Further cleanup to the magic system

src/main/java/com/minelittlepony/unicopia/EquinePredicates.java

@@ -2,8 +2,10 @@ package com.minelittlepony.unicopia;
 
 import java.util.function.Predicate;
 
+import javax.annotation.Nullable;
+
 import com.minelittlepony.unicopia.ability.magic.Caster;
-import com.minelittlepony.unicopia.ability.magic.Spell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.Equine;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.item.enchantment.UEnchantments;
@@ -28,7 +30,7 @@ public interface EquinePredicates {
 
     Predicate<LivingEntity> HAS_WANT_IT_NEED_IT = e -> EnchantmentHelper.getEquipmentLevel(UEnchantments.WANT_IT_NEED_IT, e) > 0;
 
-    static Predicate<Entity> carryingSpell(Class<? extends Spell> type) {
+    static Predicate<Entity> carryingSpell(@Nullable SpellType<?> type) {
-        return IS_PLAYER.and(entity -> Pony.of((PlayerEntity)entity).getSpellOrEmpty(type, false).isPresent());
+        return IS_PLAYER.and(entity -> Pony.of((PlayerEntity)entity).getSpellSlot().get(type, false).isPresent());
     }
 }

src/main/java/com/minelittlepony/unicopia/ability/BatEeeeAbility.java

@@ -8,7 +8,7 @@ import com.minelittlepony.unicopia.EquinePredicates;
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.USounds;
 import com.minelittlepony.unicopia.ability.data.Hit;
-import com.minelittlepony.unicopia.ability.magic.spell.ShieldSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.util.MagicalDamageSource;
 
@@ -23,7 +23,7 @@ import net.minecraft.util.math.Vec3d;
  */
 public class BatEeeeAbility implements Ability<Hit> {
 
-    private static final Predicate<Entity> HAS_SHIELD = EquinePredicates.carryingSpell(ShieldSpell.class);
+    private static final Predicate<Entity> HAS_SHIELD = EquinePredicates.carryingSpell(SpellType.SHIELD);
 
     @Override
     public int getWarmupTime(Pony player) {

src/main/java/com/minelittlepony/unicopia/ability/ChangelingDisguiseAbility.java

@@ -44,7 +44,8 @@ public class ChangelingDisguiseAbility extends ChangelingFeedAbility {
 
         Entity looked = trace.getEntity().map(e -> {
             return e instanceof PlayerEntity ? Pony.of((PlayerEntity)e)
-                    .getSpellOrEmpty(DisguiseSpell.class)
+                    .getSpellSlot()
+                    .get(SpellType.DISGUISE, true)
                     .map(DisguiseSpell::getDisguise)
                     .map(Disguise::getAppearance)
                     .orElse(e) : e;
@@ -57,7 +58,7 @@ public class ChangelingDisguiseAbility extends ChangelingFeedAbility {
 
         player.getEntityWorld().playSound(null, player.getBlockPos(), SoundEvents.ENTITY_PARROT_IMITATE_RAVAGER, SoundCategory.PLAYERS, 1.4F, 0.4F);
 
-        iplayer.getSpellOrEmpty(DisguiseSpell.class).orElseGet(() -> {
+        iplayer.getSpellSlot().get(SpellType.DISGUISE, true).orElseGet(() -> {
             DisguiseSpell disc = SpellType.DISGUISE.create();
 
             iplayer.setSpell(disc);

src/main/java/com/minelittlepony/unicopia/ability/PegasusRainboomAbility.java

@@ -40,7 +40,7 @@ public class PegasusRainboomAbility implements Ability<Hit> {
             return null;
         }
 
-        if (player.getPhysics().isFlying() && !player.hasSpell()) {
+        if (player.getPhysics().isFlying() && !player.getSpellSlot().isPresent()) {
             return Hit.INSTANCE;
         }
 
@@ -64,7 +64,7 @@ public class PegasusRainboomAbility implements Ability<Hit> {
             return;
         }
 
-        if (player.getPhysics().isFlying() && !player.hasSpell()) {
+        if (player.getPhysics().isFlying() && !player.getSpellSlot().isPresent()) {
             player.getMagicalReserves().getMana().multiply(0.1F);
             player.addParticle(new OrientedBillboardParticleEffect(UParticles.RAINBOOM_RING, player.getPhysics().getMotionAngle()), player.getOriginVector(), Vec3d.ZERO);
             player.setSpell(SpellType.JOUSTING.create());

src/main/java/com/minelittlepony/unicopia/ability/UnicornCastingAbility.java

@@ -7,6 +7,7 @@ import javax.annotation.Nullable;
 import com.google.common.collect.Streams;
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.ability.data.Hit;
+import com.minelittlepony.unicopia.ability.magic.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.item.AmuletItem;
@@ -60,7 +61,7 @@ public class UnicornCastingAbility implements Ability<Hit> {
             return Hit.of(spell != ActionResult.FAIL && manaLevel > 4F);
         }
 
-        return Hit.of(manaLevel > (player.hasSpell() ? 2F : 4F));
+        return Hit.of(manaLevel > (player.getSpellSlot().isPresent() ? 2F : 4F));
     }
 
