Resolve "In der Workcloud sind in der Liste der Programmiersprache Dupikate mit Groß/Kleinschreibung"

Related to #441 (closed)

src/main/java/at/ac/uibk/gitsearch/repository/search/MetaDataRepository.java

@@ -305,6 +305,7 @@ public class MetaDataRepository {
                         }
                     });
 
+                reloadedCachedCompletions.values().forEach(c -> simplify(c));
                 cachedCompletions = reloadedCachedCompletions;
             } catch (co.elastic.clients.elasticsearch._types.ElasticsearchException | ElasticsearchException | ConnectException ex) {
                 // this may happen mainly during testing, when
@@ -318,6 +319,23 @@ public class MetaDataRepository {
         }
     }
 
+    /**
+     * this simplifies completion lists. It combines all found entries with same
+     * lowercase representation, and sums them up under the most returned value.
+     * (e.g. Java -> 4, java -> 2, JAVA -> 1 is combined to "Java -> 7").
+     *
+     * @param entries
+     */
+    public void simplify(Map<String, Map<String, Integer>> entries) {
+        entries.forEach((lowerCaseValue, upperCaseValues) -> {
+            final Optional<Entry<String, Integer>> max = upperCaseValues.entrySet().stream().max((e1, e2) -> e1.getValue() - e2.getValue());
+            max.ifPresent(maxEntry -> {
+                int sum = upperCaseValues.entrySet().stream().mapToInt(o -> o.getValue()).sum();
+                entries.put(lowerCaseValue, Collections.singletonMap(maxEntry.getKey(), sum));
+            });
+        });
+    }
+
     public static String filterDateString(String sourceAsJSON) {
         return sourceAsJSON.replaceAll("[+-]\\d{2}:\\d{2}", "");
     }