Be a little more robust in turtle item rendering

See #1328. Also some holiday cleanup, because my commit discipline is
terrible.

projects/common/src/client/java/dan200/computercraft/client/model/turtle/TurtleModelParts.java

@@ -15,7 +15,6 @@ import dan200.computercraft.client.render.TurtleBlockEntityRenderer;
 import dan200.computercraft.client.turtle.TurtleUpgradeModellers;
 import dan200.computercraft.shared.turtle.items.TurtleItem;
 import dan200.computercraft.shared.util.Holiday;
-import dan200.computercraft.shared.util.HolidayUtil;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.resources.ResourceLocation;
@@ -71,13 +70,16 @@ public final class TurtleModelParts {
     }
 
     public Combination getCombination(ItemStack stack) {
-        var turtle = (TurtleItem) stack.getItem();
+        var christmas = Holiday.getCurrent() == Holiday.CHRISTMAS;
+
+        if (!(stack.getItem() instanceof TurtleItem turtle)) {
+            return new Combination(false, null, null, null, christmas, false);
+        }
 
         var colour = turtle.getColour(stack);
         var leftUpgrade = turtle.getUpgrade(stack, TurtleSide.LEFT);
         var rightUpgrade = turtle.getUpgrade(stack, TurtleSide.RIGHT);
         var overlay = turtle.getOverlay(stack);
-        var christmas = HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS;
         var label = turtle.getLabel(stack);
         var flip = label != null && (label.equals("Dinnerbone") || label.equals("Grumm"));
 

projects/common/src/client/java/dan200/computercraft/client/render/TurtleBlockEntityRenderer.java

@@ -17,7 +17,6 @@ import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.turtle.blocks.TurtleBlockEntity;
 import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.Holiday;
-import dan200.computercraft.shared.util.HolidayUtil;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.Font;
 import net.minecraft.client.renderer.MultiBufferSource;
@@ -112,7 +111,7 @@ public class TurtleBlockEntityRenderer implements BlockEntityRenderer<TurtleBloc
         renderModel(transform, buffer, lightmapCoord, overlayLight, getTurtleModel(family, colour != -1), colour == -1 ? null : new int[]{ colour });
 
         // Render the overlay
-        var overlayModel = getTurtleOverlayModel(overlay, HolidayUtil.getCurrentHoliday() == Holiday.CHRISTMAS);
+        var overlayModel = getTurtleOverlayModel(overlay, Holiday.getCurrent() == Holiday.CHRISTMAS);
         if (overlayModel != null) {
             renderModel(transform, buffer, lightmapCoord, overlayLight, overlayModel, null);
         }

projects/common/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java

@@ -24,7 +24,6 @@ import dan200.computercraft.shared.container.InventoryDelegate;
 import dan200.computercraft.shared.turtle.blocks.TurtleBlockEntity;
 import dan200.computercraft.shared.util.BlockEntityHelpers;
 import dan200.computercraft.shared.util.Holiday;
-import dan200.computercraft.shared.util.HolidayUtil;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.core.particles.ParticleTypes;
@@ -739,7 +738,7 @@ public class TurtleBrain implements TurtleAccessInternal {
             // Advance valentines day easter egg
             if (world.isClientSide && animation == TurtleAnimation.MOVE_FORWARD && animationProgress == 4) {
                 // Spawn love pfx if valentines day
-                var currentHoliday = HolidayUtil.getCurrentHoliday();
+                var currentHoliday = Holiday.getCurrent();
                 if (currentHoliday == Holiday.VALENTINES) {
                     var position = getVisualPosition(1.0f);
                     if (position != null) {

projects/common/src/main/java/dan200/computercraft/shared/util/Holiday.java

@@ -5,10 +5,30 @@
  */
 package dan200.computercraft.shared.util;
 
+import java.time.LocalDateTime;
+import java.time.Month;
+
 public enum Holiday {
     NONE,
+
+    /**
+     * 14th February.
+     */
     VALENTINES,
-    APRIL_FOOLS_DAY,
+
-    HALLOWEEN,
+    /**
-    CHRISTMAS,
+     * 24th-26th December.
+     *
+     * @see net.minecraft.client.renderer.blockentity.ChestRenderer
+     */
+    CHRISTMAS;
+
+    public static Holiday getCurrent() {
+        var calendar = LocalDateTime.now();
+        var month = calendar.getMonth();
+        var day = calendar.getDayOfMonth();
+        if (month == Month.FEBRUARY && day == 14) return VALENTINES;
+        if (month == Month.DECEMBER && day >= 24 && day <= 26) return CHRISTMAS;
+        return NONE;
+    }
 }

projects/common/src/main/java/dan200/computercraft/shared/util/HolidayUtil.java

@@ -1,27 +0,0 @@
-/*
- * This file is part of ComputerCraft - http://www.computercraft.info
- * Copyright Daniel Ratcliffe, 2011-2022. Do not distribute without permission.
- * Send enquiries to dratcliffe@gmail.com
- */
-package dan200.computercraft.shared.util;
-
-import java.util.Calendar;
-
-public final class HolidayUtil {
-    private HolidayUtil() {
-    }
-
-    public static Holiday getCurrentHoliday() {
-        return getHoliday(Calendar.getInstance());
-    }
-
-    private static Holiday getHoliday(Calendar calendar) {
-        var month = calendar.get(Calendar.MONTH);
-        var day = calendar.get(Calendar.DAY_OF_MONTH);
-        if (month == Calendar.FEBRUARY && day == 14) return Holiday.VALENTINES;
-        if (month == Calendar.APRIL && day == 1) return Holiday.APRIL_FOOLS_DAY;
-        if (month == Calendar.OCTOBER && day == 31) return Holiday.HALLOWEEN;
-        if (month == Calendar.DECEMBER && day >= 24 && day <= 30) return Holiday.CHRISTMAS;
-        return Holiday.NONE;
-    }
-}