     @Override
@@ -82,7 +83,7 @@ public class UnicornCastingAbility implements Ability<Hit> {
             return 4F;
         }
 
-        if (player.hasSpell()) {
+        if (player.getSpellSlot().isPresent()) {
             return 2F;
         }
 
@@ -112,7 +113,7 @@ public class UnicornCastingAbility implements Ability<Hit> {
             if (newSpell.getResult() != ActionResult.FAIL) {
                 @Nullable
                 SpellType<?> spell = newSpell.getValue();
-                if (!player.hasSpell() && spell == null) {
+                if (!player.getSpellSlot().isPresent() && spell == null) {
                     spell = SpellType.SHIELD;
                 }
 
@@ -138,7 +139,7 @@ public class UnicornCastingAbility implements Ability<Hit> {
     }
 
     private TypedActionResult<SpellType<?>> getNewSpell(Pony player) {
-        final SpellType<?> current = player.hasSpell() ? player.getSpell(true).getType() : null;
+        final SpellType<?> current = player.getSpellSlot().get(true).map(Spell::getType).orElse(null);
         return Streams.stream(player.getMaster().getItemsHand())
                 .filter(GemstoneItem::isEnchanted)
                 .map(stack -> GemstoneItem.consumeSpell(stack, player.getMaster(), current, SpellType::mayAttach))

src/main/java/com/minelittlepony/unicopia/ability/magic/Caster.java

@@ -27,48 +27,10 @@ public interface Caster<E extends LivingEntity> extends Owned<E>, Levelled, Affi
 
     Physics getPhysics();
 
-    EffectSync getPrimarySpellSlot();
+    EffectSync getSpellSlot();
 
     default void setSpell(@Nullable Spell spell) {
-        getPrimarySpellSlot().set(spell);
+        getSpellSlot().put(spell);
-    }
-
-    /**
-     * Gets the active effect for this caster.
-     */
-    @Nullable
-    default Spell getSpell(boolean update) {
-        return getSpell(null, update);
-    }
-
-    /**
-     * Gets the active effect for the matching given type.
-     * Returns null if no such effect exists for this caster.
-     */
-    @Nullable
-    default <T extends Spell> T getSpell(@Nullable Class<T> type, boolean update) {
-        return getPrimarySpellSlot().get(type, update);
-    }
-
-    /**
-     * Gets the active effect for this caster updating it if needed.
-     */
-    default <T extends Spell> Optional<T> getSpellOrEmpty(Class<T> type, boolean update) {
-        return getPrimarySpellSlot().getOrEmpty(type, update);
-    }
-
-    /**
-     * Gets the active effect for this caster updating it if needed.
-     */
-    default <T extends Spell> Optional<T> getSpellOrEmpty(Class<T> type) {
-        return getSpellOrEmpty(type, true);
-    }
-
-    /**
-     * Returns true if this caster has an active effect attached to it.
-     */
-    default boolean hasSpell() {
-        return getPrimarySpellSlot().has();
     }
 
     /**
@@ -80,7 +42,7 @@ public interface Caster<E extends LivingEntity> extends Owned<E>, Levelled, Affi
     }
 
     /**
-     * gets the minecraft world
+     * Gets the minecraft world
      */
     @Override
     default World getWorld() {

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

@@ -52,11 +52,4 @@ public interface Spell extends NbtSerialisable, Affine {
     default boolean handleProjectileImpact(ProjectileEntity projectile) {
         return false;
     }
-
-    /**
-     * Returns a new, deep-copied instance of this spell.
-     */
-    default Spell copy() {
-        return SpellType.copy(this);
-    }
 }

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

@@ -2,7 +2,6 @@ package com.minelittlepony.unicopia.ability.magic.spell;
 
 import com.minelittlepony.unicopia.ability.magic.Attached;
 import com.minelittlepony.unicopia.ability.magic.Caster;
-import com.minelittlepony.unicopia.ability.magic.Suppressable;
 import com.minelittlepony.unicopia.ability.magic.Thrown;
 import com.minelittlepony.unicopia.particle.MagicParticleEffect;
 import com.minelittlepony.unicopia.util.shape.Shape;
@@ -45,12 +44,12 @@ public class RevealingSpell extends AbstractSpell implements Attached, Thrown {
         }
 
         source.findAllSpellsInRange(15).forEach(e -> {
-            Suppressable spell = e.getSpell(Suppressable.class, false);
+            e.getSpellSlot().get(SpellPredicate.IS_SUPPRESSABLE, false)
-
+                .filter(spell -> spell.isVulnerable(source, this))
-            if (spell != null && spell.isVulnerable(source, this)) {
+                .ifPresent(spell -> {
                 spell.onSuppressed(source);
                 source.getWorld().playSound(null, e.getOrigin(), SoundEvents.ENTITY_ZOMBIE_VILLAGER_CURE, SoundCategory.PLAYERS, 0.2F, 0.5F);
-            }
+            });
         });
 
         return true;

