♻️ Refactor RecurrenceSettings

example/lib/main.dart

@@ -46,7 +46,6 @@ List<CalendarEventData> _events = [
     date: _now.subtract(Duration(days: 3)),
     recurrenceSettings: RecurrenceSettings.withCalculatedEndDate(
       startDate: _now.subtract(Duration(days: 3)),
-      endDate: _now.subtract(Duration(days: 3)),
       frequency: RepeatFrequency.daily,
       recurrenceEndOn: RecurrenceEnd.after,
       occurrences: 5,

example/lib/widgets/add_event_form.dart

@@ -25,7 +25,7 @@ class AddOrEditEventForm extends StatefulWidget {
 class _AddOrEditEventFormState extends State<AddOrEditEventForm> {
   late DateTime _startDate = DateTime.now().withoutTime;
   late DateTime _endDate = DateTime.now().withoutTime;
-  late DateTime _recurrenceEndDate = DateTime.now().withoutTime;
+  DateTime? _recurrenceEndDate;
 
   DateTime? _startTime;
   DateTime? _endTime;

lib/src/modals.dart

@@ -99,6 +99,9 @@ class LiveTimeIndicatorSettings {
 ///
 /// [weekdays]: Contains list of weekdays to repeat starting from 0 index.
 /// By default selected weekday is the start date of an event.
+///
+/// Note: Use constructor .withCalculatedEndDate to calculate
+/// end date of recurring event automatically.
 class RecurrenceSettings {
   RecurrenceSettings({
     required this.startDate,
@@ -112,22 +115,25 @@ class RecurrenceSettings {
 
   // Set by calculating end date for daily
   // Ex. If current date is 11-11-24 and interval is 5 then new end date will be
-  // 15-11-24. Interval - 1 is added because event has been already occurred
-  // once on start date.
+  // 15-11-24.
 
   // Set by calculating end date for weekly
   // Ex. If current date is 1-11-24 and interval is 5 then new end date
   // will be 29-11-24.
+  /// If recurrence event does not have an end date it will calculate end date
+  /// from the start date.
+  ///
+  /// Specify `endDate` to end an event on specific date.
   RecurrenceSettings.withCalculatedEndDate({
     required this.startDate,
-    required DateTime endDate,
+    DateTime? endDate,
     this.occurrences,
     this.frequency = RepeatFrequency.weekly,
     this.recurrenceEndOn = RecurrenceEnd.never,
     this.excludeDates,
     List<int>? weekdays,
   }) : weekdays = weekdays ?? [startDate.weekday] {
-    this.endDate = _getEndDate(endDate);
+    this.endDate = endDate ?? _getEndDate(startDate);
   }
 
   final DateTime startDate;
@@ -138,6 +144,9 @@ class RecurrenceSettings {
   final List<int> weekdays;
   final List<DateTime>? excludeDates;
 
+  // As one event has been already added on event start date it is subtracted.
+  int get _occurrences => (occurrences ?? 1) - 1;
+
   /// Calculates the end date for a monthly recurring event
   /// based on the start date and the number of occurrences.
   ///
@@ -204,26 +213,9 @@ class RecurrenceSettings {
 
     // Calculate the number of full weeks and remaining occurrences
     final fullWeeks = (targetOccurrence - 1) ~/ totalWeekdays;
-    final remainingOccurrences = (targetOccurrence - 1) % totalWeekdays;
 
     // Calculate the base date from full weeks
-    var resultDate = startDate.add(Duration(days: fullWeeks * 7));
-
-    // Find the weekday for the remaining occurrences
-    if (remainingOccurrences >= 0) {
-      final startWeekdayIndex =
-          sortedWeekdays.indexWhere((day) => day >= resultDate.weekday);
-      final weekdayIndex = startWeekdayIndex == -1
-          ? 0 + remainingOccurrences
-          : (startWeekdayIndex + remainingOccurrences) % totalWeekdays;
-
-      final targetWeekday = sortedWeekdays[weekdayIndex];
-      final daysToAdd = (targetWeekday - resultDate.weekday + 7) % 7;
-
-      resultDate = resultDate.add(Duration(days: daysToAdd));
-    }
-
-    return resultDate;
+    return startDate.add(Duration(days: fullWeeks * 7));
   }
 
   /// Calculate end date for yearly recurring event
@@ -264,39 +256,31 @@ class RecurrenceSettings {
   /// `RepeatFrequency` & `RecurrenceEnd`.
   ///
   /// Returns null if the end date is not applicable.
-  /// For example: An event that does not repeat and event that never ends.
+  /// For example: An event that "does not repeat" and event that "never ends".
   DateTime? _getEndDate(DateTime endDate) {
     if (frequency == RepeatFrequency.doNotRepeat ||
         recurrenceEndOn == RecurrenceEnd.never) {
       return null;
-    }
-
-    // TODO(Shubham): May not required to check all OR conditions verify that.
-    if (recurrenceEndOn == RecurrenceEnd.onDate &&
-        (frequency == RepeatFrequency.daily ||
-            frequency == RepeatFrequency.weekly ||
-            frequency == RepeatFrequency.monthly ||
-            frequency == RepeatFrequency.yearly)) {
+    } else if (recurrenceEndOn == RecurrenceEnd.onDate) {
       return endDate;
-    }
-
-    if (recurrenceEndOn == RecurrenceEnd.after) {
+    } else if (recurrenceEndOn == RecurrenceEnd.after) {
       return _handleOccurrence(endDate);
+    } else {
+      return null;
     }
-    return null;
   }
 
-  // Finds the end date to repeat and event for the given number of occurrences
+  /// Calculates the end date to repeat the event for the given number of
+  /// occurrences.
   DateTime? _handleOccurrence(DateTime endDate) {
-    final occurrence = occurrences ?? 1;
-    if (occurrence <= 1) {
+    if (_occurrences < 1) {
       return endDate;
     }
     switch (frequency) {
       case RepeatFrequency.doNotRepeat:
         return null;
       case RepeatFrequency.daily:
-        return endDate.add(Duration(days: occurrence - 1));
+        return endDate.add(Duration(days: _occurrences));
       case RepeatFrequency.weekly:
         return _endDateWeekly ?? endDate;
       case RepeatFrequency.monthly:
@@ -320,7 +304,7 @@ class RecurrenceSettings {
   RecurrenceSettings copyWith({
     DateTime? startDate,
     DateTime? endDate,
-    int? interval,
+    int? occurrences,
     RepeatFrequency? frequency,
     RecurrenceEnd? recurrenceEndOn,
     List<int>? weekdays,
@@ -329,7 +313,7 @@ class RecurrenceSettings {
     return RecurrenceSettings(
       startDate: startDate ?? this.startDate,
       endDate: endDate ?? this.endDate,
-      occurrences: interval ?? this.occurrences,
+      occurrences: occurrences ?? this.occurrences,
       frequency: frequency ?? this.frequency,
       recurrenceEndOn: recurrenceEndOn ?? this.recurrenceEndOn,
       weekdays: weekdays ?? this.weekdays,