refactor(pack): clarify gacha-point leader detection and drop unused grants injection

SVSim.EmulatedEntrypoint/Services/GachaPointService.cs

@@ -2,7 +2,6 @@ using Microsoft.EntityFrameworkCore;
 using SVSim.Database;
 using SVSim.Database.Enums;
 using SVSim.Database.Models;
-using SVSim.Database.Services;
 using SVSim.EmulatedEntrypoint.Models.Dtos;
 
 namespace SVSim.EmulatedEntrypoint.Services;
@@ -11,13 +10,11 @@ public sealed class GachaPointService : IGachaPointService
 {
     private readonly SVSimDbContext _db;
     private readonly ICardPoolProvider _pools;
-    private readonly RewardGrantService _grants;
 
-    public GachaPointService(SVSimDbContext db, ICardPoolProvider pools, RewardGrantService grants)
+    public GachaPointService(SVSimDbContext db, ICardPoolProvider pools)
     {
         _db = db;
         _pools = pools;
-        _grants = grants;
     }
 
     public async Task<IReadOnlyList<GachaPointRewardDto>> GetRewardsAsync(int packId, long viewerId)
@@ -27,6 +24,7 @@ public sealed class GachaPointService : IGachaPointService
 
         var pool = _pools.GetPool(pack);
 
+        // EF Core 8 has no ToHashSetAsync on IQueryable — materialize via ToListAsync then hash.
         var receivedCardIds = (await _db.Viewers
             .Where(v => v.Id == viewerId)
             .SelectMany(v => v.GachaPointReceived)
@@ -53,6 +51,7 @@ public sealed class GachaPointService : IGachaPointService
 
         foreach (var card in pool
             .Where(c => c.Rarity == Rarity.Legendary && !c.IsFoil)
+            // Neutral cards have Class=null; client wire-encodes them as class_id="0".
             .OrderBy(c => c.Class?.Id ?? 0).ThenBy(c => c.Id))
         {
             if (!cosmeticLookup.TryGetValue(card.Id, out var cosmetics)) continue;
@@ -63,7 +62,35 @@ public sealed class GachaPointService : IGachaPointService
             var classId = (card.Class?.Id ?? 0).ToString();
             var isReceived = receivedCardIds.Contains(card.Id);
 
-            if (skin is null)
+            if (IsLeaderCard(skin))
+            {
+                // Leader card — 3 entries in capture order: Sleeve/Card-cosmetic (type 6),
+                // Skin (type 10), Emblem (type 7). The reward_type=6 entry's detail id is the
+                // card_id itself, mirroring the prod capture exactly (no Sleeve cosmetic row
+                // is required — synthesizing from card.Id is robust to missing rows).
+                leader.Add(new GachaPointRewardDto
+                {
+                    ClassId = classId, CardId = card.Id, IsReceived = isReceived,
+                    RewardList =
+                    {
+                        new GachaPointRewardDetailEntry
+                        {
+                            RewardType = (int)UserGoodsType.Sleeve, RewardDetailId = card.Id, RewardNumber = 1,
+                        },
+                        new GachaPointRewardDetailEntry
+                        {
+                            RewardType = (int)UserGoodsType.Skin,
+                            RewardDetailId = skin!.CosmeticId, RewardNumber = 1,
+                        },
+                        new GachaPointRewardDetailEntry
+                        {
+                            RewardType = (int)UserGoodsType.Emblem,
+                            RewardDetailId = emblem.CosmeticId, RewardNumber = 1,
+                        },
+                    },
+                });
+            }
+            else
             {
                 standard.Add(new GachaPointRewardDto
                 {
@@ -79,33 +106,6 @@ public sealed class GachaPointService : IGachaPointService
                     },
                 });
             }
-            else
-            {
-                // Leader card — 3 entries in capture order: Sleeve/Card-cosmetic (type 6),
-                // Skin (type 10), Emblem (type 7). The reward_type=6 entry's detail id is the
-                // card_id itself, mirroring the prod capture exactly.
-                leader.Add(new GachaPointRewardDto
-                {
-                    ClassId = classId, CardId = card.Id, IsReceived = isReceived,
-                    RewardList =
-                    {
-                        new GachaPointRewardDetailEntry
-                        {
-                            RewardType = (int)UserGoodsType.Sleeve, RewardDetailId = card.Id, RewardNumber = 1,
-                        },
-                        new GachaPointRewardDetailEntry
-                        {
-                            RewardType = (int)UserGoodsType.Skin,
-                            RewardDetailId = skin.CosmeticId, RewardNumber = 1,
-                        },
-                        new GachaPointRewardDetailEntry
-                        {
-                            RewardType = (int)UserGoodsType.Emblem,
-                            RewardDetailId = emblem.CosmeticId, RewardNumber = 1,
-                        },
-                    },
-                });
-            }
         }
 
         // Standard first, then leader — matches the prod capture order for pack 10008.
@@ -113,6 +113,15 @@ public sealed class GachaPointService : IGachaPointService
         return standard;
     }
 
+    /// <summary>
+    /// Leader cards are identified purely by the data shape: a (non-foil legendary) card with
+    /// a <see cref="CosmeticType.Skin"/> cosmetic-reward row is a leader card. There is no
+    /// is_leader flag, no card-id pattern, no other signal — the presence of the Skin row is
+    /// the entire heuristic. Callers must have already filtered to Rarity.Legendary &amp;&amp;
+    /// !IsFoil before invoking this.
+    /// </summary>
+    private static bool IsLeaderCard(CardCosmeticReward? skin) => skin is not null;
+
     public void Accrue(Viewer viewer, PackConfigEntry pack, PackChildGachaEntry child, int packNumber)
         => throw new NotImplementedException();