feat(CS): authentic Crown-hold throne capture (S6 protocol) replacing Sinior-talk

Break all gates + hold both switches (defenses down) -> the Crown shield drops
(C1 B2 16=0). The guild master then stands on the Crown (176,212) and holds for
CrownHoldDuration (default 60s, client shows a 60s countdown via C1 B2 15) to
capture; capture broadcasts C1 B2 18 + golden text and sets the occupier. Losing a
switch or leaving the crown resets the hold (contestable until the siege timer ends).
Sinior (223) is now informational guidance. +2 tests (14 total).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/GameLogic/CastleSiege/CastleSiegeConfiguration.cs

@@ -35,6 +35,12 @@ public class CastleSiegeConfiguration
     /// <summary>Gets or sets how long the war (siege) period lasts.</summary>
     public TimeSpan SiegeDuration { get; set; } = TimeSpan.FromMinutes(10);
 
+    /// <summary>
+    /// Gets or sets how long the guild master must hold the Crown (with both switches held and all gates down)
+    /// to capture the throne. The client shows a 60-second countdown, so 60s matches the on-screen timer.
+    /// </summary>
+    public TimeSpan CrownHoldDuration { get; set; } = TimeSpan.FromSeconds(60);
+
     /// <summary>
     /// Gets or sets the registration fee (in zen) a guild master must pay to register the guild
     /// for the siege. 0 disables the fee.

src/GameLogic/CastleSiege/CastleSiegeContext.cs

@@ -23,6 +23,8 @@ public class CastleSiegeContext
     private string? _occupier;
     private int _defensesRemaining;
     private bool _dirty;
+    private string? _crownHoldGuild;
+    private DateTime? _crownHoldStartUtc;
 
     /// <summary>Initializes a new instance of the <see cref="CastleSiegeContext"/> class.</summary>
     /// <param name="configuration">The cycle timing configuration.</param>
@@ -188,6 +190,69 @@ public class CastleSiegeContext
         return remaining > TimeSpan.Zero ? remaining : TimeSpan.Zero;
     }
 
+    /// <summary>
+    /// Returns the guild that currently holds BOTH crown switches while all castle defenses are down (so the
+    /// crown's shield is dropped for them), or null. Only meaningful during the siege.
+    /// </summary>
+    public string? GetShieldEligibleGuild()
+    {
+        if (this.Phase != CastleSiegePhase.Siege || this._defensesRemaining > 0)
+        {
+            return null;
+        }
+
+        var holder = this._switchHolders[217];
+        return holder is not null && holder == this._switchHolders[218] ? holder : null;
+    }
+
+    /// <summary>
+    /// Advances the crown-hold capture. <paramref name="eligibleGuild"/> is the guild with both switches held
+    /// and no defenses left (shield down); <paramref name="masterHolding"/> is whether that guild's master is
+    /// standing on the crown. Captures the throne for the guild once it has held for <paramref name="holdDuration"/>.
+    /// Losing a switch or the master leaving the crown resets the hold (contestable until the siege ends).
+    /// </summary>
+    /// <param name="eligibleGuild">The guild with both switches and no defenses, or null.</param>
+    /// <param name="masterHolding">Whether that guild's master is on the crown.</param>
+    /// <param name="now">The current UTC time.</param>
+    /// <param name="holdDuration">How long the master must hold to capture.</param>
+    public CrownTickResult TickCrownHold(string? eligibleGuild, bool masterHolding, DateTime now, TimeSpan holdDuration)
+    {
+        if (this.Phase != CastleSiegePhase.Siege)
+        {
+            this._crownHoldGuild = null;
+            this._crownHoldStartUtc = null;
+            return new CrownTickResult(false, CrownEvent.None, null);
+        }
+
+        var shieldDown = eligibleGuild is not null;
+        var wasHolding = this._crownHoldGuild is not null;
+
+        if (eligibleGuild is null || !masterHolding)
+        {
+            this._crownHoldGuild = null;
+            this._crownHoldStartUtc = null;
+            return new CrownTickResult(shieldDown, wasHolding ? CrownEvent.HoldReset : CrownEvent.None, null);
+        }
+
+        if (this._crownHoldGuild != eligibleGuild || this._crownHoldStartUtc is null)
+        {
+            this._crownHoldGuild = eligibleGuild;
+            this._crownHoldStartUtc = now;
+            return new CrownTickResult(shieldDown, CrownEvent.HoldStarted, eligibleGuild);
+        }
+
+        if (now - this._crownHoldStartUtc.Value >= holdDuration)
+        {
+            this._occupier = eligibleGuild;
+            this._crownHoldGuild = null;
+            this._crownHoldStartUtc = null;
+            this._dirty = true;
+            return new CrownTickResult(shieldDown, CrownEvent.Captured, eligibleGuild);
+        }
+
+        return new CrownTickResult(shieldDown, CrownEvent.None, eligibleGuild);
+    }
+
     /// <summary>
     /// Returns whether the persistable state changed since the last call, resetting the flag.
     /// Called each tick by the plugin to decide whether to write state to the database.
@@ -296,6 +361,8 @@ public class CastleSiegeContext
         this._switchHolders[218] = null;
         this._defensesRemaining = 0;
         this._occupier = null;
+        this._crownHoldGuild = null;
+        this._crownHoldStartUtc = null;
     }
 
