[PTRun][DateTime]Setting for First week of year and First day of week (#33406)

## Summary of the Pull Request

This PR implements two new plugin settings:
- **First week of year**

![image](https://github.com/microsoft/PowerToys/assets/61519853/c866ffc2-2a21-438c-9a1a-5f4c7f68a22e)

- **First day of week**

![image](https://github.com/microsoft/PowerToys/assets/61519853/b2ec125b-d87c-40c5-8793-743a1ffae237)

## Detailed Description of the Pull Request / Additional comments

For both settings the users can decide to be in sync with the system
settings (default) or to use their own setting. The order of days for
the `first day of week` setting is based on the current system culture.

PT Run respects these settings for the relevant results:
- calendar week
- week of month
- number of day in week

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests/PluginSettingsTests.cs

@@ -22,10 +22,12 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             var result = settings?.Length;
 
             // Assert
-            Assert.AreEqual(4, result);
+            Assert.AreEqual(6, result);
         }
 
         [DataTestMethod]
+        [DataRow("CalendarFirstWeekRule")]
+        [DataRow("FirstDayOfWeek")]
         [DataRow("OnlyDateTimeNowGlobal")]
         [DataRow("TimeWithSeconds")]
         [DataRow("DateWithWeekday")]
@@ -59,5 +61,21 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             // Assert
             Assert.AreEqual(valueExpected, result);
         }
+
+        [DataTestMethod]
+        [DataRow("CalendarFirstWeekRule", -1)]
+        [DataRow("FirstDayOfWeek", -1)]
+        public void DefaultEnumValues(string name, int valueExpected)
+        {
+            // Setup
+            TimeDateSettings setting = TimeDateSettings.Instance;
+
+            // Act
+            PropertyInfo propertyInfo = setting?.GetType()?.GetProperty(name, BindingFlags.NonPublic | BindingFlags.Instance);
+            var result = propertyInfo?.GetValue(setting);
+
+            // Assert
+            Assert.AreEqual(valueExpected, result);
+        }
     }
 }

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests/TimeAndDateHelperTests.cs

@@ -0,0 +1,65 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Globalization;
+using Microsoft.PowerToys.Run.Plugin.TimeDate.Components;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
+{
+    [TestClass]
+    public class TimeAndDateHelperTests
+    {
+        [DataTestMethod]
+        [DataRow(-1, null)] // default setting
+        [DataRow(0, CalendarWeekRule.FirstDay)]
+        [DataRow(1, CalendarWeekRule.FirstFullWeek)]
+        [DataRow(2, CalendarWeekRule.FirstFourDayWeek)]
+        [DataRow(30, null)] // wrong setting
+        public void GetCalendarWeekRuleBasedOnPluginSetting(int setting, CalendarWeekRule? valueExpected)
+        {
+            // Act
+            var result = TimeAndDateHelper.GetCalendarWeekRule(setting);
+
+            // Assert
+            if (valueExpected == null)
+            {
+                // falls back to system setting.
+                Assert.AreEqual(DateTimeFormatInfo.CurrentInfo.CalendarWeekRule, result);
+            }
+            else
+            {
+                Assert.AreEqual(valueExpected, result);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow(-1, null)] // default setting
+        [DataRow(1, DayOfWeek.Monday)]
+        [DataRow(2, DayOfWeek.Tuesday)]
+        [DataRow(3, DayOfWeek.Wednesday)]
+        [DataRow(4, DayOfWeek.Thursday)]
+        [DataRow(5, DayOfWeek.Friday)]
+        [DataRow(6, DayOfWeek.Saturday)]
+        [DataRow(0, DayOfWeek.Sunday)]
+        [DataRow(70, null)] // wrong setting
+        public void GetFirstDayOfWeekBasedOnPluginSetting(int setting, DayOfWeek? valueExpected)
+        {
+            // Act
+            var result = TimeAndDateHelper.GetFirstDayOfWeek(setting);
+
+            // Assert
+            if (valueExpected == null)
+            {
+                // falls back to system setting.
+                Assert.AreEqual(DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek, result);
+            }
+            else
+            {
+                Assert.AreEqual(valueExpected, result);
+            }
+        }
+    }
+}