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

@@ -0,0 +1,14 @@
+package com.minelittlepony.unicopia.ability.magic.spell;
+
+import java.util.function.Predicate;
+
+import com.minelittlepony.unicopia.ability.magic.Attached;
+import com.minelittlepony.unicopia.ability.magic.Spell;
+import com.minelittlepony.unicopia.ability.magic.Suppressable;
+import com.minelittlepony.unicopia.ability.magic.Thrown;
+
+public interface SpellPredicate<T> extends Predicate<Spell> {
+    SpellPredicate<Thrown> IS_THROWN = s -> s instanceof Thrown;
+    SpellPredicate<Attached> IS_ATTACHED = s -> s instanceof Attached;
+    SpellPredicate<Suppressable> IS_SUPPRESSABLE = s -> s instanceof Suppressable;
+}

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

@@ -10,9 +10,7 @@ import javax.annotation.Nullable;
 
 import com.minelittlepony.unicopia.Affinity;
 import com.minelittlepony.unicopia.ability.magic.Affine;
-import com.minelittlepony.unicopia.ability.magic.Attached;
 import com.minelittlepony.unicopia.ability.magic.Spell;
-import com.minelittlepony.unicopia.ability.magic.Thrown;
 
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.text.Text;
@@ -20,7 +18,7 @@ import net.minecraft.text.TranslatableText;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.Util;
 
-public class SpellType<T extends Spell> implements Affine {
+public final class SpellType<T extends Spell> implements Affine, SpellPredicate<T> {
 
     public static final Identifier EMPTY_ID = new Identifier("unicopia", "null");
     public static final SpellType<?> EMPTY_KEY = new SpellType<>(EMPTY_ID, Affinity.NEUTRAL, 0xFFFFFF, false, t -> null);
@@ -57,7 +55,7 @@ public class SpellType<T extends Spell> implements Affine {
     @Nullable
     private String translationKey;
 
-    SpellType(Identifier id, Affinity affinity, int color, boolean obtainable, Factory<T> factory) {
+    private SpellType(Identifier id, Affinity affinity, int color, boolean obtainable, Factory<T> factory) {
         this.id = id;
         this.affinity = affinity;
         this.color = color;
@@ -65,8 +63,8 @@ public class SpellType<T extends Spell> implements Affine {
         this.factory = factory;
 
         Spell inst = create();
-        thrown = inst instanceof Thrown;
+        thrown = SpellPredicate.IS_THROWN.test(inst);
-        attached = inst instanceof Attached;
+        attached = SpellPredicate.IS_ATTACHED.test(inst);
     }
 
     public boolean isObtainable() {
@@ -119,6 +117,11 @@ public class SpellType<T extends Spell> implements Affine {
         return null;
     }
 
+    @Override
+    public boolean test(@Nullable Spell spell) {
+        return spell != null && spell.getType() == this;
+    }
+
     public static <T extends Spell> SpellType<T> register(Identifier id, Affinity affinity, int color, boolean obtainable, Factory<T> factory) {
         SpellType<T> type = new SpellType<>(id, affinity, color, obtainable, factory);
         byAffinity(affinity).add(type);
@@ -132,18 +135,13 @@ public class SpellType<T extends Spell> implements Affine {
 
     @SuppressWarnings("unchecked")
     public static <T extends Spell> SpellType<T> getKey(Identifier id) {
-        return (SpellType<T>)REGISTRY.getOrDefault(id, EMPTY_KEY);
+        return (SpellType<T>)(EMPTY_ID.equals(id) ? EMPTY_KEY : REGISTRY.getOrDefault(id, EMPTY_KEY));
     }
 
     public static Set<SpellType<?>> byAffinity(Affinity affinity) {
         return BY_AFFINITY.computeIfAbsent(affinity, a -> new HashSet<>());
     }
 
-    @SuppressWarnings("unchecked")
-    public static <T extends Spell> T copy(T effect) {
-        return (T)fromNBT(toNBT(effect));
-    }
-
     @Nullable
     public static Spell fromNBT(CompoundTag compound) {
         if (compound.contains("effect_id")) {

src/main/java/com/minelittlepony/unicopia/client/gui/UHud.java

@@ -9,6 +9,7 @@ import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.ability.AbilityDispatcher;
 import com.minelittlepony.unicopia.ability.AbilitySlot;
 import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.client.KeyBindingsHandler;
 import com.minelittlepony.unicopia.entity.behaviour.Disguise;
 import com.minelittlepony.unicopia.entity.player.Pony;
@@ -88,7 +89,7 @@ public class UHud extends DrawableHelper {
         matrices.pop();
 
         if (pony.getSpecies() == Race.CHANGELING && !client.player.isSneaking()) {
-            pony.getSpellOrEmpty(DisguiseSpell.class, false).map(DisguiseSpell::getDisguise)
+            pony.getSpellSlot().get(SpellType.DISGUISE, false).map(DisguiseSpell::getDisguise)
                 .map(Disguise::getAppearance)
                 .ifPresent(appearance -> {
 

src/main/java/com/minelittlepony/unicopia/client/render/WorldRenderDelegate.java

@@ -3,7 +3,7 @@ package com.minelittlepony.unicopia.client.render;
 import javax.annotation.Nullable;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
-import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.Equine;
 import com.minelittlepony.unicopia.entity.ItemImpl;
 import com.minelittlepony.unicopia.entity.Living;
@@ -83,7 +83,7 @@ public class WorldRenderDelegate {
 
             int fireTicks = pony.getMaster().doesRenderOnFire() ? 1 : 0;
 
