From f1cabdfa25b1869c466d47cb499ebddad833b1af Mon Sep 17 00:00:00 2001
From: Kurt <kaphotics@gmail.com>
Date: Mon, 11 Dec 2017 10:13:08 -0800
Subject: [PATCH] Handle setting decrypted pgt pkm gift data

---
 PKHeX.Core/MysteryGifts/PGT.cs | 19 +++++++++++++++++++
 PKHeX.Core/Saves/SAV4.cs       | 23 +++++++++++++++++------
 2 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/PKHeX.Core/MysteryGifts/PGT.cs b/PKHeX.Core/MysteryGifts/PGT.cs
index cdfcacbc6..1a3b180ae 100644
--- a/PKHeX.Core/MysteryGifts/PGT.cs
+++ b/PKHeX.Core/MysteryGifts/PGT.cs
@@ -190,6 +190,25 @@ public PK4 PK
         }
         private PK4 _pk;
 
+        /// <summary>
+        /// Double checks the encryption of the gift data for Pokemon data.
+        /// </summary>
+        /// <returns>True if data was encrypted, false if the data was not modified.</returns>
+        public bool VerifyPKEncryption()
+        {
+            if (!IsPokémon || BitConverter.ToUInt32(Data, 0x64 + 8) != 0)
+                return false;
+            EncryptPK();
+            return true;
+        }
+        private void EncryptPK()
+        {
+            byte[] ekdata = new byte[PKX.SIZE_4PARTY];
+            Array.Copy(Data, 8, ekdata, 0, ekdata.Length);
+            PKX.EncryptArray45(ekdata);
+            ekdata.CopyTo(Data, 8);
+        }
+
         private GiftType PGTGiftType { get => (GiftType)Data[0]; set => Data[0] = (byte)value; }
         public bool IsHatched => PGTGiftType == GiftType.Pokémon;
         public override bool IsEgg { get => PGTGiftType == GiftType.PokémonEgg; set { if (value) { PGTGiftType = GiftType.PokémonEgg; PK.IsEgg = true; } } }
diff --git a/PKHeX.Core/Saves/SAV4.cs b/PKHeX.Core/Saves/SAV4.cs
index e252b447a..783a94135 100644
--- a/PKHeX.Core/Saves/SAV4.cs
+++ b/PKHeX.Core/Saves/SAV4.cs
@@ -610,10 +610,10 @@ private static bool IsMysteryGiftAvailable(MysteryGift[] value)
             if (value == null)
                 return false;
             for (int i = 0; i < 8; i++) // 8 PGT
-                if ((value[i] as PGT)?.CardType != 0)
+                if (value[i] is PGT g && g.CardType != 0)
                     return true;
             for (int i = 8; i < 11; i++) // 3 PCD
-                if ((value[i] as PCD)?.Gift.CardType != 0)
+                if (value[i] is PCD d && d.Gift.CardType != 0)
                     return true;
             return false;
         }
@@ -626,8 +626,7 @@ private static int[] MatchMysteryGifts(MysteryGift[] value)
             int[] cardMatch = new int[8];
             for (int i = 0; i < 8; i++)
             {
-                var pgt = value[i] as PGT;
-                if (pgt == null)
+                if (!(value[i] is PGT pgt))
                     continue;
 
                 if (pgt.CardType == 0) // empty
@@ -639,8 +638,7 @@ private static int[] MatchMysteryGifts(MysteryGift[] value)
                 cardMatch[i] = pgt.Slot = 3;
                 for (byte j = 0; j < 3; j++)
                 {
-                    var pcd = value[8 + j] as PCD;
-                    if (pcd == null)
+                    if (!(value[8 + j] is PCD pcd))
                         continue;
 
                     // Check if data matches (except Slot @ 0x02)
@@ -671,6 +669,19 @@ public override MysteryGiftAlbum GiftAlbum
                 MysteryGiftActive |= available;
                 value.Flags[2047] = available;
 
+                // Check encryption for each gift (decrypted wc4 sneaking in)
+                foreach (var g in value.Gifts)
+                {
+                    if (g is PGT pgt)
+                        pgt.VerifyPKEncryption();
+                    else if (g is PCD pcd)
+                    {
+                        var g = pcd.Gift;
+                        if (g.VerifyPKEncryption())
+                            pcd.Gift = g; // set encrypted gift back to PCD.
+                    }
+                }
+
                 MysteryGiftReceivedFlags = value.Flags;
                 MysteryGiftCards = value.Gifts;