/**
 * Invites a friend to join a group via a POST request.
 *
 * @since BuddyPress (1.2)
 * @todo Audit return types
 */
function bp_legacy_theme_ajax_invite_user() {
	// Bail if not a POST action
	if ( 'POST' !== strtoupper( $_SERVER['REQUEST_METHOD'] ) )
		return;

	check_ajax_referer( 'groups_invite_uninvite_user' );

	if ( ! $_POST['friend_id'] || ! $_POST['friend_action'] || ! $_POST['group_id'] )
		return;

	if ( ! bp_groups_user_can_send_invites( $_POST['group_id'] ) )
		return;

	if ( ! friends_check_friendship( bp_loggedin_user_id(), $_POST['friend_id'] ) )
		return;

	$group_id = (int) $_POST['group_id'];
	$friend_id = (int) $_POST['friend_id'];

	if ( 'invite' == $_POST['friend_action'] ) {
		$group = groups_get_group( $group_id );

		// Users who have previously requested membership do not need
		// another invitation created for them
		if ( BP_Groups_Member::check_for_membership_request( $friend_id, $group_id ) ) {
			$user_status = 'is_pending';

		// Create the user invitation
		} elseif ( groups_invite_user( array( 'user_id' => $friend_id, 'group_id' => $group_id ) ) ) {
			$user_status = 'is_invited';

		// Miscellaneous failure
		} else {
			return;
		}

		$user = new BP_Core_User( $_POST['friend_id'] );

		echo '<li id="uid-' . esc_attr( $user->id ) . '">';
		echo $user->avatar_thumb;
		echo '<h4>' . $user->user_link . '</h4>';
		echo '<span class="activity">' . esc_attr( $user->last_active ) . '</span>';
		echo '<div class="action">
				<a class="button remove" href="' . wp_nonce_url( bp_loggedin_user_domain() . bp_get_groups_slug() . '/' . $_POST['group_id'] . '/invites/remove/' . $user->id, 'groups_invite_uninvite_user' ) . '" id="uid-' . esc_attr( $user->id ) . '">' . __( 'Remove Invite', 'buddypress' ) . '</a>
			  </div>';

		if ( 'is_pending' == $user_status ) {
			echo '<p class="description">' . sprintf( __( '%s has previously requested to join this group. Sending an invitation will automatically add the member to the group.', 'buddypress' ), $user->user_link ) . '</p>';
		}

		echo '</li>';
		exit;

	} elseif ( 'uninvite' == $_POST['friend_action'] ) {
		// Users who have previously requested membership should not
		// have their requests deleted on the "uninvite" action
		if ( BP_Groups_Member::check_for_membership_request( $friend_id, $group_id ) ) {
			return;
		}

		// Remove the unsent invitation
		if ( ! groups_uninvite_user( $friend_id, $group_id ) ) {
			return;
		}

		exit;

	} else {
		return;
	}
}