Handle Ability Patch changed abilities (#3024)

Handles conditions when Ability Patch has been used to modify the PKM's ability => hidden ability.

Per the description, it goes 1/2=>H, not the other way around.

Verify ability bit first, as mystery gift case handling skips the bit check logic :P

PKHeX.Core/Legality/LegalityCheckStrings.cs

@@ -64,6 +64,7 @@ namespace PKHeX.Core
         public static string L_XWurmpleEvo_0 { get; set; } = "Wurmple Evolution: {0}";
 
         public static string LAbilityCapsuleUsed { get; set; } = "Ability modified with Ability Capsule.";
+        public static string LAbilityPatchUsed { get; set; } = "Ability modified with Ability Patch.";
         public static string LAbilityFlag { get; set; } = "Ability matches ability number.";
         public static string LAbilityHiddenFail { get; set; } = "Hidden Ability mismatch for encounter type.";
         public static string LAbilityHiddenUnavailable { get; set; } = "Hidden Ability not available.";

PKHeX.Core/Legality/RNG/RaidRNG.cs

@@ -111,8 +111,15 @@ namespace PKHeX.Core
                 abil = ability_param;
             abil <<= 1; // 1/2/4
 
-            if ((pk.AbilityNumber == 4) != (abil == 4))
+            var current = pk.AbilityNumber;
+            if (current == 4 && abil != 4)
+            {
+                // Defer for Ability Checks
+            }
+            else if (abil == 4)
+            {
                 return false;
+            }
 
             switch (gender_ratio)
             {

PKHeX.Core/Legality/Verifiers/AbilityVerifier.cs

@@ -36,24 +36,34 @@ namespace PKHeX.Core
             if (abilval < 0)
                 return GetInvalid(LAbilityUnexpected);
 
-            var enc = data.EncounterMatch;
             var abilities = pi.Abilities;
+            int format = pkm.Format;
+            if (format >= 6)
+            {
+                // Check AbilityNumber is a single set bit
+                var num = pkm.AbilityNumber;
+                if (!(num != 0 && (num & (num - 1)) == 0)) // not [!zero, and power of 2]
+                    return GetInvalid(LAbilityMismatchFlag);
+
+                // Check AbilityNumber points to ability
+                int an = num >> 1;
+                if (an >= abilities.Count || abilities[an] != ability)
+                    return GetInvalid(LAbilityMismatchFlag);
+            }
+
+            if (format >= 8) // Ability Patch
+            {
+                if (pkm.AbilityNumber == 4 && CanAbilityPatch(format, abilities))
+                    return GetValid(LAbilityPatchUsed);
+            }
+
+            var enc = data.EncounterMatch;
             if (enc is MysteryGift g && g.Format >= 4)
                 return VerifyAbilityMG(data, g, abilities);
 
-            if (pkm.Format < 6)
+            if (format < 6)
                 return VerifyAbility345(data, enc, abilities, abilval);
 
-            // Check AbilityNumber is a single set bit
-            var num = pkm.AbilityNumber;
-            if (num == 0 || num == 0b101 || num == 0b110 || num == 0b011)
-                return GetInvalid(LAbilityMismatchFlag);
-
-            // Check AbilityNumber points to ability
-            int an = num >> 1;
-            if (an >= abilities.Count || abilities[an] != ability)
-                return GetInvalid(LAbilityMismatchFlag);
-
             return VerifyAbility(data, abilities, abilval);
         }
 
@@ -225,9 +235,10 @@ namespace PKHeX.Core
         private CheckResult VerifyAbilityPCD(LegalityAnalysis data, IReadOnlyList<int> abilities, PCD pcd)
         {
             var pkm = data.pkm;
-            if (pkm.Format >= 6)
+            var format = pkm.Format;
+            if (format >= 6)
             {
-                if (abilities[0] == abilities[1])
+                if (CanAbilityCapsule(format, abilities))
                 {
                     // Gen3-5 transfer with same ability -> 1st ability that matches
                     if (pkm.AbilityNumber == 1)
@@ -334,10 +345,8 @@ namespace PKHeX.Core
         // Ability Capsule can change between 1/2
         private static bool IsAbilityCapsuleModified(PKM pkm, IReadOnlyList<int> abilities, int EncounterAbility)
         {
-            if (pkm.Format < 6)
+            if (!CanAbilityCapsule(pkm.Format, abilities))
-                return false; // Ability Capsule does not exist
+                return false;
-            if (abilities[0] == abilities[1])
-                return false; // Cannot alter ability index if it is the same as the other ability.
             if (pkm.AbilityNumber == 4)
                 return false; // Cannot alter to hidden ability.
             if (EncounterAbility == 4)
@@ -345,6 +354,21 @@ namespace PKHeX.Core
             return true;
         }
 
+        private static bool CanAbilityCapsule(int format, IReadOnlyList<int> abilities)
+        {
+            if (format < 6) // Ability Capsule does not exist
+                return false;
+            return abilities[0] != abilities[1]; // Cannot alter ability index if it is the same as the other ability.
+        }
+
+        public static bool CanAbilityPatch(int format, IReadOnlyList<int> abilities)
+        {
+            if (format < 8) // Ability Patch does not exist
+                return false;
+            var h = abilities[2];
+            return h != abilities[0] || h != abilities[1]; // Cannot alter ability index if it is the same as the other abilities.
+        }
+
         private static int GetEncounterFixedAbilityNumber(IEncounterable enc)
         {
             return enc switch