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests/TimeDateResultTests.cs

@@ -65,7 +65,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void LocalFormatsWithShortTimeAndShortDate(string formatLabel, string expectedResult)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, false, false, GetDateTimeForTest());
+            var helperResults = AvailableResultsList.GetList(true, false, false, GetDateTimeForTest(), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
 
             // Act
             var result = helperResults.FirstOrDefault(x => x.Label.Equals(formatLabel, StringComparison.OrdinalIgnoreCase));
@@ -100,7 +100,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void LocalFormatsWithShortTimeAndLongDate(string formatLabel, string expectedResult)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, false, true, GetDateTimeForTest());
+            var helperResults = AvailableResultsList.GetList(true, false, true, GetDateTimeForTest(), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
 
             // Act
             var result = helperResults.FirstOrDefault(x => x.Label.Equals(formatLabel, StringComparison.OrdinalIgnoreCase));
@@ -135,7 +135,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void LocalFormatsWithLongTimeAndShortDate(string formatLabel, string expectedResult)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, true, false, GetDateTimeForTest());
+            var helperResults = AvailableResultsList.GetList(true, true, false, GetDateTimeForTest(), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
 
             // Act
             var result = helperResults.FirstOrDefault(x => x.Label.Equals(formatLabel, StringComparison.OrdinalIgnoreCase));
@@ -170,7 +170,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void LocalFormatsWithLongTimeAndLongDate(string formatLabel, string expectedResult)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, true, true, GetDateTimeForTest());
+            var helperResults = AvailableResultsList.GetList(true, true, true, GetDateTimeForTest(), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
 
             // Act
             var result = helperResults.FirstOrDefault(x => x.Label.Equals(formatLabel, StringComparison.OrdinalIgnoreCase));
@@ -189,7 +189,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void UtcFormatsWithShortTimeAndShortDate(string formatLabel, string expectedFormat)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, false, false, GetDateTimeForTest(true));
+            var helperResults = AvailableResultsList.GetList(true, false, false, GetDateTimeForTest(true), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = GetDateTimeForTest().ToString(expectedFormat, CultureInfo.CurrentCulture);
 
             // Act
@@ -209,7 +209,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void UtcFormatsWithShortTimeAndLongDate(string formatLabel, string expectedFormat)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, false, true, GetDateTimeForTest(true));
+            var helperResults = AvailableResultsList.GetList(true, false, true, GetDateTimeForTest(true), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = GetDateTimeForTest().ToString(expectedFormat, CultureInfo.CurrentCulture);
 
             // Act
@@ -229,7 +229,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void UtcFormatsWithLongTimeAndShortDate(string formatLabel, string expectedFormat)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, true, false, GetDateTimeForTest(true));
+            var helperResults = AvailableResultsList.GetList(true, true, false, GetDateTimeForTest(true), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = GetDateTimeForTest().ToString(expectedFormat, CultureInfo.CurrentCulture);
 
             // Act
@@ -249,7 +249,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
         public void UtcFormatsWithLongTimeAndLongDate(string formatLabel, string expectedFormat)
         {
             // Setup
-            var helperResults = AvailableResultsList.GetList(true, true, true, GetDateTimeForTest(true));
+            var helperResults = AvailableResultsList.GetList(true, true, true, GetDateTimeForTest(true), CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = GetDateTimeForTest().ToString(expectedFormat, CultureInfo.CurrentCulture);
 
             // Act
@@ -265,7 +265,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             // Setup
             string formatLabel = "Unix epoch time";
             DateTime timeValue = DateTime.Now.ToUniversalTime();
-            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue);
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = (long)timeValue.Subtract(new DateTime(1970, 1, 1)).TotalSeconds;
 
             // Act
@@ -281,7 +281,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             // Setup
             string formatLabel = "Unix epoch time in milliseconds";
             DateTime timeValue = DateTime.Now.ToUniversalTime();
-            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue);
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = (long)timeValue.Subtract(new DateTime(1970, 1, 1)).TotalMilliseconds;
 
