Standardize language codes and improve locale handling (#4353)

Use standard BCP 47 language codes
Move Culture utils into WinFormsUtil
Detect system language on first launch

PKHeX.Core/Editing/Showdown/ShowdownSet.cs

@@ -323,7 +323,7 @@ public sealed class ShowdownSet : IBattleTemplate
     /// <summary>
     /// Gets the localized Text representation of the set details.
     /// </summary>
-    /// <param name="lang">2 character language code</param>
+    /// <param name="lang">Language code</param>
     public string LocalizedText(string lang = DefaultLanguage) => LocalizedText(GameLanguage.GetLanguageIndex(lang));
 
     /// <summary>

PKHeX.Core/Game/GameStrings/GameInfo.cs

@@ -22,7 +22,7 @@ public static class GameInfo
 
     public static GameStrings GetStrings(int index)
     {
-        return Languages[index] ??= new GameStrings(GameLanguage.Language2Char(index));
+        return Languages[index] ??= new GameStrings(GameLanguage.LanguageCode(index));
     }
 
     public static GameStrings Strings

PKHeX.Core/Game/GameStrings/GameLanguage.cs

@@ -10,14 +10,13 @@ public static class GameLanguage
 {
     public const string DefaultLanguage = "en"; // English
     public static int DefaultLanguageIndex => Array.IndexOf(LanguageCodes, DefaultLanguage);
-    public static string Language2Char(int lang) => (uint)lang >= LanguageCodes.Length ? DefaultLanguage : LanguageCodes[lang];
-
+    public static string LanguageCode(int lang) => (uint)lang >= LanguageCodes.Length ? DefaultLanguage : LanguageCodes[lang];
     public static int LanguageCount => LanguageCodes.Length;
 
     /// <summary>
-    /// Gets the language from the requested 2-char <see cref="lang"/> code.
+    /// Gets the language from the requested language code.
     /// </summary>
-    /// <param name="lang">2 character language code</param>
+    /// <param name="lang">Language code</param>
     /// <returns>Index of the language code; if not a valid language code, returns the <see cref="DefaultLanguageIndex"/>.</returns>
     public static int GetLanguageIndex(string lang)
     {
@@ -25,11 +24,18 @@ public static class GameLanguage
         return l < 0 ? DefaultLanguageIndex : l;
     }
 
+    /// <summary>
+    /// Checks whether the language code is supported.
+    /// </summary>
+    /// <param name="lang">Language code</param>
+    /// <returns>True if valid, False otherwise</returns>
+    public static bool IsLanguageValid(string lang) => Array.IndexOf(LanguageCodes, lang) != -1;
+
     /// <summary>
     /// Language codes supported for loading string resources
     /// </summary>
     /// <see cref="ProgramLanguage"/>
-    private static readonly string[] LanguageCodes = ["ja", "en", "fr", "it", "de", "es", "ko", "zh", "zh2"];
+    private static readonly string[] LanguageCodes = ["ja", "en", "fr", "it", "de", "es", "ko", "zh-Hans", "zh-Hant"];
 
     /// <summary>
     /// Pokétransporter location names, ordered per index of <see cref="LanguageCodes"/>

PKHeX.Core/Game/GameStrings/GameStrings.cs

@@ -715,7 +715,7 @@ public sealed class GameStrings : IBasicStrings
         // in Generation 9, TM #'s are padded to 3 digits; format them appropriately here
         var clone = (string[])itemlist.Clone();
         var span = clone.AsSpan();
-        var zero = lang is "ja" or "zh" or "zh2" ? "０" : "0";
+        var zero = lang is "ja" or "zh-Hans" or "zh-Hant" ? "０" : "0";
         InsertZero(span[328..420], zero); // 01-92
         InsertZero(span[618..621], zero); // 93-95
         InsertZero(span[690..694], zero); // 96-99

PKHeX.Core/Game/GameStrings/GeoLocation.cs

@@ -8,14 +8,14 @@ namespace PKHeX.Core;
 public static class GeoLocation
 {
     private static readonly string[]?[] CountryList = GetCountryList();
-    private static readonly string[] lang_geo = ["ja", "en", "fr", "de", "it", "es", "zh", "ko", "zh2"];
+    private static readonly string[] lang_geo = ["ja", "en", "fr", "de", "it", "es", "zh-Hans", "ko", "zh-Hant"];
     private static readonly string[]?[]?[] RegionList = new string[CountryList.Length][][];
 
     /// <summary>
     /// Returns the index of which the <see cref="language"/> is in the country/region list.
     /// </summary>
     public static int GetLanguageIndex(string language) => Array.IndexOf(lang_geo, language);
-    private static int GetLanguageIndex(LanguageID language) => GetLanguageIndex(language.GetLanguage2CharName());
+    private static int GetLanguageIndex(LanguageID language) => GetLanguageIndex(language.GetLanguageCode());
 
     private const string INVALID = nameof(INVALID);
 

