librednet

openSides = {}

local function getPath(side)
  local periphs = {}
  for k,v in pairs(fs.list("/dev/")) do
    if v:find("ttyS") then
      local A = fs.open("/dev/"..v,"r")
	  local B = fs.open("/dev/"..v,"w")
	  B.write("getSide")
	  periphs[v] = A.readAll()
    end
  end
  for k,v in pairs(periphs) do
	if v == side then
		return "/dev/"..k
	end
  end
end

local function cap()
  modem.close(os.getComputerID())
  modem.close(65535)
  modem.open(65533)
  modem.open(65534)
  event, side, sChannel, rChannel, data, dist = os.pullEvent("modem_message")
  local table = {
      event = event,
      side = side,
      recipient = sChannel,
      sender = rChannel,
      data = data,
      distance = dist}
  modem.close(65533)
  modem.close(65534)
  modem.open(65535)
  modem.open(os.getComputerID())
  return table
end

local function send(msg, to, from)
  id = math.random(1, 800000)
  local message = {
    nMessageID = id,
    nRecipient = to,
    message = msg,
    sProtocol = nil,
  }
  modem.transmit(to, from, message)
end

function open(side)
	local periph = getPath(side)
	local file = fs.open(periph,"w")
	file.write("open",os.getComputerID())
	file.close()
	table.insert(openSides,side)
end

function close(side)
	for k,v in pairs(openSides) do
		if v == "side" then
			local path = getPath(side)
			local file = fs.open(path,"w")
			file.write("close",os.getComputerID())
			file.close()
			table.remove(openSides,k)
		end
	end
end