andersnm · GradlonGwen · Jul 26, 2024
diff --git a/src/ExcelNumberFormat/Formatter.cs b/src/ExcelNumberFormat/Formatter.cs
@@ -35,7 +35,7 @@ static public string Format(object value, Section node, CultureInfo culture, boo
                 case SectionType.Date:
                     if (ExcelDateTime.TryConvert(value, isDate1904, culture, out var excelDateTime))
                     {
-                        return FormatDate(excelDateTime, node.GeneralTextDateDurationParts, culture);
+                        return FormatDate(excelDateTime, node.GeneralTextDateDurationParts, culture, node.Lcid);
                     }
                     else
                     {
@@ -45,12 +45,12 @@ static public string Format(object value, Section node, CultureInfo culture, boo
                 case SectionType.Duration:
                     if (value is TimeSpan ts)
                     {
-                        return FormatTimeSpan(ts, node.GeneralTextDateDurationParts, culture);
+                        return FormatTimeSpan(ts, node.GeneralTextDateDurationParts, culture, node.Lcid);
                     }
                     else
                     {
                         var d = Convert.ToDouble(value);
-                        return FormatTimeSpan(TimeSpan.FromDays(d), node.GeneralTextDateDurationParts, culture);
+                        return FormatTimeSpan(TimeSpan.FromDays(d), node.GeneralTextDateDurationParts, culture, node.Lcid);
                     }
 
                 case SectionType.General:
@@ -86,8 +86,13 @@ static string FormatGeneralText(string text, List<string> tokens)
             return result.ToString();
         }
 
-        private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, CultureInfo culture)
+        private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, CultureInfo culture, WindowsLanguageCodeIdentifier lcid)
         {
+            if (lcid != null && lcid.IsLongSystemTime && lcid.TimeTokens?.Count > 0)
+            {
+                tokens = lcid.TimeTokens;
+            }
+
             // NOTE/TODO: assumes there is exactly one [hh], [mm] or [ss] using the integer part of TimeSpan.TotalXXX when formatting.
             // The timeSpan input is then truncated to the remainder fraction, which is used to format mm and/or ss.
             var result = new StringBuilder();
@@ -154,8 +159,13 @@ private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, Cul
             return result.ToString();
         }
 
-        private static string FormatDate(ExcelDateTime date, List<string> tokens, CultureInfo culture)
+        private static string FormatDate(ExcelDateTime date, List<string> tokens, CultureInfo culture, WindowsLanguageCodeIdentifier lcid)
         {
+            if (lcid != null && lcid.IsLongSystemDate)
+            {
+                return date.ToString(culture.DateTimeFormat.LongDatePattern, culture);
+            }
+
             var containsAmPm = ContainsAmPm(tokens);
 
             var result = new StringBuilder();

diff --git a/src/ExcelNumberFormat/Parser.cs b/src/ExcelNumberFormat/Parser.cs
@@ -36,6 +36,7 @@ private static Section ParseSection(Tokenizer reader, int index, out bool syntax
             bool hasPlaceholders = false;
             Condition condition = null;
             Color color = null;
+            WindowsLanguageCodeIdentifier localeIdentifier = null;
             string token;
             List<string> tokens = new List<string>();
 
@@ -72,6 +73,8 @@ private static Section ParseSection(Tokenizer reader, int index, out bool syntax
                         condition = parseCondition;
                     else if (TryParseColor(expression, out var parseColor))
                         color = parseColor;
+                    else if (TryParseLocaleIdentifier(expression, out var parseLocaleIdentifier))
+                        localeIdentifier = parseLocaleIdentifier;
                     else if (TryParseCurrencySymbol(expression, out var parseCurrencySymbol))
                         tokens.Add("\"" + parseCurrencySymbol + "\"");
                 }
@@ -153,7 +156,8 @@ private static Section ParseSection(Tokenizer reader, int index, out bool syntax
                 Fraction = fraction,
                 Exponential = exponential,
                 Number = number,
-                GeneralTextDateDurationParts = generalTextDateDuration
+                GeneralTextDateDurationParts = generalTextDateDuration,
+                Lcid = localeIdentifier
             };
         }
 
@@ -394,5 +398,48 @@ private static bool TryParseCurrencySymbol(string token, out string currencySymb
 
             return true;
         }
+
+        private static bool TryParseLocaleIdentifier(string token, out WindowsLanguageCodeIdentifier lcid)
+        {
+            if (string.IsNullOrEmpty(token)
+                || !token.StartsWith("$-"))
+            {
+                lcid = null;
+                return false;
+            }
+
+            var localeStr = token.Substring(2);
+            if (!int.TryParse(localeStr, NumberStyles.AllowHexSpecifier, CultureInfo.InvariantCulture, out int localeId))
+            {
+                lcid = null;
+                return false;
+            }
+
+            lcid = new WindowsLanguageCodeIdentifier { LocaleId = localeId };
+
+            if (!lcid.IsLongSystemTime) return true;
+
+            // because in .net 2.0, TimeSpan does not have a ToString method with arguments, we will parse here the long time pattern to get the tokens that will be used in the parser.
+
+            var timeTokensList = new List<string>();
+            var tokenizer = new Tokenizer(CultureInfo.CurrentCulture.DateTimeFormat.LongTimePattern);
+            string timeToken;
+            bool syntaxError;
+
+            while ((timeToken = ReadToken(tokenizer, out syntaxError)) != null)
+            {
+                if (syntaxError)
+                {
+                    break;
+                }
+                timeTokensList.Add(timeToken);
+            }
+
+            if (!syntaxError)
+            {
+                lcid.TimeTokens = timeTokensList;
+            }
+            return true;
+        }
     }
 }
diff --git a/src/ExcelNumberFormat/Section.cs b/src/ExcelNumberFormat/Section.cs
@@ -19,5 +19,7 @@ internal class Section
         public DecimalSection Number { get; set; }
 
