not-LUA

init.lua

local http = require"ssl.https"
local url = require"socket.url"
local json = require"cjson"

local token = os.getenv("TOKEN")
local tguri = "https://api.telegram.org/bot"..token
local last_update_id = 0

local function process_update(update)
  if not update.message then return end
  local text = update.message.text or ""
  local chat_id = (update.message.chat or {}).id
  local reply_text = [[<a href="https://www.lua.org/about.html#name">Lua*</a>]]
  if chat_id and text:match("LU[AА]") then
    local query = ("chat_id=%d&text=%s&reply_to_message_id=%d&parse_mode=HTML")
      :format(chat_id, url.escape(reply_text), update.message.message_id)
    http.request(tguri.."/sendMessage?"..query)
  end
end

while true do
  local raw_body = http.request(
    ("%s/getUpdates?offset=%d&timeout=30"):format(tguri, last_update_id+1)
  )
  local ok, body = pcall(json.decode, raw_body)
  if not ok or not body.ok then goto cont end
  for _, update in ipairs(body.result) do
    process_update(update)
    last_update_id = update.update_id
  end
  ::cont::
end