Add Calendar_Gregorian support and placeholders for dayOfYear

Author: parkera

Sources/FoundationEssentials/Calendar/Calendar_Gregorian.swift

@@ -56,6 +56,7 @@ extension Date {
 /// This helper records which components should take precedence.
 enum ResolvedDateComponents {
 
+    case dayOfYear(year: Int, dayOfYear: Int)
     case day(year: Int, month: Int, day: Int?, weekOfYear: Int?)
     case weekdayOrdinal(year: Int, month: Int, weekdayOrdinal: Int, weekday: Int?)
     case weekOfYear(year: Int, weekOfYear: Int?, weekday: Int?)
@@ -112,7 +113,10 @@ enum ResolvedDateComponents {
     init(dateComponents components: DateComponents) {
         var (year, month) = Self.yearMonth(forDateComponent: components)
         let minWeekdayOrdinal = 1
-        if let d = components.day {
+        
+        if #available(FoundationPreview 0.4, *), let doy = components.dayOfYear {
+            fatalError("TODO - day of year calculation")
+        } else if let d = components.day {
             if components.yearForWeekOfYear != nil, let weekOfYear = components.weekOfYear {
                 if components.month == nil && weekOfYear >= 52 {
                     year += 1
@@ -344,6 +348,15 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             return 1..<max + 1
         case .month:
             return 1..<13
+        case .dayOfYear:
+            guard let year = dateComponent.year else {
+                return nil
+            }
+            if gregorianYearIsLeap(year) {
+                return 1..<367
+            } else {
+                return 1..<366
+            }
         case .day: // day in month
             guard let month = dateComponent.month, let year = dateComponent.year else {
                 return nil
@@ -465,7 +478,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             dc.day = minMaxRange(of: .day, in: dc)?.lowerBound
             fallthrough
 
-        case .weekdayOrdinal, .weekday, .day:
+        case .weekdayOrdinal, .weekday, .day, .dayOfYear:
             dc.hour = minMaxRange(of: .hour, in: dc)?.lowerBound
             fallthrough
 
@@ -539,7 +552,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             return Date(timeIntervalSinceReferenceDate: floor(time))
         case .nanosecond:
             return Date(timeIntervalSinceReferenceDate: floor(time * 1.0e+9) * 1.0e-9)
-        case .year, .yearForWeekOfYear, .quarter, .month, .day, .weekOfMonth, .weekOfYear:
+        case .year, .yearForWeekOfYear, .quarter, .month, .day, .dayOfYear, .weekOfMonth, .weekOfYear:
             // Continue to below
             break
         case .weekdayOrdinal, .weekday:
@@ -1083,7 +1096,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             return DateInterval(start: Date(timeIntervalSinceReferenceDate: floor(time)), duration: 1.0)
         case .nanosecond:
             return DateInterval(start: Date(timeIntervalSinceReferenceDate: floor(time * 1.0e+9) * 1.0e-9), duration: 1.0e-9)
-        case .year, .yearForWeekOfYear, .quarter, .month, .day, .weekOfMonth, .weekOfYear:
+        case .year, .yearForWeekOfYear, .quarter, .month, .day, .dayOfYear, .weekOfMonth, .weekOfYear:
             // Continue to below
             break
         case .weekdayOrdinal, .weekday:
@@ -1122,7 +1135,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
         case .weekOfMonth:
             upperBound = add(.weekOfMonth, to: start, amount: 1, inTimeZone: timeZone)
 
-        case .day:
+        case .day, .dayOfYear:
             upperBound = add(.day, to: start, amount: 1, inTimeZone: timeZone)
 
         default:
@@ -1247,6 +1260,8 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
 
         var rawYear: Int
         switch resolvedComponents {
+        case .dayOfYear(_, _):
+            fatalError("TODO - day of year calculation")
         case .day(let year, let month, _, _):
             rawMonth = month
             rawYear = year
@@ -1270,6 +1285,8 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
 
         let julianDay: Int
         switch resolvedComponents {
+        case .dayOfYear(_, _):
+            fatalError("TODO - day of year calculation")
         case .day(_, _, let day, _):
             julianDay = julianDayAtBeginningOfYear + (day ?? 1)
         case .weekdayOrdinal(_, _, let weekdayOrdinal, let weekday):
@@ -1337,6 +1354,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             useJulianReference = year == gregorianStartYear
         case .weekOfMonth(_, _, _, _): break
         case .day(_, _, _, _): break
+        case .dayOfYear(_, _): break
         case .weekdayOrdinal(_, _, _, _): break
         }
 
