From 663959d8c2116065458054683dff9e5664b172a0 Mon Sep 17 00:00:00 2001
From: Egil Ballestad <egil.ballestad@vigoiks.no>
Date: Tue, 15 Oct 2024 13:43:39 +0200
Subject: [PATCH] add custom pagination in events

---
 src/main/java/no/fintlabs/EventService.java | 67 ++++++++++++---------
 1 file changed, 40 insertions(+), 27 deletions(-)

diff --git a/src/main/java/no/fintlabs/EventService.java b/src/main/java/no/fintlabs/EventService.java
index 056b578..8896c2b 100644
--- a/src/main/java/no/fintlabs/EventService.java
+++ b/src/main/java/no/fintlabs/EventService.java
@@ -36,26 +36,50 @@ public Page<EventDto> findAll(Pageable pageable) {
     }
 
     public Page<EventDto> getMergedLatestEvents(Pageable pageable) {
-        Page<Event> latestEventsPage = eventRepository
-                .findLatestEventPerSourceApplicationInstanceId(pageable);
+        List<EventDto> mergedEvents = fetchAndMergeEvents();
 
-        Page<Event> latestNonDeletedEventsPage = eventRepository
-                .findLatestEventNotDeletedPerSourceApplicationInstanceId(pageable);
-
-        long totalLatestEvents = eventRepository.countLatestEventPerSourceApplicationInstanceId();
-        long totalLatestNonDeletedEvents = eventRepository.countLatestEventNotDeletedPerSourceApplicationInstanceId();
-
-        List<EventDto> mergedEvents = mergeEvents(latestEventsPage.getContent(), latestNonDeletedEventsPage.getContent());
-
-        long totalElements = totalLatestEvents + totalLatestNonDeletedEvents;
-
-        return new PageImpl<>(mergedEvents, pageable, totalElements);
+        return getEventDtos(pageable, mergedEvents);
     }
 
+
     public Page<EventDto> getMergedLatestEventsWhereSourceApplicationIdIn(
             List<Long> sourceApplicationIds,
             Pageable pageable
     ) {
+        List<EventDto> mergedEvents = fetchAndMergeEventsWithSourceApplicationIds(sourceApplicationIds);
+
+        return getEventDtos(pageable, mergedEvents);
+    }
+
+    private PageImpl<EventDto> getEventDtos(Pageable pageable, List<EventDto> mergedEvents) {
+        sortMergedEvents(mergedEvents, pageable.getSort());
+
+        long totalElements = mergedEvents.size();
+
+        int start = (int) pageable.getOffset();
+        int end = Math.min(start + pageable.getPageSize(), mergedEvents.size());
+
+        if (start >= mergedEvents.size()) {
+            return new PageImpl<>(new ArrayList<>(), pageable, totalElements);
+        }
+
+        List<EventDto> paginatedList = mergedEvents.subList(start, end);
+        return new PageImpl<>(paginatedList, pageable, totalElements);
+    }
+
+    private List<EventDto> fetchAndMergeEvents() {
+        List<Event> latestEvents = eventRepository
+                .findLatestEventPerSourceApplicationInstanceId(Pageable.unpaged())
+                .getContent();
+
+        List<Event> latestNonDeletedEvents = eventRepository
+                .findLatestEventNotDeletedPerSourceApplicationInstanceId(Pageable.unpaged())
+                .getContent();
+
+        return mergeEvents(latestEvents, latestNonDeletedEvents);
+    }
+
+    private List<EventDto> fetchAndMergeEventsWithSourceApplicationIds(List<Long> sourceApplicationIds) {
         List<Event> latestEvents = eventRepository
                 .findLatestEventPerSourceApplicationInstanceIdAndSourceApplicationIdIn(
                         sourceApplicationIds,
@@ -68,9 +92,10 @@ public Page<EventDto> getMergedLatestEventsWhereSourceApplicationIdIn(
                         Pageable.unpaged()
                 ).getContent();
 
-        List<EventDto> mergedEvents = mergeEvents(latestEvents, latestNonDeletedEvents);
+        return mergeEvents(latestEvents, latestNonDeletedEvents);
+    }
 
-        Sort sort = pageable.getSort();
+    private void sortMergedEvents(List<EventDto> mergedEvents, Sort sort) {
         if (sort.isSorted()) {
             mergedEvents.sort((e1, e2) -> {
                 for (Sort.Order order : sort) {
@@ -82,18 +107,6 @@ public Page<EventDto> getMergedLatestEventsWhereSourceApplicationIdIn(
                 return 0;
             });
         }
-
-        long totalElements = mergedEvents.size();
-
-        int start = (int) pageable.getOffset();
-        int end = Math.min(start + pageable.getPageSize(), mergedEvents.size());
-
-        if (start >= mergedEvents.size()) {
-            return new PageImpl<>(new ArrayList<>(), pageable, totalElements);
-        }
-
-        List<EventDto> paginatedList = mergedEvents.subList(start, end);
-        return new PageImpl<>(paginatedList, pageable, totalElements);
     }
 
     private int compareEvents(EventDto e1, EventDto e2, Sort.Order order) {