Fixed spell entities becoming detached when cancelling the spell from very far away

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

@@ -6,6 +6,7 @@ import org.jetbrains.annotations.Nullable;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
+import com.minelittlepony.unicopia.block.data.Ether;
 import com.minelittlepony.unicopia.entity.CastSpellEntity;
 import com.minelittlepony.unicopia.entity.EntityReference;
 import com.minelittlepony.unicopia.entity.UEntities;
@@ -86,6 +87,7 @@ public class PlaceableSpell extends AbstractDelegatingSpell {
                     entity.getSpellSlot().put(spell.toPlaceable());
                     entity.setMaster(source);
                     entity.world.spawnEntity(entity);
+                    Ether.get(entity.world).put(getType(), entity);
 
                     castEntity.set(entity);
                     setDirty();
@@ -96,6 +98,16 @@ public class PlaceableSpell extends AbstractDelegatingSpell {
         }
 
         if (situation == Situation.GROUND_ENTITY) {
+
+            if (!source.isClient()) {
+                Ether ether = Ether.get(source.getReferenceWorld());
+                if (ether.getEntry(getType(), source).filter(Ether.Entry::isAlive).isEmpty()) {
+                    ether.remove(getType(), source);
+                    setDead();
+                    return false;
+                }
+            }
+
             particlEffect.update(getUuid(), source, spawner -> {
                 spawner.addParticle(new OrientedBillboardParticleEffect(UParticles.MAGIC_RUNES, 90, 0), source.getOriginVector(), Vec3d.ZERO);
             }).ifPresent(p -> {
@@ -108,24 +120,15 @@ public class PlaceableSpell extends AbstractDelegatingSpell {
         return !isDead();
     }
 
-    /**
-     * Detaches this spell from the placed version.
-     * This spell and the placed entity effectively become independent.
-     *
-     * @return The previous cast spell entity if one existed, otherwise empty.
-     */
-    protected Optional<CastSpellEntity> detach(Caster<?> source) {
-        return getSpellEntity(source).map(e -> {
-            castEntity.set(null);
-            return e;
-        });
-    }
-
     @Override
     public void onDestroyed(Caster<?> source) {
         if (!source.isClient()) {
+            castEntity.getId().ifPresent(id -> {
+                getWorld(source).map(Ether::get)
+                    .flatMap(ether -> ether.getEntry(getType(), id))
+                    .ifPresent(Ether.Entry::markDead);
+            });
             getSpellEntity(source).ifPresent(e -> {
-                e.getSpellSlot().clear();
                 castEntity.set(null);
             });
         }

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

@@ -34,7 +34,7 @@ public class PortalSpell extends AbstractSpell {
         if (situation == Situation.GROUND) {
             teleportationTarget.getPosition().ifPresentOrElse(
                     targetPos -> tickWithTargetLink(source, targetPos),
-                    () -> advertiseAvailable(source)
+                    () -> findLink(source)
             );
 
             if (!publishedPosition) {
@@ -76,15 +76,15 @@ public class PortalSpell extends AbstractSpell {
     }
 
     @SuppressWarnings("unchecked")
-    private void advertiseAvailable(Caster<?> source) {
+    private void findLink(Caster<?> source) {
         Ether ether = Ether.get(source.getReferenceWorld());
-        ether.getIds(getType())
+        ether.getEntries(getType())
             .stream()
-            .filter(id -> !id.referenceEquals(source.getEntity()))
+            .filter(entry -> entry.isAvailable() && !entry.entity.referenceEquals(source.getEntity()))
             .findAny()
-            .ifPresent(ref -> {
-                ether.remove(getType(), ref.getId().get());
-                teleportationTarget.copyFrom((EntityReference<CastSpellEntity>)ref);
+            .ifPresent(entry -> {
+                entry.setTaken(true);
+                teleportationTarget.copyFrom((EntityReference<CastSpellEntity>)entry.entity);
             });
     }
 
@@ -106,4 +106,10 @@ public class PortalSpell extends AbstractSpell {
         publishedPosition = compound.getBoolean("publishedPosition");
         teleportationTarget.fromNBT(compound.getCompound("teleportationTarget"));
     }
+
+    @Override
+    public void setDead() {
+        super.setDead();
+        particlEffect.destroy();
+    }
 }

src/main/java/com/minelittlepony/unicopia/block/data/Ether.java

@@ -6,6 +6,7 @@ import com.minelittlepony.unicopia.Unicopia;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
 import com.minelittlepony.unicopia.entity.EntityReference;
+import com.minelittlepony.unicopia.util.NbtSerialisable;
 
 import net.minecraft.nbt.*;
 import net.minecraft.util.Identifier;
@@ -20,7 +21,7 @@ public class Ether extends PersistentState {
         return WorldOverlay.getPersistableStorage(world, ID, Ether::new, Ether::new);
     }
 