PKHeX.Core/Legality/Verifiers/BallVerifier.cs

@@ -122,7 +122,7 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Safari.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4)
+                if (IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -130,7 +130,7 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Apricorn6.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4)
+                if (IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -138,13 +138,13 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Sport.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4)
+                if (IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
             if (ball == Dream) // Dream Ball
             {
-                if (pkm.AbilityNumber == 4 && Legal.Ban_DreamHidden.Contains(species))
+                if (Legal.Ban_DreamHidden.Contains(species) && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 if (Legal.Inherit_Dream.Contains(species))
                     return GetValid(LBallSpeciesPass);
@@ -160,7 +160,7 @@ namespace PKHeX.Core
             {
                 if (Legal.Ban_Gen3Ball.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && Legal.Ban_Gen3BallHidden.Contains(pkm.SpecForm))
+                if (Legal.Ban_Gen3BallHidden.Contains(pkm.SpecForm) && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -191,7 +191,7 @@ namespace PKHeX.Core
             {
                 if (!(Legal.Inherit_Safari.Contains(species) || Legal.Inherit_SafariMale.Contains(species)))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && Legal.Ban_SafariBallHidden_7.Contains(species))
+                if (Legal.Ban_SafariBallHidden_7.Contains(species) && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -199,7 +199,7 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Apricorn7.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && Legal.Ban_NoHidden7Apricorn.Contains(species | pkm.AltForm << 11)) // lineage is 3->2->origin
+                if (Legal.Ban_NoHidden7Apricorn.Contains(species | pkm.AltForm << 11) && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -207,7 +207,7 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Sport.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && (species == (int)Species.Volbeat || species == (int)Species.Illumise)) // Volbeat/Illumise
+                if ((species == (int)Species.Volbeat || species == (int)Species.Illumise) && IsHiddenAndNotPossible(pkm)) // Volbeat/Illumise
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -232,9 +232,9 @@ namespace PKHeX.Core
 
             if (ball == Beast)
             {
-                if (species == (int)Species.Flabébé && pkm.AltForm == 3 && pkm.AbilityNumber == 4)
+                if (species == (int)Species.Flabébé && pkm.AltForm == 3 && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility); // Can't obtain Flabébé-Blue with Hidden Ability in wild
-                if (species == (int)Species.Voltorb && pkm.AbilityNumber == 4)
+                if (species == (int)Species.Voltorb && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility); // Can't obtain with Hidden Ability in wild (can only breed with Ditto)
                 if (((int)Species.Pikipek <= species && species <= (int)Species.Kommoo) || (Legal.AlolanCaptureOffspring.Contains(species) && !Legal.PastGenAlolanNativesUncapturable.Contains(species)))
                     return GetValid(LBallSpeciesPass);
@@ -275,7 +275,7 @@ namespace PKHeX.Core
             {
                 if (!(Legal.Inherit_Safari.Contains(species) || Legal.Inherit_SafariMale.Contains(species)))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && Legal.Ban_SafariBallHidden_7.Contains(species))
+                if (Legal.Ban_SafariBallHidden_7.Contains(species) && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -283,7 +283,7 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Apricorn7.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && Legal.Ban_NoHidden8Apricorn.Contains(species | pkm.AltForm << 11)) // lineage is 3->2->origin
+                if (Legal.Ban_NoHidden8Apricorn.Contains(species | pkm.AltForm << 11) && IsHiddenAndNotPossible(pkm)) // lineage is 3->2->origin
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -291,7 +291,7 @@ namespace PKHeX.Core
             {
                 if (!Legal.Inherit_Sport.Contains(species))
                     return GetInvalid(LBallSpecies);
-                if (pkm.AbilityNumber == 4 && (species == (int)Species.Volbeat || species == (int)Species.Illumise)) // Volbeat/Illumise
+                if ((species == (int)Species.Volbeat || species == (int)Species.Illumise) && IsHiddenAndNotPossible(pkm)) // Volbeat/Illumise
                     return GetInvalid(LBallAbility);
                 return GetValid(LBallSpeciesPass);
             }
@@ -316,7 +316,7 @@ namespace PKHeX.Core
 
             if (ball == Beast)
             {
-                if (species == (int)Species.Flabébé && pkm.AltForm == 3 && pkm.AbilityNumber == 4)
+                if (species == (int)Species.Flabébé && pkm.AltForm == 3 && IsHiddenAndNotPossible(pkm))
                     return GetInvalid(LBallAbility); // Can't obtain Flabébé-Blue with Hidden Ability in wild
                 if (((int)Species.Pikipek <= species && species <= (int)Species.Kommoo) || (Legal.AlolanCaptureOffspring.Contains(species) && !Legal.PastGenAlolanNativesUncapturable.Contains(species)))
                     return GetValid(LBallSpeciesPass);
@@ -337,6 +337,13 @@ namespace PKHeX.Core
             return NONE;
         }
 
+        private static bool IsHiddenAndNotPossible(PKM pkm)
+        {
+            if (pkm.AbilityNumber != 4)
+                return false;
+            return !AbilityVerifier.CanAbilityPatch(pkm.Format, pkm.PersonalInfo.Abilities);
+        }
+
         public static bool IsGalarCatchAndBreed(int species)
         {
             if ((int)Species.Grookey <= species && species <= (int)Species.Inteleon) // starter

PKHeX.Core/Legality/Verifiers/IndividualValueVerifier.cs

@@ -80,7 +80,7 @@ namespace PKHeX.Core
             var pkm = data.pkm;
             if (pkm.GO)
                 VerifyIVsGoTransfer(data);
-            else if (pkm.AbilityNumber == 4)
+            else if (pkm.AbilityNumber == 4 && !AbilityVerifier.CanAbilityPatch(pkm.Format, pkm.PersonalInfo.Abilities))
                 VerifyIVsFlawless(data, 2); // Chain of 10 yields 5% HA and 2 flawless IVs
         }