-            return ((Caster<?>)pony).getSpellOrEmpty(DisguiseSpell.class, true).map(effect -> {
+            return ((Caster<?>)pony).getSpellSlot().get(SpellType.DISGUISE, true).map(effect -> {
                 effect.update(pony, false);
 
                 Disguise ve = effect.getDisguise();

src/main/java/com/minelittlepony/unicopia/command/DisguiseCommand.java

@@ -2,7 +2,6 @@ package com.minelittlepony.unicopia.command;
 
 import java.util.function.Function;
 
-import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.mojang.brigadier.CommandDispatcher;
@@ -61,13 +60,10 @@ public class DisguiseCommand {
             throw FAILED_EXCEPTION.create();
         }
 
-        DisguiseSpell effect = iplayer.getSpell(DisguiseSpell.class, true);
+        iplayer.getSpellSlot()
-
+            .get(SpellType.DISGUISE, true)
-        if (effect == null) {
+            .orElseGet(SpellType.DISGUISE::create)
-            iplayer.setSpell(SpellType.DISGUISE.create().setDisguise(entity));
+            .setDisguise(entity);
-        } else {
-            effect.setDisguise(entity);
-        }
 
         if (!isSelf) {
             source.sendFeedback(new TranslatableText("commands.disguise.success.other", player.getName(), entity.getName()), true);
@@ -83,7 +79,7 @@ public class DisguiseCommand {
 
     static int reveal(ServerCommandSource source, PlayerEntity player) {
         Pony iplayer = Pony.of(player);
-        iplayer.getSpellOrEmpty(DisguiseSpell.class).ifPresent(disguise -> {
+        iplayer.getSpellSlot().get(SpellType.DISGUISE, true).ifPresent(disguise -> {
             disguise.onDestroyed(iplayer);
         });
 

src/main/java/com/minelittlepony/unicopia/entity/Creature.java

@@ -4,7 +4,6 @@ import com.minelittlepony.unicopia.Affinity;
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.ability.magic.Affine;
 import com.minelittlepony.unicopia.ability.magic.Levelled;
-import com.minelittlepony.unicopia.ability.magic.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.ai.BreakHeartGoal;
 import com.minelittlepony.unicopia.entity.ai.DynamicTargetGoal;
@@ -89,11 +88,9 @@ public class Creature extends Living<LivingEntity> {
     @Override
     public void toNBT(CompoundTag compound) {
         super.toNBT(compound);
-        Spell effect = getSpell(true);
+        getSpellSlot().get(true).ifPresent(effect -> {
-
-        if (effect != null) {
             compound.put("effect", SpellType.toNBT(effect));
-        }
+        });
         physics.toNBT(compound);
     }
 

src/main/java/com/minelittlepony/unicopia/entity/Living.java

@@ -5,10 +5,9 @@ import java.util.stream.Stream;
 
 import javax.annotation.Nullable;
 
-import com.minelittlepony.unicopia.ability.magic.Attached;
 import com.minelittlepony.unicopia.ability.magic.Caster;
-import com.minelittlepony.unicopia.ability.magic.Spell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellPredicate;
-import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.item.UItems;
 import com.minelittlepony.unicopia.network.EffectSync;
 
@@ -60,7 +59,7 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
     }
 
     @Override
-    public EffectSync getPrimarySpellSlot() {
+    public EffectSync getSpellSlot() {
         return effectDelegate;
     }
 
@@ -79,15 +78,11 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
 
     @Override
     public void tick() {
-        if (hasSpell()) {
+        getSpellSlot().get(SpellPredicate.IS_ATTACHED, true).ifPresent(effect -> {
-            Attached effect = getSpell(Attached.class, true);
-
-            if (effect != null) {
             if (!effect.onBodyTick(this)) {
                 setSpell(null);
             }
-            }
+        });
-        }
 
         if (invinsibilityTicks > 0) {
             invinsibilityTicks--;
@@ -142,18 +137,13 @@ public abstract class Living<T extends LivingEntity> implements Equine<T>, Caste
 
