local version =
1.7

function detectModem()
  for _,side in ipairs(rs.getSides()) do
    if peripheral.isPresent(side) then
      if peripheral.getType(side) == "modem" then
        if not rednet.isOpen(side) then
          rednet.open(side)
        end
        return side
      end
    end
  end
  return false
end

--[[
Huge thanks goes to Cranium
for showing me a updating
technic!
]]--

local modem = detectModem()
if modem == false then
  if term.isColor then
    if term.isColor() then
      term.setTextColor(colors.red)
      term.setBackgroundColor(colors.black)
    end
  end
  print("No modem found!")
  return
else
  rednet.open(modem)
end
local siteUrl = "http://Ninety7Seven.com/CC/prog/JagChat.lua"
local width, height = term.getSize()
local event,param1,param2,param3
local written = ""
local output = ""
local scrolls = 2
local site, siteFile, writeFile
local newVersion
local x,y
local id, message = 0, ""
local table1 = {}
local table2 = {}
local usersTable = {}
local command = ""
local commands = {
  "logout",
  "list",
  "update",
  "help",
  "commands",
}
term.setCursorBlink(true)

function setColor(txtColor,bgColor)
  if term.isColor then
    if term.isColor() then
      if txtColor then
        term.setTextColor(txtColor)
      end
      if bgColor then
        term.setBackgroundColor(bgColor)
      end
    end
  end
end

function printC(inputString,spaces)
  if not spaces then
    spaces = " "
  else
    spaces = tostring(spaces)
  end
  string_len = string.len(inputString)
  num = math.floor(width/2 - string_len/2)
  for j = 1,num do
    output = output..spaces
  end
  output = output..tostring(inputString)
  for j = 1,num do
    output = output..spaces
  end
  setColor(colors.red,colors.gray)
  term.clearLine()
  write(string.sub(output,1,width-1))
  output = ""
end

function printN(name,inputString)
  inputString = tostring(inputString)
  setColor(colors.lightGray,colors.black)
  term.clearLine()
  if name then write(name) end
  setColor(colors.yellow)
  write(inputString.."\n")
  term.clearLine()
  if scrolls > height-2 then
    term.scroll(1)
  else
    scrolls = scrolls + 1
  end
end

function listUsers()
  term.setCursorBlink(false)
  usersTable = {}
  rednet.broadcast(textutils.serialize({chat={listAll=true}}))
  repeat
    id, message = 0,""
    id, message = rednet.receive(.5)
    if message == textutils.serialize({chat={listMe=true}}) then
      table.insert(usersTable, id)
    end
  until id == nil
  if #usersTable == 0 then
    clearF()
    term.setCursorPos(x,y)
    printN(_,"No users active!")
  else
    clearF()
    term.setCursorPos(x,y)
    printN(_,"Users active: ")
    for h = 1,#usersTable do
      clearF()
      term.setCursorPos(x,y)
      printN(h..": ",usersTable[h])
    end
  end
  term.setCursorBlink(true)
end

function check4update()
  term.setCursorBlink(false)
  term.setCursorPos(x,y)
  printN(_,"Searching for updates...")
  clearF()
  term.setCursorPos(x,y)
  site = http.get(siteUrl)
  if not site then
    printN(_,"Failed! Try again later.")
    term.setCursorBlink(true)
    return false
  end
  site.readLine()
  newVersion = site.readLine()
  if tonumber(newVersion) > version then
    printN(_,"Program is out of date, updating...")
    clearF()
    term.setCursorPos(x,y)
    site = http.get(siteUrl)
    if not site then
      printN(_,"Failed! Try again later.")
      term.setCursorBlink(true)
      return false
    end
    siteFile = site.readAll()
    writeFile = fs.open(shell.getRunningProgram(),"w")
    writeFile.write(siteFile)
    writeFile.close()
    printN(_,"Update successful! Restarting program...")
    clearF()
    sleep(2)
    rednet.broadcast(textutils.serialize({chat={login=false}}))
    rednet.close("top")
    shell.run(shell.getRunningProgram())
    os.reboot()
  else
    printN(_,"Program is up to date!")
  end
  term.setCursorBlink(true)
end

function commandList()
  clearF()
  term.setCursorPos(x,y)
  printN(_,"Commands:")
  for o = 1,#commands do
    clearF()
    term.setCursorPos(x,y)
    printN(o..": ","/"..commands[o])
  end
end

function clearF()
  term.setCursorPos(1,1)
  printC(" JagChat v"..version.." ","-")
  term.setCursorPos(1,scrolls)
  x,y = term.getCursorPos()
  term.setCursorPos(1,height-1)
  term.clearLine()
  printC(" Your id is #"..os.getComputerID().." ","-")
  term.setCursorPos(1,height)
  setColor(colors.orange,colors.gray)
  term.clearLine()
  write("> ")
  setColor(colors.yellow)
  write(written)
end

rednet.broadcast(textutils.serialize({chat={login=true}}))
setColor(_,colors.black)
term.clear()

while true do
  clearF()
  event,param1,param2,param3 = os.pullEvent()
  if event == "char" then
    if string.len(written) < width-string.len(tostring(os.getComputerID()))-4 then
      written = written .. param1
    end
  end
  if event == "key" then
    if param1 == 28 then
      if string.len(written) ~= 0 then
        if string.sub(written,0,1) == "/" then
          --commands
          command = string.sub(written,2)
          if command == "logout" then
            break
          elseif command == "list" then
            listUsers()
          elseif command == "update" then
            check4update()
          elseif command == "help" or command == "commands" then
            commandList()
          else
            term.setCursorPos(x,y)
            printN(_,"Command \""..command.."\" does not exists!")
          end
        else
          term.setCursorPos(x,y)
          printN("<"..os.getComputerID().."> ",written)
          table1 = {chat={isWritten=written}}
          rednet.broadcast(textutils.serialize(table1))
        end
        written = ""
      end
    elseif param1 == 14 then
      written = string.sub(written,1,-2)
    end
  elseif event == "rednet_message" then
    term.setCursorPos(x,y)
    table2 = textutils.unserialize(param2)
    if type(table2) == "table" then
      if table2.chat then
        if table2.chat.isWritten then 
          if param1 ~= os.getComputerID() then
            printN("<"..param1.."> ",table2.chat.isWritten)
          end
        elseif table2.chat.login == true or table2.chat.login == false then
          if table2.chat.login == true then
            printN("User #"..param1.." joined the chat!","")
          elseif table2.chat.login == false then
            printN("User #"..param1.." left the chat!","")
          end
        elseif table2.chat.listAll then
          if table2.chat.listAll == true then
            rednet.send(param1,textutils.serialize({chat={listMe=true}}))
          end
        end
      end
    end
    table2 = {}
  end
end

rednet.broadcast(textutils.serialize({chat={login=false}}))
rednet.close(modem)
term.setCursorPos(1,height-1)
printC(" Chat shut down ","-")
term.setCursorPos(1,height)
setColor(colors.white,colors.black)
term.clearLine()