public function commutator()
    {
        // verificar si tiene una sessi�n

        // si no tiene solicitar ID

    }

    public function closeSesion($chatId){
        $close = cerrarSesion($chatId);
        $this->sendMessage($message['chatId'], 'Gracias por utilizar nuestros servicios'.$message['chatId'].'@');
    }

    //this function calls function sendRequest to send a simple message
    //@param $chatId [string] [required] - the ID of chat where we send a message
    //@param $text [string] [required] - text of the message
    public function welcome($chatId, $session)
    {
        $welcomeString = "Bienvenido a *Gresst Bot*\n";
        if(count($session['Sessions'])>0){
            $welcomeString .= "Menú\n0. Finalizar sesión\n\n";
            $welcomeString .= "Tienes una sesión activa = " . $chatId;
        }else{
            // Crear sesión step 0
            crearSesion($chatId, '0');
            $welcomeString .= "Indicanos tu numero de identificación";
        }


        // Responde al cliente
        $this->sendMessage($chatId, $welcomeString);
    }

    //sends Id of the current chat. it is called when the bot gets the command "chatId"
    //@param $chatId [string] [required] - the ID of chat where we send a message
    public function showChatId($chatId)
    {
        $this->sendMessage($chatId, 'ChatID: ' . $chatId);
    }
    //sends current server time. it is called when the bot gets the command "time"
    //@param $chatId [string] [required] - the ID of chat where we send a message
    public function time($chatId)
    {
        $this->sendMessage($chatId, date('d.m.Y H:i:s'));
    }
    //sends your nickname. it is called when the bot gets the command "me"
    //@param $chatId [string] [required] - the ID of chat where we send a message
    //@param $name [string] [required] - the "senderName" property of the message
    public function me($chatId, $name)
    {
        $this->sendMessage($chatId, $name);
    }
    //sends a file. it is called when the bot gets the command "file"
    //@param $chatId [string] [required] - the ID of chat where we send a message
    //@param $format [string] [required] - file format, from the params in the message body (text[1], etc)
    public function file($chatId, $format)
    {
        $availableFiles = array(
            'doc' => 'document.doc',
            'gif' => 'gifka.gif',
            'jpg' => 'jpgfile.jpg',
            'png' => 'pngfile.png',
            'pdf' => 'presentation.pdf',
            'mp4' => 'video.mp4',
            'mp3' => 'mp3file.mp3',
        );

        if (isset($availableFiles[$format])) {
            $data = array(
                'chatId' => $chatId,
                'body' => 'https://domain.com/PHP/' . $availableFiles[$format],
                'filename' => $availableFiles[$format],
                'caption' => 'Get your file ' . $availableFiles[$format],
            );
            $this->sendRequest('sendFile', $data);}}

    //sends a voice message. it is called when the bot gets the command "ptt"
    //@param $chatId [string] [required] - the ID of chat where we send a message
    public function ptt($chatId)
    {
        $data = array(
            'audio' => 'https://domain.com/PHP/ptt.ogg',
            'chatId' => $chatId,
        );
        $this->sendRequest('sendAudio', $data);}

    //sends a location. it is called when the bot gets the command "geo"
    //@param $chatId [string] [required] - the ID of chat where we send a message
    public function geo($chatId)
    {
        $data = array(
            'lat' => 51.51916,
            'lng' => -0.139214,
            'address' => '??? ?????',
            'chatId' => $chatId,
        );
        $this->sendRequest('sendLocation', $data);}

    //creates a group. it is called when the bot gets the command "group"
    //@param chatId [string] [required] - the ID of chat where we send a message
    //@param author [string] [required] - "author" property of the message
    public function group($author)
    {
        $phone = str_replace('@c.us', '', $author);
        $data = array(
            'groupName' => 'Group with the bot PHP',
            'phones' => array($phone),
            'messageText' => 'It is your group. Enjoy',
        );
        $this->sendRequest('group', $data);}

    public function sendMessage($chatId, $text)
    {
        $data = array('chatId' => $chatId, 'body' => $text);
        $this->sendRequest('message', $data);}

    public function sendRequest($method, $data)
    {
        $url = $this->APIurl . $method . '?token=' . $this->token;
        if (is_array($data)) {$data = json_encode($data);}
        $options = stream_context_create(['http' => [
            'method' => 'POST',
            'header' => 'Content-type: application/json',
            'content' => $data]]);
        $response = file_get_contents($url, false, $options);
        file_put_contents('requests.log', $response . PHP_EOL, FILE_APPEND);}