doorControl

local t = turtle
local error = 0
local pause = 0.5

function rotateBlock()
  rs.setOutput("left",true)
  sleep(0.1)
  rs.setOutput("left",false)
  os.pullEvent("redstone")
  if(not rs.getInput("left")) then
    print("Warning: wrong redstone signal received")
    local signal = false
    while not signal do
      os.pullEvent("redstone")
      signal = rs.getInput("left")
    end
    print("Warning: correct redstone signal received after wrong signal")
  end
end

function openDoor()
  t.select(2)
  if(t.getItemCount(2) > 0) then
    print("Error: ItemCount slot 2 > 0")
    error = 11
    return
  end
  rs.setOutput("top",true)
  sleep(0.05)
  rs.setOutput("top",false)
  if(t.getItemCount(2) == 0) then
    print("Error: ItemCount slot 2 == 0")
    error = 12
    return
  end
  if(not t.transferTo(3)) then
    print("Error: transfer to slot 3 failed")
    error = 13
    return
  end
  if(not t.digUp()) then
    print("Error: cannot break Block Breaker")
    error = 21
    return
  end
  t.select(1)
  if(not t.placeUp()) then
    print("Error: cannot place Auto Placer")
    error = 22
    return
  end
  if(t.getItemCount(1) < 1) then
    print("Error: less than one Auto Placer remaining")
    error = 14
    return
  end
  rotateBlock()
  t.select(3)
  if(t.getItemCount(3) < 3) then
    print("Error: less than three door blocks in slot 3")
    error = 15
    return
  end
  if(not t.dropUp(2)) then
    print("Error: cannot drop two items into Auto Placer")
    error = 31
    return
  end
  sleep(pause)
end

function closeDoor()
  t.select(3)
  local nDoorBlocks = t.getItemCount(3)
  if(nDoorBlocks < 1) then
    print("Error: less than one door block(s) in slot 3")
    error = 16
    return
  end
  if(not t.dropUp()) then
    print("Error: cannot drop items into Auto Placer")
    error = 32
    return
  end
  --wait for door to close
  sleep(pause * nDoorBlocks)
  t.select(1)
  local nPlacers = t.getItemCount(1)
  if(not t.digUp()) then
    print("Error: cannot break Auto Placer")
    error = 23
    return
  end
  if(t.getItemCount(1) ~= nPlacers + 1) then
    print("Error: inventory mix up; nPlacers = "..nPlacers)
    error = 17
    return
  end
  t.select(2)
  if(not t.placeUp()) then
    print("Error: cannot place Block Breaker")
    error = 24
    return
  end
  rotateBlock()
end

function consistencyCheck()

end

local open = false

while error == 0 do
  os.pullEvent("redstone")
  if(rs.getInput("back")) then
    if(open) then
      closeDoor()
      open = false
    else
      openDoor()
      open = true
    end
  end
end
print("error code: "..error)