     @Override
     public boolean onProjectileImpact(ProjectileEntity projectile) {
-        if (hasSpell()) {
+        return getSpellSlot().get(true)
-            Spell effect = getSpell(true);
+                .filter(effect -> !effect.isDead() && effect.handleProjectileImpact(projectile))
-            if (!effect.isDead() && effect.handleProjectileImpact(projectile)) {
+                .isPresent();
-                return true;
-            }
-        }
-
-        return false;
     }
 
     protected void handleFall(float distance, float damageMultiplier) {
-        getSpellOrEmpty(DisguiseSpell.class, false).ifPresent(spell -> {
+        getSpellSlot().get(SpellType.DISGUISE, false).ifPresent(spell -> {
             spell.getDisguise().onImpact(this, distance, damageMultiplier);
         });
     }

src/main/java/com/minelittlepony/unicopia/entity/behaviour/Disguise.java

@@ -14,7 +14,7 @@ import com.minelittlepony.unicopia.FlightType;
 import com.minelittlepony.unicopia.InteractionManager;
 import com.minelittlepony.unicopia.Owned;
 import com.minelittlepony.unicopia.ability.magic.Caster;
-import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.player.PlayerAttributes;
 import com.minelittlepony.unicopia.entity.player.Pony;
 import com.minelittlepony.unicopia.projectile.ProjectileUtil;
@@ -345,7 +345,7 @@ public class Disguise implements NbtSerialisable {
         VoxelShape entityShape = VoxelShapes.cuboid(box.expand(1.0E-6D));
 
         world.getOtherEntities(entity, box.expand(0.5), predicate.and(e -> {
-            Caster.of(e).flatMap(c -> c.getSpellOrEmpty(DisguiseSpell.class, false)).ifPresent(p -> {
+            Caster.of(e).flatMap(c -> c.getSpellSlot().get(SpellType.DISGUISE, false)).ifPresent(p -> {
                 p.getDisguise().getCollissionShapes(ctx, shape -> {
                     if (!shape.isEmpty() && VoxelShapes.matchesAnywhere(shape, entityShape, BooleanBiFunction.AND)) {
                         shapes.add(shape);

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerCamera.java

@@ -4,6 +4,7 @@ import java.util.Optional;
 
 import com.minelittlepony.common.util.animation.MotionCompositor;
 import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 
 import net.minecraft.util.math.Vec3d;
 
@@ -46,7 +47,8 @@ public class PlayerCamera extends MotionCompositor {
     }
 
     public Optional<Double> calculateDistance(double distance) {
-        return player.getSpellOrEmpty(DisguiseSpell.class, false)
+        return player.getSpellSlot()
+            .get(SpellType.DISGUISE, false)
             .map(DisguiseSpell::getDisguise)
             .flatMap(d -> d.getDistance(player))
             .map(d -> distance * d);

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerDimensions.java

@@ -5,7 +5,6 @@ import java.util.Optional;
 import javax.annotation.Nullable;
 
 import com.minelittlepony.unicopia.Unicopia;
-import com.minelittlepony.unicopia.ability.magic.Spell;
 
 import net.minecraft.entity.EntityDimensions;
 
@@ -72,13 +71,9 @@ public final class PlayerDimensions {
     }
 
     Optional<Provider> getPredicate() {
-        if (pony.hasSpell()) {
+        return pony.getSpellSlot().get(true)
-            Spell effect = pony.getSpell(true);
+                .filter(effect -> !effect.isDead() && effect instanceof Provider)
-            if (!effect.isDead() && effect instanceof Provider) {
+                .map(effect -> (Provider)effect);
-                return Optional.of(((Provider)effect));
-            }
-        }
-        return Optional.empty();
     }
 
     public interface Provider {

src/main/java/com/minelittlepony/unicopia/entity/player/PlayerPhysics.java

@@ -3,8 +3,7 @@ package com.minelittlepony.unicopia.entity.player;
 import com.minelittlepony.unicopia.FlightType;
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.USounds;
-import com.minelittlepony.unicopia.ability.magic.Spell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
-import com.minelittlepony.unicopia.ability.magic.spell.JoustingSpell;
 import com.minelittlepony.unicopia.entity.Creature;
 import com.minelittlepony.unicopia.entity.EntityPhysics;
 import com.minelittlepony.unicopia.entity.Jumper;
@@ -78,7 +77,7 @@ public class PlayerPhysics extends EntityPhysics<Pony> implements Tickable, Moti
 
     @Override
     public boolean isRainbooming() {
-        return pony.getSpellOrEmpty(JoustingSpell.class).isPresent();
+        return pony.getSpellSlot().get(SpellType.JOUSTING, true).isPresent();
     }
 
     @Override
@@ -448,14 +447,10 @@ public class PlayerPhysics extends EntityPhysics<Pony> implements Tickable, Moti
             return FlightType.ARTIFICIAL;
         }
 
-        if (pony.hasSpell()) {
+        return pony.getSpellSlot().get(true)
-            Spell effect = pony.getSpell(true);
+            .filter(effect -> !effect.isDead() && effect instanceof FlightType.Provider)
-            if (!effect.isDead() && effect instanceof FlightType.Provider) {
+            .map(effect -> ((FlightType.Provider)effect).getFlightType(pony))
-                return ((FlightType.Provider)effect).getFlightType(pony);
+            .orElse(pony.getSpecies().getFlightType());
-            }
-        }
-
-        return pony.getSpecies().getFlightType();
     }
 
     public void updateFlightStat(boolean flying) {

src/main/java/com/minelittlepony/unicopia/entity/player/Pony.java

@@ -14,7 +14,6 @@ import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.WorldTribeManager;
 import com.minelittlepony.unicopia.ability.AbilityDispatcher;
 import com.minelittlepony.unicopia.ability.magic.Spell;
-import com.minelittlepony.unicopia.ability.magic.spell.ShieldSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.Physics;
 import com.minelittlepony.unicopia.entity.PonyContainer;
@@ -134,7 +133,7 @@ public class Pony extends Living<PlayerEntity> implements Transmittable, Copieab
 
