Rewrite changeling ability to apply over time. Closes #312

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

@@ -2,26 +2,22 @@ package com.minelittlepony.unicopia.ability;
 
 import java.util.List;
 import java.util.Optional;
-import java.util.stream.Collectors;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
 
 import org.jetbrains.annotations.Nullable;
 
 import com.minelittlepony.unicopia.Race;
 import com.minelittlepony.unicopia.USounds;
 import com.minelittlepony.unicopia.ability.data.Hit;
-import com.minelittlepony.unicopia.entity.damage.UDamageTypes;
+import com.minelittlepony.unicopia.ability.magic.spell.ChangelingFeedingSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
 import com.minelittlepony.unicopia.entity.player.Pony;
-import com.minelittlepony.unicopia.particle.FollowingParticleEffect;
-import com.minelittlepony.unicopia.particle.ParticleUtils;
-import com.minelittlepony.unicopia.particle.UParticles;
 import com.minelittlepony.unicopia.util.TraceHelper;
 import com.minelittlepony.unicopia.util.VecHelper;
 
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.LivingEntity;
-import net.minecraft.entity.damage.DamageSource;
-import net.minecraft.entity.effect.StatusEffectInstance;
-import net.minecraft.entity.effect.StatusEffects;
 import net.minecraft.entity.mob.HostileEntity;
 import net.minecraft.entity.passive.CowEntity;
 import net.minecraft.entity.passive.MerchantEntity;
@@ -34,6 +30,13 @@ import net.minecraft.particle.ParticleTypes;
  * Changeling ability to restore health from mobs
  */
 public class ChangelingFeedAbility implements Ability<Hit> {
+    private static final Predicate<Entity> TARGET_PREDICATE = e -> (e instanceof LivingEntity)
+            && (e instanceof CowEntity
+            || e instanceof MerchantEntity
+            || e instanceof PlayerEntity
+            || e instanceof SheepEntity
+            || e instanceof PigEntity
+            || e instanceof HostileEntity);
 
     @Override
     public int getWarmupTime(Pony player) {
@@ -42,7 +45,7 @@ public class ChangelingFeedAbility implements Ability<Hit> {
 
     @Override
     public int getCooldownTime(Pony player) {
-        return canFeed(player) ? 15 : 80;
+        return !SpellType.FEED.isOn(player) && ChangelingFeedingSpell.canFeed(player) ? 15 : 80;
     }
 
     @Override
@@ -53,22 +56,7 @@ public class ChangelingFeedAbility implements Ability<Hit> {
     @Nullable
     @Override
     public Optional<Hit> prepare(Pony player) {
-        return Hit.of(canFeed(player) && !getTargets(player).isEmpty());
+        return Hit.of(ChangelingFeedingSpell.canFeed(player) && !getTargets(player).findAny().isEmpty());
-    }
-
-    private boolean canFeed(Pony player) {
-        return player.asEntity().getHealth() < player.asEntity().getMaxHealth()
-            || player.asEntity().canConsume(false);
-    }
-
-    private boolean canDrain(Entity e) {
-        return (e instanceof LivingEntity)
-            && (e instanceof CowEntity
-            || e instanceof MerchantEntity
-            || e instanceof PlayerEntity
-            || e instanceof SheepEntity
-            || e instanceof PigEntity
-            || e instanceof HostileEntity);
     }
 
     @Override
@@ -76,16 +64,6 @@ public class ChangelingFeedAbility implements Ability<Hit> {
         return Hit.SERIALIZER;
     }
 
-    protected List<LivingEntity> getTargets(Pony player) {
-        List<Entity> list = VecHelper.findInRange(player.asEntity(), player.asWorld(), player.getOriginVector(), 3, this::canDrain);
-
-        TraceHelper.<LivingEntity>findEntity(player.asEntity(), 17, 1,
-                looked -> looked instanceof LivingEntity && !list.contains(looked) && canDrain(looked))
-            .ifPresent(list::add);
-
-        return list.stream().map(i -> (LivingEntity)i).collect(Collectors.toList());
-    }
-
     @Override
     public double getCostEstimate(Pony player) {
         return 0;
@@ -93,7 +71,7 @@ public class ChangelingFeedAbility implements Ability<Hit> {
 
     @Override
     public boolean apply(Pony iplayer, Hit data) {
-        if (!canFeed(iplayer)) {
+        if (!ChangelingFeedingSpell.canFeed(iplayer)) {
             return false;
         }
 
@@ -103,64 +81,25 @@ public class ChangelingFeedAbility implements Ability<Hit> {
         int maximumFoodGain = player.canConsume(false) ? (20 - player.getHungerManager().getFoodLevel()) : 0;
 
         if (maximumHealthGain > 0 || maximumFoodGain > 0) {
+            List<LivingEntity> targets = getTargets(iplayer).map(LivingEntity.class::cast).toList();
 
