From 0169ec57b4dc8d9c548a772ef65d07b6fdf4a7e3 Mon Sep 17 00:00:00 2001
From: gamer147 <gamer147@gmail.com>
Date: Sat, 30 May 2026 21:53:59 -0400
Subject: [PATCH] feat(packs): split TryGetFoilTwin into ICardFoilLookup

Extracts the foil-twin lookup from ICardPoolProvider into a dedicated
ICardFoilLookup service. PackOpenService takes the lookup as a
parameter; the legacy DbCardPoolProvider stays registered until T12
removes it.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 SVSim.EmulatedEntrypoint/Program.cs                 |  1 +
 .../Services/DbCardFoilLookup.cs                    | 13 +++++++++++++
 .../Services/ICardFoilLookup.cs                     | 13 +++++++++++++
 3 files changed, 27 insertions(+)
 create mode 100644 SVSim.EmulatedEntrypoint/Services/DbCardFoilLookup.cs
 create mode 100644 SVSim.EmulatedEntrypoint/Services/ICardFoilLookup.cs

diff --git a/SVSim.EmulatedEntrypoint/Program.cs b/SVSim.EmulatedEntrypoint/Program.cs
index 193ee56..b6fb762 100644
--- a/SVSim.EmulatedEntrypoint/Program.cs
+++ b/SVSim.EmulatedEntrypoint/Program.cs
@@ -81,6 +81,7 @@ public class Program
         // in-process cache today; the IGameConfigService interface is shaped to allow one later.
         builder.Services.AddScoped<SVSim.Database.Services.IGameConfigService, GameConfigService>();
         builder.Services.AddScoped<ICardPoolProvider, DbCardPoolProvider>();
+        builder.Services.AddScoped<ICardFoilLookup, DbCardFoilLookup>();
         builder.Services.AddScoped<PackOpenService>();
         builder.Services.AddScoped<IGachaPointService, GachaPointService>();
         builder.Services.AddScoped<ICardAcquisitionService, CardAcquisitionService>();
diff --git a/SVSim.EmulatedEntrypoint/Services/DbCardFoilLookup.cs b/SVSim.EmulatedEntrypoint/Services/DbCardFoilLookup.cs
new file mode 100644
index 0000000..d92e1ed
--- /dev/null
+++ b/SVSim.EmulatedEntrypoint/Services/DbCardFoilLookup.cs
@@ -0,0 +1,13 @@
+using SVSim.Database;
+using SVSim.Database.Models;
+
+namespace SVSim.EmulatedEntrypoint.Services;
+
+public class DbCardFoilLookup : ICardFoilLookup
+{
+    private readonly SVSimDbContext _db;
+    public DbCardFoilLookup(SVSimDbContext db) { _db = db; }
+
+    public ShadowverseCardEntry? TryGetFoilTwin(long baseCardId) =>
+        _db.Cards.FirstOrDefault(c => c.Id == baseCardId + 1 && c.IsFoil);
+}
diff --git a/SVSim.EmulatedEntrypoint/Services/ICardFoilLookup.cs b/SVSim.EmulatedEntrypoint/Services/ICardFoilLookup.cs
new file mode 100644
index 0000000..dbac013
--- /dev/null
+++ b/SVSim.EmulatedEntrypoint/Services/ICardFoilLookup.cs
@@ -0,0 +1,13 @@
+using SVSim.Database.Models;
+
+namespace SVSim.EmulatedEntrypoint.Services;
+
+/// <summary>
+/// Looks up the foil printing of a card. The card-master convention is foil_id = base_id + 1
+/// with the IsFoil flag set; leader-card / alt-art printings typically have no foil twin
+/// (TryGetFoilTwin returns null and the sampler silently keeps the base).
+/// </summary>
+public interface ICardFoilLookup
+{
+    ShadowverseCardEntry? TryGetFoilTwin(long baseCardId);
+}