     @Override
     public boolean isInvisible() {
-        return invisible && hasSpell();
+        return invisible && getSpellSlot().isPresent();
     }
 
     public boolean isSpeciesPersisted() {
@@ -289,7 +288,7 @@ public class Pony extends Living<PlayerEntity> implements Transmittable, Copieab
 
         float g = gravity.getGravityModifier();
 
-        boolean extraProtection = getSpell(ShieldSpell.class, false) != null;
+        boolean extraProtection = getSpellSlot().get(SpellType.SHIELD, false).isPresent();
 
         if (g != 1 || extraProtection || getSpecies().canFly() && !entity.isCreative() && !entity.isSpectator()) {
 
@@ -384,11 +383,9 @@ public class Pony extends Living<PlayerEntity> implements Transmittable, Copieab
         compound.put("powers", powers.toNBT());
         compound.put("gravity", gravity.toNBT());
 
-        Spell effect = getSpell(true);
+        getSpellSlot().get(true).ifPresent(effect ->{
-
-        if (effect != null) {
             compound.put("effect", SpellType.toNBT(effect));
-        }
+        });
     }
 
     @Override
@@ -403,7 +400,7 @@ public class Pony extends Living<PlayerEntity> implements Transmittable, Copieab
         magicExhaustion = compound.getFloat("magicExhaustion");
 
         if (compound.contains("effect")) {
-            getPrimarySpellSlot().set(SpellType.fromNBT(compound.getCompound("effect")));
+            getSpellSlot().put(SpellType.fromNBT(compound.getCompound("effect")));
         }
     }
 
@@ -411,7 +408,7 @@ public class Pony extends Living<PlayerEntity> implements Transmittable, Copieab
     public void copyFrom(Pony oldPlayer) {
         speciesPersisted = oldPlayer.speciesPersisted;
         if (!oldPlayer.getEntity().removed) {
-            setSpell(oldPlayer.getSpell(true));
+            setSpell(oldPlayer.getSpellSlot().get(true).orElse(null));
         }
         setSpecies(oldPlayer.getSpecies());
         setDirty();

src/main/java/com/minelittlepony/unicopia/mixin/MixinLivingEntity.java

@@ -14,6 +14,7 @@ import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.Creature;
 import com.minelittlepony.unicopia.entity.PonyContainer;
 import com.minelittlepony.unicopia.entity.behaviour.Disguise;
@@ -82,7 +83,7 @@ abstract class MixinLivingEntity extends Entity implements PonyContainer<Equine<
     @Inject(method = "isClimbing()Z", at = @At("HEAD"), cancellable = true)
     public void onIsClimbing(CallbackInfoReturnable<Boolean> info) {
         if (get() instanceof Pony && horizontalCollision) {
-            ((Pony)get()).getSpellOrEmpty(DisguiseSpell.class, false)
+            ((Pony)get()).getSpellSlot().get(SpellType.DISGUISE, false)
             .map(DisguiseSpell::getDisguise)
             .filter(Disguise::canClimbWalls)
             .ifPresent(v -> {
@@ -95,7 +96,7 @@ abstract class MixinLivingEntity extends Entity implements PonyContainer<Equine<
     @Inject(method = "isPushable()Z", at = @At("HEAD"), cancellable = true)
     private void onIsPushable(CallbackInfoReturnable<Boolean> info) {
         Caster.of(this)
-            .flatMap(c -> c.getSpellOrEmpty(DisguiseSpell.class, false))
+            .flatMap(c -> c.getSpellSlot().get(SpellType.DISGUISE, false))
             .map(DisguiseSpell::getDisguise)
             .map(Disguise::getAppearance)
             .filter(Entity::isPushable)

src/main/java/com/minelittlepony/unicopia/mixin/MixinTargetPredicate.java

@@ -7,7 +7,7 @@ import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
-import com.minelittlepony.unicopia.ability.magic.spell.DisguiseSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.Equine;
 import com.minelittlepony.unicopia.entity.player.Pony;
 
@@ -20,7 +20,7 @@ abstract class MixinTargetPredicate {
     public void onTest(@Nullable LivingEntity baseEntity, LivingEntity targetEntity, CallbackInfoReturnable<Boolean> info) {
         Equine<?> eq = Equine.of(targetEntity);
         if (eq instanceof Pony) {
-            ((Pony)eq).getSpellOrEmpty(DisguiseSpell.class).ifPresent(spell -> {
+            ((Pony)eq).getSpellSlot().get(SpellType.DISGUISE, true).ifPresent(spell -> {
                 if (spell.getDisguise().getAppearance() == baseEntity) {
                     info.setReturnValue(false);
                 }

src/main/java/com/minelittlepony/unicopia/network/EffectSync.java

@@ -6,6 +6,7 @@ import javax.annotation.Nullable;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.Spell;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellPredicate;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 
 import net.minecraft.entity.data.TrackedData;
@@ -13,7 +14,7 @@ import net.minecraft.nbt.CompoundTag;
 import net.minecraft.util.Identifier;
 
