[CC API][1.1] Protocol Manager

--[[
Coded By HPWebcamAble

==== Description ====
This is my protocol API

It allows you to assign functions to messages
When a message is received, the function  will be run (With any arguments provided)
See the CC Forum Post in 'Documentation' for a quick start guide


==== Documentation ====
Computer Craft Forum Post:
http://www.computercraft.info/forums2/index.php?/topic/22510-protocol-manager/

Below 'Update History' is a description of all the functions and how to use them


==== Installation and Use ====
Pastebin Code:Not on pb yet

This won't do anything on its own. You use this to help write your programs

You have two options:
1. Copy and paste the functions into your program and call them like you would normally call a function
2. In your program, call os.loadAPI("filename"), then call functions with filename.functionName()


==== Update History ====
The pastebin will always have the latest version

|1.2|  <--This program
  -Fixed small bug in nAssert function

|1.1|
  -waitForMessage stops when a function is called

|1.0|
  -Release


==== Functions and How to Use Them ====

WARNING! This API doesn't interact with channels
You need to open the channels you want to use yourself!

new
  Creates a new protocol set
  name: A string to help distinguish the messages from other programs. protocols are stored by the name
  protocolVersion: When you change how the program deals with messages, increment this number to tell the clients/servers that it is a different version
  setDefault: Pass true to make this the defualt protocol, most functions use the defualt if you don't specify a protocol

addMessage
  Adds a message and function to the protocol set
  msg: The message to look for
  func: The function to run if the message is received
  protocol: The name of the protocol to add to (Will use the default if not specified)

waitForMessage
  WARNING! OPEN CHANNELS FIRST! This function doesn't open channels
  Waits for an event, if it is modem_message, it checks to see if it was a message from the protocol, and runs the function
  with the arguments (sender ID, distance, arguments from message). Stops when a message is received
  protocol: Which protocol's messages to look for (Will use the default if not specified)
  timeout: How long to wait, in seconds. Leave nil to wait forever
  useRaw: If true, uses os.pullEventRaw

sendMessage
  Sends a message
  modem: Pass the value the is returned by 'peripheral.wrap(side)'
  channel: The channel to send the message on. Only computers with this channel open can receive it
  protocol: The name of the protocol that will be receiving the message (Will use the default if not specified)
  msg: The message to send
  ...: Any number of arguments, which will be sent as well

==== Examples ====

An example function that you might add for a message

function addUser(id,distance,name)
  users[name] = id
end
(Assume users is a table already)

==== Program ====
]]--

--Variables--
local protocolSets = {}
local default

--Functions--
--Like assert, but takes a third arguemnt, used by the API
local function nAssert(toTest,err,lvl)
  lvl = lvl or 1
  if not toTest then
    error(err,lvl+1)
  end
end

function new(name,protocolVersion,setDefault)
  nAssert(type(protocolVersion)=="number" and name,"expected string,number got "..type(name)..","..type(protocolVersion),2)
  nAssert(not protocolSets[name],"The protocol "..name.." already exists",2)
  protocolSets[name] = {
    functions = {},
    version = protocolVersion
  }
  if setDefault then default = name end
end

function addMessage(msg,func,protocol)
  protocol = protocol or default
  nAssert(protocolSets[protocol],"protocol doesn't exist",2)
  nAssert(type(msg)=="string" and type(func)=="function","expected string,function, got "..type(msg)..","..type(func),2)
  protocolSets[protocol][msg] = func
end

function sendMessage(modem,channel,protocol,msg,...)
  protocol = protocol or default
  nAssert(protocolSets[protocol],"protocol doesn't exist",2)
  channel = tonumber(channel)
  nAssert(channel and msg,"expected modem(table),number,string, got "..type(modem)..","..type(channel)..","..type(msg),2)
  modem.transmit(channel,os.getComputerID(),{protocol,protocolSets[protocol].version,msg,{...}})
end

function waitForMessage(protocol,timeout,useRaw)
  protocol = protocol or default
  timeout = tonumber(timeout)
  nAssert(protocolSets[protocol],"protocol doesn't exist",2)
  local pull = useRaw and os.pullEventRaw or os.pullEvent
  if timeout then local timer = os.startTimer(timeout) end
  while true do
    local eArgs = {pull()}
    if eArgs[1] == "modem_message" then
      if type(eArgs[5]) == "table" and eArgs[5][1] == protocol and eArgs[5][2] == protocolSets[protocol].version then
        if protocolSets[protocol][eArgs[5][3]] then
          protocolSets[protocol][eArgs[5][3]](eArgs[4],eArgs[6],unpack(eArgs[5][4]))
          return true
        end
      end
    elseif eArgs[1] == "timer" and eArgs[2] == timer then
      return false
    end
  end
  return false
end