PKHeX.Core/Legality/Encounters/Data/Gen7/Encounters7SM.cs

@@ -13,7 +13,7 @@ internal static class Encounters7SM
     internal static readonly EncounterArea7[] SlotsMN = EncounterArea7.GetAreas(Get("mn", "sm"u8), MN);
 
     private const string tradeSM = "tradesm";
-    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeSM);
+    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeSM, "zh");
 
     public static readonly EncounterStatic7[] StaticSM = // @ a\1\5\5
     [

PKHeX.Core/Legality/Encounters/Data/Gen7/Encounters7USUM.cs

@@ -13,7 +13,7 @@ internal static class Encounters7USUM
     internal static readonly EncounterArea7[] SlotsUM = EncounterArea7.GetAreas(Get("um", "uu"u8), UM);
 
     private const string tradeUSUM = "tradeusum";
-    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeUSUM);
+    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeUSUM, "zh");
 
     public static readonly EncounterStatic7[] StaticUSUM =
     [

PKHeX.Core/Legality/Encounters/Data/Gen8/Encounters8.cs

@@ -758,7 +758,7 @@ internal static class Encounters8
     ];
 
     private const string tradeSWSH = "tradeswsh";
-    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeSWSH, "zh2");
+    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeSWSH);
     private static readonly string[] TradeOT_R1 = [string.Empty, "チホコ", "Regina", "Régiona", "Regionalia", "Regine", string.Empty, "Tatiana", "지민", "易蒂", "易蒂"];
     private static readonly IndividualValueSet TradeIVs = new(15, 15, 15, 15, 15, 15);
 

PKHeX.Core/Legality/Encounters/Data/Gen8/Encounters8b.cs

@@ -93,7 +93,7 @@ internal static class Encounters8b
     ];
 
     private const string tradeBDSP = "tradebdsp";
-    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeBDSP, "zh2");
+    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeBDSP);
 
     internal static readonly EncounterTrade8b[] TradeGift_BDSP =
     [

PKHeX.Core/Legality/Encounters/Data/Gen9/Encounters9.cs

@@ -152,7 +152,7 @@ internal static class Encounters9
     ];
 
     private const string tradeSV = "tradesv";
-    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeSV, "zh2");
+    private static readonly string[][] TradeNames = Util.GetLanguageStrings10(tradeSV);
 
     internal static readonly EncounterTrade9[] TradeGift_SV =
     [

PKHeX.Core/PKM/Util/Language.cs

@@ -63,11 +63,11 @@ public static class Language
     };
 
     /// <summary>
-    /// Gets the 2-character language name for the given <see cref="LanguageID"/>.
+    /// Gets the language code for the given <see cref="LanguageID"/>.
     /// </summary>
-    /// <param name="language">Language ID to get the 2-character name for.</param>
-    /// <returns>2-character language name.</returns>
-    public static string GetLanguage2CharName(this LanguageID language) => language switch
+    /// <param name="language">Language ID to get the language code for.</param>
+    /// <returns>Language code.</returns>
+    public static string GetLanguageCode(this LanguageID language) => language switch
     {
         Japanese => "ja",
         French => "fr",
@@ -75,8 +75,8 @@ public static class Language
         German => "de",
         Spanish => "es",
         Korean => "ko",
-        ChineseS => "zh",
-        ChineseT => "zh2",
+        ChineseS => "zh-Hans",
+        ChineseT => "zh-Hant",
         _ => GameLanguage.DefaultLanguage,
     };
 

PKHeX.Core/PKM/Util/SpeciesName.cs

@@ -24,8 +24,8 @@ public static class SpeciesName
         Util.GetSpeciesList("es"), // 6 (reserved for Gen3 KO?, unused)
         Util.GetSpeciesList("es"), // 7
         Util.GetSpeciesList("ko"), // 8
-        Util.GetSpeciesList("zh"), // 9 Simplified
-        Util.GetSpeciesList("zh2"), // 10 Traditional
+        Util.GetSpeciesList("zh-Hans"), // 9 Simplified
+        Util.GetSpeciesList("zh-Hant"), // 10 Traditional
     ];
 
     /// <summary>
@@ -221,7 +221,7 @@ public static class SpeciesName
     /// For a Gen7 species name request, return the old species name (hardcoded... yay).
     /// In an updated Gen8 game, the species nickname will automatically reset to the correct localization (on save/load ?), fixing existing entries.
     /// We don't differentiate patch revisions, just generation; Gen8 will return the latest localization.
-    /// Gen8 did revise CHT species names, but only for Barraskewda, Urshifu, and Zarude. These species are new (Gen8); we can just use the latest.
+    /// Gen8 did revise CHS species names, but only for Barraskewda, Urshifu, and Zarude. These species are new (Gen8); we can just use the latest.
     /// </remarks>
     private static string GetSpeciesName7ZH(ushort species, int language) => species switch
     {