feat(inventory): TrySpendAsync covers all 4 wallets + freeplay

Crystal/Rupy/RedEther freeplay no-op (returns configured amount,
balance unchanged); SpotPoint always real. Insufficient returns
current balance; success returns post-deduction balance.
SVSimTestFactory gains freeplayEnabled ctor overload that upserts
the Freeplay GameConfigSection row after EnsureSeedData.

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

SVSim.Database/Services/Inventory/InventoryTransaction.cs

@@ -38,9 +38,48 @@ internal sealed class InventoryTransaction : IInventoryTransaction
         _log = log;
     }
 
-    // Implementations land in later tasks. Throw NotImplementedException to keep the build green.
     public Task<SpendResult> TrySpendAsync(SpendCurrency currency, long cost, CancellationToken ct = default)
-        => throw new NotImplementedException();
+    {
+        ThrowIfCommitted();
+        if (cost < 0) cost = 0;
+
+        if (_freeplay.Enabled && currency != SpendCurrency.SpotPoint)
+        {
+            long amount = checked((long)_freeplay.CurrencyAmount);
+            _ops.Add(new SpendOp(currency, cost, amount));
+            return Task.FromResult(new SpendResult(SpendOutcome.Success, amount));
+        }
+
+        ulong current = ReadBalance(currency);
+        if (current < (ulong)cost)
+            return Task.FromResult(new SpendResult(SpendOutcome.Insufficient, (long)current));
+
+        ulong post = current - (ulong)cost;
+        WriteBalance(currency, post);
+        _ops.Add(new SpendOp(currency, cost, (long)post));
+        return Task.FromResult(new SpendResult(SpendOutcome.Success, (long)post));
+    }
+
+    private ulong ReadBalance(SpendCurrency c) => c switch
+    {
+        SpendCurrency.Crystal => Viewer.Currency.Crystals,
+        SpendCurrency.Rupee => Viewer.Currency.Rupees,
+        SpendCurrency.RedEther => Viewer.Currency.RedEther,
+        SpendCurrency.SpotPoint => Viewer.Currency.SpotPoints,
+        _ => throw new ArgumentOutOfRangeException(nameof(c)),
+    };
+
+    private void WriteBalance(SpendCurrency c, ulong value)
+    {
+        switch (c)
+        {
+            case SpendCurrency.Crystal: Viewer.Currency.Crystals = value; break;
+            case SpendCurrency.Rupee: Viewer.Currency.Rupees = value; break;
+            case SpendCurrency.RedEther: Viewer.Currency.RedEther = value; break;
+            case SpendCurrency.SpotPoint: Viewer.Currency.SpotPoints = value; break;
+            default: throw new ArgumentOutOfRangeException(nameof(c));
+        }
+    }
 
     public Task<SpendResult> TryDebitAsync(UserGoodsType type, long detailId, int num, CancellationToken ct = default)
         => throw new NotImplementedException();

SVSim.UnitTests/Infrastructure/SVSimTestFactory.cs

@@ -28,9 +28,11 @@ internal sealed class SVSimTestFactory : WebApplicationFactory<Program>
 {
     private readonly SqliteConnection _connection;
     private long _nextSeededShortUdid = 400_000_001;
+    private readonly bool _freeplayEnabled;
 
-    public SVSimTestFactory()
+    public SVSimTestFactory(bool freeplayEnabled = false)
     {
+        _freeplayEnabled = freeplayEnabled;
         // SQLite :memory: lives only as long as a connection is open — keep ours open for the
         // factory's lifetime so the DbContext can reattach to the same DB across scopes.
         _connection = new SqliteConnection("DataSource=:memory:");
@@ -59,6 +61,19 @@ internal sealed class SVSimTestFactory : WebApplicationFactory<Program>
         db.Database.EnsureCreated();
         db.EnsureSeedDataAsync().GetAwaiter().GetResult();
 
+        if (_freeplayEnabled)
+        {
+            using var seedScope = host.Services.CreateScope();
+            var seedDb = seedScope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            const string freeplayJson = "{\"Enabled\":true,\"CurrencyAmount\":99999,\"CardCopies\":3}";
+            var existing = seedDb.GameConfigs.FirstOrDefault(s => s.SectionName == "Freeplay");
+            if (existing is null)
+                seedDb.GameConfigs.Add(new SVSim.Database.Models.GameConfigSection { SectionName = "Freeplay", ValueJson = freeplayJson });
+            else
+                existing.ValueJson = freeplayJson;
+            seedDb.SaveChanges();
+        }
+
         // Reference data is no longer HasData-seeded; load the CSVs via the same importer
         // production uses so tests exercise the same code path. CardCosmeticRewards skipped —
         // FK to Cards would reject every row against the minimal 3-card test seed below.

SVSim.UnitTests/Services/Inventory/InventorySpendTests.cs

@@ -0,0 +1,70 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Database;
+using SVSim.Database.Models.Config;
+using SVSim.Database.Services;
+using SVSim.Database.Services.Inventory;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Services.Inventory;
+
+public class InventorySpendTests
+{
+    [Test]
+    public async Task Spend_sufficient_returns_post_deduction_total()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers.FirstAsync(x => x.Id == viewerId);
+        v.Currency.Crystals = 1000;
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var r = await tx.TrySpendAsync(SpendCurrency.Crystal, 300);
+
+        Assert.That(r.Success, Is.True);
+        Assert.That(r.PostStateTotal, Is.EqualTo(700));
+        Assert.That(tx.Viewer.Currency.Crystals, Is.EqualTo(700UL));
+    }
+
+    [Test]
+    public async Task Spend_insufficient_returns_insufficient_with_current_balance()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers.FirstAsync(x => x.Id == viewerId);
+        v.Currency.Crystals = 100;
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var r = await tx.TrySpendAsync(SpendCurrency.Crystal, 300);
+
+        Assert.That(r.Outcome, Is.EqualTo(SpendOutcome.Insufficient));
+        Assert.That(r.PostStateTotal, Is.EqualTo(100));
+        Assert.That(tx.Viewer.Currency.Crystals, Is.EqualTo(100UL), "balance unchanged");
+    }
+
+    [Test]
+    public async Task Freeplay_returns_success_with_configured_amount_for_main_currencies()
+    {
+        using var factory = new SVSimTestFactory(freeplayEnabled: true);
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        ulong balanceBefore = tx.Viewer.Currency.Crystals;
+        var r = await tx.TrySpendAsync(SpendCurrency.Crystal, 99999);
+
+        Assert.That(r.Success, Is.True);
+        var freeCfg = scope.ServiceProvider.GetRequiredService<IGameConfigService>().Get<FreeplayConfig>();
+        Assert.That(r.PostStateTotal, Is.EqualTo(checked((long)freeCfg.CurrencyAmount)));
+        Assert.That(tx.Viewer.Currency.Crystals, Is.EqualTo(balanceBefore), "freeplay never deducts");
+    }
+}