protected function getEmojiMap()
    {
        if (!isset($this->emojiMapFile)) {
            $this->emojiMapFile = realpath(__DIR__.self::DEFAULT_EMOJI_MAP_FILE);
        }

        if (!file_exists($this->emojiMapFile)) {
            throw new TelegramEmojiMapFileNotFoundException();
        }

        return json_decode(file_get_contents($this->emojiMapFile), true);
    }