OC-DALNET: DALNET For OpenComputers

local component = require("component")
local term = require("term")
local event = require("event")
local keyboard = require("keyboard")
local filesystem = require("filesystem")
local computer = require("computer")

if not component.isAvailable("internet") then
  io.stderr:write("This program requires an Internet Card to function.\n")
  return
end

local gpu = component.gpu
local internet = component.internet

local function getGPUTier()
  local w, h = gpu.maxResolution()
  if w == 50 and h == 16 then return 1
  elseif w == 80 and h == 25 then return 2
  else return 3 end
end

local isColorSupported = false
if gpu and gpu.maxDepth then
    isColorSupported = gpu.maxDepth() > 1
end

local servers = {
  {address = "atw.hu.eu.dal.net", port = 6667},
  {address = "bifrost.ca.us.dal.net", port = 6667},
  {address = "bitcoin.uk.eu.dal.net", port = 6667},
  {address = "choopa.nj.us.dal.net", port = 6667},
  {address = "halcyon.il.us.dal.net", port = 6667},
  {address = "istana.il.us.dal.net", port = 6667},
  {address = "lair.nl.eu.dal.net", port = 6667},
  {address = "lion.tx.us.dal.net", port = 6667},
  {address = "punch.wa.us.dal.net", port = 6667},
  {address = "sakura.jp.as.dal.net", port = 6667},
  {address = "serenity.fl.us.dal.net", port = 6667},
  {address = "nonstop.ix.me.dal.net", port = 6667},
}

local selectedServerIndex = 1
local username = "User"
local socket = nil
local currentChannel = nil

local messageBuffer = {}
local currentBufferIndex = 1

local function saveUsername()
  local file = io.open("/home/dalnet_username.txt", "w")
  if file then
    file:write(username)
    file:close()
  end
end

local function loadUsername()
  local file = io.open("/home/dalnet_username.txt", "r")
  if file then
    username = file:read("*all"):gsub("%s+", "")
    file:close()
  end
end

loadUsername()

local function drawLogo()
  if getGPUTier() == 1 then return end

  local logo = {
    " ________  ________          ________  ________  ___       ________   _______  _________   ",
    "|\\   __  \\|\\   ____\\        |\\   ___ \\|\\   __  \\|\\  \\     |\\   ___  \\|\\  ___ \\|\\___   ___\\ ",
    "\\ \\  \\|\\  \\ \\  \\___|        \\ \\  \\_|\\ \\ \\  \\|\\  \\ \\  \\    \\ \\  \\\\ \\  \\ \\  \\_/__\\|___ \\  \\_| ",
    " \\ \\  \\\\\\  \\ \\  \\            \\ \\  \\ \\\\ \\ \\  __  \\ \\  \\    \\ \\  \\\\ \\  \\ \\  \\_|/__    \\ \\  \\  ",
    "  \\ \\  \\\\\\  \\ \\  \\____        \\ \\  \\_\\\\ \\ \\  \\ \\  \\ \\  \\____\\ \\  \\\\ \\  \\ \\  \\_|\\ \\   \\ \\  \\ ",
    "   \\ \\_______\\ \\_______\\        \\ \\_______\\ \\__\\ \\__\\ \\_______\\ \\__\\\\ \\__\\ \\_______\\   \\ \\__\\",
    "    \\|_______|\\|_______|         \\|_______|\\|__|\\|__|\\|_______|\\|__| \\|__|\\|_______|    \\|__|"
  }

  local width, height = gpu.getResolution()
  local startY = height - #logo - 1

  for i, line in ipairs(logo) do
    gpu.set(1, startY + i, line)
  end
end

local function drawServerList()
  local oldForeground = gpu.getForeground()
  local oldBackground = gpu.getBackground()

  gpu.setBackground(0x000000)
  term.clear()

  for i, server in ipairs(servers) do
    if i == selectedServerIndex then
      if getGPUTier() == 1 then
        gpu.set(1, i, "-> " .. string.format("%d. %s:%d", i, server.address, server.port))
      else
        gpu.setForeground(0x00FF00)
        gpu.set(1, i, string.format("%d. %s:%d", i, server.address, server.port))
        gpu.setForeground(0xFFFFFF)
      end
    else
      gpu.set(1, i, string.format("%d. %s:%d", i, server.address, server.port))
    end
  end

