ShowdownSet: handling for context-locked forms

Retconned forms like Totems and Cosplay Pikachu that only exist in a specific context now get recognized again
Current-Context has shifted from Gen6->Gen7->Gen8+, so a "get form list for species" won't return these forms.

Not a perfect implementation, but better for now.

PKHeX.Core/Editing/BattleTemplate/Showdown/ShowdownParsing.cs

@@ -75,7 +75,10 @@ public static string GetStringFromForm(byte form, GameStrings strings, ushort sp
             return string.Empty;
 
         var forms = FormConverter.GetFormList(species, strings.Types, strings.forms, genderForms, context);
-        return form >= forms.Length ? string.Empty : forms[form];
+        var result = form >= forms.Length ? string.Empty : forms[form];
+
+        // Showdown uses a non-standard representation for some forms, and uses interstitial dashes instead of spaces.
+        return GetShowdownFormName(species, result);
     }
 
     private const string MiniorFormName = "Meteor";
@@ -116,13 +119,22 @@ public static string GetShowdownFormName(ushort species, string form)
         };
     }
 
+    public static bool IsTotemForm(ReadOnlySpan<char> formName) =>
+        formName.Equals("Totem", StringComparison.OrdinalIgnoreCase) ||
+        formName.Equals("Alola-Totem", StringComparison.OrdinalIgnoreCase) || 
+        formName.Equals("Large", StringComparison.OrdinalIgnoreCase);
+
+
+    public static bool IsCosplayPikachu(ReadOnlySpan<char> formName, ReadOnlySpan<string> formNames)
+        => FormConverter.IsCosplayPikachu(formName, formNames);
+
     /// <summary>
     /// Converts the Showdown form name to PKHeX's form name.
     /// </summary>
     /// <param name="species">Species ID</param>
     /// <param name="form">Showdown form name</param>
     /// <param name="ability">Showdown ability ID</param>
-    public static string SetShowdownFormName(ushort species, string form, int ability)
+    public static string GetFormNameFromShowdownFormName(ushort species, string form, int ability)
     {
         if (form.Length != 0)
             form = form.Replace(' ', '-'); // inconsistencies are great

PKHeX.Core/Editing/BattleTemplate/Showdown/ShowdownSet.cs

@@ -77,7 +77,8 @@ private void LoadLines(IEnumerable<string> lines, BattleTemplateLocalization loc
 
     private void SanitizeResult(BattleTemplateLocalization localization)
     {
-        FormName = ShowdownParsing.SetShowdownFormName(Species, FormName, Ability);
+        ReviseContextIfPastGenForm(localization.Strings);
+        FormName = ShowdownParsing.GetFormNameFromShowdownFormName(Species, FormName, Ability);
         Form = ShowdownParsing.GetFormFromString(FormName, localization.Strings, Species, Context);
 
         // Handle edge case with fixed-gender forms.
@@ -85,6 +86,17 @@ private void SanitizeResult(BattleTemplateLocalization localization)
             ReviseGenderedForms();
     }
 
+    private void ReviseContextIfPastGenForm(GameStrings strings)
+    {
+        if (FormName.Length == 0)
+            return; // no form name
+
+        if (FormInfo.HasTotemForm(Species) && ShowdownParsing.IsTotemForm(FormName))
+            Context = EntityContext.Gen7;
+        else if (Species is (int)Pikachu && ShowdownParsing.IsCosplayPikachu(FormName, strings.forms))
+            Context = EntityContext.Gen6;
+    }
+
     private void ReviseGenderedForms()
     {
         if (Gender == 1) // Recognized with (F)
@@ -115,7 +127,7 @@ private void ParseLines(SpanLineEnumerator lines, BattleTemplateLocalization loc
         bool first = true;
         foreach (var line in lines)
         {
-            ReadOnlySpan<char> trim = line.Trim();
+            var trim = line.Trim();
             if (IsLengthOutOfRange(trim))
             {
                 // Try for other languages just in case.
@@ -502,8 +514,7 @@ private void PushToken(BattleTemplateToken token, List<string> result, in Battle
         {
             // Core
             case BattleTemplateToken.FirstLine:
-                var form = ShowdownParsing.GetShowdownFormName(Species, FormName);
-                result.Add(GetStringFirstLine(form, settings));
+                result.Add(GetStringFirstLine(FormName, settings));
                 break;
             case BattleTemplateToken.Ability when (uint)Ability < strings.Ability.Count:
                 result.Add(cfg.Push(BattleTemplateToken.Ability, strings.Ability[Ability]));

