eatlava

-- eatlava
-- Refuels from lava directly below turtle
-- Must start with one lava bucket in slot 1
-- Turtle travels requested area refueling when lava is directly below, then returns
-- Written by HarvDad, March 2014

args = {...}
nArgs = #args

print("eatLava: Rev 2.1")
x = 0
y = 0
z = 0
face = 0
minimumFuel = 100
missionMessage = "Mission complete."
usage = "Usage: eatlava <length> <width>"
abort = false
local currentFuelLevel = turtle.getFuelLevel()

if nArgs == 0 or (nArgs == 1 and args[1]== "help") then
	print("Refuels from lava directly below turtle.")
	print("First time: Must start with one lava bucket in slot 1")
	print("Usage: eatLava <length> <width>")
	return
end

if nArgs ~= 2 then
  print("Usage: eatLava <distance>")
  return
end

length = tonumber(args[1])
if length == nil then
  print("\"", args[1], "\" is not a valid length")
  return
end
if length < 1 then
  print("length must be a positive number greater than zero")
  return
end

width = tonumber(args[2])
if width == nil then
  print("\"", args[1], "\" is not a valid width")
  return
end
if width < 1 then
  print("width must be a positive number greater than zero")
  return
end

areaCovered = 0;

function eatLava()
	turtle.select(1)
	if turtle.placeDown() then
		turtle.refuel()
	end
end

function setFace(f)
	if f == 0 then
	  if face == 0 then return end
	  if face == 1 then right() return end
	  if face == 2 then right() right() return end
	  if face == 3 then left() return end
	end

	if f == 1 then
	  if face == 0 then left() return end
	  if face == 1 then return end
	  if face == 2 then right() return end
	  if face == 3 then right() right() return end
	end

	if f == 2 then
	  if face == 0 then left() left() return end
	  if face == 1 then left() return end
	  if face == 2 then return end
	  if face == 3 then right() return end
	end

	if f == 3 then
	  if face == 0 then right() return end
	  if face == 1 then left() left() return end
	  if face == 2 then left() return end
	  if face == 3 then return end
	end
end

function forward()
	while turtle.detect() do	-- This loop added in case of falling sand or whatever
	  turtle.dig()
	end
	for i=1,10 do				-- This loop trys to handle pests (mob) that might be in the way
		if turtle.forward() then
			break
		end
		turtle.attack()
		sleep(2)
	end
	areaCovered = areaCovered + 1

  	if face == 0 then z = z+1 return end
  	if face == 1 then x = x-1 return end
  	if face == 2 then z = z-1 return end
  	if face == 3 then x = x+1 return end
end

function left()
 if face == 0 then face = 1 turtle.turnLeft() return end
 if face == 1 then face = 2 turtle.turnLeft() return end
 if face == 2 then face = 3 turtle.turnLeft() return end
 if face == 3 then face = 0 turtle.turnLeft() return end
 print("function left\(\): Bad face value: ", face)
end

function right()
 if face == 0 then face = 3 turtle.turnRight() return end
 if face == 1 then face = 0 turtle.turnRight() return end
 if face == 2 then face = 1 turtle.turnRight() return end
 if face == 3 then face = 2 turtle.turnRight() return end
 print("function right\(\): Bad face value: ", face)
end

function home(targetY)
--  print("home:face ", face, ", x = ", x, ", z = ", z)
  if x < 0 then
	setFace(3)
	while x < 0 do
	  forward()
	end
  else
    if x > 0 then
  	  setFace(1)
	  while x > 0 do
	    forward()
	  end
    end
  end

  if z < 0 then
	setFace(0)
	while z < 0 do
	  forward()
	end
  else
    if z > 0 then
  	  setFace(2)
	  while z > 0 do
	    forward()
	  end
    end
  end
  setFace(0)
end


-- MAIN PROGRAM

turtle.select(1)

print("Current Fuel Level: ", currentFuelLevel)

if currentFuelLevel ~= "unlimited" then
	if currentFuelLevel < minimumFuel then
		if not turtle.refuel() then
		  print("No fuel")
		  return
		end
	end
end

nextTurn = "left"

forward()
targetArea = length * width
while areaCovered < targetArea do
	if abort then
		break
	end
	for w=1,width do
		if abort then
			break
		end
		for z=1,length do
			if abort then
				break
			end
			eatLava()
			if z < length then
				forward()
			end
		end
		if nextTurn == "left" then
			if areaCovered < targetArea then
				left()
				forward()
				left()
				nextTurn = "right"
			end
		else
			if areaCovered < targetArea then
				right()
				forward()
				right()
				nextTurn = "left"
			end
		end
	end
end

home()
print (missionMessage)
print ("Fuel level is now ", turtle.getFuelLevel())