             // Act
@@ -297,7 +297,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             // Setup
             string formatLabel = "Windows file time (Int64 number)";
             DateTime timeValue = DateTime.Now;
-            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue);
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = timeValue.ToFileTime().ToString(CultureInfo.CurrentCulture);
 
             // Act
@@ -313,7 +313,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             // Setup
             string formatLabel = "Era";
             DateTime timeValue = DateTime.Now;
-            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue);
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = DateTimeFormatInfo.CurrentInfo.GetEraName(CultureInfo.CurrentCulture.Calendar.GetEra(timeValue));
 
             // Act
@@ -329,7 +329,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             // Setup
             string formatLabel = "Era abbreviation";
             DateTime timeValue = DateTime.Now;
-            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue);
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, CalendarWeekRule.FirstDay, DayOfWeek.Sunday);
             var expectedResult = DateTimeFormatInfo.CurrentInfo.GetAbbreviatedEraName(CultureInfo.CurrentCulture.Calendar.GetEra(timeValue));
 
             // Act
@@ -339,6 +339,48 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.UnitTests
             Assert.AreEqual(expectedResult, result?.Value);
         }
 
+        [DataTestMethod]
+        [DataRow(CalendarWeekRule.FirstDay, "3")]
+        [DataRow(CalendarWeekRule.FirstFourDayWeek, "2")]
+        [DataRow(CalendarWeekRule.FirstFullWeek, "2")]
+        public void DifferentFirstWeekSettingConfigurations(CalendarWeekRule weekRule, string expectedWeekOfYear)
+        {
+            // Setup
+            DateTime timeValue = new DateTime(2021, 1, 12);
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, weekRule, DayOfWeek.Sunday);
+
+            // Act
+            var resultWeekOfYear = helperResults.FirstOrDefault(x => x.Label.Equals("week of the year (calendar week, week number)", StringComparison.OrdinalIgnoreCase));
+
+            // Assert
+            Assert.AreEqual(expectedWeekOfYear, resultWeekOfYear?.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow(DayOfWeek.Monday, "2", "2", "5")]
+        [DataRow(DayOfWeek.Tuesday, "3", "3", "4")]
+        [DataRow(DayOfWeek.Wednesday, "3", "3", "3")]
+        [DataRow(DayOfWeek.Thursday, "3", "3", "2")]
+        [DataRow(DayOfWeek.Friday, "3", "3", "1")]
+        [DataRow(DayOfWeek.Saturday, "2", "2", "7")]
+        [DataRow(DayOfWeek.Sunday, "2", "2", "6")]
+        public void DifferentFirstDayOfWeekSettingConfigurations(DayOfWeek dayOfWeek, string expectedWeekOfYear, string expectedWeekOfMonth, string expectedDayInWeek)
+        {
+            // Setup
+            DateTime timeValue = new DateTime(2024, 1, 12); // Friday
+            var helperResults = AvailableResultsList.GetList(true, false, false, timeValue, CalendarWeekRule.FirstDay, dayOfWeek);
+
+            // Act
+            var resultWeekOfYear = helperResults.FirstOrDefault(x => x.Label.Equals("week of the year (calendar week, week number)", StringComparison.OrdinalIgnoreCase));
+            var resultWeekOfMonth = helperResults.FirstOrDefault(x => x.Label.Equals("week of the month", StringComparison.OrdinalIgnoreCase));
+            var resultDayInWeek = helperResults.FirstOrDefault(x => x.Label.Equals("day of the week (week day)", StringComparison.OrdinalIgnoreCase));
+
+            // Assert
+            Assert.AreEqual(expectedWeekOfYear, resultWeekOfYear?.Value);
+            Assert.AreEqual(expectedWeekOfMonth, resultWeekOfMonth?.Value);
+            Assert.AreEqual(expectedDayInWeek, resultDayInWeek?.Value);
+        }
+
         [TestCleanup]
         public void CleanUp()
         {

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate/Components/AvailableResultsList.cs

