feat(CS-P3): throne capture + settlement winner in state machine + tests

src/GameLogic/CastleSiege/CastleSiegeContext.cs

@@ -12,6 +12,7 @@ public class CastleSiegeContext
 {
     private readonly List<string> _registeredGuilds = new();
     private DateTime _phaseStartedUtc;
+    private string? _occupier;
 
     /// <summary>Initializes a new instance of the <see cref="CastleSiegeContext"/> class.</summary>
     /// <param name="configuration">The cycle timing configuration.</param>
@@ -36,6 +37,9 @@ public class CastleSiegeContext
     /// <summary>Gets the guild names registered for the current cycle.</summary>
     public IReadOnlyList<string> RegisteredGuilds => this._registeredGuilds;
 
+    /// <summary>Gets the guild currently holding the throne during the siege (P3), or null.</summary>
+    public string? OccupierGuildName => this._occupier;
+
     /// <summary>Advances the state machine based on the current time.</summary>
     /// <param name="now">The current UTC time.</param>
     public ValueTask TickAsync(DateTime now)
@@ -71,7 +75,13 @@ public class CastleSiegeContext
 
                 break;
             case CastleSiegePhase.Settlement:
-                // P1: no battle -> no winner determination yet. Settle immediately back to ownership.
+                // Winner = guild holding the throne at siege end (P3). If none captured, owner unchanged.
+                if (this._occupier is { } occupier)
+                {
+                    this.SetOwner(occupier);
+                }
+
+                this._occupier = null;
                 return this.TransitionAsync(CastleSiegePhase.Ownership, now);
             default:
                 break;
@@ -85,6 +95,7 @@ public class CastleSiegeContext
     public ValueTask ForceStartRegistrationAsync(DateTime now)
     {
         this._registeredGuilds.Clear();
+        this._occupier = null;
         return this.TransitionAsync(CastleSiegePhase.Registration, now);
     }
 
@@ -99,6 +110,7 @@ public class CastleSiegeContext
     public ValueTask ResetAsync(DateTime now)
     {
         this._registeredGuilds.Clear();
+        this._occupier = null;
         return this.TransitionAsync(CastleSiegePhase.Ownership, now);
     }
 
@@ -117,6 +129,16 @@ public class CastleSiegeContext
     /// <param name="guildName">The owner guild name, or null to clear.</param>
     public void SetOwner(string? guildName) => this.OwnerGuildName = guildName;
 
+    /// <summary>P3: a registered guild captures the throne during the siege. No-op outside the siege phase.</summary>
+    /// <param name="guildName">The capturing guild's name.</param>
+    public void CaptureThrone(string guildName)
+    {
+        if (this.Phase == CastleSiegePhase.Siege)
+        {
+            this._occupier = guildName;
+        }
+    }
+
     /// <summary>Returns a human-readable status summary for admin display.</summary>
     public string GetStatusText()
         => $"CS phase={this.Phase}, owner={this.OwnerGuildName ?? "(none)"}, "

tests/MUnique.OpenMU.Tests/CastleSiege/CastleSiegeContextTest.cs

@@ -67,6 +67,30 @@ public class CastleSiegeContextTest
         Assert.That(ctx.RegisteredGuilds, Does.Contain("Attackers"));
     }
 
+    /// <summary>Tests that the throne-holding guild at siege end becomes the owner on settlement (P3).</summary>
+    [Test]
+    public async Task ThroneCaptureDuringSiegeBecomesOwnerOnSettlementAsync()
+    {
+        var ctx = new CastleSiegeContext(Config());
+        await ctx.ForceStartRegistrationAsync(T0);
+        await ctx.ForcePhaseAsync(CastleSiegePhase.Siege, T0);
+        ctx.CaptureThrone("Attackers");
+        Assert.That(ctx.OccupierGuildName, Is.EqualTo("Attackers"));
+        await ctx.TickAsync(T0.AddMinutes(20)); // Siege -> Settlement
+        await ctx.TickAsync(T0.AddMinutes(20)); // Settlement -> Ownership (owner assigned)
+        Assert.That(ctx.Phase, Is.EqualTo(CastleSiegePhase.Ownership));
+        Assert.That(ctx.OwnerGuildName, Is.EqualTo("Attackers"));
+    }
+
+    /// <summary>Tests that capturing the throne outside the siege phase is a no-op.</summary>
+    [Test]
+    public void CaptureThroneOutsideSiegeIsNoOp()
+    {
+        var ctx = new CastleSiegeContext(Config());
+        ctx.CaptureThrone("Attackers");
+        Assert.That(ctx.OccupierGuildName, Is.Null);
+    }
+
     private static CastleSiegeConfiguration Config() => new()
     {
         RegistrationDuration = TimeSpan.FromMinutes(5),