Strip alicorn amulet effects when doing the mind swap spell

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/Spell.java

@@ -81,6 +81,7 @@ public interface Spell extends NbtSerialisable, Affine {
      * Gets the default form of this spell used to apply to a caster.
      * @param caster    The caster currently fueling this spell
      */
+    @Nullable
     default Spell prepareForCast(Caster<?> caster, CastingMethod method) {
         return this;
     }

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/ThrowableSpell.java

@@ -59,12 +59,20 @@ public final class ThrowableSpell extends AbstractDelegatingSpell {
 
         caster.playSound(USounds.SPELL_CAST_SHOOT, 0.7F, 0.4F / (world.random.nextFloat() * 0.4F + 0.8F));
 
-        if (!caster.isClient()) {
+        if (caster.isClient()) {
+            return Optional.empty();
+        }
+
+        Spell s = spell.prepareForCast(caster, CastingMethod.STORED);
+        if (s == null) {
+            return Optional.empty();
+        }
+
         MagicProjectileEntity projectile = UEntities.MAGIC_BEAM.create(world);
         projectile.setPosition(entity.getX(), entity.getEyeY() - 0.1F, entity.getZ());
         projectile.setOwner(entity);
         projectile.setItem(UItems.GEMSTONE.getDefaultStack(spell.getType()));
-            spell.prepareForCast(caster, CastingMethod.STORED).apply(projectile);
+        s.apply(projectile);
         projectile.setVelocity(entity, entity.getPitch(), entity.getYaw(), 0, 1.5F, divergance);
         projectile.setNoGravity(true);
         configureProjectile(projectile, caster);
@@ -73,9 +81,6 @@ public final class ThrowableSpell extends AbstractDelegatingSpell {
         return Optional.of(projectile);
     }
 
-        return Optional.empty();
-    }
-
     @Override
     protected void loadDelegates(NbtCompound compound) {
         spell = Spell.SERIALIZER.read(compound.getCompound("spell"));

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/effect/CustomisedSpellType.java

@@ -39,9 +39,12 @@ public record CustomisedSpellType<T extends Spell> (
         }
 
         T spell = create();
-        if (spell != null && spell.prepareForCast(caster, method).apply(caster)) {
+        if (spell != null) {
+            Spell s = spell.prepareForCast(caster, method);
+            if (s != null && s.apply(caster)) {
                 return spell;
             }
+        }
 
         return null;
     }

src/main/java/com/minelittlepony/unicopia/ability/magic/spell/effect/MindSwapSpell.java

@@ -3,6 +3,8 @@ package com.minelittlepony.unicopia.ability.magic.spell.effect;
 import java.util.Optional;
 import java.util.UUID;
 
+import org.jetbrains.annotations.Nullable;
+
 import com.minelittlepony.unicopia.USounds;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.CastingMethod;
@@ -13,6 +15,8 @@ import com.minelittlepony.unicopia.entity.EntityReference;
 import com.minelittlepony.unicopia.entity.Living;
 import com.minelittlepony.unicopia.entity.behaviour.EntitySwap;
 import com.minelittlepony.unicopia.entity.behaviour.Inventory;
+import com.minelittlepony.unicopia.item.AlicornAmuletItem;
+import com.minelittlepony.unicopia.item.UItems;
 import com.minelittlepony.unicopia.projectile.MagicProjectileEntity;
 import com.minelittlepony.unicopia.projectile.ProjectileDelegate;
 
@@ -38,8 +42,12 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
         super(type);
     }
 
+    @Nullable
     @Override
     public Spell prepareForCast(Caster<?> caster, CastingMethod method) {
+        if (caster.asEntity() instanceof LivingEntity living && isValidTarget(living)) {
+            return null;
+        }
         return method == CastingMethod.STAFF ? toThrowable() : this;
     }
 
@@ -50,11 +58,17 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
             counterpart.ifPresent(caster.asWorld(), e -> {
                 initialized = false;
                 LivingEntity master = caster.getMaster();
-
                 Caster<?> other = Caster.of(e).get();
+
                 other.getSpellSlot().removeIf(SpellType.MIMIC, true);
                 caster.getSpellSlot().removeIf(getType(), true);
 
