View difference between Paste ID: RFBig4M1 and JDU4wJxX

 -- [ --------------------------------------------------------------------- ] --
 -- [ RedNetChat - A public chat program for ComputerCraft                  ] --
 -- [ Created by gpgautier (ign gpgauier), 2012                             ] --
 -- [ Licence: Creative Commons Attribution-ShareAlike 3.0 Unported License ] --
 -- [ ComputerCraft version: 1.3 and up                                     ] --
 -- [ Posted to:                                                            ] --
 -- [ GitHub: https://github.com/gpgautier/RedNetChat                       ] --
 -- [ Pastebin: http://pastebin.com/JDU4wJxX                                ] --
 -- [ --------------------------------------------------------------------- ] --
 
 local VERSION = "0.6"
 local MODEM = nil
 local NICKNAME = nil
 local ACTIVE = false
 local BUFFER = {}
 local POINTER = 0
 local ONLINE = {}
 local ISONLINE = false
 local ID = os.computerID()
 local LAST_MSG_TARGET = nil
 local CHANNEL = 1
 local SCROLL_POINTER = POINTER
 local WIDTH, HEIGHT = term.getSize()
 local LINES = HEIGHT - 6
 local START_LINE = 5
 local OPERATOR = "RNC"
 
 -- [ --------------------------------------------------------------------- ] --
 
 -- Split a string
 function split(str, pat)
     local t = {}  -- NOTE: use {n = 0} in Lua-5.0
     if str ~= nil then
        local fpat = "(.-)" .. pat
        local last_end = 1
        local s, e, cap = str:find(fpat, 1)
        while s do
           if s ~= 1 or cap ~= "" then
             table.insert(t,cap)
           end
           last_end = e+1
           s, e, cap = str:find(fpat, last_end)
        end
        if last_end <= #str then
           cap = str:sub(last_end)
           table.insert(t, cap)
        end
     else
         print("##ERROR failed to split ["..str.."] by:"..pat)
     end
     return t
 end
 
 -- Log a message to file
 function log(message)
   local file = io.open("rednetchat.log", "a")
   file:write("\n" .. message)
   file:close()
 end
 
 -- Application entry
 function main()
   term.clear()
   term.setCursorPos(1, 1)
 
   if not setPeripherals() then
     print("[FATAL ERROR] Not able to setup peripherals.")
     return false
   end
 
   welcome()
 end
 
 -- Set the attached peripherals. Opens rednet modem and warps monitor
 function setPeripherals()
   local i, side
 
   for i, side in pairs(rs.getSides()) do
     if peripheral.isPresent(side) then
       if peripheral.getType(side) == "modem" then
         MODEM = side
         if not rednet.isOpen(side) then
           rednet.open(MODEM)
         end
       end
     end
   end
 
   -- Exit with a fatal error when modem not found
   if MODEM == nil then
     print("[FATAL ERROR] No modem was detected. Plase attach a modem on any side.")
     return false
   end
 
   return true
 end
 
 -- Start the welcome screen
 function welcome()
   local x, y
 
   term.clear()
   writeHeader()
 
   print("")
   print("")
   print("Enter a nickname and press [enter].")
   print("")
   term.write("Nickname: ")
 
   x, y = term.getCursorPos()
 
   while NICKNAME == nil or NICKNAME == "" do
     term.setCursorPos(x, y)
     NICKNAME = read()
     execute("/online")
     appendBuffer("[" .. OPERATOR .. "]: Type /help for a list of commands")
   end
 
   start()
 end
 
 -- Writes the screen header
 function writeHeader()
   local col
 
   term.setCursorPos(1, 1)
   term.write("RedNet Chat " .. VERSION .. "")
   term.setCursorPos(1, 2)
 
   for col = 1, WIDTH do
     term.write("-")
   end
 end
 
 -- Writes the list of online users
 function writeOnlineList()
   local i, v, count, x, y, col
 
   count = 0
 
   x, y = term.getCursorPos()
 
   term.setCursorPos(1, HEIGHT - 1)
 
   for col = 1, WIDTH do
     term.write("-")
   end
 
   term.setCursorPos(1, HEIGHT)
   term.clearLine()
   term.write("Online: ")
 
   for i, v in pairs(ONLINE) do
     if count == 0 then
       term.write(i)
     else
       term.write(", " .. i)
     end
 
     count = count + 1
   end
 
   if count == 0 then
     term.write("Nobody online in channel " .. CHANNEL)
   end
 
   term.setCursorPos(x, y)
 end
 
 -- Start the chat
 function start()
   term.clear()
   writeHeader()
   writeOnlineList()
 