-    private final Map<Identifier, Set<EntityReference<?>>> advertisingEndpoints = new HashMap<>();
+    private final Map<Identifier, Set<Entry>> advertisingEndpoints = new HashMap<>();
 
     private final Object locker = new Object();
 
@@ -29,9 +30,11 @@ public class Ether extends PersistentState {
         compound.getKeys().forEach(key -> {
             Identifier typeId = Identifier.tryParse(key);
             if (typeId != null) {
-                Set<EntityReference<?>> uuids = getIds(typeId);
+                Set<Entry> uuids = getEntries(typeId);
                 compound.getList(key, NbtElement.COMPOUND_TYPE).forEach(entry -> {
-                    uuids.add(new EntityReference<>((NbtCompound)entry));
+                    Entry e = new Entry();
+                    e.fromNBT((NbtCompound)entry);
+                    uuids.add(e);
                 });
             }
         });
@@ -56,7 +59,7 @@ public class Ether extends PersistentState {
 
     public void put(SpellType<?> spellType, Caster<?> caster) {
         synchronized (locker) {
-            getIds(spellType.getId()).add(new EntityReference<>(caster.getEntity()));
+            getEntries(spellType.getId()).add(new Entry(caster));
         }
         markDirty();
     }
@@ -64,9 +67,9 @@ public class Ether extends PersistentState {
     public void remove(SpellType<?> spellType, UUID id) {
         synchronized (locker) {
             Identifier typeId = spellType.getId();
-            Set<EntityReference<?>> refs = advertisingEndpoints.get(typeId);
+            Set<Entry> refs = advertisingEndpoints.get(typeId);
             if (refs != null) {
-                refs.removeIf(ref -> ref.getId().orElse(Util.NIL_UUID).equals(id));
+                refs.removeIf(ref -> ref.entity.getId().orElse(Util.NIL_UUID).equals(id));
                 if (refs.isEmpty()) {
                     advertisingEndpoints.remove(typeId);
                 }
@@ -75,13 +78,89 @@ public class Ether extends PersistentState {
         }
     }
 
-    public Set<EntityReference<?>> getIds(SpellType<?> spellType) {
-        return getIds(spellType.getId());
+    public void remove(SpellType<?> spellType, Caster<?> caster) {
+        remove(spellType, caster.getEntity().getUuid());
     }
 
-    private Set<EntityReference<?>> getIds(Identifier typeId) {
+    public Set<Entry> getEntries(SpellType<?> spellType) {
+        return getEntries(spellType.getId());
+    }
+
+    private Set<Entry> getEntries(Identifier typeId) {
         synchronized (locker) {
             return advertisingEndpoints.computeIfAbsent(typeId, i -> new HashSet<>());
         }
     }
+
+    public Optional<Entry> getEntry(SpellType<?> spellType, Caster<?> caster) {
+        synchronized (locker) {
+            return getEntries(spellType).stream().filter(e -> e.entity.referenceEquals(caster.getEntity())).findFirst();
+        }
+    }
+
+    public Optional<Entry> getEntry(SpellType<?> spellType, UUID uuid) {
+        synchronized (locker) {
+            return getEntries(spellType).stream().filter(e -> e.equals(uuid)).findFirst();
+        }
+    }
+
+    public class Entry implements NbtSerialisable {
+        public final EntityReference<?> entity;
+        private boolean removed;
+        private boolean taken;
+
+        public Entry() {
+            entity = new EntityReference<>();
+        }
+
+        public Entry(Caster<?> caster) {
+            entity = new EntityReference<>(caster.getEntity());
+        }
+
+        public boolean isAlive() {
+            return !removed;
+        }
+
+        public void markDead() {
+            removed = true;
+            markDirty();
+        }
+
+        public boolean isAvailable() {
+            return !removed && !taken;
+        }
+
+        public void setTaken(boolean taken) {
+            this.taken = taken;
+            markDirty();
+        }
+
+        @Override
+        public void toNBT(NbtCompound compound) {
+            entity.toNBT(compound);
+            compound.putBoolean("remove", removed);
+            compound.putBoolean("taken", taken);
+        }
+        @Override
+        public void fromNBT(NbtCompound compound) {
+            entity.fromNBT(compound);
+            removed = compound.getBoolean("removed");
+            taken = compound.getBoolean("taken");
+        }
+
+        @Override
+        public boolean equals(Object other) {
+            return other instanceof Entry e
+                && e.equals(entity.getId().orElse(Util.NIL_UUID));
+        }
+
+        public boolean equals(UUID uuid) {
+            return entity.getId().orElse(Util.NIL_UUID).equals(uuid);
+        }
+
+        @Override
+        public int hashCode() {
+            return entity.getId().orElse(Util.NIL_UUID).hashCode();
+        }
+    }
 }