Platform II with Torch Placing, Mob Killing and Inventory Requesting

--[[
Credit to Zach Dyer for the original program that I based this on
'Easy Platform Builder'.

Current version: 2.0
Pastebin: M0i8fDU5

Changelog:
5/20/2014 - added torch placing, block detection
5/31/2014 - added mob attacking, better block detection,
inventory requests when empty, resume on keypress.
--]]

local tArgs = {...}

local length = tonumber(tArgs[1])
local width = tonumber(tArgs[2])
local torch_interval = tonumber(tArgs[3])

if torch_interval == nil then
	torch_interval = 0
end

local turnRight = true
local slot = 1
local interval = 0

function pauseAnyKey()
   -- if event == "key" and p1 == keys.q then
   while true do
		local event, p1,p2,p3 = os.pullEvent()
		if event == "key" then
			return p1
		end
		sleep(0.5)
   end
end

-- Kudos to BlockSmith on ComputerCraft.info forums for the suggestion!
function refuel(dim1,dim2)
		dim1 = dim1 or 1
dim2 = dim2 or 1
fuelReq = dim1 * dim2
turtle.select(15)  
while (turtle.getFuelLevel() < fuelReq) do
--inform the user that the turtle is out of fuel
print("Waiting for fuel in slot 15...")
				print("Press any key to continue.")
pauseAnyKey()
-- use all of the fuel in slot 15
turtle.refuel()
-- then go back and check the level again
end

-- select the active slot
turtle.select(slot)
end

function flip()
	turtle.turnRight()
	turtle.turnRight()
end

function digDetect()
	while turtle.detect() do
		turtle.dig()
	end
end

function psycho()
	turtle.attack()
	turtle.attackUp()
	turtle.attackDown()
	turtle.turnLeft()
	turtle.attack()
	turtle.turnRight()
	turtle.turnRight()
	turtle.attack()
	turtle.turnLeft()
end

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

function tryForward()
	while not turtle.forward() do
		psycho() --turtle.attack()
		turtle.dig()
	end
end

function tryPlaceDown(mode)
	mode = mode or "ignore me"
	while not turtle.placeDown() do
		if mode == "dig" then
			turtle.digDown()
		end
		--turtle.attackDown()
		psycho()
		turtle.attack()
	end
end

function findInventory()
	for i=slot,14 do
		if turtle.getItemCount(i) > 0 then
			return i
		end
	end
	for i=1,slot-1 do
		if turtle.getItemCount(i) > 0 then
			return i
		end
	end
	return -1
end

function torchPlacer()
	turtle.select(16)
	if turtle.getItemCount(16) == 0 then
		print("I need more torches!")
		print("Put more torches in slot 16 and press any key to make me resume!")
		pauseAnyKey()
	end
	digDetectUp()
	turtle.up()
	flip()
	digDetect()
	flip()
	turtle.back()
	tryPlaceDown()
	--turtle.placeDown()
	tryForward()
	turtle.down()
end

if width == nil then
	print("1. Place turtle facing direction of said platform on left side.")
	print("2. Load turtle with materials for the platform. If placing torches, add light source blocks to slot 16.")
	print("3. Type 'platform <length> <width> [torch_interval]'")
	return
end

turtle.select(slot)


-- set the initial fuel load
refuel(length,width)
tryForward()

for j = 1, width, 1 do

  for i = 1, length, 1 do
	if turtle.getItemCount(slot) == 0 then
		x = findInventory()
	  while x == -1 do	
		  if x == -1 then
			  print("I ran out of materials!")
			  print("Put mats in slots 1 to 14 then")
			  print("press any key to continue.")
			  pauseAnyKey()
			  x = findInventory()
		  end
	 end
	 slot = x
	end

	turtle.select(slot)
	tryPlaceDown("dig")

	if i < length then
	  digDetect()
	  tryForward()
	end

	if torch_interval > 0 then
		interval = interval + 1
		if interval == torch_interval then
		  interval = 0
		  torchPlacer()
		end
	end

  end

  if j < width then

	if turnRight == true then
	  turtle.turnRight()
	  digDetect()
	  tryForward()
	  turtle.turnRight()
	  turnRight = false
	else
	  turtle.turnLeft()
	  digDetect()
	  tryForward()
	  turtle.turnLeft()
	  turnRight = true
	end

  end

  refuel(5) -- cursory check for fuel
end