feat(inventory): GrantAsync handles Item branch

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.Database/Services/Inventory/InventoryTransaction.cs

@@ -99,6 +99,26 @@ internal sealed class InventoryTransaction : IInventoryTransaction
                 _ops.Add(new GrantOp(type, detailId, num, 1, false));
                 return Single(type, detailId, 1);
 
+            case UserGoodsType.Item:
+            {
+                var owned = Viewer.Items.FirstOrDefault(i => i.Item.Id == (int)detailId);
+                int post;
+                if (owned is null)
+                {
+                    var item = _db.Items.Find((int)detailId)
+                               ?? throw new InventoryCatalogException($"Item {detailId} not in catalog");
+                    Viewer.Items.Add(new OwnedItemEntry { Item = item, Count = num, Viewer = Viewer });
+                    post = num;
+                }
+                else
+                {
+                    owned.Count += num;
+                    post = owned.Count;
+                }
+                _ops.Add(new GrantOp(type, detailId, num, post, false));
+                return Single(type, detailId, post);
+            }
+
             default:
                 throw new NotImplementedException(
                     $"UserGoodsType {type} grant lands in a subsequent task");

SVSim.UnitTests/Services/Inventory/InventoryGrantItemTests.cs

@@ -0,0 +1,53 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Database;
+using SVSim.Database.Enums;
+using SVSim.Database.Models;
+using SVSim.Database.Services.Inventory;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Services.Inventory;
+
+public class InventoryGrantItemTests
+{
+    [Test]
+    public async Task Item_first_grant_creates_owned_entry()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        const int itemId = 31000;
+        ctx.Items.Add(new ItemEntry { Id = itemId });
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var granted = await tx.GrantAsync(UserGoodsType.Item, itemId, 3);
+
+        Assert.That(granted[0].RewardNum, Is.EqualTo(3));
+        Assert.That(tx.Viewer.Items.Single(i => i.Item.Id == itemId).Count, Is.EqualTo(3));
+    }
+
+    [Test]
+    public async Task Item_second_grant_accumulates_post_state()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        const int itemId = 31001;
+        var item = new ItemEntry { Id = itemId };
+        ctx.Items.Add(item);
+        var v = await ctx.Viewers.Include(x => x.Items).ThenInclude(i => i.Item).FirstAsync(x => x.Id == viewerId);
+        v.Items.Add(new OwnedItemEntry { Item = item, Count = 5, Viewer = v });
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var granted = await tx.GrantAsync(UserGoodsType.Item, itemId, 4);
+
+        Assert.That(granted[0].RewardNum, Is.EqualTo(9));
+        Assert.That(tx.Viewer.Items.Single(i => i.Item.Id == itemId).Count, Is.EqualTo(9));
+    }
+}