Translate the ISO-639-2/B codes to ISO-639-2/T. (#13068)

* Translate the ISO-639-2/B codes to ISO-639-2/T.

This enables 19 additional languages to be displayed correctly.

* Convert the 2-dimensional array to a dictionary

* Added the French language to the list of ISO-639-2/B codes

* Don't change the property, use a local variable instead.

* When creating the MediaStream in the MediaStreamRepository ensure that the ISO 639-2/T (f.e. deu) code is used for the language as that is the one the .NET culture info knows.
The other code is most likely the ISO 639-2/B code (f.e. ger) which is unknown to the .NET culture info and will result in just displaying the code instead of the display name.

* Move the substitution of ISO 639-2/B to /T to the localization manager.
Some language (like Chinese) have multiple entries in the iso6392.txt file (f.e. zho|chi|zh|..., zho|chi|zh-tw|...) but the conversation between /T and /B is the same so use .TryAdd.

* Change the method definition from GetISO6392TFromB to TryGetISO6392TFromB and return true if a case was found.

* Add unit tests for TryGetISO6392TFromB.

2 files changed, 12 insertions, 2 deletions

diff --git a/MediaBrowser.Model/Entities/MediaStream.cs b/MediaBrowser.Model/Entities/MediaStream.cs
index 95b5b43f8..5c8f37fcd 100644
--- a/MediaBrowser.Model/Entities/MediaStream.cs
+++ b/MediaBrowser.Model/Entities/MediaStream.cs
@@ -2,6 +2,7 @@
 #pragma warning disable CS1591
 
 using System;
+using System.Collections.Frozen;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Globalization;
@@ -272,7 +273,7 @@ namespace MediaBrowser.Model.Entities
                         // Do not display the language code in display titles if unset or set to a special code. Show it in all other cases (possibly expanded).
                         if (!string.IsNullOrEmpty(Language) && !_specialCodes.Contains(Language, StringComparison.OrdinalIgnoreCase))
                         {
-                            // Get full language string i.e. eng -> English. Will not work for some languages which use ISO 639-2/B instead of /T codes.
+                            // Get full language string i.e. eng -> English.
                             string fullLanguage = CultureInfo
                                 .GetCultures(CultureTypes.NeutralCultures)
                                 .FirstOrDefault(r => r.ThreeLetterISOLanguageName.Equals(Language, StringComparison.OrdinalIgnoreCase))
@@ -375,7 +376,7 @@ namespace MediaBrowser.Model.Entities
 
                         if (!string.IsNullOrEmpty(Language))
                         {
-                            // Get full language string i.e. eng -> English. Will not work for some languages which use ISO 639-2/B instead of /T codes.
+                            // Get full language string i.e. eng -> English.
                             string fullLanguage = CultureInfo
                                 .GetCultures(CultureTypes.NeutralCultures)
                                 .FirstOrDefault(r => r.ThreeLetterISOLanguageName.Equals(Language, StringComparison.OrdinalIgnoreCase))
diff --git a/MediaBrowser.Model/Globalization/ILocalizationManager.cs b/MediaBrowser.Model/Globalization/ILocalizationManager.cs
index d9df95325..f6e65028e 100644
--- a/MediaBrowser.Model/Globalization/ILocalizationManager.cs
+++ b/MediaBrowser.Model/Globalization/ILocalizationManager.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using MediaBrowser.Model.Entities;
 
 namespace MediaBrowser.Model.Globalization;
@@ -61,4 +62,12 @@ public interface ILocalizationManager
     /// <param name="language">The language.</param>
     /// <returns>The correct <see cref="CultureDto" /> for the given language.</returns>
     CultureDto? FindLanguageInfo(string language);
+
+    /// <summary>
+    /// Returns the language in ISO 639-2/T when the input is ISO 639-2/B.
+    /// </summary>
+    /// <param name="isoB">The language in ISO 639-2/B.</param>
+    /// <param name="isoT">The language in ISO 639-2/T.</param>
+    /// <returns>Whether the language could be converted.</returns>
+    public bool TryGetISO6392TFromB(string isoB, [NotNullWhen(true)] out string? isoT);
 }