From b3fdd3a4a564dc467f06753beccd5809ad972c3e Mon Sep 17 00:00:00 2001
From: Min Ji Choi <min@oxd.com>
Date: Mon, 18 May 2026 11:27:02 -0600
Subject: [PATCH] DBC22-6284: Added internal notes changes in event history

---
 src/frontend/app/events/History/Version.jsx   |  9 +++-
 .../app/events/History/preprocessors.jsx      | 22 +++++++++-
 src/webapp/apps/events/serializers.py         | 43 ++++++++++++++++++-
 3 files changed, 70 insertions(+), 4 deletions(-)

diff --git a/src/frontend/app/events/History/Version.jsx b/src/frontend/app/events/History/Version.jsx
index 690bf88e..2d4a197e 100644
--- a/src/frontend/app/events/History/Version.jsx
+++ b/src/frontend/app/events/History/Version.jsx
@@ -30,10 +30,11 @@ const GROUPING = {
   end_time: 'timing',
   ongoing: 'timing',
   schedules: 'timing',
-  link: 'external'
+  link: 'external',
+  notes: 'internal',
 }
 
-const GROUP_ORDER = ['location', 'details', 'impacts', 'delays', 'restrictions', 'conditions', 'timing', 'schedule', 'additional', 'external'];
+const GROUP_ORDER = ['location', 'details', 'impacts', 'delays', 'restrictions', 'conditions', 'timing', 'schedule', 'additional', 'external', 'internal'];
 
 const GROUPS = {
   start: {
@@ -80,6 +81,10 @@ const GROUPS = {
     label: 'Additional details external site',
     preprocessor: funcs.external,
   },
+  internal: {
+    label: 'Internal Notes',
+    preprocessor: funcs.internal,
+  },
 };
 
 function group(data) {
diff --git a/src/frontend/app/events/History/preprocessors.jsx b/src/frontend/app/events/History/preprocessors.jsx
index 0a31e8e5..30e48651 100644
--- a/src/frontend/app/events/History/preprocessors.jsx
+++ b/src/frontend/app/events/History/preprocessors.jsx
@@ -185,8 +185,28 @@ export function external(event, diff) {
   return [{ label: `${verb} more information link`, icon, verb, previous, current }];
 }
 
+export function internal(event, diff) {
+  const items = [];
+  diff.add?.forEach((add) => {
+    items.push({ label: 'Added internal note', icon: faPlus, verb: 'Added', current: add.text });
+  });
+  diff.remove?.forEach((remove) => {
+    items.push({ label: 'Removed internal note', icon: faMinus, verb: 'Removed', previous: remove.text });
+  });
+  diff.change?.forEach((change) => {
+    items.push({
+      label: 'Updated internal note',
+      icon: faArrowsRotate,
+      verb: 'Updated',
+      previous: change.previous,
+      current: change.current,
+    });
+  });
+  return items;
+}
+
 export default {
-  location, details, impacts, delays, restrictions, timing, schedule, conditions, additional, external
+  location, details, impacts, delays, restrictions, timing, schedule, conditions, additional, external, internal
 };
 
 function getTypeOfChange(current, previous) {
diff --git a/src/webapp/apps/events/serializers.py b/src/webapp/apps/events/serializers.py
index d4e6018e..6d3335f2 100644
--- a/src/webapp/apps/events/serializers.py
+++ b/src/webapp/apps/events/serializers.py
@@ -235,8 +235,49 @@ def get_id(self):
             return f'{EVENT_PREFIX}-{int(event.id.split('-')[-1]) + 1}'
 
 
+def notes_diff_for_event_version(event):
+    '''
+    Return note add/update/remove changes that occurred between the prior
+    event version and this one (by last_updated timestamp).
+    '''
+    prior = event.prior() if event.version > 0 else None
+    start = prior.last_updated if prior else None
+    end = event.last_updated
+
+    qs = Note.objects.filter(event=str(event.id), last_updated__lte=end)
+    if start:
+        qs = qs.filter(last_updated__gt=start)
+
+    result = {}
+    for note in qs.order_by('id', 'version'):
+        if note.deleted:
+            prior_note = note.prior()
+            result.setdefault('remove', []).append({
+                'id': note.id,
+                'text': prior_note.text if prior_note else note.text,
+            })
+        elif note.version == 0:
+            result.setdefault('add', []).append({'id': note.id, 'text': note.text})
+        else:
+            prior_note = note.prior()
+            if prior_note and prior_note.text != note.text:
+                result.setdefault('change', []).append({
+                    'id': note.id,
+                    'previous': prior_note.text,
+                    'current': note.text,
+                })
+
+    return result
+
+
 class EventHistorySerializer(EventSerializer, HistorySerializer):
-    pass
+
+    def get_diff(self, obj):
+        changes = obj.diff()
+        notes_diff = notes_diff_for_event_version(obj)
+        if notes_diff:
+            changes['internal'] = notes_diff
+        return changes
 
 
 class EventDiffSerializer(EventSerializer, HistorySerializer):