os.loadAPI("file")

parent = 1637
stop = false
dists = 1
is = 1
js = 1

fwd = function()
  refuel()

  turtle.digUp()

  turtle.digDown()

  while turtle.forward()==false do
    turtle.dig()
  end
end

refuel = function()
  if turtle.getFuelLevel()<20 then
    if turtle.getItemCount(16)==1 then
      send(":OOF", true)
    end

    turtle.select(16)

    if turtle.refuel(1)==false then
      send(":PF", true)
    end

    turtle.select(15)
  end

  if isfull()==true then
    empty()
  end
end

isfull = function()
  local full = true

  for i=1,14 do
    if turtle.getItemCount(i)==0 then
      full = false
    end
  end

  return full
end

empty = function()
  turtle.digDown()
  turtle.select(15)
  turtle.placeDown()
  for i=1,14 do
    turtle.select(i)
    turtle.dropDown()
  end
  turtle.select(15)
  turtle.digDown()
end

write = function(dist, i, j)
  file.write("state", {dist, i, j})
end

spiral = function()
  dist = dists

  turtle.select(15)
  if turtle.detectDown()==true then
    turtle.digDown()
  end

  while true do
    dist = dist + 1

    for i=is,2 do
      for j=js,dist do
        fwd()
        write(dist-1, i, j+1)

        if stop then
          print("Received kill message! Stopping..")
          send("stop", true)
        end
      end
      js = 1
      turtle.turnRight()
      write(dist-1, i+1, 1)
    end
    is = 1
  end
end

rednetWait = function()
  while true do
    ID, message = rednet.receive()
    if message == "stop" then
      stop = true
    else
      send(message, false)
    end
  end
end

start = function(dist, i, j)
  dists = dist
  is = i
  js = j
  stop = false

  rednet.open("right")

  send("start", false)

  parallel.waitForAny(spiral, rednetWait)
end

send = function(msg, quit)
  --0 for start signal, 1 for kill signal
  rednet.send(parent, msg)
  if quit then
    os.reboot()
  end
end