 /**
- * Synchronisation class for spell effects.
+ * Synchronisation class for spells.
  * Since we can't have our own serializers, we have to intelligently
  * determine whether to update it from an nbt tag.
  *
@@ -21,85 +22,83 @@ import net.minecraft.util.Identifier;
  */
 public class EffectSync {
 
-    @Nullable
+    private Optional<Spell> spell = Optional.empty();
-    private Spell effect;
 
-    private final Caster<?> owned;
+    private final Caster<?> owner;
 
     private final TrackedData<CompoundTag> param;
 
     @Nullable
     private CompoundTag lastValue;
 
-    public EffectSync(Caster<?> owned, TrackedData<CompoundTag> param) {
+    public EffectSync(Caster<?> owner, TrackedData<CompoundTag> param) {
-        this.owned = owned;
+        this.owner = owner;
         this.param = param;
     }
 
-    public <T extends Spell> Optional<T> getOrEmpty(Class<T> type, boolean update) {
+    /**
-        T effect = get(type, update);
+     * Gets the active effect for this caster updating it if needed.
-
+     */
-        if (effect == null || effect.isDead()) {
+    public <T extends Spell> Optional<T> get(boolean update) {
-            return Optional.empty();
+        return get(null, update);
-        }
-
-        return Optional.of(effect);
     }
 
+    /**
+     * Gets the active effect for this caster updating it if needed.
+     */
     @SuppressWarnings("unchecked")
-    public <E extends Spell> E get(Class<E> type, boolean update) {
+    public <T extends Spell> Optional<T> get(@Nullable SpellPredicate<T> type, boolean update) {
         if (update) {
             sync(true);
         }
 
-        if (effect == null || type == null || type.isAssignableFrom(effect.getClass())) {
+        if (checkReference() && (type == null || type.test(spell.get()))) {
-            return (E)effect;
+            return (Optional<T>)spell;
         }
 
-        return null;
+        return Optional.empty();
     }
 
-    public boolean has() {
+    /**
+     * Returns true if this caster has an active effect attached to it.
+     */
+    public boolean isPresent() {
         sync(false);
-        return effect != null;
+        return checkReference();
+    }
+
+    private boolean checkReference() {
+        return spell.isPresent() && !spell.get().isDead();
     }
 
     private void sync(boolean force) {
-        CompoundTag comp = owned.getEntity().getDataTracker().get(param);
+        CompoundTag comp = owner.getEntity().getDataTracker().get(param);
+
+        Spell effect = spell.orElse(null);
 
         if (comp == null || !comp.contains("effect_id")) {
-            if (effect != null) {
+            updateReference(null);
-                effect.setDead();
+        } else if (!checkReference() || !effect.getType().getId().equals(new Identifier(comp.getString("effect_id")))) {
-                effect = null;
+            updateReference(SpellType.fromNBT(comp));
-            }
+        } else if (owner.getEntity().world.isClient()) {
-            return;
-        } else {
-            if (effect == null || !effect.getType().getId().equals(new Identifier(comp.getString("effect_id")))) {
-                if (effect != null) {
-                    effect.setDead();
-                }
-                effect = SpellType.fromNBT(comp);
-            } else if (owned.getEntity().world.isClient()) {
             if (lastValue != comp || !(comp == null || comp.equals(lastValue))) {
                 lastValue = comp;
                 effect.fromNBT(comp);
             }
-            } else if ((force || !owned.getEntity().world.isClient()) && effect.isDirty()) {
+        } else if ((force || !owner.isClient()) && effect.isDirty()) {
-                set(effect);
+            put(effect);
-            }
         }
     }
 
-    public void set(@Nullable Spell effect) {
+    public void put(@Nullable Spell effect) {
-        if (this.effect != null && this.effect != effect) {
+        updateReference(effect);
-            this.effect.setDead();
+        owner.getEntity().getDataTracker().set(param, effect == null ? new CompoundTag() : SpellType.toNBT(effect));
     }
-        this.effect = effect;
 
-        if (effect == null) {
+    private void updateReference(@Nullable Spell effect) {
-            owned.getEntity().getDataTracker().set(param, new CompoundTag());
+        if (spell.isPresent() && spell.get() != effect) {
-        } else {
+            spell.get().setDead();
-            owned.getEntity().getDataTracker().set(param, SpellType.toNBT(effect));
+        }
-        }
+        spell = Optional.ofNullable(effect);
     }
 }

src/main/java/com/minelittlepony/unicopia/particle/ParticleHandle.java

@@ -4,6 +4,7 @@ import java.util.Optional;
 import java.util.function.Consumer;
 
 import com.minelittlepony.unicopia.ability.magic.Caster;
+import com.minelittlepony.unicopia.ability.magic.Spell;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.Equine;
 
