From 54525da20b002eec920b6458f33cea6631080dcf Mon Sep 17 00:00:00 2001
From: Kurt <kaphotics@gmail.com>
Date: Sat, 20 Apr 2024 13:59:24 -0500
Subject: [PATCH] Add tradeback wipe of Gen2 initial moves

---
 .../Encounters/Information/EncounterDate.cs   |   2 +-
 .../Legality/LearnSource/Group/LearnGroup2.cs |  20 +++++++++++++++++-
 .../Verify/LearnVerifierHistory.cs            |   3 ++-
 .../0061 - Poliwhirl - 4B4A648BA093.pk7       | Bin 0 -> 260 bytes
 .../0149 - Dragonite - B1A1E209D2E0.pk7       | Bin 0 -> 260 bytes
 .../0149 - Dragonite - D1C5E209D2E0.pk7       | Bin 0 -> 260 bytes
 6 files changed, 22 insertions(+), 3 deletions(-)
 create mode 100644 Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0061 - Poliwhirl - 4B4A648BA093.pk7
 create mode 100644 Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0149 - Dragonite - B1A1E209D2E0.pk7
 create mode 100644 Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0149 - Dragonite - D1C5E209D2E0.pk7

diff --git a/PKHeX.Core/Legality/Encounters/Information/EncounterDate.cs b/PKHeX.Core/Legality/Encounters/Information/EncounterDate.cs
index 70f0abe40..2d1101c67 100644
--- a/PKHeX.Core/Legality/Encounters/Information/EncounterDate.cs
+++ b/PKHeX.Core/Legality/Encounters/Information/EncounterDate.cs
@@ -70,7 +70,7 @@ public static bool IsValidDate3DS(DateOnly date)
     /// </summary>
     public static bool IsValidDateSwitch(DateOnly date)
     {
-        if (date.Year is < 2000 or > 2050)
+        if (date.Year is < 2000 or > 2060)
             return false;
         return true;
     }
diff --git a/PKHeX.Core/Legality/LearnSource/Group/LearnGroup2.cs b/PKHeX.Core/Legality/LearnSource/Group/LearnGroup2.cs
index 6390e76cc..ba637d17e 100644
--- a/PKHeX.Core/Legality/LearnSource/Group/LearnGroup2.cs
+++ b/PKHeX.Core/Legality/LearnSource/Group/LearnGroup2.cs
@@ -38,7 +38,25 @@ public sealed class LearnGroup2 : ILearnGroup
         if (enc is EncounterEgg { Generation: Generation } egg)
             CheckEncounterMoves(result, current, egg);
 
-        return MoveResult.AllParsed(result);
+        bool vc1 = pk.VC1;
+        if (!vc1 && MoveResult.AllParsed(result))
+            return true;
+
+        // Uh-oh, not all moves are verified yet.
+        // To visit Gen1, we need to invalidate moves that can't be learned in Gen1 or re-learned in Gen2.
+        for (int i = 0; i < result.Length; i++)
+        {
+            if (current[i] <= Legal.MaxMoveID_1)
+                continue;
+            var move = result[i];
+            if (!move.IsParsed)
+                continue;
+            var method = move.Info.Method;
+            if ((vc1 && move.Generation == 2) || method is LearnMethod.Initial || method.IsEggSource())
+                result[i] = MoveResult.Unobtainable();
+        }
+
+        return false;
     }
 
     private static void CheckEncounterMoves(PKM pk, Span<MoveResult> result, ReadOnlySpan<ushort> current, IEncounterTemplate enc)
diff --git a/PKHeX.Core/Legality/LearnSource/Verify/LearnVerifierHistory.cs b/PKHeX.Core/Legality/LearnSource/Verify/LearnVerifierHistory.cs
index 3afbd592a..752ad3e39 100644
--- a/PKHeX.Core/Legality/LearnSource/Verify/LearnVerifierHistory.cs
+++ b/PKHeX.Core/Legality/LearnSource/Verify/LearnVerifierHistory.cs
@@ -32,7 +32,8 @@ public static void Verify(Span<MoveResult> result, ReadOnlySpan<ushort> current,
                 MarkRelearnMoves(result, current, pk);
 
             // Knock off initial moves if available.
-            MarkSpecialMoves(result, current, enc, pk);
+            if (enc.Generation != 2) // Handle trade-backs in Gen2 separately.
+                MarkSpecialMoves(result, current, enc, pk);
         }
 
         // Iterate games to identify move sources.
diff --git a/Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0061 - Poliwhirl - 4B4A648BA093.pk7 b/Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0061 - Poliwhirl - 4B4A648BA093.pk7
new file mode 100644
index 0000000000000000000000000000000000000000..39d8780631d0436cef34a3a9a36565fb0f03d737
GIT binary patch
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literal 0
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diff --git a/Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0149 - Dragonite - B1A1E209D2E0.pk7 b/Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0149 - Dragonite - B1A1E209D2E0.pk7
new file mode 100644
index 0000000000000000000000000000000000000000..8ee95d4ff0ac5a1df58feb3fe62bcd4c46a82f59
GIT binary patch
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literal 0
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diff --git a/Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0149 - Dragonite - D1C5E209D2E0.pk7 b/Tests/PKHeX.Core.Tests/Legality/Illegal/Gen2 Tradeback/0149 - Dragonite - D1C5E209D2E0.pk7
new file mode 100644
index 0000000000000000000000000000000000000000..db39343379c2177684e522878c1907aa9a0bd88c
GIT binary patch
literal 260
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literal 0
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