   ACTIVE = true
 
   showBuffer()
 
   parallel.waitForAll(input, watchEvents)
 end
 
 -- Stop the application
 function stop()
   ACTIVE = false
 end
 
 -- Reset the application
 function reset()
   execute("/offline")
 
   if rednet.isOpen(MODEM) then
     rednet.close(MODEM)
   end
 
   sleep(1.5)
   os.reboot()
 end
 
 -- Watch all input to provide possible shortcuts (for example usernames)
 function watchEvents()
   local type, param, param2, param3, i, v
 
   while ACTIVE do
     type, param, param2, param3 = os.pullEvent()
 
     if type == "key" then
       if param == 200 then -- up
         scroll(-1)
       elseif param == 208 then -- down
         scroll(1)
       elseif param == 201 then -- pageup
         scroll(-12)
       elseif param == 209 then -- pagedown
         scroll(12)
       --else
       --  appendBuffer(tostring(param))
       end
     elseif type == "mouse_scroll" then
       if param == -1 then
         scroll(-1)
       else
         scroll(1)
       end
     elseif type == "rednet_message" then
       receive(param2)
     end
   end
 end
 
 -- Scroll through the chat
 function scroll(amount)
   SCROLL_POINTER = SCROLL_POINTER + amount
   showBuffer()
 end
 
 -- Handle input from the prompt
 function input()
   local message, col
 
   term.setCursorPos(1, 4)
 
   for col = 1, WIDTH do
     term.write("-")
   end
 
   while ACTIVE do
     term.setCursorPos(1, 3)
     term.clearLine()
     term.write("[" .. CHANNEL .. "] > ")
 
     message = read()
 
     if message ~= nil and message ~= "" then
       execute(message, "local")
     end
   end
 end
 
 -- Send a message
 function send(message, target)
   local request, serialized, x, encrypted
 
   request = {protocol = "rnc", nickname = NICKNAME, sender = ID, target = target, channel = CHANNEL, message = message}
   serialized = textutils.serialize(request)
 
   encrypted = ""
   for x = 1, #serialized do
     encrypted = encrypted .. string.char(serialized:byte(x) + 1)
   end
 
   if request.target ~= nil then
     rednet.send(request.target, encrypted)
   else
     rednet.broadcast(encrypted)
   end
 end
 
 -- Recieve a message
 function receive(message)
   local request, decrypted, x
 
   if message ~= nil and message ~= "" then
 
     decrypted = ""
     for x = 1, #message do
       decrypted = decrypted .. string.char(message:byte(x) - 1)
     end
 
     request = textutils.unserialize(decrypted)
 
     if request.protocol == "rnc" and request.channel == CHANNEL then
       if request.nickname ~= nil and request.nickname ~= "" then
         execute(request, "remote")
       end
     end
   end
 end
 
 -- Execute a command or add a chat message
 function execute(message, source)
   local command, splitCommand, nickname, id, body, onlineUser
 
   if message.nickname ~= nil then
     executeRemote(message)
     return
   end
 
   if message:sub(0, 1) == "/" then
       command = message:sub(2)
 
       if command == "quit"
           or command == "reset"
           or command == "restart"
           or command == "reboot"
           or command == "stop"
         then
           appendBuffer("[" .. OPERATOR .. "]: Stopping application")
           reset()
       elseif command == "online" then
         if not ISONLINE then
           send("/online")
           putOnline()
           appendBuffer("[" .. OPERATOR .. "]: You are now online")
           ISONLINE = true
         else
           appendBuffer("[" .. OPERATOR .. "]: You are already online")
         end
       elseif command == "offline" then
         if ISONLINE then
           send("/offline")
           takeOffline()
           appendBuffer("[" .. OPERATOR .. "]: You are now offline")
           ISONLINE = false
         else
           appendBuffer("[" .. OPERATOR .. "]: You are already offline")
         end
       elseif command:sub(0, 5) == "nick " then
         takeOffline()
         NICKNAME = command:sub(6)
         putOnline()
         appendBuffer("[" .. OPERATOR .. "]: Your nickname has been changed")
       elseif command:sub(0, 5) == "slap " then
         appendBuffer(command:sub(6) .. " was slapped by " .. NICKNAME)
       elseif command:sub(0, 4) == "msg " then
         splitCommand = split(command:sub(5), "%s")
 