         public List<string> GeneralTextDateDurationParts { get; set; }
+
+        public WindowsLanguageCodeIdentifier Lcid { get; set; }
     }
 }
diff --git a/src/ExcelNumberFormat/WindowsLanguageCodeIdentifier.cs b/src/ExcelNumberFormat/WindowsLanguageCodeIdentifier.cs
@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+
+namespace ExcelNumberFormat
+{
+    /// <summary>
+    /// Represents a Windows Language Code Identifier (LCID) as defined by [MS-LCID] (https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-lcid/70feba9f-294e-491e-b6eb-56532684c37f)
+    /// </summary>
+    internal class WindowsLanguageCodeIdentifier
+    {
+        public int LocaleId { get; set; }
+
+        public bool IsLongSystemDate => LocaleId == 0xF800;
+
+        public bool IsLongSystemTime => LocaleId == 0xF400;
+
+        /// <summary>
+        /// If IsLongSystemTime is true, then contains the tokens for the time formatter.
+        /// </summary>
+        public List<string> TimeTokens { get; set; }
+    }
+}
diff --git a/test/ExcelNumberFormat.Tests/Class1.cs b/test/ExcelNumberFormat.Tests/Class1.cs
@@ -110,6 +110,7 @@ public void TestIsDateFormatString()
             Assert.IsTrue(IsDateFormatString("mm:ss"));
             Assert.IsTrue(IsDateFormatString("mm:ss.0"));
             Assert.IsTrue(IsDateFormatString("[$-809]dd mmmm yyyy"));
+            Assert.IsTrue(IsDateFormatString(@"[$-F800]dddd\,\ mmmm\ dd\,\ yyyy"));
             Assert.IsFalse(IsDateFormatString("#,##0;[Red]-#,##0"));
             Assert.IsFalse(IsDateFormatString("0_);[Red](0)"));
             Assert.IsFalse(IsDateFormatString(@"0\h"));
@@ -143,6 +144,9 @@ public void TestDate()
             Test(new DateTime(2017, 10, 16, 0, 0, 0), "dddd,,, MMMM d,, yyyy,,,,", "Monday, October 16, 2017,");
             Test(new DateTime(2020, 1, 1, 0, 35, 55), "m/d/yyyy\\ hh:mm:ss AM/PM;@", "1/1/2020 12:35:55 AM");
             Test(new DateTime(2020, 1, 1, 12, 35, 55), "m/d/yyyy\\ hh:mm:ss AM/PM;@", "1/1/2020 12:35:55 PM");
+            Test(new DateTime(2017, 10, 16, 0, 0, 0), "[$-F800]m/d/yyyy\\ h:mm:ss a/P;@", "Monday, 16 October 2017");
+            Test(new DateTime(2017, 10, 16, 0, 0, 0), @"[$-F800]dddd\,\ mmmm\ dd\,\ yyyy", "Monday, 16 October 2017");
+            TestWithCulture(new CultureInfo("Fr-fr"), new DateTime(2017, 10, 16, 0, 0, 0), @"[$-F800]dddd\,\ mmmm\ dd\,\ yyyy", "lundi 16 octobre 2017");
         }
 
         [TestMethod]
@@ -192,11 +196,18 @@ public void TestTimeSpan()
             Test(new TimeSpan(0, -2, -31, -45), "[hh]:mm:ss", "-02:31:45");
             Test(new TimeSpan(0, -2, -31, -44, -500), "[hh]:mm:ss", "-02:31:45");
             Test(new TimeSpan(0, -2, -31, -44, -500), "[hh]:mm:ss.000", "-02:31:44.500");
+            Test(new TimeSpan(1, 2, 31, 44, 500), @"[$-F400]h:mm:ss\ AM/PM", "1.02:31:44.5000000");
+            TestWithCulture(new CultureInfo("Fr-fr"),new TimeSpan(1, 2, 31, 44, 500), @"[$-F400]h:mm:ss\ AM/PM", "1.02:31:44.5000000");
         }
 
         void Test(object value, string format, string expected, bool isDate1904 = false)
         {
-            var result = Format(value, format, CultureInfo.InvariantCulture, isDate1904);
+            TestWithCulture(CultureInfo.InvariantCulture, value, format, expected, isDate1904);
+        }
+
+        void TestWithCulture(CultureInfo culture, object value, string format, string expected, bool isDate1904 = false)
+        {
+            var result = Format(value, format, culture, isDate1904);
             Assert.AreEqual(expected, result);
         }