
			for i=1,moveAmt,1 do move(directions.FORWARD, true) end
		end

		if(curX > dest.x) then
			setOrientation(orientations.WEST)
			moveAmt = curX - dest.x
			print("Moving west " .. moveAmt .. " blocks")
			for i=1,moveAmt,1 do move(directions.FORWARD, true) end
		end

		if(curZ < dest.z) then
			setOrientation(orientations.SOUTH)
			moveAmt = dest.z - curZ
			print("Moving south " .. moveAmt .. " blocks")
			for i=1,moveAmt,1 do move(directions.FORWARD, true) end
		end

		if(curZ > dest.z) then
			setOrientation(orientations.NORTH)
			moveAmt = curZ - dest.z
			print("Moving north " .. moveAmt .. " blocks")
			for i=1,moveAmt,1 do move(directions.FORWARD, true) end
		end
	end

	function handleMove(dir)
		if(dir == directions.UP) then
			curY = curY + 1
		end

		if(dir == directions.DOWN) then
			curY = curY - 1
		end

		if(dir == directions.FORWARD) then
			if(curO == orientations.NORTH) then
				curZ = curZ - 1
			elseif(curO == orientations.SOUTH) then
				curZ = curZ + 1
			elseif(curO == orientations.EAST) then
				curX = curX + 1
			else
				curX = curX - 1
			end
		end
	end

	function turnLeft()
		if(turtle.turnLeft()) then
			curO = curO - 1
			if(curO < 1) then curO = 4 end
		end
	end

	function turnRight()
		if(turtle.turnRight()) then
			curO = curO + 1
			if(curO > 4) then curO = 1 end
		end
	end

	function setOrientation(o)
		while(curO ~= o) do
			turnLeft()
		end
	end

	function excavateUp(l, w, h)
		local isForward = true
		local startPos = getPosition()

		for ch=1,h,1 do
			for cw=1,w,1 do
				for cl=1,l-1,1 do
					move(directions.FORWARD, true)
				end

				if(cw < w) then
					if(isForward) then
						turnRight()
						move(directions.FORWARD, true)
						turnRight()

						isForward = false
					else
						turnLeft()
						move(directions.FORWARD, true)
						turnLeft()

						isForward = true
					end
				end
			end

			if(ch < h) then
				move(directions.UP, true)
				turnLeft()
				turnLeft()
			end
		end

		for rl=1,h-1,1 do
			move(directions.DOWN, true)
		end

		setOrientation(startPos.o)

		if(curX ~= startPos.x) then
			turnLeft()
			for rsw=1,w-1,1 do move(directions.FORWARD, true) end
			turnLeft()
			for rsl=1,l-1,1 do move(directions.FORWARD, true) end
			setOrientation(startPos.o)
		end
	end