         onlineUser = false
 
         for nickname, id in pairs(ONLINE) do
           if nickname == splitCommand[1] then
             body = command:sub(5 + splitCommand[1]:len() + 1)
             send(body, id)
             appendBuffer(NICKNAME .. " > " .. nickname .. ": " .. body)
             onlineUser = true
             LAST_MSG_TARGET = nickname
           end
         end
 
         if not onlineUser then
             appendBuffer("[" .. OPERATOR .. "]: User " .. splitCommand[1] .. " is not online")
         end
       elseif command:sub(0, 2) == "r " then
         if LAST_MSG_TARGET ~= nil then
           execute("/msg " .. LAST_MSG_TARGET .. " " .. command:sub(3), "local")
         else
           appendBuffer("[" .. OPERATOR .. "]: No valid user for message")
         end
       elseif command:sub(0, 5) == "join " then
         if CHANNEL ~= tonumber(command:sub(6)) then
           execute("/offline")
           CHANNEL = tonumber(command:sub(6))
           execute("/online")
           appendBuffer("[" .. OPERATOR .. "]: Joined channel " .. CHANNEL)
         else
           appendBuffer("[" .. OPERATOR .. "]: Already in channel " .. CHANNEL)
         end
       elseif command == "help" then
         appendBuffer("[" .. OPERATOR .. "] Commands:")
         appendBuffer("/quit : Exit the chat")
         appendBuffer("/msg <nickname> <message> : Send a private message")
         appendBuffer("/r <message> : Reply to a private message")
         appendBuffer("/join <channel> : Switch channel")
       else
         appendBuffer("[" .. OPERATOR .. "]: Unknown command")
       end
 
       return
   end
 
   appendBuffer(NICKNAME .. ": " .. message)
   send(message)
 end
 
 --
 function putOnline(nickname, id)
   if nickname == nil or id == nil then
     nickname = NICKNAME
     id = ID
   end
 
   ONLINE[nickname] = id
 
   writeOnlineList()
 end
 
 --
 function takeOffline(nickname, id)
   if nickname == nil or id == nil then
     nickname = NICKNAME
     id = ID
   end
 
   ONLINE[nickname] = nil
 
   writeOnlineList()
 end
 
 --
 function executeRemote(request)
   local command
 
   if request.message:sub(0, 1) == "/" then
     command = request.message:sub(2)
 
     if command == "online" then
       putOnline(request.nickname, request.sender)
       appendBuffer("[" .. OPERATOR .. "]: " .. request.nickname .. " is now online")
       send("/metoo")
     elseif command == "offline" then
       takeOffline(request.nickname, request.sender)
       appendBuffer("[" .. OPERATOR .. "]: " .. request.nickname .. " is now offline")
     elseif command == "metoo" then
       putOnline(request.nickname, request.sender)
     end
     return
   end
 
   if request.target ~= nil then
     appendBuffer(request.nickname .. " > " .. NICKNAME .. ": " .. request.message)
     LAST_MSG_TARGET = request.nickname
   else
     appendBuffer(request.nickname .. ": " .. request.message)
   end
 end
 
 --
 function appendBuffer(message)
   local length
 
   length = message:len()
 
   if length > WIDTH then
     table.insert(BUFFER, message:sub(1, WIDTH))
     POINTER = POINTER + 1
     appendBuffer(message:sub(WIDTH + 1))
   else
     table.insert(BUFFER, message)
     POINTER = POINTER + 1
   end
 
   SCROLL_POINTER = POINTER
 
   showBuffer()
 end
 
 --
 function showBuffer()
   local i, line, bufferPointer, x, y, pointer
 
   pointer = SCROLL_POINTER
 
   if pointer == 0 then
     return
   elseif SCROLL_POINTER > POINTER then
     SCROLL_POINTER = POINTER
     pointer = POINTER
   elseif POINTER < LINES + 1 then
     SCROLL_POINTER = POINTER
     pointer = POINTER
   elseif POINTER > LINES and SCROLL_POINTER < LINES then
     SCROLL_POINTER = LINES
     pointer = SCROLL_POINTER
   end
 
   x, y = term.getCursorPos()
 
   line = START_LINE
 
   bufferPointer = -(LINES - 1 - pointer)
 
   for i = bufferPointer, bufferPointer + (LINES - 1) do
     term.setCursorPos(1, line)
     term.clearLine()
 
     if BUFFER[i] ~= nil then
       term.write(tostring(BUFFER[i]))
     end
 
     line = line + 1
   end
 
   term.setCursorPos(x, y)
 end
 
 -- Fire up the application
 main()