netlib

-- SharpNet library v1 --

protocols = {INTERNET_REQUEST = "internet1.request", INTERNET_RESPONSE = "internet1.response"}

function getModem()
  local modemside = nil
  for n,side in ipairs(rs.getSides()) do
    if(peripheral.getType(side) == "modem") then
      modemside = side
      break
    end
  end
  return modemside
end

function waitForProtocol(proto, pings)
  while true do
    id, msg, prot = rednet.receive()
    print("Recieved message from " .. id .. " with protocol '" .. prot .. "'")
    if(prot == proto) then
      return {senderID = id, message = msg, protocol = prot}
    elseif(prot == "ping" and pings == true) then
      print("Returning ping to " .. id)
      rednet.send(id, message, "ping")
    end
  end
end

function ping(server, time)
  modem = getModem()
  if(modem ~= nil) then
    rednet.open(modem)

    packet = math.random(1000)

    rednet.send(server, packet, "ping")

    obj = waitForProtocol("ping")
    if(obj["senderID"] ~= server) then
      print("Recieved senderID differs from server")
      print("Sent to: " .. server .. "; recieved: '" .. obj["senderID"] .. "'")
    else
      print("Recieved ping from " .. obj["senderID"])
    end
  else
    print("Could not find modem")
  end
end