Apnet

os.loadAPI("Queue")

function GetComputerDetails()
 local details = {}
 details.ComputerId = _id
 details.ComputerLabel = _label
 details.ComputerType = _type
 return details
end

function GetNextInboundMessage()
 return Queue.Dequeue(_queue)
end

function Initialize(type, doForwarding)
 Apnet.MSG_TYPE_SYSTEM = "system"
 Apnet.MSG_TYPE_APPLICATION = "application"
 Apnet.MSG_SUBTYPE_ABORT = "abort"
 Apnet.MSG_SUBTYPE_PING_REQUEST = "ping"
 Apnet.MSG_SUBTYPE_PING_RESPONSE = "pingresponse"

 math.randomseed(os.time() * 1000)
 _id = os.getComputerID()
 _label = os.getComputerLabel()
 _type = type
 _doForwarding = doForwarding
 readConfig()
 initModems()
 _queue = Queue.New()
end

function Listen()
 local _seen = {}

 Apnet.Kill = false
 while (Apnet.Kill ~= true) do
  local id, rawMessage, dist = rednet.receive()
  local message = textutils.unserialize(rawMessage)
  if (message.Network == _network and _seen[message.Id] ~= "true" and message.Route[1].ComputerId ~= _id) then
   _seen[message.Id] = "true"
   if (_doForwarding == "true") then
    Send(message)
   end
   if (isMatchingDestination(message)) then
    if (message.MessageType == Apnet.MSG_TYPE_SYSTEM) then
     handleSystemMessage(message)
    elseif (message.MessageType == Apnet.MSG_TYPE_APPLICATION) then
     Queue.Enqueue(_queue, message)
    else
     print("Unknown message type")
    end
   end
  end
 end
end

function NewMessage()
 local message = {}
 message.Network = _network
 message.Id = generateMessageId()
 message.RouteLength = 0
 message.Route = {}
 message.Destination = getDefaultDestination()
 return message
end

function Reply(originalMsg, msg)
 msg.OriginalMessage = originalMsg
 msg.Destination.ComputerId = originalMsg.Route[1].ComputerId
 Send(msg)
end

function Send(msg)
 addToRoute(msg)
 rednet.broadcast(textutils.serialize(msg))
 msg.Route[msg.RouteLength] = nil
 msg.RouteLength = msg.RouteLength - 1
end

function addToRoute(msg)
 msg.RouteLength = msg.RouteLength + 1
 msg.Route[msg.RouteLength] = GetComputerDetails()
end

function generateMessageId()
 local id = ""
 id = id .. os.day() .. "_"
 id = id .. os.time() * 1000 .. "_"
 id = id .. _id .. "_"
 id = id .. math.random(1000)
 return id
end

function getDefaultDestination()
 local destination = {}
 destination.ComputerId = "*"
 destination.ComputerLabel = "*"
 destination.ComputerType = "*"
 return destination
end

function handleSystemMessage(msg)
 if (msg.MessageSubType == Apnet.MSG_SUBTYPE_ABORT) then
  Apnet.Kill = true
 elseif (msg.MessageSubType == Apnet.MSG_SUBTYPE_PING_REQUEST) then
  local response = NewMessage()
  response.MessageType = Apnet.MSG_TYPE_SYSTEM
  response.MessageSubType = Apnet.MSG_SUBTYPE_PING_RESPONSE
  Reply(msg, response)
 elseif (msg.MessageSubType == Apnet.MSG_SUBTYPE_PING_RESPONSE) then
  print("Ping Response received")
  print("Ping Request ID:" .. msg.OriginalMessage.Id)
  print("Ping Request Route:" .. textutils.serialize(msg.OriginalMessage.Route))
  print("Ping Response ID:" .. msg.Id)
  print("Ping Response Route:" .. textutils.serialize(msg.Route))
  print("End of ping details")
 end
end

function initModem(side)
 if (peripheral.getType(side) == "modem") then
  rednet.open(side)
 end
end

function initModems()
 initModem("left")
 initModem("right")
 initModem("front")
 initModem("back")
 initModem("bottom")
 initModem("top")
end

function isMatchingDestination(msg)
 local dest = msg.Destination
 if (dest.ComputerId ~= "*" and dest.ComputerId ~= _id) then
  return false
 elseif (dest.ComputerLabel ~= "*" and dest.ComputerLabel ~= _label) then
  return false
 elseif (dest.ComputerType ~= "*" and dest.ComputerType ~= _type) then
  return false
 else
  return true
 end
end

function readConfig()
 local configHandle = fs.open("Apnet.config", "r")
 _network = configHandle.readLine()
 configHandle.close()
end