@@ -1589,6 +1607,9 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
         }
         if components.contains(.month) { dc.month = month }
         if components.contains(.day) { dc.day = day }
+        if #available(FoundationPreview 0.4, *) {
+            if components.contains(.dayOfYear) { dc.dayOfYear = dayOfYear }
+        }
         if components.contains(.hour) { dc.hour = hour }
         if components.contains(.minute) { dc.minute = minute }
         if components.contains(.second) { dc.second = second }
@@ -1764,7 +1785,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             // nothing to do for the below fields
         case .calendar, .timeZone, .isLeapMonth:
             return date
-        case .day, .hour, .minute, .second, .weekday, .weekdayOrdinal, .weekOfMonth, .weekOfYear, .nanosecond:
+        case .day, .dayOfYear, .hour, .minute, .second, .weekday, .weekdayOrdinal, .weekOfMonth, .weekOfYear, .nanosecond:
             // Handle below
             break
         }
@@ -1794,11 +1815,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             amountInSeconds = kSecondsInWeek * amount
             keepWallTime = true
 
-        case .day:
-            amountInSeconds = amount * kSecondsInDay
-            keepWallTime = true
-
-        case .weekday:
+        case .day, .dayOfYear, .weekday:
             amountInSeconds = amount * kSecondsInDay
             keepWallTime = true
 
@@ -1866,7 +1883,7 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
 
         // month-based calculations uses .day, .month, and .year, while week-based uses .weekday, .weekOfYear and .yearForWeekOfYear.
         // When performing date adding calculations, we need to be specific whether it's "month based" or "week based". We do not want existing week-related fields in the DateComponents to conflict with the newly set month-related fields when doing month-based calculation, and vice versa. So it's necessary to only include relevant components rather than all components when performing adding calculation.
-        let monthBasedComponents : Calendar.ComponentSet = [.era, .year, .month, .day, .hour, .minute, .second, .nanosecond]
+        let monthBasedComponents : Calendar.ComponentSet = [.era, .year, .month, .day, .dayOfYear, .hour, .minute, .second, .nanosecond]
         let weekBasedComponents: Calendar.ComponentSet = [.era, .weekday, .weekOfYear, .yearForWeekOfYear, .hour, .minute, .second, .nanosecond ]
 
         var result: Date
@@ -1908,6 +1925,33 @@ internal final class _CalendarGregorian: _CalendarProtocol, @unchecked Sendable
             capDay(in: &dc) // adding 1 month to Jan 31 should return Feb 29, not Feb 31
             result = self.date(from: dc, inTimeZone: timeZone)!
 
+        case .dayOfYear:
+            if #available(FoundationPreview 0.4, *) {
+                let dc = dateComponents(monthBasedComponents, from: date, in: timeZone)
+                guard let year = dc.year, let dayOfYear = dc.dayOfYear else {
+                    preconditionFailure("dateComponents(:from:in:) unexpectedly returns nil for requested component")
+                }
+                
+                let range: Range<Int>
+                if gregorianYearIsLeap(year) {
+                    // max is 366
+                    range = 1..<367
+                } else {
+                    // max is 365
+                    range = 1..<366
+                }
+                
+                let newDayOfYear = add(amount: amount, to: dayOfYear, wrappingTo: range)
+                // Clear the month and day from the date components. Keep the era, year, and time values (hour, min, etc.)
+                var adjustedDateComponents = dc
+                adjustedDateComponents.month = nil
+                adjustedDateComponents.day = nil
+                adjustedDateComponents.dayOfYear = newDayOfYear
+                result = self.date(from: adjustedDateComponents, inTimeZone: timeZone)!
+            } else {
+                result = date
+            }
+
         case .day:
             let (_, monthStart, daysInMonth, inGregorianCutoverMonth) = dayOfMonthConsideringGregorianCutover(date, inTimeZone: timeZone)
 

Sources/FoundationEssentials/Calendar/DateComponents.swift

@@ -227,7 +227,7 @@ public struct DateComponents : Hashable, Equatable, Sendable {
         get { _dayOfYear }
         set { _dayOfYear = converted(newValue) }
     }
-
+    
     /// This exists only for compatibility with NSDateComponents deprecated `week` value.
     package var week: Int? {
         get { _week }