class Horde_Service_Gravatar
{
    const STANDARD = 'http://www.gravatar.com';
    const SECURE = 'https://secure.gravatar.com';

    private $_base;

    public function __construct($base = self::STANDARD)
    {
        $this->_base = $base;
    }

    public function getId($mail)
    {
        if (!is_string($mail)) {
            throw new InvalidArgumentException('The mail address must be a string!');
        }
        return md5(strtolower(trim($mail)));
    }

    public function getAvatarUrl($mail)
    {
        return $this->_base . '/avatar/' . $this->getId($mail);
    }

    public function getProfileUrl($mail)
    {
        return $this->_base . '/' . $this->getId($mail) . '.json';
    }
}