Scaffolded project

Services/Festivities/ItalianFestivitySource.cs

@@ -0,0 +1,46 @@
+namespace WorkTracker.Services.Festivities;
+
+public sealed class ItalianFestivitySource : IItalianFestivitySource
+{
+    public IReadOnlyCollection<DateOnly> GetFestivities(int year)
+    {
+        var easterSunday = GetEasterSunday(year);
+        var easterMonday = easterSunday.AddDays(1);
+
+        return new HashSet<DateOnly>
+        {
+            new(year, 1, 1),
+            new(year, 1, 6),
+            easterSunday,
+            easterMonday,
+            new(year, 4, 25),
+            new(year, 5, 1),
+            new(year, 6, 2),
+            new(year, 8, 15),
+            new(year, 11, 1),
+            new(year, 12, 8),
+            new(year, 12, 25),
+            new(year, 12, 26)
+        };
+    }
+
+    private static DateOnly GetEasterSunday(int year)
+    {
+        var a = year % 19;
+        var b = year / 100;
+        var c = year % 100;
+        var d = b / 4;
+        var e = b % 4;
+        var f = (b + 8) / 25;
+        var g = (b - f + 1) / 3;
+        var h = (19 * a + b - d - g + 15) % 30;
+        var i = c / 4;
+        var k = c % 4;
+        var l = (32 + 2 * e + 2 * i - h - k) % 7;
+        var m = (a + 11 * h + 22 * l) / 451;
+        var month = (h + l - 7 * m + 114) / 31;
+        var day = ((h + l - 7 * m + 114) % 31) + 1;
+
+        return new DateOnly(year, month, day);
+    }
+}