@@ -10,25 +10,30 @@ using Microsoft.PowerToys.Run.Plugin.TimeDate.Properties;
 
 namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
 {
-    internal class AvailableResultsList
+    internal static class AvailableResultsList
     {
         /// <summary>
         /// Returns a list with all available date time formats
         /// </summary>
         /// <param name="isKeywordSearch">Is this a search with plugin activation keyword or not</param>
-        /// <param name="timeLong">Required for UnitTest: Show time in long format</param>
-        /// <param name="dateLong">Required for UnitTest: Show date in long format</param>
-        /// <param name="timestamp">Required for UnitTest: Use custom <see cref="DateTime"/> object to calculate results</param>
+        /// <param name="timeLongFormat">Required for UnitTest: Show time in long format</param>
+        /// <param name="dateLongFormat">Required for UnitTest: Show date in long format</param>
+        /// <param name="timestamp">Use custom <see cref="DateTime"/> object to calculate results instead of the system date/time</param>
+        /// <param name="firstWeekOfYear">Required for UnitTest: Use custom first week of the year instead of the plugin setting.</param>
+        /// <param name="firstDayOfWeek">Required for UnitTest: Use custom first day of the week instead the plugin setting.</param>
         /// <returns>List of results</returns>
-        internal static List<AvailableResult> GetList(bool isKeywordSearch, bool? timeLong = null, bool? dateLong = null, DateTime? timestamp = null)
+        internal static List<AvailableResult> GetList(bool isKeywordSearch, bool? timeLongFormat = null, bool? dateLongFormat = null, DateTime? timestamp = null, CalendarWeekRule? firstWeekOfYear = null, DayOfWeek? firstDayOfWeek = null)
         {
             List<AvailableResult> results = new List<AvailableResult>();
-            bool timeExtended = timeLong ?? TimeDateSettings.Instance.TimeWithSeconds;
-            bool dateExtended = dateLong ?? TimeDateSettings.Instance.DateWithWeekday;
-            bool isSystemDateTime = timestamp == null;
             Calendar calendar = CultureInfo.CurrentCulture.Calendar;
+
+            bool timeExtended = timeLongFormat ?? TimeDateSettings.Instance.TimeWithSeconds;
+            bool dateExtended = dateLongFormat ?? TimeDateSettings.Instance.DateWithWeekday;
+            bool isSystemDateTime = timestamp == null;
             DateTime dateTimeNow = timestamp ?? DateTime.Now;
             DateTime dateTimeNowUtc = dateTimeNow.ToUniversalTime();
+            CalendarWeekRule firstWeekRule = firstWeekOfYear ?? TimeAndDateHelper.GetCalendarWeekRule(TimeDateSettings.Instance.CalendarFirstWeekRule);
+            DayOfWeek firstDayOfTheWeek = firstDayOfWeek ?? TimeAndDateHelper.GetFirstDayOfWeek(TimeDateSettings.Instance.FirstDayOfWeek);
 
             results.AddRange(new[]
             {
@@ -62,7 +67,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
                 // We use long instead of int for unix time stamp because int is too small after 03:14:07 UTC 2038-01-19
                 long unixTimestamp = ((DateTimeOffset)dateTimeNowUtc).ToUnixTimeSeconds();
                 long unixTimestampMilliseconds = ((DateTimeOffset)dateTimeNowUtc).ToUnixTimeMilliseconds();
-                int weekOfYear = calendar.GetWeekOfYear(dateTimeNow, DateTimeFormatInfo.CurrentInfo.CalendarWeekRule, DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek);
+                int weekOfYear = calendar.GetWeekOfYear(dateTimeNow, firstWeekRule, firstDayOfTheWeek);
                 string era = DateTimeFormatInfo.CurrentInfo.GetEraName(calendar.GetEra(dateTimeNow));
                 string eraShort = DateTimeFormatInfo.CurrentInfo.GetAbbreviatedEraName(calendar.GetEra(dateTimeNow));
 