     private ValueTask TransitionAsync(CastleSiegePhase phase, DateTime now)
@@ -307,3 +374,25 @@ public class CastleSiegeContext
         return ValueTask.CompletedTask;
     }
 }
+
+/// <summary>The event produced by a single <see cref="CastleSiegeContext.TickCrownHold"/> call.</summary>
+public enum CrownEvent
+{
+    /// <summary>Nothing changed this tick.</summary>
+    None,
+
+    /// <summary>A guild master just started holding the crown (start the client countdown).</summary>
+    HoldStarted,
+
+    /// <summary>The crown was held long enough — the guild captured the throne.</summary>
+    Captured,
+
+    /// <summary>An in-progress hold was interrupted (switch lost or master left the crown).</summary>
+    HoldReset,
+}
+
+/// <summary>The result of a crown-hold tick: the shield state and any event that occurred.</summary>
+/// <param name="ShieldDown">Whether the crown shield is currently down (both switches held, defenses cleared).</param>
+/// <param name="Event">The event that occurred this tick.</param>
+/// <param name="Guild">The guild the event refers to, if any.</param>
+public readonly record struct CrownTickResult(bool ShieldDown, CrownEvent Event, string? Guild);

src/GameLogic/CastleSiege/CastleSiegeThroneCaptureTalkPlugIn.cs

@@ -65,17 +65,34 @@ public class CastleSiegeThroneCaptureTalkPlugIn : IPlayerTalkToNpcPlugIn
             return;
         }
 
-        var (success, reason) = context.TryCaptureThrone(guildName);
-        if (success)
+        // The throne is taken by holding the Crown, not by talking here — give guidance based on the state.
+        await ShowAsync(player, DescribeThroneStep(context, guildName)).ConfigureAwait(false);
+    }
+
+    private static string DescribeThroneStep(CastleSiegeContext context, string guildName)
+    {
+        if (context.Phase != CastleSiegePhase.Siege)
         {
-            await player.GameContext.ForEachPlayerAsync(p =>
-                p.InvokeViewPlugInAsync<IShowMessagePlugIn>(v =>
-                    v.ShowMessageAsync($"Guild '{guildName}' has CAPTURED THE THRONE! They will win the castle if they hold it until the siege ends.", MessageType.GoldenCenter)).AsTask()).ConfigureAwait(false);
+            return "The siege is not running yet.";
         }
-        else
+
+        if (context.DefensesRemaining > 0)
         {
-            await ShowAsync(player, reason).ConfigureAwait(false);
+            return $"Destroy all castle gates first ({context.DefensesRemaining} remaining), then hold both Crown Switches.";
         }
+
+        var eligible = context.GetShieldEligibleGuild();
+        if (eligible is null)
+        {
+            return "All gates are down! Hold BOTH Crown Switches with your guild — the Crown's shield will drop.";
+        }
+
+        if (eligible == guildName)
+        {
+            return "Your guild holds both switches and the shield is down — send your GUILD MASTER to hold the Crown to take the throne!";
+        }
+
+        return $"Guild '{eligible}' is holding both switches. Take a switch back to raise their shield.";
     }
 
     private static ValueTask ShowAsync(Player player, string text)

src/GameLogic/PlugIns/PeriodicTasks/CastleSiegeEventPlugIn.cs

@@ -63,6 +63,10 @@ public sealed class CastleSiegeEventPlugIn : IPeriodicTaskPlugIn, ISupportCustom
         (218, 184, 195),
     };
 
