feat: Fixes spawner bugs with position finding, Adds [ShowSpawnerBorders (#2297)

### Summary

- Fixes BaseSpawner and Spawner bugs.
- Adds [ShowSpawnerBorders to see the spawn bounds.

Projects/UOContent/Engines/Spawners/BaseSpawner.cs

@@ -195,19 +195,32 @@ public abstract partial class BaseSpawner : Item, ISpawner
         }
         set
         {
-            // Find the surface below the spawner (handles spawners placed in air)
-            var surfaceZ = Map != null && Map != Map.Internal
-                ? Map.GetTopSurfaceZ(Location)
-                : Location.Z;
+            int z;
+            int depth;
+            if (SpawnBounds != default)
+            {
+                z = SpawnBounds.Start.Z;
+                depth = SpawnBounds.Depth;
+            }
+            else if (value == 0)
+            {
+                z = Location.Z;
+                depth = 0;
+            }
+            else
+            {
+                z = -128;
+                depth = 256;
+            }
 
             // Create square bounds centered on spawner, Z range from surface to surface + 16
             SpawnBounds = new Rectangle3D(
                 Location.X - value,
                 Location.Y - value,
-                surfaceZ,
+                z,
                 value * 2 + 1,
                 value * 2 + 1,
-                17 // Z range: surface to surface + 16
+                depth
             );
             this.MarkDirty();
             InvalidateProperties();
@@ -297,21 +310,34 @@ public abstract partial class BaseSpawner : Item, ISpawner
         json.GetProperty("minDelay", options, DefaultMinDelay, out TimeSpan minDelay);
         json.GetProperty("maxDelay", options, DefaultMaxDelay, out TimeSpan maxDelay);
         json.GetProperty("team", options, out int team);
-        json.GetProperty("homeRange", options, out int homeRange);
+        json.GetProperty("homeRange", options, -1, out int homeRange);
         json.GetProperty("walkingRange", options, out _walkingRange);
 
         // Handle legacy homeRange format (new spawnBounds format handled by derived classes)
-        if (homeRange > 0 && json.GetProperty("location", options, out Point3D location))
+        if (homeRange >= 0 && json.GetProperty("location", options, out Point3D location))
         {
+            int z;
+            int depth;
+            if (homeRange == 0)
+            {
+                z = location.Z;
+                depth = 0;
+            }
+            else
+            {
+                z = -128;
+                depth = 256;
+            }
+
             // Fall back to homeRange with location for oldest format
             // Note: Map not available during JSON loading, so use location.Z directly
             SpawnBounds = new Rectangle3D(
                 location.X - homeRange,
                 location.Y - homeRange,
-                location.Z,
+                z,
                 homeRange * 2 + 1,
                 homeRange * 2 + 1,
-                17
+                depth
             );
         }
 
@@ -438,9 +464,8 @@ public abstract partial class BaseSpawner : Item, ISpawner
     {
         Defrag();
 
-        if (spawn != null)
+        if (spawn != null && Spawned?.Remove(spawn, out var entry) == true)
         {
-            Spawned.Remove(spawn, out var entry);
             entry?.RemoveFromSpawned(spawn);
         }
 
@@ -749,6 +774,16 @@ public abstract partial class BaseSpawner : Item, ISpawner
         }
     }
 
+    public override void OnMapChange()
+    {
+        base.OnMapChange();
+
+        if (IsHomeRangeStyleAt(Location))
+        {
+            ShowSpawnerBordersCommand.RemoveProjection(this);
+        }
+    }
+
     public override void OnLocationChange(Point3D oldLocation)
     {
         base.OnLocationChange(oldLocation);
@@ -757,6 +792,7 @@ public abstract partial class BaseSpawner : Item, ISpawner
         if (IsHomeRangeStyleAt(oldLocation))
         {
             HomeRange = SpawnBounds.Width / 2;
+            ShowSpawnerBordersCommand.RemoveProjection(this);
         }
 
         // Reset spawn position optimization state when spawner moves
@@ -1359,7 +1395,7 @@ public abstract partial class BaseSpawner : Item, ISpawner
 
                 if (e != null)
                 {
-                    Spawned.Remove(e);
+                    Spawned?.Remove(e);
                     entry.Spawned.RemoveAt(j);
                     e.Delete();
                 }
@@ -1398,14 +1434,13 @@ public abstract partial class BaseSpawner : Item, ISpawner
         // Handle v10 migration - convert HomeRange to SpawnBounds now that Location is available
         if (_pendingHomeRangeMigrations.Remove(this, out var homeRange))
         {
-            var surfaceZ = Map?.GetTopSurfaceZ(Location) ?? Location.Z;
             SpawnBounds = new Rectangle3D(
                 Location.X - homeRange,
                 Location.Y - homeRange,
-                surfaceZ,
+                -128,
                 homeRange * 2 + 1,
                 homeRange * 2 + 1,
-                17
+                256
             );
         }
 

