Automatically create user when email of non-member is invited

I just want to start off with thanks for creating/maintaining this module! I couldn't find anything else on this subject (but if I missed it, I'm sorry!), so I hope this helps anyone trying to find a similar solution...

One thing I wanted to do is automatically create a user if an email of a non-member is entered into the invite member form. Not sure if anyone else was looking for a solution to do this, but I thought I'd share what I came up with. Always open for suggestions on how to do this better :)

First off, I implemented a hook_form_alter in a custom module to add a nice admin interface to configure this new option:

<?php
function mymodule_form_alter(&$form, &$form_state, $form_id) {
  switch ($form_id) {
    case 'og_invite_link_admin':
      $form['registration']['mymodule_og_invite_link_allow_auto_registration'] = array(
        '#type' => 'checkbox',
        '#title' => t('Allow automatic user registration.'),
        '#description' => t('If enabled, non-member email invitations will be automatically registered to a new user account.'),
        '#default_value' => variable_get('mymodule_og_invite_link_allow_auto_registration', 0),
      );
      $roles = user_roles(TRUE);
      $form['registration']['mymodule_og_invite_link_auto_registration_role'] = array(
        '#type' => 'checkboxes',
        '#title' => t('Automatic User Registration Role(s)'),
        '#description' => t('If automatic user registration is enabled, the new user will be assigned the selected role.'),
        '#options' => $roles,
        '#default_value' => variable_get('mymodule_og_invite_link_auto_registration_roles', -1),
      );
      break;
?>

I'm also overriding the submit handler of the og_invite_link_invite_page_form in the same form alter:

<?php
    case 'og_invite_link_invite_page_form':
      $form['#submit'][0] = 'mymodule_invite_page_form_submit';
      break;
    default:
      break;
  }
}
?>

New custom submit handler...
As you can see, I just copied the entire og_invite_link_invite_page_form_submit callback function and have $invitation_result call mymodule_invite_users_to_groups() instead of og_invite_link_invite_users_to_groups():

<?php
function mymodule_invite_page_form_submit($form, &$form_state) {
  // $invitation_result = og_invite_link_invite_users_to_groups(array(
  $invitation_result = mymodule_invite_users_to_groups(array(
      'groups' => $form_state['values']['groups'],
      'invitees' => $form_state['values']['invitees'],
      'additional_message' => $form_state['values']['additional_message'],
    )
  );
  // Here we should not have more than one group.
  $group = current($form_state['values']['groups']);
  // Set a message for the invited users
  if (!empty($invitation_result['invitees'][$group->nid])) {
    drupal_set_message(t('An invite has been sent to !users', array('!users' => implode(', ', $invitation_result['invitees'][$group->nid]))));
  }

  // Set a message for the invitees already in the group
  if (!empty($invitation_result['in_group'][$group->nid])) {
    drupal_set_message(t('The following invitees are already members: !users', array('!users' => implode(', ', $invitation_result['in_group'][$group->nid]))), 'warning');
  }

  // Set a message for the invalid invitees
  if (!empty($invitation_result['invalid'])) {
    drupal_set_message(t('The following invitees are either not users, or are invalid email addresses: !users', array('!users' => implode(', ', $invitation_result['invalid']))), 'error');
  }
?>

Then, I pretty much copied the entire og_invite_link_invite_users_to_groups function to my custom callback function:

<?php
function mymodule_invite_users_to_groups($params) {
  if (count($params['groups'])) {
    // Extract the additional message from the parameters.
    $message = filter_xss($params['additional_message']);
    // Extract the user names to send invites to
    $names = explode(',', $params['invitees']);
    // Track the valid invitees
    $invitees = array();
    // Track the invalid invitees
    $invalid = array();
    // Track the valid invitees that are already group members
    $in_group = array();

    // Attempt to load the users based on names, to determine which are real
    // users and which are not. We need to load each user individually instead
    // of using a single query because we need to determine which groups each
    // user belongs to in order to avoid inviting them to a group of theirs
    foreach ($names as $name) {
      // Trim and sanitize the name
      $name = trim(filter_xss(strip_tags($name)));

      // Make sure we have a name to invite after the filtering
      if (strlen($name) == 0) {
        continue;
      }

      // Attempt to load the user
      if (valid_email_address($name)) {
        // Load based on email address
        $account = user_load(array('mail' => $name));
      }
      else {
        // Load based on user name
        $account = user_load(array('name' => $name));  
      }
      
      // Check if we have a valid user object
      if (is_object($account)) {
        // Invalid if the user is inactive
        if (!$account->status) {
          $invalid[] = $name;
          continue; 
        }
      }
      // Check if we are allowed to invite non-users
      else if (variable_get('og_invite_link_invite_unregistered', 0)) {
        // Make sure we have a valid, non-banned email address
        if (valid_email_address($name) && !drupal_is_denied('mail', $name)) {

?>

Added my overrides here:

<?php
        // start custom overrides ******************************** //
          if (variable_get('mymodule_og_invite_link_allow_auto_registration', 0)) {
	    $fields = array(
              'name' => $name,
              'mail' => $name,
              'pass' => user_password(8),
              'status' => 1,
              'roles' => variable_get('mymodule_og_invite_link_auto_registration_roles', -1),
            );
            $account = user_save('', $fields);
          }
          else {
            // Build a user object
            $account = new stdClass;
            $account->uid = 0;
            $account->mail = $name;
          }
        // end custom overrides ******************************** //
?>

And the rest of the stock code from the og_invite_link_invite_users_to_groups function:

<?php
        }
        else {
          $invalid[] = $name;
          continue; 
        }
      }
      // We have nothing valid
      else {
        $invalid[] = $name;
        continue; 
      }
      
      foreach ($params['groups'] as $key => $group) {
        if (!is_array($invitees[$group->nid])) {
          $invitees[$group->nid] = array();
        }
        if (!is_array($in_group[$group->nid])) {
          $in_group[$group->nid] = array();
        }
        // Check for duplicates
        if (isset($invitees[$group->nid][$account->uid]) || 
         isset($invitees[$group->nid][$account->mail]) || 
         isset($in_group[$group->nid][$account->uid])) {
          continue;
        }
        // See if the user is already a member
        // Don't use og_is_group_member() because it's horrible
        if (isset($account->og_groups[$group->nid])) {
          $in_group[$group->nid][$account->uid] = theme('username', $account);
        }
        else {
          // Invite the user
          og_invite_link_send_invite($account, $group, $message);
          if ($account->uid) {
            $invitees[$group->nid][$account->uid] = theme('username', $account);  
          }
          else {
            $invitees[$group->nid][$account->mail] = $account->mail; 
          }
          
        }
      }
    }
    return array('invitees' => $invitees, 'in_group' => $in_group, 'invalid' => $invalid);
  }
}
?>

Hope this helps!