From e7174770f3e7f7454c245ca1f9ce49c6f40934e8 Mon Sep 17 00:00:00 2001
From: Guido Schmit <scarriffle@MacBook-Pro.local>
Date: Tue, 5 May 2026 18:16:56 +0200
Subject: [PATCH] =?UTF-8?q?fix:=20Ganzt=C3=A4gig-Termine=20zeigen=20End-Da?=
 =?UTF-8?q?tum=20jetzt=20korrekt=20inklusive=20iCal=20speichert=20DTEND=20?=
 =?UTF-8?q?exklusiv=20(Tag=20NACH=20dem=20letzten=20Tag).=20Bisher=20f?=
 =?UTF-8?q?=C3=BChrte=20das=20dazu,=20dass=20ein=20Termin=20mit=20Ende=3D1?=
 =?UTF-8?q?8.08=20nur=20bis=20zum=2017.08=20angezeigt=20wurde,=20obwohl=20?=
 =?UTF-8?q?der=20User=2018.08=20als=20letzten=20Tag=20erwartete.=20Fix:=20?=
 =?UTF-8?q?Im=20Date-Picker=20arbeiten=20wir=20jetzt=20mit=20inklusiven=20?=
 =?UTF-8?q?End-Daten=20('endet=20am=2018.08'=20=3D=2018.08=20ist=20letzter?=
 =?UTF-8?q?=20Tag)=20und=20konvertieren=20beim=20Speichern=20auf=20exklusi?=
 =?UTF-8?q?v=20(DTEND=3D19.08).=20Beim=20Laden=20umgekehrt:=20-1=20Tag=20f?=
 =?UTF-8?q?=C3=BCrs=20Anzeigen=20im=20Picker.=20Betrifft:=20openEditEventM?=
 =?UTF-8?q?odal,=20openCopyEditModal,=20Save-Handler.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 frontend/js/calendar.js | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/frontend/js/calendar.js b/frontend/js/calendar.js
index a7faea5..7b3b41b 100644
--- a/frontend/js/calendar.js
+++ b/frontend/js/calendar.js
@@ -1127,6 +1127,21 @@ function populateCalendarSelect(selectedId) {
 }
 
 // ── Date field helpers ────────────────────────────────────
+
+// All-day events use exclusive end-dates (iCal RFC 5545 convention):
+// DTEND points to the day AFTER the last visible day. The user picker
+// uses inclusive end-dates ("ends on 18.08" means 18.08 is the last
+// day). These helpers convert between the two.
+function shiftDate(isoDate, deltaDays) {
+  if (!isoDate) return isoDate;
+  const [y, m, d] = isoDate.slice(0, 10).split('-').map(Number);
+  const dt = new Date(Date.UTC(y, m - 1, d));
+  dt.setUTCDate(dt.getUTCDate() + deltaDays);
+  return dt.toISOString().slice(0, 10);
+}
+const allDayEndToInclusive = iso => shiftDate(iso, -1); // storage → picker
+const allDayEndToExclusive = iso => shiftDate(iso, +1); // picker → storage
+
 function setDtValue(id, isoStr, mode) {
   const input = document.getElementById(id);
   if (input) input.value = isoStr || '';
@@ -1177,7 +1192,7 @@ function openCopyEditModal(ev, targetCal) {
 
   if (ev.allDay) {
     setDtValue('ev-start-date', (ev.start || '').slice(0, 10), 'date');
-    setDtValue('ev-end-date',   (ev.end   || '').slice(0, 10), 'date');
+    setDtValue('ev-end-date',   allDayEndToInclusive((ev.end || '').slice(0, 10)), 'date');
   } else {
     const s = new Date(ev.start);
     const e = new Date(ev.end);
@@ -1213,7 +1228,7 @@ function openEditEventModal(ev) {
 
   if (ev.allDay) {
     setDtValue('ev-start-date', ev.start.slice(0, 10), 'date');
-    setDtValue('ev-end-date',   ev.end.slice(0, 10),   'date');
+    setDtValue('ev-end-date',   allDayEndToInclusive(ev.end.slice(0, 10)), 'date');
     toggleAlldayFields(true);
   } else {
     const s = new Date(ev.start);
@@ -1473,6 +1488,8 @@ function bindEventModal() {
       end   = document.getElementById('ev-end-date').value;
       if (!start) { showToast(t('error_enter_date'), true); return; }
       if (!end || end < start) end = start;
+      // User picker uses inclusive end; storage uses exclusive (iCal convention)
+      end = allDayEndToExclusive(end);
     } else {
       const sv = document.getElementById('ev-start').value;
       const ev2 = document.getElementById('ev-end').value;