feat: 🎸 Filter our embedded groups where user is member

Filter out embedded groups from options where user is already member. If
empty set of options remains, filter out form item copletely.

Author: Dominik Frantisek Bucik

perun-registrar-lib/src/main/java/cz/metacentrum/perun/registrar/impl/RegistrarManagerImpl.java

@@ -2997,13 +2997,24 @@ public List<ApplicationFormItemWithPrefilledValue> getFormItemsWithPrefilledValu
 			throw new MissingRequiredDataException("The administrator set up this form wrongly OR you don't match any conditions OR your IDP doesn't provide data required by this application form.", itemsWithMissingData);
 		}
 
-		itemsWithValues.stream()
-			.filter(item -> item.getFormItem().getType() == EMBEDDED_GROUP_APPLICATION)
-			.forEach(item -> setGroupsToCheckBoxForGroups(sess, item, vo, group));
+		Iterator<ApplicationFormItemWithPrefilledValue> itemsIt = itemsWithValues.iterator();
+		while (itemsIt.hasNext()) {
+			ApplicationFormItemWithPrefilledValue item = itemsIt.next();
+			// Process only EMBEDDED_GROUP_APPLICATION items in this block
+			if (item.getFormItem().getType() != EMBEDDED_GROUP_APPLICATION) {
+				continue;
+			}
+			// Generate options for EMBEDDED_GROUP_APPLICATION items.
+			setGroupsToCheckBoxForGroups(sess, item, user, vo, group);
+			// If the item has no options for the user to offer (bcs user is already member in all possible options,
+			// remove it from the form completely
+			if (StringUtils.isBlank(item.getFormItem().getI18n().get(ApplicationFormItem.EN).getOptions())) {
+				it.remove();
+			}
+		}
 
 		// return prefilled form
 		return itemsWithValues;
-
 	}
 
 	private List<Pair<String, String>> getPrincipalsReservedLogins(PerunSession sess) {
@@ -3022,16 +3033,16 @@ private List<Pair<String, String>> getPrincipalsReservedLogins(PerunSession sess
 
 	/**
 	 * To the given EMBEDDED_GROUP_APPLICATION item, sets options of allowed groups.
-	 *
 	 * Example format:
 	 * 111#GroupA|222#GroupB
 	 *
-	 * @param sess session
-	 * @param item item, to which the group options will be set, only EMBEDDED_GROUP_APPLICATION is supported
-	 * @param vo vo, from which the groups for auto registration are taken
+	 * @param sess              session
+	 * @param item              item, to which the group options will be set, only EMBEDDED_GROUP_APPLICATION is supported
+	 * @param user
+	 * @param vo                vo, from which the groups for auto registration are taken
 	 * @param registrationGroup group, from which the subgroups for auto registration are taken - if not null, then it is a group application
 	 */
-	private void setGroupsToCheckBoxForGroups(PerunSession sess, ApplicationFormItemWithPrefilledValue item, Vo vo, Group registrationGroup) {
+	private void setGroupsToCheckBoxForGroups(PerunSession sess, ApplicationFormItemWithPrefilledValue item, User user, Vo vo, Group registrationGroup) {
 		if (item.getFormItem().getType() != EMBEDDED_GROUP_APPLICATION) {
 			throw new InternalErrorException("Group options can be set only to the EMBEDDED_GROUP_APPLICATION item.");
 		}
@@ -3042,10 +3053,18 @@ private void setGroupsToCheckBoxForGroups(PerunSession sess, ApplicationFormItem
 			groups = perun.getGroupsManagerBl().getGroupsForAutoRegistration(sess, vo, item.getFormItem());
 		}
 
-		String groupOptions = groups.stream()
-			.sorted(Comparator.comparing(Group::getName))
-			.map(group -> group.getId() + "#" + group.getName())
-			.collect(Collectors.joining("|"));
+		if (user != null) {
+			List<Group> userGroups = groupsManager.getGroupsWhereUserIsActiveMember(sess, user, vo);
+			groups = groups.stream().filter(g -> !userGroups.contains(g)).collect(Collectors.toList());
+		}
+
+		String groupOptions = null;
+		if (!groups.isEmpty()) {
+			groupOptions = groups.stream()
+				.sorted(Comparator.comparing(Group::getName))
+				.map(group -> group.getId() + "#" + group.getName())
+				.collect(Collectors.joining("|"));
+		}
 
 		if (ApplicationFormItem.CS != null) {
 			item.getFormItem().getI18n().get(ApplicationFormItem.CS).setOptions(groupOptions);