Yet another simple ComputerCraft tower builder

--[[  Tower Builder

This is a code fragment to a larger future project.  The intent is to demonstrate
a problem I am having placing ladders using a ComputerCraft Turtle in FTB Ultimate 1.4.7 v 1.1.2.

This code only produces the desired results if the turtle is initially placed facing SOUTH!

As it stands this code isn't very useful at the moment.  Hopefully some day it will be usable by others.


blocks go in the first 12 slots
ladders go in 13-15
fuel in 16  - not implemented yet

]]

activeslot = 1       --  current slot for pulling building blocks from
ladderslot = 13      --  current slot for pulling ladders from
MaxBlock = 12        --  last slot to look in for building blocks
blockcount = 0       --  running total of successful plocks placed
MinFuelLevel = 10    --  Minimum initial fuel level
TowerHeight = 3      --  How high to make the tower to initial platform

startfuel = turtle.getFuelLevel()

function fillrup()
   turtle.select(16)
   if turtle.getFuelLevel() < MinFuelLevel then
      print("refueling from slot 16(",turtle.getItemCount(16) , ")")
      if turtle.getItemCount(16) < 1 then
          print("Place fuel in slot 16 and press Enter")
          read()
      end -- do we have aningthing in slot 16 to refuel with?
      turtle.refuel()   -- *****add future checks to see if we have just enough fuel to complete the job
   end -- fuel status check
end  -- fillerup

function placeLadder()
      ladderslot = 13
      if turtle.getItemCount(ladderslot) > 0 then
		turtle.select(ladderslot)
                if not turtle.placeDown(ladderslot) then
			print("I can't place the ladder \nPlease fix and hit Enter")
			read()
			end
      elseif ladderslot < 16 then -- search inventory for a block in valid slots
                while ladderslot < 16 and turtle.getItemCount(ladderslot) < 1 do
                    ladderslot = ladderslot + 1
		    turtle.select(ladderslot)
                end  -- while
                while not turtle.placeDown(ladderslot) do
			print(" can't place the ladder \nPlease fix, reload and hit Enter")
			read()
			end
      end
      if turtle.getItemCount(ladderslot) == 0 and ladderslot >= 15 then
                print("I seem to be out of ladders")
                print("Please refill slots 13-15 \nand press Enter to continue.")
                read()
      end
end -- function placeLadder

function placeBlock()
      activeslot = 1
      if turtle.getItemCount(activeslot) > 0 then
		turtle.select(activeslot)
		if turtle.place(activeslot) then blockcount = blockcount +1 end
      elseif activeslot < MaxBlock then -- search inventory for a block in valid slots
                while activeslot < MaxBlock and turtle.getItemCount(activeslot) < 1 do
                    activeslot = activeslot + 1
		    turtle.select(activeslot)
                end  -- while
                if turtle.getItemCount(activeslot) > 0 and turtle.place(activeslot) then blockcount = blockcount + 1 end
      end
      if turtle.getItemCount(activeslot) == 0 and activeslot == MaxBlock then
                print("I seem to be out of building materials")
                print("Please refill slots 1-12 \nand press Enter to continue.")
                -- os.pullEvent("key")
                read()
      end
end -- Function placeBlock


--  Future fuel check location   fuel slot = 16
fillrup()

print("Place blocks in top 3 rows of slots 1-12 \nNO sand,gravel, glass and the like\nladders in 13-15 and fuel in 16")

while (turtle.getItemCount(activeslot) < 1) and (activeslot < MaxBlock + 1) do -- skip empty slots at the begining of inventory
   activeslot = activeslot + 1
end -- while

if activeslot > MaxBlock then
   print("I can't seem to find any \nbuilding materials in slots 1-", MaxBlock)
   print("please reload turtle")
   print("press Enter to continue")
   read()
   end

while turtle.getItemCount(ladderslot) < 1 and ladderslot < 16 do -- looking for ladders
   ladderslot = ladderslot + 1
end -- while looking for ladders

if ladderslot > 15 then  -- no ladders found
    print("I seem to be out of ladders")
    print("Please refill slots 13-15 \nand press Enter to continue.")
    read()
end -- no ladders found

for j = 1, TowerHeight do -- tower height

   for i = 1,4 do  -- build walls
      if i == 3 and j < 3 then turtle.turnLeft() end  -- make the door to the tower face the user

      if j > 1 and i == 1 then
         placeLadder()
         end

      placeBlock()

     if not (i == 3 and j < 3) then turtle.turnLeft() end
     end -- build walls
   turtle.up()  -- next row
end -- tower height

placeLadder() -- finish up placing ladder sections

print("Fuel used = ", startfuel - turtle.getFuelLevel(), " Block count = ",blockcount)

print("I seem to be done.  Have a nice day:)")