interface MailSystemInterface

interface MailSystemInterface {
    
    /**
     * Format a message composed by drupal_mail() prior sending.
     *
     * @param $message
     *   A message array, as described in hook_mail_alter().
     *
     * @return
     *   The formatted $message.
     */
    public function format(array $message);
    
    /**
     * Send a message composed by drupal_mail().
     *
     * @param $message
     *   Message array with at least the following elements:
     *   - id: A unique identifier of the e-mail type. Examples: 'contact_user_copy',
     *     'user_password_reset'.
     *   - to: The mail address or addresses where the message will be sent to.
     *     The formatting of this string will be validated with the
     *     @link http://php.net/manual/filter.filters.validate.php PHP e-mail validation filter. @endlink
     *     Some examples are:
     *     - user@example.com
     *     - user@example.com, anotheruser@example.com
     *     - User <user@example.com>
     *     - User <user@example.com>, Another User <anotheruser@example.com>
     *   - subject: Subject of the e-mail to be sent. This must not contain any
     *     newline characters, or the mail may not be sent properly.
     *   - body: Message to be sent. Accepts both CRLF and LF line-endings.
     *     E-mail bodies must be wrapped. You can use drupal_wrap_mail() for
     *     smart plain text wrapping.
     *   - headers: Associative array containing all additional mail headers not
     *     defined by one of the other parameters.  PHP's mail() looks for Cc and
     *     Bcc headers and sends the mail to addresses in these headers too.
     *
     * @return
     *   TRUE if the mail was successfully accepted for delivery, otherwise FALSE.
     */
    public function mail(array $message);

}