Projects/UOContent/Engines/Spawners/Commands/ShowSpawnerBordersCommand.cs

@@ -0,0 +1,182 @@
+using System.Collections.Generic;
+using ModernUO.Serialization;
+using Server.Commands.Generic;
+using Server.Items;
+
+namespace Server.Engines.Spawners;
+
+public class ShowSpawnerBordersCommand : BaseCommand
+{
+    // ItemID constants for border pieces
+    private const int SouthEastCorner = 0xF8; // Bottom-right corner
+    private const int NorthSouthWall = 0xF9;  // Horizontal walls
+    private const int EastWestWall = 0xFA;    // Vertical walls
+    private const int NorthWestCorner = 0xFB; // Top-left corner
+
+    private static readonly Dictionary<Item, List<SpawnerBorder>> _projectedSpawners = [];
+
+    public static void Configure()
+    {
+        TargetCommands.Register(new ShowSpawnerBordersCommand());
+    }
+
+    public ShowSpawnerBordersCommand()
+    {
+        AccessLevel = AccessLevel.Developer;
+        Supports = CommandSupport.Simple;
+        Commands = ["ShowSpawnerBorders"];
+        ObjectTypes = ObjectTypes.Items;
+        Usage = "ShowSpawnerBorders";
+        Description = "Toggles a projection of the targeted spawner's borders.";
+    }
+
+    public override void Execute(CommandEventArgs e, object obj)
+    {
+        if (obj is not BaseSpawner spawner)
+        {
+            LogFailure("That is not a spawner.");
+            return;
+        }
+
+        if (_projectedSpawners.Remove(spawner, out var borders))
+        {
+            foreach (var border in borders)
+            {
+                border.Delete();
+            }
+
+            e.Mobile.SendMessage("Spawner projection removed.");
+            return;
+        }
+
+        var bounds = spawner.SpawnBounds;
+        if (bounds == default)
+        {
+            LogFailure("Spawner has no spawn bounds defined.");
+            return;
+        }
+
+        borders = CreateBorders(spawner, bounds);
+        if (borders.Count == 0)
+        {
+            LogFailure("Could not create borders for spawner bounds.");
+            return;
+        }
+
+        _projectedSpawners[spawner] = borders;
+        e.Mobile.SendMessage($"Spawner projection created with {borders.Count} border tiles.");
+    }
+
+    private static List<SpawnerBorder> CreateBorders(Item spawner, Rectangle3D bounds)
+    {
+        var borders = new List<SpawnerBorder>();
+        var map = spawner.Map;
+        var z = spawner.Z;
+
+        var minX = bounds.Start.X;
+        var minY = bounds.Start.Y;
+        var maxX = bounds.End.X; // Exclusive
+        var maxY = bounds.End.Y; // Exclusive
+
+        // NW Corner at (minX - 1, minY - 1)
+        borders.Add(CreateBorder(spawner, NorthWestCorner, minX - 1, minY - 1, z, map));
+
+        // SE Corner at (maxX - 1, maxY - 1)
+        borders.Add(CreateBorder(spawner, SouthEastCorner, maxX - 1, maxY - 1, z, map));
+
+        // North bound: y = minY - 1, x from minX to maxX - 1
+        for (var x = minX; x < maxX; x++)
+        {
+            borders.Add(CreateBorder(spawner, NorthSouthWall, x, minY - 1, z, map));
+        }
+
+        // South bound: y = maxY - 1, x from minX to maxX - 2 (excluding SE corner)
+        for (var x = minX; x < maxX - 1; x++)
+        {
+            borders.Add(CreateBorder(spawner, NorthSouthWall, x, maxY - 1, z, map));
+        }
+
+        // West bound: x = minX - 1, y from minY to maxY - 1
+        for (var y = minY; y < maxY; y++)
+        {
+            borders.Add(CreateBorder(spawner, EastWestWall, minX - 1, y, z, map));
+        }
+
+        // East bound: x = maxX - 1, y from minY to maxY - 2 (excluding SE corner)
+        for (var y = minY; y < maxY - 1; y++)
+        {
+            borders.Add(CreateBorder(spawner, EastWestWall, maxX - 1, y, z, map));
+        }
+
+        return borders;
+    }
+
+    private static SpawnerBorder CreateBorder(Item spawner, int itemId, int x, int y, int z, Map map)
+    {
+        var border = new SpawnerBorder(itemId)
+        {
+            Spawner = spawner
+        };
+        border.MoveToWorld(new Point3D(x, y, z), map);
+        return border;
+    }
+
+    public static void RemoveProjection(Item spawner)
+    {
+        if (_projectedSpawners.Remove(spawner, out var borders))
+        {
+            foreach (var border in borders)
+            {
+                border.Delete();
+            }
+        }
+    }
+
+    public static void RemoveBorderFromProjection(Item spawner, SpawnerBorder border)
+    {
+        if (_projectedSpawners.TryGetValue(spawner, out var borders))
+        {
+            borders.Remove(border);
+            if (borders.Count == 0)
+            {
+                _projectedSpawners.Remove(spawner);
+            }
+        }
+    }
+}
+
+[SerializationGenerator(0)]
+public partial class SpawnerBorder : ProjectedItem
+{
+    public override string DefaultName => "Spawn Border";
+
+    [CommandProperty(AccessLevel.Developer, readOnly: true)]
+    public Item Spawner { get; set; }
+
+    [Constructible]
+    public SpawnerBorder(int effectItemId) : base(effectItemId)
+    {
+        Hue = 0x3F;
+        MinimumVisible = AccessLevel.Developer;
+    }
+
+    [AfterDeserialization(false)]
+    private void AfterDeserialization()
+    {
+        Delete();
+    }
+
+    protected override bool SendEffect()
+    {
+        // Check if spawner was deleted
+        if (Spawner.Deleted)
+        {
+            ShowSpawnerBordersCommand.RemoveBorderFromProjection(Spawner, this);
+            Spawner = null;
+            Delete();
+            return false;
+        }
+
+        return base.SendEffect();
+    }
+}

Projects/UOContent/Engines/Spawners/Spawner.cs

@@ -23,6 +23,7 @@ public partial class Spawner : BaseSpawner
     private bool ShouldSerializeSpawnBounds() => _spawnBounds != default;
 
     [SerializableProperty(1)]
+    [CommandProperty(AccessLevel.Developer)]
     public override Rectangle3D SpawnBounds
     {
         get => _spawnBounds;