+                if (!isValidTarget(master) || !isValidTarget(e)) {
+                    master.damage(caster.asWorld().getDamageSources().magic(), Float.MAX_VALUE);
+                    master.setHealth(0);
+                    e.damage(caster.asWorld().getDamageSources().magic(), Float.MAX_VALUE);
+                    e.setHealth(0);
+                } else {
                     if (master instanceof ServerPlayerEntity sMaster && e instanceof ServerPlayerEntity sE) {
                         swapPlayerData(sMaster, sE);
                     } else {
@@ -66,6 +80,7 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
                                 a -> {}
                         );
                     }
+                }
 
                 other.playSound(USounds.SPELL_MINDSWAP_UNSWAP, 0.2F);
                 caster.playSound(USounds.SPELL_MINDSWAP_UNSWAP, 0.2F);
@@ -84,8 +99,20 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
         if (!caster.isClient()) {
             if (!initialized) {
                 counterpart.ifPresent(caster.asWorld(), e -> {
+                    if (!isValidTarget(e)) {
+                        counterpart.set(null);
+                        setDead();
+                        return;
+                    }
+
                     LivingEntity master = caster.getMaster();
 
+                    if (!isValidTarget(master)) {
+                        counterpart.set(null);
+                        setDead();
+                        return;
+                    }
+
                     setDisguise(e);
                     Caster<?> other = Caster.of(e).get();
                     MimicSpell mimic = SpellType.MIMIC.withTraits().apply(other, CastingMethod.INDIRECT);
@@ -144,7 +171,9 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
     @Override
     public void onImpact(MagicProjectileEntity projectile, EntityHitResult hit) {
         Caster.of(projectile.getMaster()).ifPresent(master -> {
-            if (getTypeAndTraits().apply(master, CastingMethod.DIRECT) instanceof HomingSpell homing) {
+            if (hit.getEntity() instanceof LivingEntity living
+                    && isValidTarget(living)
+                    && getTypeAndTraits().apply(master, CastingMethod.DIRECT) instanceof HomingSpell homing) {
                 homing.setTarget(hit.getEntity());
             }
         });
@@ -152,13 +181,19 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
 
     @Override
     public boolean setTarget(Entity target) {
-        if (target instanceof LivingEntity living && Caster.of(target).isPresent()) {
+        if (target instanceof LivingEntity living) {
             counterpart.set(living);
         }
 
         return false;
     }
 
+    protected boolean isValidTarget(LivingEntity entity) {
+        return Caster.of(entity).isPresent()
+                //&& !UItems.ALICORN_AMULET.isApplicable(entity)
+                && !UItems.PEARL_NECKLACE.isApplicable(entity);
+    }
+
     @Override
     public void toNBT(NbtCompound compound) {
         super.toNBT(compound);
@@ -178,6 +213,8 @@ public class MindSwapSpell extends MimicSpell implements ProjectileDelegate.Enti
     }
 
     private static void swapPlayerData(ServerPlayerEntity a, ServerPlayerEntity b) {
+        AlicornAmuletItem.updateAttributes(Living.living(a), 0);
+        AlicornAmuletItem.updateAttributes(Living.living(b), 0);
 
         final GameMode aMode = a.interactionManager.getGameMode();
         final GameMode bMode = b.interactionManager.getGameMode();

src/main/java/com/minelittlepony/unicopia/item/AlicornAmuletItem.java

@@ -169,8 +169,12 @@ public class AlicornAmuletItem extends AmuletItem implements ItemTracker.Trackab
             wearer.updateVelocity();
         }
 
-        EFFECT_SCALES.keySet().forEach(attribute -> {
+        updateAttributes(wearer, 0);
-            wearer.updateAttributeModifier(EFFECT_UUID, attribute, 0F, EFFECT_FACTORY, false);
+    }
+
+    public static void updateAttributes(Living<?> wearer, float effectScale) {
+        EFFECT_SCALES.entrySet().forEach(attribute -> {
+            wearer.updateAttributeModifier(EFFECT_UUID, attribute.getKey(), attribute.getValue() * effectScale, EFFECT_FACTORY, false);
         });
     }
 
@@ -291,10 +295,7 @@ public class AlicornAmuletItem extends AmuletItem implements ItemTracker.Trackab
 
         // every 1 second, update modifiers
         if (fullSecond) {
-            EFFECT_SCALES.entrySet().forEach(attribute -> {
+            updateAttributes(living, (float)attachedTicks / ItemTracker.SECONDS);
-                float seconds = (float)attachedTicks / ItemTracker.SECONDS;
-                living.updateAttributeModifier(EFFECT_UUID, attribute.getKey(), attribute.getValue() * seconds, EFFECT_FACTORY, false);
-            });
         }
     }