wall

-- wall
-- Build a wall of specified length and height specified
-- Turtle returns to its starting point when mission is completed or fuel runs low
-- Written by HarvDad, May 2014

args = {...}
nArgs = #args

version = "walls: Rev 0.1"
mission = "Build a wall of length and height specified"
instructions = "Place stack(s) of material starting in first slot."

usage = "wall <start> <end> <height>"

x = 0
y = 0
z = 0
face = 0
minimumFuel = 100
missionMessage = "Mission complete."
abort = false
startLevel = 0
local currentFuelLevel = turtle.getFuelLevel()

if nArgs == 0 or (nArgs == 1 and args[1]== "help") then
	print(version)
	print(mission)
	print(instructions)
	print(usage)
	return
end

if nArgs ~= 2 then
  print(usage)
  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")
end

height = tonumber(args[2])
if startLevel == nil then
  print("\"", args[2], "\" is not a valid height")
return
end

currentSlot = 2
materialSlot = 1
maxSlot = 16

nextTurn = "left"

local clock = os.clock
function sleep(n)  -- seconds
  local t0 = clock()
    while clock() - t0 <= n do 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 up()
  turtle.up()
  y = y+1
end

function rise(nBlocks)
  local i
  for i=1,nBlocks do
    up()
  end
end

function down()
  if turtle.detectDown() then
    turtle.digDown()
  end
  turtle.down()
  y = y-1
end

function turn()
  if nextTurn == "left" then
    left()
  else
    right()
  end
  chomp()
  forward()
  if nextTurn == "left" then
	left()
  	nextTurn = "right"
  else
	right()
    nextTurn = "left"
  end
  areaCovered = areaCovered + 1
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

  	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 back()
	turtle.back()

  	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 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 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

  if y > 0 then
  	while y > 0 do
		down()
	end
  end

  setFace(0)
end

function ensureMaterial()
	if turtle.getItemCount(materialSlot) < 3 then
		organizeMaterial()
	end
	if turtle.getItemCount(materialSlot) < 3 then
		print("No more material")
		return false
	end
	return true
end

function organizeMaterial()
	local i
	materialCount = turtle.getItemCount(materialSlot)

	if materialCount < 3 then
--		print("Attempting to refill slot ", materialSlot)
		for i=2,16 do
			turtle.select(i)
			if turtle.compareTo(materialSlot) then
				turtle.transferTo(materialSlot)
			end
		end
	end
	turtle.select(materialSlot)
end

function layBlock()
	turtle.select(materialSlot)

	if startLevel > 2 then
		if turtle.detectUp() then
			if turtle.compareUp() then
				return
			else
				turtle.digUp()
			end
		end
		if ensureMaterial() then
			turtle.placeUp()
		end
	else
		if turtle.detectDown() then
			if turtle.compareDown() then
				return
			else
				turtle.digDown()
			end
		end
		if ensureMaterial() then
			turtle.placeDown()
		end
	end
end

function checkFuel()
	if currentFuelLevel == "unlimited" then
		return true
	end

	if currentFuelLevel < minimumFuel then
	  if not turtle.refuel() then
		  areaCovered = targetArea
		  missionMessage = "Mission aborted due to low fuel."
		  abort = true
	    return false
	  end
	end
  return true
end

currentSlot = 1

directon = "forward"

function layRow(nBlocks)
	turtle.select(currentSlot)

	for i=1,nBlocks do
		if turtle.getItemCount(currentSlot) > 0 then
			turtle.placeDown()
			if direction == "forward" then
				if i < length then
					forward()
				end
			else
				if i < length then
					back()
				end
			end
		else
			currentSlot = currentSlot + 1
			if turtle.getItemCount(currentSlot) > 0 then
				turtle.select(currentSlot)
				turtle.placeDown()
				if direction == "forward" then
					if i < length then
						forward()
					end
				else
					if i < length then
						back()
					end
				end
			else
				print("Can't find more material")
				return
			end
		end
	end
end

-- MAIN PROGRAM

turtle.select(1)

print("fuelLevel = ", currentFuelLevel)
print("length = ", length)
print("face = ", face)

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

notFinished = true
direction = "forward"
print("wall: Setting face to local north")
setFace(0)
z = 0

while notFinished do
	if y == height then
		notFinished = false
		break
	end

	up()

	layRow(length)
	if direction == "forward" then
		direction = "backward"
	else
		direction = "forward"
	end
end

while z > 0 do
	turtle.back()
	z = z - 1
end
back()
while y > 0 do
	turtle.down()
	y = y - 1
end
print(missionMessage)
print(" Current fuel level is ", turtle.getFuelLevel())