@@ -133,7 +138,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
                     },
                     new AvailableResult()
                     {
-                        Value = TimeAndDateHelper.GetNumberOfDayInWeek(dateTimeNow).ToString(CultureInfo.CurrentCulture),
+                        Value = TimeAndDateHelper.GetNumberOfDayInWeek(dateTimeNow, firstDayOfTheWeek).ToString(CultureInfo.CurrentCulture),
                         Label = Resources.Microsoft_plugin_timedate_DayOfWeek,
                         AlternativeSearchTag = ResultHelper.SelectStringFromResources(isSystemDateTime, "Microsoft_plugin_timedate_SearchTagDate"),
                         IconType = ResultIconType.Date,
@@ -154,7 +159,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
                     },
                     new AvailableResult()
                     {
-                        Value = TimeAndDateHelper.GetWeekOfMonth(dateTimeNow).ToString(CultureInfo.CurrentCulture),
+                        Value = TimeAndDateHelper.GetWeekOfMonth(dateTimeNow, firstDayOfTheWeek).ToString(CultureInfo.CurrentCulture),
                         Label = Resources.Microsoft_plugin_timedate_WeekOfMonth,
                         AlternativeSearchTag = ResultHelper.SelectStringFromResources(isSystemDateTime, "Microsoft_plugin_timedate_SearchTagDate"),
                         IconType = ResultIconType.Date,

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate/Components/TimeAndDateHelper.cs

@@ -57,16 +57,17 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
         /// </summary>
         /// <param name="date">date</param>
         /// <returns>Number of week in the month</returns>
-        internal static int GetWeekOfMonth(DateTime date)
+        internal static int GetWeekOfMonth(DateTime date, DayOfWeek formatSettingFirstDayOfWeek)
         {
             DateTime beginningOfMonth = new DateTime(date.Year, date.Month, 1);
+            int adjustment = 1; // We count from 1 to 7 and not from 0 to 6
 
-            while (date.Date.AddDays(1).DayOfWeek != CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek)
+            while (date.Date.AddDays(1).DayOfWeek != formatSettingFirstDayOfWeek)
             {
                 date = date.AddDays(1);
             }
 
-            return (int)Math.Truncate((double)date.Subtract(beginningOfMonth).TotalDays / 7f) + 1;
+            return (int)Math.Truncate((double)date.Subtract(beginningOfMonth).TotalDays / 7f) + adjustment;
         }
 
         /// <summary>
@@ -74,13 +75,12 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
         /// </summary>
         /// <param name="date">Date</param>
         /// <returns>Number of the day in the week</returns>
-        internal static int GetNumberOfDayInWeek(DateTime date)
+        internal static int GetNumberOfDayInWeek(DateTime date, DayOfWeek formatSettingFirstDayOfWeek)
         {
             int daysInWeek = 7;
             int adjustment = 1; // We count from 1 to 7 and not from 0 to 6
-            int formatSettingFirstDayOfWeek = (int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek;
 
-            return ((int)(date.DayOfWeek + daysInWeek - formatSettingFirstDayOfWeek) % daysInWeek) + adjustment;
+            return ((date.DayOfWeek + daysInWeek - formatSettingFirstDayOfWeek) % daysInWeek) + adjustment;
         }
 
         /// <summary>
@@ -133,6 +133,52 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
         {
             return Regex.IsMatch(input, @"^.*(u|ums|ft)\d");
         }
+
+        /// <summary>
+        /// Returns a CalendarWeekRule enum value based on the plugin setting.
+        /// </summary>
+        internal static CalendarWeekRule GetCalendarWeekRule(int pluginSetting)
+        {
+            switch (pluginSetting)
+            {
+                case 0:
+                    return CalendarWeekRule.FirstDay;
+                case 1:
+                    return CalendarWeekRule.FirstFullWeek;
+                case 2:
+                    return CalendarWeekRule.FirstFourDayWeek;
+                default:
+                    // Wrong json value and system setting (-1).
+                    return DateTimeFormatInfo.CurrentInfo.CalendarWeekRule;
+            }
+        }
+
+        /// <summary>
+        /// Returns a DayOfWeek enum value based on the FirstDayOfWeek plugin setting.
+        /// </summary>
+        internal static DayOfWeek GetFirstDayOfWeek(int pluginSetting)
+        {
+            switch (pluginSetting)
+            {
+                case 0:
+                    return DayOfWeek.Sunday;
+                case 1:
+                    return DayOfWeek.Monday;
+                case 2:
+                    return DayOfWeek.Tuesday;
+                case 3:
+                    return DayOfWeek.Wednesday;
+                case 4:
+                    return DayOfWeek.Thursday;
+                case 5:
+                    return DayOfWeek.Friday;
+                case 6:
+                    return DayOfWeek.Saturday;
+                default:
+                    // Wrong json value and system setting (-1).
+                    return DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek;
+            }
+        }
     }
 