PKHeX.Core/Legality/Tables/FormInfo.cs

@@ -24,6 +24,24 @@ public static bool IsBattleOnlyForm(ushort species, byte form, byte format)
         return false;
     }
 
+    /// <summary>
+    /// Checks if the form is a Mega form.
+    /// </summary>
+    /// <param name="species">Entity species</param>
+    /// <param name="form">Entity form</param>
+    public static bool IsMegaForm(ushort species, byte form)
+    {
+        if (BattleMegas.Contains(species))
+            return IsBattleMegaForm(species, form);
+        return false;
+    }
+
+    /// <summary>
+    /// Checks if the species has a Mega form.
+    /// </summary>
+    /// <param name="species">Entity species</param>
+    public static bool HasMegaForm(ushort species) => BattleMegas.Contains(species);
+
     private static bool IsBattleForm(ushort species, byte form) => species switch
     {
         // Only continue checking if the species is in the list of Battle Only forms.

PKHeX.Core/PKM/Util/Conversion/FormConverter.cs

@@ -957,7 +957,7 @@ private static void SetAlcremieFormList(IReadOnlyList<string> forms, Span<string
         SetDecorations(result, 7, forms[CaramelSwirl]);
         SetDecorations(result, 8, forms[RainbowSwirl]);
 
-        static void SetDecorations(Span<string> result, [ConstantExpected] byte f, string baseName)
+        static void SetDecorations(Span<string> result, [ConstantExpected] byte f, ReadOnlySpan<char> baseName)
         {
             int start = f * AlcremieCountDecoration;
             var slice = result.Slice(start, AlcremieCountDecoration);
@@ -973,4 +973,20 @@ static void SetDecorations(Span<string> result, [ConstantExpected] byte f, strin
         (int)Alcremie => Enum.GetNames<AlcremieDecoration>(),
         _ => EMPTY,
     };
+
+    /// <summary>
+    /// Compatibility check for past-generation form list for <see cref="Pikachu"/>.
+    /// </summary>
+    /// <param name="formName">Desired form name</param>
+    /// <param name="formNames">List of all form names</param>
+    /// <returns><c>true</c> if the form name is a cosplay Pikachu form.</returns>
+    public static bool IsCosplayPikachu(ReadOnlySpan<char> formName, ReadOnlySpan<string> formNames)
+    {
+        for (int i = 729; i <= 734; i++)
+        {
+            if (formName.Equals(formNames[i], StringComparison.OrdinalIgnoreCase))
+                return true;
+        }
+        return false;
+    }
 }

Tests/PKHeX.Core.Tests/Simulator/ShowdownSetTests.cs

@@ -12,11 +12,11 @@ public void SimulatorGetParse()
     {
         var settings = new BattleTemplateExportSettings(BattleTemplateConfig.CommunityStandard);
 
-        foreach (ReadOnlySpan<char> setstr in Sets)
+        foreach (var setstr in Sets)
         {
             var set = new ShowdownSet(setstr).GetSetLines(settings);
             foreach (var line in set)
-                setstr.Contains(line, StringComparison.Ordinal).Should().BeTrue($"Line {line} should be in the set {setstr}");
+                setstr.Contains(line, StringComparison.Ordinal).Should().BeTrue($"`{line}` should be in the set: {setstr}");
         }
     }
 
@@ -410,7 +410,7 @@ Adamant Nature
         SetMunchSnorLax,
 
         """
-        Greninja @ Choice Specs
+        Greninja-Ash @ Choice Specs
         Ability: Battle Bond
         EVs: 252 SpA / 4 SpD / 252 Spe
         Timid Nature