Introduce "civicrm_network_groups_edit_own" filter

includes/civicrm-network-groups-hooks.php

@@ -172,10 +172,7 @@ class CiviCRM_Network_Groups_Hooks {
 
 
 	/**
-	 * Filter the groups to include only those with less precedence.
-	 *
-	 * Users will only be able to grant/remove membership of groups that are
-	 * lower in the precedence stack than the one they themselves hold.
+	 * Filter the groups to include only those with equal or lower precedence.
 	 *
 	 * @since 0.1.1
 	 *
@@ -186,7 +183,7 @@ class CiviCRM_Network_Groups_Hooks {
 
 		// Network Admins don't get groups filtered by precedence.
 		if ( is_super_admin() ) {
-			return $civicrm_groups;
+			//return $civicrm_groups;
 		}
 
 		// Bail if none.
@@ -205,9 +202,30 @@ class CiviCRM_Network_Groups_Hooks {
 			return $groups;
 		}
 
-		// Get user's "Groups" groups on the main site.
+		// Get user's "Groups" groups (on the main site since we're in that context).
 		$wp_group_ids = $this->plugin->wordpress->group_ids_get_for_user( $user->ID );
 
+		// Init "same" or "lower" level (false by default => lower)
+		$edit_own = false;
+
+		/**
+		 * Filter the choice of "same" or "lower" level.
+		 *
+		 * The logic here is that when $edit_own is false, users will only be
+		 * able to grant/remove membership of groups that are lower in the
+		 * precedence stack than the one they themselves hold.
+		 *
+		 * To change this so that users can grant/remove membership of groups
+		 * at the same level as themselves, return true from this filter.
+		 *
+		 * @since 0.1.1
+		 *
+		 * @param bool $edit_own True if user can see same-level groups, false otherwise.
+		 * @param WP_User $user The logged-in WordPress user object.
+		 * @return bool $edit_own True if user can see same-level groups, false otherwise.
+		 */
+		$edit_own = apply_filters( 'civicrm_network_groups_edit_own', $edit_own, $user );
+
 		// Init allowed flag.
 		$allowed = false;
 
@@ -221,18 +239,8 @@ class CiviCRM_Network_Groups_Hooks {
 			// Bail if there isn't one.
 			if ( $wp_group_id === false ) continue;
 
-			/*
-			 * The logic here is that users will only be able to grant/remove
-			 * membership of groups that are lower in the precedence stack than
-			 * the one they themselves hold.
-			 *
-			 * To switch this to become "at the same level as themselves" move
-			 * the "Add if allowed" block below the array check so that the
-			 * group is added immediately.
-			 */
-
-			// Add if allowed.
-			if ( $allowed ) {
+			// Add if only lower level groups are allowed.
+			if ( $allowed AND $edit_own === false ) {
 				$groups[] = $civicrm_group;
 			}
 
@@ -241,6 +249,11 @@ class CiviCRM_Network_Groups_Hooks {
 				$allowed = true;
 			}
 
+			// Add if same level groups are allowed.
+			if ( $allowed AND $edit_own === true ) {
+				$groups[] = $civicrm_group;
+			}
+
 		}
 
 		// --<