     /// <summary>

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate/Components/TimeDateSettings.cs

@@ -2,7 +2,9 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using Microsoft.PowerToys.Run.Plugin.TimeDate.Properties;
@@ -28,6 +30,16 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
         /// </summary>
         private static TimeDateSettings instance;
 
+        /// <summary>
+        /// Gets the value of the "First Week Rule" setting
+        /// </summary>
+        internal int CalendarFirstWeekRule { get; private set; }
+
+        /// <summary>
+        /// Gets the value of the "First Day Of Week" setting
+        /// </summary>
+        internal int FirstDayOfWeek { get; private set; }
+
         /// <summary>
         /// Gets a value indicating whether to show only the time and date for system time in global results or not
         /// </summary>
@@ -87,6 +99,29 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
         {
             var optionList = new List<PluginAdditionalOption>
             {
+                new PluginAdditionalOption()
+                {
+                    Key = nameof(CalendarFirstWeekRule),
+                    DisplayLabel = Resources.Microsoft_plugin_timedate_SettingFirstWeekRule,
+                    DisplayDescription = Resources.Microsoft_plugin_timedate_SettingFirstWeekRule_Description,
+                    PluginOptionType = PluginAdditionalOption.AdditionalOptionType.Combobox,
+                    ComboBoxItems = new List<KeyValuePair<string, string>>
+                    {
+                        new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_Setting_UseSystemSetting, "-1"),
+                        new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstWeekRule_FirstDay, "0"),
+                        new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFullWeek, "1"),
+                        new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFourDayWeek, "2"),
+                    },
+                    ComboBoxValue = -1,
+                },
+                new PluginAdditionalOption()
+                {
+                    Key = nameof(FirstDayOfWeek),
+                    DisplayLabel = Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek,
+                    PluginOptionType = PluginAdditionalOption.AdditionalOptionType.Combobox,
+                    ComboBoxItems = GetSortedListForWeekDaySetting(),
+                    ComboBoxValue = -1,
+                },
                 new PluginAdditionalOption()
                 {
                     Key = nameof(OnlyDateTimeNowGlobal),
@@ -130,6 +165,8 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
                 return;
             }
 
+            CalendarFirstWeekRule = GetEnumSettingOrDefault(settings, nameof(CalendarFirstWeekRule));
+            FirstDayOfWeek = GetEnumSettingOrDefault(settings, nameof(FirstDayOfWeek));
             OnlyDateTimeNowGlobal = GetSettingOrDefault(settings, nameof(OnlyDateTimeNowGlobal));
             TimeWithSeconds = GetSettingOrDefault(settings, nameof(TimeWithSeconds));
             DateWithWeekday = GetSettingOrDefault(settings, nameof(DateWithWeekday));
@@ -150,5 +187,57 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
             // We can use First() instead of FirstOrDefault() because the values must exist. Otherwise, we made a mistake when defining the settings.
             return option?.Value ?? GetAdditionalOptions().First(x => x.Key == name).Value;
         }
+
+        /// <summary>
+        /// Return the combobox value of the given settings list with the given name.
+        /// </summary>
+        /// <param name="settings">The object that contain all settings.</param>
+        /// <param name="name">The name of the setting.</param>
+        /// <returns>A settings value.</returns>
+        private static int GetEnumSettingOrDefault(PowerLauncherPluginSettings settings, string name)
+        {
+            var option = settings?.AdditionalOptions?.FirstOrDefault(x => x.Key == name);
+
+            // If a setting isn't available, we use the value defined in the method GetAdditionalOptions() as fallback.
+            // We can use First() instead of FirstOrDefault() because the values must exist. Otherwise, we made a mistake when defining the settings.
+            return option?.ComboBoxValue ?? GetAdditionalOptions().First(x => x.Key == name).ComboBoxValue;
+        }
+
+        /// <summary>
+        /// Returns a sorted list of values for the combo box of 'first day of week' setting.
+        /// The list is sorted based on the current system culture setting.
+        /// </summary>
+        /// <remarks>In the world we have three groups of countries: Saturday, Sunday, Monday (Everything else is chosen by the user.)</remarks>
+        /// <returns>List of values for combo box.</returns>
+        private static List<KeyValuePair<string, string>> GetSortedListForWeekDaySetting()
+        {
+            // List (Sorted for first day is Sunday)
+            var list = new List<KeyValuePair<string, string>>
+            {
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_Setting_UseSystemSetting, "-1"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Sunday, "0"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Monday, "1"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Tuesday, "2"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Wednesday, "3"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Thursday, "4"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Friday, "5"),
+                new KeyValuePair<string, string>(Resources.Microsoft_plugin_timedate_SettingFirstDayOfWeek_Saturday, "6"),
+            };
+
+            // Order Rules
+            string[] orderRuleSaturday = new string[] { "-1", "6", "0", "1", "2", "3", "4", "5" };
+            string[] orderRuleMonday = new string[] { "-1", "1", "2", "3", "4", "5", "6", "0" };
+
+            switch (DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek)
+            {
+                case DayOfWeek.Saturday:
+                    return list.OrderBy(x => Array.IndexOf(orderRuleSaturday, x.Value)).ToList();
+                case DayOfWeek.Monday:
+                    return list.OrderBy(x => Array.IndexOf(orderRuleMonday, x.Value)).ToList();
+                default:
+                    // DayOfWeek.Sunday
+                    return list;
+            }
+        }
     }
 }

