From a10d1df9ca6b287ffe27a198d7bd8908be040296 Mon Sep 17 00:00:00 2001
From: Kurt <kaphotics@gmail.com>
Date: Wed, 28 Jul 2021 19:28:56 -0700
Subject: [PATCH] Extract pkm filename'ing logic to allow behavior replacing

injecting dependencies

replace the virtual inheritance with a type check
---
 PKHeX.Core/PKM/PKM.cs                  | 10 +----
 PKHeX.Core/PKM/Shared/GBPKM.cs         | 10 -----
 PKHeX.Core/PKM/Util/EntityFileNamer.cs | 53 ++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 19 deletions(-)
 create mode 100644 PKHeX.Core/PKM/Util/EntityFileNamer.cs

diff --git a/PKHeX.Core/PKM/PKM.cs b/PKHeX.Core/PKM/PKM.cs
index 24134c2ec..f007801fe 100644
--- a/PKHeX.Core/PKM/PKM.cs
+++ b/PKHeX.Core/PKM/PKM.cs
@@ -365,15 +365,7 @@ public int FlawlessIVCount
 
         public string FileName => $"{FileNameWithoutExtension}.{Extension}";
 
-        public virtual string FileNameWithoutExtension
-        {
-            get
-            {
-                string form = Form > 0 ? $"-{Form:00}" : string.Empty;
-                string star = IsShiny ? " ★" : string.Empty;
-                return $"{Species:000}{form}{star} - {Nickname} - {Checksum:X4}{EncryptionConstant:X8}";
-            }
-        }
+        public string FileNameWithoutExtension => EntityFileNamer.GetName(this);
 
         public int[] IVs
         {
diff --git a/PKHeX.Core/PKM/Shared/GBPKM.cs b/PKHeX.Core/PKM/Shared/GBPKM.cs
index e847ee88c..8ac797103 100644
--- a/PKHeX.Core/PKM/Shared/GBPKM.cs
+++ b/PKHeX.Core/PKM/Shared/GBPKM.cs
@@ -20,16 +20,6 @@ public abstract class GBPKM : PKM
 
         public sealed override IReadOnlyList<ushort> ExtraBytes => Array.Empty<ushort>();
 
-        public sealed override string FileNameWithoutExtension
-        {
-            get
-            {
-                string form = Form > 0 ? $"-{Form:00}" : string.Empty;
-                string star = IsShiny ? " ★" : string.Empty;
-                return $"{Species:000}{form}{star} - {Nickname} - {Checksums.CRC16_CCITT(Encrypt()):X4}";
-            }
-        }
-
         protected GBPKM(int size) : base(size) { }
         protected GBPKM(byte[] data) : base(data) { }
 
diff --git a/PKHeX.Core/PKM/Util/EntityFileNamer.cs b/PKHeX.Core/PKM/Util/EntityFileNamer.cs
new file mode 100644
index 000000000..0ff5a6bbb
--- /dev/null
+++ b/PKHeX.Core/PKM/Util/EntityFileNamer.cs
@@ -0,0 +1,53 @@
+namespace PKHeX.Core
+{
+    public static class EntityFileNamer
+    {
+        /// <summary>
+        /// Object that converts the <see cref="PKM"/> data into a <see cref="string"/> file name.
+        /// </summary>
+        public static IFileNamer<PKM> Namer { get; set; } = new DefaultEntityNamer();
+
+        /// <summary>
+        /// Gets the file name (without extension) for the input <see cref="pk"/> data.
+        /// </summary>
+        /// <param name="pk">Input entity to create a file name for.</param>
+        /// <returns>File name for the <see cref="pk"/> data</returns>
+        public static string GetName(PKM pk) => Namer.GetName(pk);
+    }
+
+    public sealed class DefaultEntityNamer : IFileNamer<PKM>
+    {
+        public string GetName(PKM obj)
+        {
+            if (obj is GBPKM gb)
+                return GetGBPKM(gb);
+            return GetRegular(obj);
+        }
+
+        private static string GetRegular(PKM pk)
+        {
+            string form = pk.Form > 0 ? $"-{pk.Form:00}" : string.Empty;
+            string star = pk.IsShiny ? " ★" : string.Empty;
+            return $"{pk.Species:000}{form}{star} - {pk.Nickname} - {pk.Checksum:X4}{pk.EncryptionConstant:X8}";
+        }
+
+        private static string GetGBPKM(GBPKM gb)
+        {
+            string form = gb.Form > 0 ? $"-{gb.Form:00}" : string.Empty;
+            string star = gb.IsShiny ? " ★" : string.Empty;
+            var raw = gb switch
+            {
+                PK1 pk1 => new PokeList1(pk1).Write(),
+                PK2 pk2 => new PokeList2(pk2).Write(),
+                _ => gb.Data
+            };
+            var checksum = Checksums.CRC16_CCITT(raw);
+            return $"{gb.Species:000}{form}{star} - {gb.Nickname} - {checksum:X4}";
+        }
+    }
+
+    public interface IFileNamer<in T>
+    {
+        string GetName(T obj);
+    }
+}