RedNet Chat

-- [ --------------------------------------------------------------------- ] --
-- [ RedNetChat                                                           ] --
-- [ A public chat client for ComputerCraft                                ] --
-- [ Created by GPG Incorporated.                                          ] --
-- [ --------------------------------------------------------------------- ] --

-- [ --------------------------------------------------------------------- ] --

local VERSION = "0.3 beta"
local MODEM = nil
local MONITOR = nil
local NICKNAME = nil
local ACTIVE = false
local BUFFER = {}
local POINTER = 0
local ONLINE = {}
local ISONLINE = false

-- [ --------------------------------------------------------------------- ] --

-- Application entry
function main()
  term.clear()
  term.setCursorPos(1, 1)
  print("Starting RedNetChat " .. VERSION)

  --sleep(0.5)

  if not setPeripherals() then
    return false
  end

  print("")
  print("")
  print("Peripherals are setup.")
  print("")
  term.write("Starting application")

  --simulateLoading(8)

  if MONITOR ~= nil then
    MONITOR.clear()
    MONITOR.setTextScale(1.5)
    MONITOR.setCursorPos(1, 2)
    MONITOR.write("        RedNet Chat")
    MONITOR.setCursorPos(1, 4)
    MONITOR.write("   Chatception in Tekkit")
  end

  welcome()
end

-- Simulate a loading effect
function simulateLoading(amount)
  local i

  sleep(0.2)
  term.write(" ")
  for i = 0, amount do
    term.write(".")
    sleep(0.2)
  end
  term.write " Done"
end

-- Set the attached peripherals. Opens rednet modem and warps monitor
function setPeripherals()
  local i, side

  for i, side in pairs(redstone.getSides()) do
    if peripheral.isPresent(side) then
      if peripheral.getType(side) == "modem" then
        MODEM = side
        print("")
        term.write("Opening modem on " .. side)
        rednet.open(MODEM)
        --simulateLoading(6)
      elseif peripheral.getType(side) == "monitor" then
        print("")
        term.write("Wrapping monitor on " .. side)
        MONITOR = peripheral.wrap(side)
        --simulateLoading(4)
      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("[RedNet Chat]: Type /help for a list of commands")
  end

  start()
end

-- Writes the screen header
function writeHeader()
  term.setCursorPos(1, 1)
  term.write("RedNet Chat " .. VERSION .. "           by GPG Incorporated")
  term.setCursorPos(1, 2)
  term.write("--------------------------------------------------")
end

-- Writes the list of online users
function writeOnlineList()
  local i, v, count, x, y

  count = 0

  x, y = term.getCursorPos()

  term.setCursorPos(1, 17)
  term.write("--------------------------------------------------")
  term.setCursorPos(1, 18)
  term.clearLine()
  term.write("Online: ")

  for i, v in ipairs(ONLINE) do
    if i == 1 then
      term.write(ONLINE[i])
    else
      term.write(", " .. ONLINE[i])
    end

    count = count + 1
  end

  if count == 0 then
    term.write("There is nobody online at this moment")
  end

  term.setCursorPos(x, y)
end

-- Start the chat
function start()
  term.clear()
  writeHeader()
  writeOnlineList()

  ACTIVE = true

  showBuffer()

  parallel.waitForAll(input, watchEvents, receive)
end

-- Stop the application
function stop()
  ACTIVE = false
end

-- Reset the application
function reset()
  execute("/offline")
  rednet.close(MODEM)
  sleep(2)
  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()
  end
end

-- Handle input from the prompt
function input()
  local message

  term.setCursorPos(1, 4)
  term.write("--------------------------------------------------")

  while ACTIVE do
    term.setCursorPos(1, 3)
    term.clearLine()
    term.write("Send > ")

    message = read()

    if message ~= nil and message ~= "" then
      execute(message, "local")
    end
  end
end

-- Send a message
function send(message)
  local request = {protocol = "rnc", nickname = NICKNAME, message = message}
  rednet.broadcast(textutils.serialize(request))
end

-- Recieve a message
function receive()
  local sender, message, distance, request

  while ACTIVE do
    sender, message, distance = rednet.receive(1)

    if message ~= nil and message ~= "" then
      request = textutils.unserialize(message)
      if request.protocol == "rnc" then
        if request.nickname ~= nil and request.nickname ~= "" then
          execute(request, "remote")
        end
      end
    end
  end
end

-- Execute a command or add a chat message
function execute(message, source)
  local command

  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("[RedNet Chat]: Restarting application")
          reset()
      elseif command == "online" then
        if not ISONLINE then
          send("/online")
          putOnline()
          appendBuffer("[RedNet Chat]: You are now online")
          ISONLINE = true
        else
          appendBuffer("[RedNet Chat]: You are already online")
        end
      elseif command == "offline" then
        if ISONLINE then
          send("/offline")
          takeOffline()
          appendBuffer("[RedNet Chat]: You are now offline")
          ISONLINE = false
        else
          appendBuffer("[RedNet Chat]: You are already offline")
        end
      elseif command:sub(0, 5) == "nick " then
        takeOffline()
        NICKNAME = command:sub(6)
        putOnline()
        appendBuffer("[RedNet Chat]: Your nickname has been changed")
      elseif command:sub(0, 5) == "slap " then
        appendBuffer(command:sub(6) .. " was slapped by " .. NICKNAME)
      elseif command == "help" then
        appendBuffer("[RedNet Chat] Commands:")
        appendBuffer("/quit : Exit the chat")
      end

      return
  end

  appendBuffer(NICKNAME .. ": " .. message)
  send(message)
end

--
function putOnline(nickname)
  local i, v, exists

  if nickname == nil then
    nickname = NICKNAME
  end

  for i, v in ipairs(ONLINE) do
    if ONLINE[i] == nickname then
      exists = true
    end
  end

  if not exists then
    table.insert(ONLINE, nickname)
  end

  writeOnlineList()
end

--
function takeOffline(nickname)
  local i, v

  if nickname == nil then
    nickname = NICKNAME
  end

  for i, v in ipairs(ONLINE) do
    if ONLINE[i] == nickname then
      table.remove(ONLINE, i)
    end
  end

  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)
      appendBuffer("[RedNet Chat]: " .. request.nickname .. " is now online")
      send("/metoo")
    elseif command == "offline" then
      takeOffline(request.nickname)
      appendBuffer("[RedNet Chat]: " .. request.nickname .. " is now offline")
    elseif command == "metoo" then
      putOnline(request.nickname)
    end
    return
  end

  appendBuffer(request.nickname .. ": " .. request.message)
end

--
function appendBuffer(message)
  local length

  length = message:len()

  if length > 50 then
    table.insert(BUFFER, message:sub(1, 50))
    POINTER = POINTER + 1
    appendBuffer(message:sub(51))
  else
    table.insert(BUFFER, message)
    POINTER = POINTER + 1
  end

  showBuffer()
end

--
function showBuffer()
  local i, line, bufferPointer, x, y

  if POINTER == 0 then
    return
  end

  x, y = term.getCursorPos()

  line = 5

  bufferPointer = -(11 - POINTER)

  for i = bufferPointer, bufferPointer + 11 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
--welcome()
main()