+    // The Crown (NPC 216) position on Valley of Loren — the guild master holds it here to capture the throne.
+    private static readonly Point CrownPosition = new(176, 212);
+    private const int CrownHoldRange = 4;
+
     private static readonly ConcurrentDictionary<IGameContext, CastleSiegeContext> Contexts = new();
 
     private string? _cachedFlagOwner;
@@ -350,9 +354,35 @@ public sealed class CastleSiegeEventPlugIn : IPeriodicTaskPlugIn, ISupportCustom
                 context.SetSwitchHolder(switchNumber, holder);
             }
 
+            var now = DateTime.UtcNow;
+
+            // Crown-hold capture: when a guild holds both switches with every gate down, the crown shield drops;
+            // that guild's master then holds the crown for CrownHoldDuration to take the throne (contestable).
+            var eligible = context.GetShieldEligibleGuild();
+            var masterOnCrown = false;
+            if (eligible is not null)
+            {
+                foreach (var player in map.GetAttackablesInRange(CrownPosition, CrownHoldRange).OfType<Player>())
+                {
+                    if (player.GuildStatus?.Position == GuildPosition.GuildMaster
+                        && await GetGuildNameAsync(player).ConfigureAwait(false) == eligible)
+                    {
+                        masterOnCrown = true;
+                        break;
+                    }
+                }
+            }
+
+            var holdDuration = context.Configuration.CrownHoldDuration;
+            var crown = context.TickCrownHold(eligible, masterOnCrown, now, holdDuration);
+            await BroadcastCrownAsync(gameContext, crown).ConfigureAwait(false);
+            if (crown.Event == CrownEvent.Captured && crown.Guild is { } capturedGuild)
+            {
+                await AnnounceAsync(gameContext, $"Guild '{capturedGuild}' has taken the Crown and now holds the throne!").ConfigureAwait(false);
+            }
+
             // Keep the client's on-map countdown armed and in sync. Resend every 10s so players who just
             // loaded the battle map pick it up, without visibly resetting the second-counter too often.
-            var now = DateTime.UtcNow;
             if ((int)(now - context.PhaseStartedUtc).TotalSeconds % 10 == 0)
             {
                 var remaining = context.GetRemainingSiegeTime(now);
@@ -386,6 +416,36 @@ public sealed class CastleSiegeEventPlugIn : IPeriodicTaskPlugIn, ISupportCustom
             }
         });
 
+    /// <summary>
+    /// Sends the crown shield state (each tick) and any crown-hold event (start/reset/capture) to every player
+    /// currently on the battle map.
+    /// </summary>
+    private static ValueTask BroadcastCrownAsync(IGameContext gameContext, CrownTickResult crown)
+        => gameContext.ForEachPlayerAsync(async player =>
+        {
+            if (player.CurrentMap?.Definition.Number != ValleyOfLorenMapNumber)
+            {
+                return;
+            }
+
+            await player.InvokeViewPlugInAsync<ICastleSiegeStatusViewPlugIn>(p => p.SetCrownShieldAsync(crown.ShieldDown)).ConfigureAwait(false);
+
+            switch (crown.Event)
+            {
+                case CrownEvent.HoldStarted:
+                    await player.InvokeViewPlugInAsync<ICastleSiegeStatusViewPlugIn>(p => p.SetCrownRegistAsync(0, 0)).ConfigureAwait(false);
+                    break;
+                case CrownEvent.HoldReset:
+                    await player.InvokeViewPlugInAsync<ICastleSiegeStatusViewPlugIn>(p => p.SetCrownRegistAsync(2, 0)).ConfigureAwait(false);
+                    break;
+                case CrownEvent.Captured when crown.Guild is { } guild:
+                    await player.InvokeViewPlugInAsync<ICastleSiegeStatusViewPlugIn>(p => p.AnnounceSealCapturedAsync(guild)).ConfigureAwait(false);
+                    break;
+                default:
+                    break;
+            }
+        });
+
     private async ValueTask BroadcastCastleFlagAsync(IGameContext gameContext, CastleSiegeContext context)
     {
         try