  gpu.setForeground(0xFFFFFF)
  gpu.set(1, #servers + 2, "Press N to change username. Current username: " .. username)
  gpu.set(1, #servers + 3, "Use arrow keys to navigate, Enter to connect, X to exit")

  drawLogo()

  gpu.setForeground(oldForeground)
  gpu.setBackground(oldBackground)
end

local function changeNickname()
  term.write("\nEnter new nickname: ")
  local newNick = term.read()
  if not newNick then return username end
  newNick = newNick:gsub("[\r\n%s]", "")
  if socket and #newNick > 0 then
    socket.write("NICK " .. newNick .. "\r\n")
  end
  if #newNick > 0 then
    username = newNick
    saveUsername()
  end
  return username
end

-- Strips IRC color formatting codes, bold, underline, and annoying ASCII control characters
local function cleanIRCFormatting(str)
  if not str then return "" end
  -- 1. Strip color codes: \x03 followed by up to 2 digits, optionally a comma and up to 2 more digits
  str = str:gsub("\x03%d?%d?,?%d?%d?", "")
  -- 2. Strip other formatting bytes: \x02 (bold), \x1F (underline), \x16 (reverse video), \x0F (reset)
  str = str:gsub("[\x02\x1F\x16\x0F]", "")
  -- 3. Strip remaining structural low ASCII control chars (except standard space)
  str = str:gsub("[\x01-\x1F\x7F]", "")
  return str
end

local function addMessage(message)
  table.insert(messageBuffer, cleanIRCFormatting(message))
  if #messageBuffer > 150 then
    table.remove(messageBuffer, 1)
  end
  currentBufferIndex = #messageBuffer
end

local function displayBuffer()
  term.clear()
  local w, h = gpu.getResolution()
  local viewHeight = h - 2

  local startIndex = math.max(1, currentBufferIndex - viewHeight + 1)
  local endIndex = math.min(#messageBuffer, startIndex + viewHeight - 1)

  local row = 1
  for i = startIndex, endIndex do
    gpu.set(1, row, messageBuffer[i] or "")
    row = row + 1
  end

  local status = string.format("[Channel: %s] [Ctrl: Chat | Alt: Cmd] ", currentChannel or "None")
  gpu.set(1, h - 1, string.rep("-", w))
  gpu.set(1, h, status)
end

local networkBuffer = ""
local function parseIncomingNetwork()
  if not socket then return nil end

  local success, chunk = pcall(socket.read, 2048)
  if not success or not chunk or #chunk == 0 then return nil end

  networkBuffer = networkBuffer .. chunk
  local lines = {}
  while networkBuffer:find("\r\n") do
    local line, rest = networkBuffer:match("^([^\r\n]*)\r\n(.*)$")
    table.insert(lines, line)
    networkBuffer = rest
  end
  return lines
end

local function connectToServer(server)
  term.clear()
  addMessage("Connecting to " .. server.address .. " as " .. username)
  displayBuffer()

  socket = internet.connect(server.address, server.port)
  if not socket then
    addMessage("Failed to initialize connection to " .. server.address)
    displayBuffer()
    return nil
  end

  local timeout = 10
  local start = computer.uptime()
  while not socket.finishConnect() do
    if computer.uptime() - start > timeout then
      addMessage("Connection timed out.")
      displayBuffer()
      socket.close()
      socket = nil
      return nil
    end
    os.sleep(0.1)
  end

  socket.write("NICK " .. username .. "\r\n")
  socket.write("USER " .. username .. " 0 * :" .. username .. "\r\n")

  local connected = false
  timeout = 20
  start = computer.uptime()

  while computer.uptime() - start < timeout do
    local lines = parseIncomingNetwork()
    if lines then
      for _, line in ipairs(lines) do
        addMessage(line)
        if line:find(" 433 ") then
          addMessage("Nickname is already in use!")
          displayBuffer()
          username = changeNickname()
          socket.write("NICK " .. username .. "\r\n")
        elseif line:find(" 001 ") then
          addMessage("Successfully connected to " .. server.address)
          connected = true
          break
        end
      end
      displayBuffer()
    end
    if connected then break end
    os.sleep(0.1)
  end

  if not connected then
    addMessage("Connection failed/Rejected.")
    displayBuffer()
    if socket then socket.close() end
    socket = nil
    return nil
  end