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate/Properties/Resources.Designer.cs

@@ -438,6 +438,15 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Use system setting.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_Setting_UseSystemSetting {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_Setting_UseSystemSetting", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Show date with weekday and name of month.
         /// </summary>
@@ -456,6 +465,123 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to First day of the week.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Friday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Friday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Friday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Monday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Monday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Monday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Saturday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Saturday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Saturday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Sunday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Sunday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Sunday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Thursday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Thursday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Thursday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Tuesday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Tuesday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Tuesday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Wednesday.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstDayOfWeek_Wednesday {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstDayOfWeek_Wednesday", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to First week of the year.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstWeekRule {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstWeekRule", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Configure the calendar rule for the first week of the year..
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstWeekRule_Description {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstWeekRule_Description", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to First day of year.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstWeekRule_FirstDay {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstWeekRule_FirstDay", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to First four day week.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFourDayWeek {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFourDayWeek", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to First full week.
+        /// </summary>
+        internal static string Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFullWeek {
+            get {
+                return ResourceManager.GetString("Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFullWeek", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Hide &apos;Invalid number input&apos; error message on global queries.
         /// </summary>

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate/Properties/Resources.resx

@@ -315,4 +315,46 @@
   <data name="Microsoft_plugin_timedate_Unix_Milliseconds" xml:space="preserve">
     <value>Unix epoch time in milliseconds</value>
   </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek" xml:space="preserve">
+    <value>First day of the week</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Friday" xml:space="preserve">
+    <value>Friday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Monday" xml:space="preserve">
+    <value>Monday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Saturday" xml:space="preserve">
+    <value>Saturday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Sunday" xml:space="preserve">
+    <value>Sunday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Thursday" xml:space="preserve">
+    <value>Thursday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Tuesday" xml:space="preserve">
+    <value>Tuesday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstDayOfWeek_Wednesday" xml:space="preserve">
+    <value>Wednesday</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstWeekRule" xml:space="preserve">
+    <value>First week of the year</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstWeekRule_Description" xml:space="preserve">
+    <value>Configure the calendar rule for the first week of the year.</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstWeekRule_FirstDay" xml:space="preserve">
+    <value>First day of year</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFourDayWeek" xml:space="preserve">
+    <value>First four day week</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_SettingFirstWeekRule_FirstFullWeek" xml:space="preserve">
+    <value>First full week</value>
+  </data>
+  <data name="Microsoft_plugin_timedate_Setting_UseSystemSetting" xml:space="preserve">
+    <value>Use system setting</value>
+  </data>
 </root>