From 78add732782a79a8da1aba1f4bfba4542edbc1a4 Mon Sep 17 00:00:00 2001
From: DragonSlayer_14 <dragonslayer14@murena.io>
Date: Sun, 25 Jan 2026 16:34:14 +0100
Subject: [PATCH] Fix: Passt an, dass bei monatlichen Transaktionen der Tag
 entsprechend hergenommen wird

---
 lib/PlatformDependent/Web/date_utils_web.dart | 28 +++++++++++++
 lib/Tasks/generate_transactions_task.dart     | 40 ++++++++++++++++++-
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/lib/PlatformDependent/Web/date_utils_web.dart b/lib/PlatformDependent/Web/date_utils_web.dart
index 08e53e3..866dba1 100644
--- a/lib/PlatformDependent/Web/date_utils_web.dart
+++ b/lib/PlatformDependent/Web/date_utils_web.dart
@@ -16,4 +16,32 @@ class DateUtils {
     final DateTime monthDate,
     final int monthsToAdd,
   ) => DateTime(monthDate.year, monthDate.month + monthsToAdd);
+
+  /// Returns the number of days in a month, according to the proleptic
+  /// Gregorian calendar.
+  ///
+  /// This applies the leap year logic introduced by the Gregorian reforms of
+  /// 1582. It will not give valid results for dates prior to that time.
+  static int getDaysInMonth(final int year, final int month) {
+    if (month == DateTime.february) {
+      final bool isLeapYear =
+          (year % 4 == 0) && (year % 100 != 0) || (year % 400 == 0);
+      return isLeapYear ? 29 : 28;
+    }
+    const List<int> daysInMonth = <int>[
+      31,
+      -1,
+      31,
+      30,
+      31,
+      30,
+      31,
+      31,
+      30,
+      31,
+      30,
+      31,
+    ];
+    return daysInMonth[month - 1];
+  }
 }
diff --git a/lib/Tasks/generate_transactions_task.dart b/lib/Tasks/generate_transactions_task.dart
index 0dc8df7..93ba2c9 100644
--- a/lib/Tasks/generate_transactions_task.dart
+++ b/lib/Tasks/generate_transactions_task.dart
@@ -67,15 +67,51 @@ class GenerateTransactionsTask extends Task {
         case TimeFrameEnum.weekly:
           newTransactionDate = lastTransactionDate.add(const Duration(days: 7));
         case TimeFrameEnum.monthly:
-          newTransactionDate = DateUtils.addMonthsToMonthDate(
+          final DateTime monthDate = DateUtils.addMonthsToMonthDate(
             lastTransactionDate,
             1,
           );
+
+          final int day =
+              recurringTransaction.startDate!.day <
+                  DateUtils.getDaysInMonth(
+                    monthDate.year,
+                    monthDate.day,
+                  )
+              ? recurringTransaction.startDate!.day
+              : DateUtils.getDaysInMonth(
+                monthDate.year,
+                monthDate.month,
+                );
+
+          newTransactionDate = DateTime(
+            monthDate.year,
+            monthDate.month,
+            day,
+          );
         case TimeFrameEnum.yearly:
-          newTransactionDate = DateUtils.addMonthsToMonthDate(
+          final DateTime monthDate = DateUtils.addMonthsToMonthDate(
             lastTransactionDate,
             12,
           );
+
+          final int day =
+          recurringTransaction.startDate!.day <
+              DateUtils.getDaysInMonth(
+                monthDate.year,
+                monthDate.day,
+              )
+              ? recurringTransaction.startDate!.day
+              : DateUtils.getDaysInMonth(
+            monthDate.year,
+            monthDate.month,
+          );
+
+          newTransactionDate = DateTime(
+            monthDate.year,
+            monthDate.month,
+            day,
+          );
       }
     } else {
       newTransactionDate = recurringTransaction.startDate!;