  return socket
end

local function disconnectFromServer()
  if socket then
    socket.write("QUIT :Disconnecting\r\n")
    socket.close()
    socket = nil
    currentChannel = nil
    addMessage("Disconnected from server.")
    displayBuffer()
    return true
  end
  return false
end

local function exitChannel()
  if currentChannel then
    socket.write("PART " .. currentChannel .. " :Leaving\r\n")
    addMessage("Left channel: " .. currentChannel)
    currentChannel = nil
    displayBuffer()
    return true
  end
  return false
end

local function showHelp()
  addMessage("Available commands:")
  addMessage(":helpoc          - Show this help message")
  addMessage("join #channel    - Join an IRC channel")
  addMessage("exit             - Leave the current channel")
  addMessage("disconnect       - Disconnect from the server")
  displayBuffer()
end

local function handleUserInput(isCommand)
  local w, h = gpu.getResolution()
  gpu.set(1, h, string.rep(" ", w))
  gpu.set(1, h, isCommand and "Command> " or "Chat> ")

  local input = term.read()
  if input then
    input = input:gsub("[\r\n]", "")
    if #input == 0 then displayBuffer() return false end

    if isCommand then
      local joinMatch = input:match("^join%s+(#%S+)") or input:match("^connect%s+(#%S+)")
      if joinMatch then
        currentChannel = joinMatch
        socket.write("JOIN " .. currentChannel .. "\r\n")
      elseif input == "disconnect" then
        return disconnectFromServer()
      elseif input == "exit" then
        return exitChannel()
      elseif input == ":helpoc" then
        showHelp()
      else
        socket.write(input .. "\r\n")
      end
    else
      if currentChannel then
        socket.write("PRIVMSG " .. currentChannel .. " :" .. input .. "\r\n")
        addMessage("<" .. username .. "> " .. input)
      else
        addMessage("Not in a channel. Tap Alt and type: join #channel")
      end
    end
    displayBuffer()
  end
  return false
end

local function handleServerCommunication()
  addMessage("Connected! Tap L/R Ctrl to type messages, Tap L/R Alt for commands.")
  displayBuffer()

  while socket do
    local lines = parseIncomingNetwork()
    if lines then
      for _, line in ipairs(lines) do
        if line:find("^PING") then
          local pingId = line:match("PING :?(.*)")
          socket.write("PONG :" .. pingId .. "\r\n")
        else
          local nick, target, msg = line:match("^:(.-)!.- PRIVMSG%s+(%S+)%s+:(.*)$")
          if nick and msg then
            addMessage("[" .. target .. "] <" .. nick .. "> " .. msg)
          else
            addMessage(line)
          end
        end
      end
      displayBuffer()
    end

    local eventName, _, char, code = event.pull(0.05)
    if eventName == "key_down" then
      if code == keyboard.keys.lcontrol or code == keyboard.keys.rcontrol then
        if handleUserInput(false) then return end
      elseif code == keyboard.keys.lmenu or code == keyboard.keys.rmenu then
        if handleUserInput(true) then return end
      elseif code == keyboard.keys.up then
        currentBufferIndex = math.max(1, currentBufferIndex - 1)
        displayBuffer()
      elseif code == keyboard.keys.down then
        currentBufferIndex = math.min(#messageBuffer, currentBufferIndex + 1)
        displayBuffer()
      end
    end
  end
end

local function main()
  while true do
    drawServerList()
    local eventName, _, char, code = event.pull("key_down")

    if char == 120 or char == 88 then
      term.clear()
      print("Exiting program...")
      break
    elseif code == keyboard.keys.up or code == keyboard.keys.left then
      selectedServerIndex = math.max(1, selectedServerIndex - 1)
    elseif code == keyboard.keys.down or code == keyboard.keys.right then
      selectedServerIndex = math.min(#servers, selectedServerIndex + 1)
    elseif char == 110 or char == 78 then
      username = changeNickname()
    elseif code == keyboard.keys.enter then
      term.clear()
      if connectToServer(servers[selectedServerIndex]) then
        if isColorSupported then
          gpu.setResolution(gpu.maxResolution())
          gpu.setBackground(0x000000)
          gpu.setForeground(0xFFFFFF)
        end
        handleServerCommunication()
      else
        addMessage("Press any key to return to server list.")
        displayBuffer()
        event.pull("key_down")
      end
    end
  end
end

main()