From 70ff2ad79f3af87ddd7e5761434cc0ebaa9b81b3 Mon Sep 17 00:00:00 2001
From: Hady <71843721+hady-exc@users.noreply.github.com>
Date: Fri, 21 Mar 2025 10:52:43 +0200
Subject: [PATCH] fix of two minor misbehaviors in date-time handling (#3248)

---
 .../main/java/org/tasks/compose/pickers/DatePickerDialog.kt | 6 +++++-
 .../java/org/tasks/repeats/CustomRecurrenceViewModel.kt     | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/app/src/main/java/org/tasks/compose/pickers/DatePickerDialog.kt b/app/src/main/java/org/tasks/compose/pickers/DatePickerDialog.kt
index 740c7ea5a..94e173a15 100644
--- a/app/src/main/java/org/tasks/compose/pickers/DatePickerDialog.kt
+++ b/app/src/main/java/org/tasks/compose/pickers/DatePickerDialog.kt
@@ -25,7 +25,11 @@ fun DatePickerDialog(
 ) {
     val initialDateUTC by remember(initialDate) {
         derivedStateOf {
-            DateTime(initialDate).toUTC().millis
+            // DateTime(initialDate).toUTC().millis
+            // DateTime.toUTC() does not change DateTime.millis value, but DatePicker expects it
+            // is in local timezone and decrements it by TimeZone.offset. This shifts the date to
+            // the previous date in timezones to East of GMT, which is unexpected
+            DateTime(initialDate).let { it.millis + it.offset }
         }
     }
     val datePickerState = rememberDatePickerState(
diff --git a/app/src/main/java/org/tasks/repeats/CustomRecurrenceViewModel.kt b/app/src/main/java/org/tasks/repeats/CustomRecurrenceViewModel.kt
index 7b232cf04..d5cd03d3a 100644
--- a/app/src/main/java/org/tasks/repeats/CustomRecurrenceViewModel.kt
+++ b/app/src/main/java/org/tasks/repeats/CustomRecurrenceViewModel.kt
@@ -172,7 +172,11 @@ class CustomRecurrenceViewModel @Inject constructor(
             builder.interval(state.interval)
         }
         when (state.endSelection) {
-            1 -> builder.until(Date(state.endDate))
+            // 1 -> builder.until(Date(state.endDate))
+            // builder.until expects that Date() is in local timezone and strips it, which effectively
+            // equivalent to decrementing the "endDate" value by TimeZone.offset. This changes the date
+            // to the previous day in timezones to the East of GMT, so this value shall be pre-shifted
+            1 -> builder.until(Date(DateTime(state.endDate).let { it.millis + it.offset }))
             2 -> builder.count(state.endCount.coerceAtLeast(1))
         }
         return builder.build().toString()