src/GameLogic/Views/CastleSiege/ICastleSiegeStatusViewPlugIn.cs

@@ -28,4 +28,25 @@ public interface ICastleSiegeStatusViewPlugIn : IViewPlugIn
     /// </summary>
     /// <param name="guildLogo">The owner guild's 32-byte logo/emblem.</param>
     ValueTask SetCastleFlagAsync(ReadOnlyMemory<byte> guildLogo);
+
+    /// <summary>
+    /// Drops (down = true) or raises (down = false) the shield/barrier over the crown (C1 B2 16).
+    /// The crown is only clickable/capturable while the shield is down.
+    /// </summary>
+    /// <param name="down">Whether the shield should be down.</param>
+    ValueTask SetCrownShieldAsync(bool down);
+
+    /// <summary>
+    /// Sends the crown-hold registration state (C1 B2 15): state 0 = started/in-progress (starts the client's
+    /// 60-second countdown), 1 = success, 2 = failed/reset.
+    /// </summary>
+    /// <param name="state">The registration state (0 progress, 1 success, 2 fail).</param>
+    /// <param name="accessMilliseconds">Accumulated hold time in milliseconds (client shows 60000 - this).</param>
+    ValueTask SetCrownRegistAsync(byte state, uint accessMilliseconds);
+
+    /// <summary>
+    /// Broadcasts that a guild registered the official seal / took the crown (C1 B2 18, state 1).
+    /// </summary>
+    /// <param name="guildName">The capturing guild's name (max 8 bytes).</param>
+    ValueTask AnnounceSealCapturedAsync(string guildName);
 }

src/GameServer/RemoteView/CastleSiege/CastleSiegeStatusViewPlugIn.cs

@@ -101,4 +101,82 @@ public class CastleSiegeStatusViewPlugIn : ICastleSiegeStatusViewPlugIn
 
         await connection.SendAsync(WritePacket).ConfigureAwait(false);
     }
+
+    /// <inheritdoc />
+    public async ValueTask SetCrownShieldAsync(bool down)
+    {
+        var connection = this._player.Connection;
+        if (connection is null)
+        {
+            return;
+        }
+
+        int WritePacket()
+        {
+            // C1 0C B2 16 <state> <pad> <dword=0> ; state 0 = shield down, 1 = shield up
+            var span = connection.Output.GetSpan(12)[..12];
+            span.Clear();
+            span[0] = 0xC1;
+            span[1] = 0x0C;
+            span[2] = 0xB2;
+            span[3] = 0x16;
+            span[4] = (byte)(down ? 0 : 1);
+            return span.Length;
+        }
+
+        await connection.SendAsync(WritePacket).ConfigureAwait(false);
+    }
+
+    /// <inheritdoc />
+    public async ValueTask SetCrownRegistAsync(byte state, uint accessMilliseconds)
+    {
+        var connection = this._player.Connection;
+        if (connection is null)
+        {
+            return;
+        }
+
+        int WritePacket()
+        {
+            // C1 0C B2 15 <state> <pad3> <accessMs:4 LE @offset 8>
+            var span = connection.Output.GetSpan(12)[..12];
+            span.Clear();
+            span[0] = 0xC1;
+            span[1] = 0x0C;
+            span[2] = 0xB2;
+            span[3] = 0x15;
+            span[4] = state;
+            System.Buffers.Binary.BinaryPrimitives.WriteUInt32LittleEndian(span.Slice(8, 4), accessMilliseconds);
+            return span.Length;
+        }
+
+        await connection.SendAsync(WritePacket).ConfigureAwait(false);
+    }
+
+    /// <inheritdoc />
+    public async ValueTask AnnounceSealCapturedAsync(string guildName)
+    {
+        var connection = this._player.Connection;
+        if (connection is null)
+        {
+            return;
+        }
+
+        int WritePacket()
+        {
+            // C1 0D B2 18 <state=1> <guildName[8] utf8>
+            var span = connection.Output.GetSpan(13)[..13];
+            span.Clear();
+            span[0] = 0xC1;
+            span[1] = 0x0D;
+            span[2] = 0xB2;
+            span[3] = 0x18;
+            span[4] = 1;
+            var bytes = System.Text.Encoding.UTF8.GetBytes(guildName);
+            bytes.AsSpan(0, Math.Min(8, bytes.Length)).CopyTo(span.Slice(5, 8));
+            return span.Length;
+        }
+
+        await connection.SendAsync(WritePacket).ConfigureAwait(false);
+    }
 }