@@ -66,7 +67,7 @@ public class ParticleHandle {
         public void attach(Caster<?> caster) {
             this.linked = true;
             this.caster = Optional.of(caster);
-            this.effect = caster.getSpell(false).getType();
+            this.effect = caster.getSpellSlot().get(false).map(Spell::getType).orElse(null);
         }
 
         public void detach() {
@@ -81,10 +82,10 @@ public class ParticleHandle {
             caster = caster.filter(c -> {
                 Entity e = c.getEntity();
 
-
                 return Equine.of(e) == c
-                        && c.hasSpell()
+                        && c.getSpellSlot().get(false)
-                        && c.getSpell(false).getType().equals(effect)
+                            .filter(s -> s.getType() == effect)
+                            .isPresent()
                         && e != null
                         && c.getWorld().getEntityById(e.getEntityId()) != null;
             });

src/main/java/com/minelittlepony/unicopia/projectile/MagicProjectileEntity.java

@@ -2,11 +2,12 @@ package com.minelittlepony.unicopia.projectile;
 
 import com.minelittlepony.unicopia.Affinity;
 import com.minelittlepony.unicopia.UEntities;
+import com.minelittlepony.unicopia.ability.magic.Affine;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.Levelled;
 import com.minelittlepony.unicopia.ability.magic.Magical;
 import com.minelittlepony.unicopia.ability.magic.Spell;
-import com.minelittlepony.unicopia.ability.magic.Thrown;
+import com.minelittlepony.unicopia.ability.magic.spell.SpellPredicate;
 import com.minelittlepony.unicopia.ability.magic.spell.SpellType;
 import com.minelittlepony.unicopia.entity.EntityPhysics;
 import com.minelittlepony.unicopia.entity.Physics;
@@ -77,7 +78,7 @@ public class MagicProjectileEntity extends ThrownItemEntity implements Magical,
 
     @Override
     protected Item getDefaultItem() {
-        switch (getSpellOrEmpty(Spell.class, false).map(Spell::getAffinity).orElse(Affinity.NEUTRAL)) {
+        switch (getSpellSlot().get(false).map(Spell::getAffinity).orElse(Affinity.NEUTRAL)) {
             case GOOD: return Items.SNOWBALL;
             case BAD: return Items.MAGMA_CREAM;
             default: return Items.AIR;
@@ -111,11 +112,11 @@ public class MagicProjectileEntity extends ThrownItemEntity implements Magical,
 
     @Override
     public Affinity getAffinity() {
-        return hasSpell() ? getSpell(true).getAffinity() : Affinity.NEUTRAL;
+        return getSpellSlot().get(true).map(Affine::getAffinity).orElse(Affinity.NEUTRAL);
     }
 
     @Override
-    public EffectSync getPrimarySpellSlot() {
+    public EffectSync getSpellSlot() {
         return effectDelegate;
     }
 
@@ -158,17 +159,13 @@ public class MagicProjectileEntity extends ThrownItemEntity implements Magical,
             setNoGravity(false);
         }
 
-        if (hasSpell()) {
+        if (getSpellSlot().isPresent()) {
             if (lastBlockPos == null || !lastBlockPos.equals(getBlockPos())) {
                 lastBlockPos = getBlockPos();
             }
 
-            Thrown spell = getSpell(Thrown.class, true);
+            if (!getSpellSlot().get(SpellPredicate.IS_THROWN, true).filter(spell -> spell.onThrownTick(this)).isPresent()) {
-
-            if (spell.isDead()) {
                 remove();
-            } else {
-                spell.onThrownTick(this);
             }
         }
 
@@ -228,10 +225,9 @@ public class MagicProjectileEntity extends ThrownItemEntity implements Magical,
     public void writeCustomDataToTag(CompoundTag compound) {
         super.writeCustomDataToTag(compound);
         physics.toNBT(compound);
-
+        getSpellSlot().get(true).ifPresent(effect -> {
-        if (hasSpell()) {
+            compound.put("effect", SpellType.toNBT(effect));
-            compound.put("effect", SpellType.toNBT(getSpell(true)));
+        });
-        }
     }
 
     @Override
@@ -249,13 +245,9 @@ public class MagicProjectileEntity extends ThrownItemEntity implements Magical,
 
     @Override
     protected void onBlockHit(BlockHitResult hit) {
-        if (hasSpell()) {
+        getSpellSlot().get(SpellPredicate.IS_THROWN, true).ifPresent(effect -> {
-            Spell effect = getSpell(true);
+            effect.onImpact(this, hit.getBlockPos(), world.getBlockState(hit.getBlockPos()));
-
+        });
-            if (effect instanceof ProjectileDelegate) {
-                ((ProjectileDelegate)effect).onImpact(this, hit.getBlockPos(), world.getBlockState(hit.getBlockPos()));
-            }
-        }
 
         if (getItem().getItem() instanceof ProjectileDelegate) {
             ((ProjectileDelegate)getItem().getItem()).onImpact(this, hit.getBlockPos(), world.getBlockState(hit.getBlockPos()));