====== Send via Telegram bot messages to multiply persons chat from Lua via Telegram API ======
<WRAP center round alert 60%>
Nota bene, \\ 
This bot will work only with Raspberry PI and VirtualBox machine.

It is purpose is the ability to be <wrap em>invited in the chat</wrap>.
 \\ 

OTHERWISE, please use [[level2:send_telegram_messages_via_level2|Level 2 bot]], which is running on the Level2 server, unlike this one, which should be ran on VM via Lua script.

</WRAP>

<WRAP center round download 60%>
{{ :telegram:telegram-api-bot-groups-chat-backup-2021-03-11-firmware-4.0_1_.zip |Sample Project (token used from @WHtest2_bot, human host @tolstov_x)}}
</WRAP>


When WebHMI is connected to internet it is possible to send Telegram messages via Telegram API.

There is a need to create a new bot via [[https://telegram.me/BotFather|@BotFather]].
{{ :telegram:bot_father.png?nolink |}} 
Send him ''/start'' command. Then it will show all of comands you can use to create and manage your bots.
Pick ''/newbot'' command.\\ 

Then type in the name of bot. It will be telegram link, like ''@BotFather_bot'' for example. The only note, all of bot names should end with regular expression ''_bot''
When you will finish the creation you will get your own bot token.

{{ :telegram:bot_token_api.png?direct |}}

Keep it secure, because everyone can get control if it is compromised.

<wrap em>Copy HTTP API Token to ''botToken'' variable in the first line of script.</wrap>

<WRAP center round important 60%>
Also, there is a few registers should be created to work correctly.
There is a register map to import to your project to make creation easier.

If it is unable to import it with tool, you <wrap hi>should create it manually</wrap>.
\\ 
{{ ::telegram:registers_map_for_telegram_api_chat_bot.zip |Download register map.zip}}
</WRAP>


Copypaste that script to you device.

<code lua - TelegramChatBot.lua>
function main (userId)
    local botToken = "1556884060:AAFjT5F4IWXTbrcbuUkoL7qhDTrZCf8EA94" --example of Token
    local bot_id = tonumber(string.sub(botToken, 1, string.find( botToken, ":")-1))
     
    
    lastSentTime = R("telegram_last_sent_time")

    -- function main (userId)
     
    now = os.time();
    local message = "Hello, Telegram! It's " .. tostring(os.date("%H:%M", os.time())) .. " o'clock!"  -- your message that will be sent
    TRACE(message)
    
    
    local condition_to_send = (tonumber(os.date("%s")) % 10 == 0 and now - lastSentTime >= ( 1 * 60 - 5))
        -- check if it is initialisation or not
    if (R("chat_id")) == "" then
        first_request_no_chat_id = true
        -- chat_id = ""
        -- return
    else
        first_request_no_chat_id = false
        chat_id = R("chat_id")
    end
    if first_request_no_chat_id then TRACE("first_request_no_chat_id " .. tostring(first_request_no_chat_id)) end
     
                                -- initialisation branch
        if first_request_no_chat_id == true then 
            local initialisation_request_ulr = 'https://api.telegram.org/bot'.. botToken .. "/getUpdates"
            DEBUG(initialisation_request_ulr )
            c = cURL.easy_init()
            c:setopt_timeout(5)
            c:setopt_url(initialisation_request_ulr)
            local res = ""
            c:perform({
            writefunction = function(str)
                                res = res .. str;
                            end})
                                    DEBUG(res)
            local table = cjson.decode(res)
                    --- Check when bot is invited to group
            for jj, jvalue in pairs ( table.result) do
                if tonumber(table.result[jj].my_chat_member.chat.id) < 0 then
                    new_chat_id = tostring(table.result[1].my_chat_member.chat.id)
                    WriteReg("chat_id", new_chat_id)
                    break
                end
            end
            
                                -- work branch  
        else 
     
            lastSentTime = R("telegram_last_sent_time")
            --        local condition_to_send = (tonumber(os.date("%s")) % 10 == 0 and now - lastSentTime >= ( 1 * 60 - 5))
            if condition_to_send == true then
                local url = 'https://api.telegram.org/bot'.. botToken .. '/sendMessage?chat_id=' .. chat_id .. '&text=' .. urlencode(message);
     
                local res = "";
                c = cURL.easy_init()
                c:setopt_url(url)
                --INFO(message);
                c:perform({
                writefunction = function(str)
                                res = res .. str;
                            end})
     
                local table = cjson.decode(res)
                local error_code = nil
     
                if table.ok == false then
                    error_code = table.error_code
                    lastErrorCode = error_code
                    lastSentTime = tonumber(os.date("%s"))
                    -- DEBUG(lastErrorCode) 
                    WriteReg("telegram_last_sent_status_unsuccesful", lastErrorCode); 
     
                else
                    lastSentTime = tonumber(os.date("%s"))
                    lastSentTimeSuccesful = lastSentTime
                    lastStatus = table.result.message_id
     
                    WriteReg("telegram_last_sent_status", lastStatus)
                end
                c:close()
                WriteReg("telegram_last_sent_time", lastSentTime); -- Останній час повідомлення в Telegram (DS15@WebHMI)
                WriteReg("telegram_last_sent_time_succesful", lastSentTimeSuccesful);
            end
        end
    -- end
     


end

    function urlencode(str)
        if (str) then
            str = string.gsub (str, "\n", "\r\n")
            str = string.gsub (str, "([^%w ])",
            function (c) return string.format ("%%%02X", string.byte(c)) end)
            str = string.gsub (str, " ", "+")
        end
        return str    
    end
</code>



At the rest, invite that bot to your chat.

<WRAP center round tip 60%>
Do not forget to enable bot access to messages in BotFather's settings. 
</WRAP>


Run script and it will initialise. In the ''chat_id'' register will became id like ''//-123456789//''. From this moment, your ''message'' variable content will be sent to your Telegram chat, when your variable ''condition_to_send'' equals to **''true''**