Simplify date component construction

Author: hristost

Sources/FoundationEssentials/Calendar/Calendar_Recurrence.swift

@@ -316,34 +316,38 @@ extension Calendar {
                 var componentCombinations = Calendar._DateComponentCombinations()
 
                 if recurrence.frequency == .yearly || recurrence.frequency == .monthly {
-                    if recurrence.daysOfTheYear.isEmpty {
+                    if dayOfYearAction == .expand {
+                        componentCombinations.months = nil
+                        componentCombinations.daysOfMonth = nil
+                        componentCombinations.daysOfYear = recurrence.daysOfTheYear
+                    } else {
                         componentCombinations.months = if recurrence.months.isEmpty { [RecurrenceRule.Month(from: components)!] } else { recurrence.months }
                         componentCombinations.daysOfMonth = if recurrence.daysOfTheMonth.isEmpty { [components.day!] } else { recurrence.daysOfTheMonth}
                         componentCombinations.daysOfYear = nil
-                    } else {
-                        componentCombinations.months = nil
-                        componentCombinations.daysOfMonth = nil
-                        componentCombinations.daysOfYear = if recurrence.daysOfTheYear.isEmpty { [components.day!] } else { recurrence.daysOfTheYear}
                     }
                 } else {
                     componentCombinations.months = nil
                     componentCombinations.daysOfMonth = nil
                     componentCombinations.daysOfYear = nil
                 }
-                let searchInterval = calendar.dateInterval(of: recurrence.frequency.component, for: anchor)!
-                let searchRange = searchInterval.start..<searchInterval.end
-                let searchStart = searchInterval.start
+
                 if weekdayAction == .expand {
                     componentCombinations.weekdays = recurrence.weekdays
                     componentCombinations.daysOfYear = nil
                     componentCombinations.daysOfMonth = nil
-                } else if recurrence.frequency == .weekly || !recurrence.weeks.isEmpty {
+                } else if recurrence.frequency == .weekly || weekAction == .expand {
                    if let weekdayIdx = components.weekday, let weekday = Locale.Weekday(weekdayIdx) {
+                       // In a weekly recurrence (or one that expands weeks of year), we want results to fall on the same weekday as the initial date
                        componentCombinations.weekdays = [.every(weekday)]
                        componentCombinations.daysOfYear = nil
                        componentCombinations.daysOfMonth = nil
                     }
                 }
+                if weekAction == .expand {
+                    // In a yearly recurrence with weeks specified, results do not land on any specific month
+                    componentCombinations.weeksOfYear = recurrence.weeks
+                    componentCombinations.months = nil
+                }
                 if recurrence.frequency != .hourly, recurrence.frequency != .minutely {
                     componentCombinations.hours = if hourAction == .expand { recurrence.hours } else { components.hour.map { [$0] } }
                 }
@@ -352,12 +356,10 @@ extension Calendar {
                 }
                 componentCombinations.seconds = if secondAction == .expand { recurrence.seconds } else { components.second.map { [$0] } }
 
-                if !recurrence.weeks.isEmpty {
-                    if recurrence.frequency == .yearly {
-                        componentCombinations.weeksOfYear = recurrence.weeks
-                        componentCombinations.months = nil
-                    }
-                }
+
+                let searchInterval = calendar.dateInterval(of: recurrence.frequency.component, for: anchor)!
+                let searchRange = searchInterval.start..<searchInterval.end
+                let searchStart = searchInterval.start
 
                 // First expand the set of dates, and then filter it. The order
                 // of expansions is fixed, and must stay exactly as it is so we