-            float healAmount = 0;
+            if (targets.size() > 0) {
+                new ChangelingFeedingSpell(targets, maximumHealthGain, maximumFoodGain).apply(iplayer);
 
-            for (LivingEntity i : getTargets(iplayer)) {
-                healAmount += drainFrom(iplayer, i);
-            }
-
-            int foodAmount = (int)Math.floor(Math.min(healAmount / 3, maximumFoodGain));
-
-            if (foodAmount > 0) {
-                healAmount -= foodAmount;
-            }
-            player.getHungerManager().add(Math.max(1, foodAmount), 0.125f);
-
-            player.heal(Math.max(1, Math.min(healAmount, maximumHealthGain)));
-        }
-
-
-        if (!canFeed(iplayer)) {
-            iplayer.playSound(USounds.Vanilla.ENTITY_PLAYER_BURP, 1, (float)player.getWorld().random.nextTriangular(1F, 0.2F));
-        } else {
                 iplayer.playSound(USounds.ENTITY_PLAYER_CHANGELING_FEED, 0.1F, iplayer.getRandomPitch());
+                return true;
+            }
         }
 
+        iplayer.playSound(USounds.Vanilla.ENTITY_PLAYER_BURP, 1, (float)player.getWorld().random.nextTriangular(1F, 0.2F));
         return true;
     }
 
-    public float drainFrom(Pony changeling, LivingEntity living) {
+    protected Stream<Entity> getTargets(Pony player) {
-
+        return Stream.concat(
-        DamageSource d = changeling.damageOf(UDamageTypes.LOVE_DRAINING, changeling);
+                VecHelper.findInRange(player.asEntity(), player.asWorld(), player.getOriginVector(), 3, TARGET_PREDICATE).stream(),
-
+                TraceHelper.findEntity(player.asEntity(), 17, 1, TARGET_PREDICATE).stream()
-        float damage = living.getHealth()/2;
+        ).distinct();
-
-        if (damage > 0) {
-            living.damage(d, damage);
-        }
-
-        ParticleUtils.spawnParticles(UParticles.CHANGELING_MAGIC, living, 7);
-        ParticleUtils.spawnParticles(new FollowingParticleEffect(UParticles.HEALTH_DRAIN, changeling.asEntity(), 0.2F), living, 1);
-
-        if (changeling.asEntity().hasStatusEffect(StatusEffects.NAUSEA)) {
-            StatusEffectInstance effect = changeling.asEntity().getStatusEffect(StatusEffects.NAUSEA);
-            changeling.asEntity().removeStatusEffect(StatusEffects.NAUSEA);
-            living.addStatusEffect(effect);
-        } else if (changeling.asWorld().random.nextInt(2300) == 0) {
-            living.addStatusEffect(new StatusEffectInstance(StatusEffects.WITHER, 20, 1));
-        }
-
-        if (living instanceof PlayerEntity) {
-            damage ++;
-            damage *= 1.6F;
-
-            if (!changeling.asEntity().hasStatusEffect(StatusEffects.HEALTH_BOOST)) {
-                changeling.asEntity().addStatusEffect(new StatusEffectInstance(StatusEffects.HEALTH_BOOST, 13000, 1));
-            }
-        }
-
-        return damage;
     }
 
     @Override

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

@@ -0,0 +1,162 @@
+package com.minelittlepony.unicopia.ability.magic.spell;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import com.minelittlepony.unicopia.USounds;
+import com.minelittlepony.unicopia.ability.Abilities;
+import com.minelittlepony.unicopia.ability.magic.Caster;
+import com.minelittlepony.unicopia.ability.magic.spell.effect.AbstractSpell;
+import com.minelittlepony.unicopia.ability.magic.spell.effect.CustomisedSpellType;
+import com.minelittlepony.unicopia.ability.magic.spell.effect.SpellType;
+import com.minelittlepony.unicopia.entity.EntityReference;
+import com.minelittlepony.unicopia.entity.damage.UDamageTypes;
+import com.minelittlepony.unicopia.entity.player.Pony;
+import com.minelittlepony.unicopia.particle.FollowingParticleEffect;
+import com.minelittlepony.unicopia.particle.ParticleUtils;
+import com.minelittlepony.unicopia.particle.UParticles;
+
+import net.minecraft.entity.LivingEntity;
+import net.minecraft.entity.damage.DamageSource;
+import net.minecraft.entity.effect.StatusEffectInstance;
+import net.minecraft.entity.effect.StatusEffects;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.nbt.NbtCompound;
+import net.minecraft.nbt.NbtElement;
+import net.minecraft.util.math.MathHelper;
+
+public class ChangelingFeedingSpell extends AbstractSpell {
+    private List<EntityReference<LivingEntity>> targets = List.of();
+    private int nextTargetIndex;
+
+    private float healthToDrain;
+    private int foodToDrain;
+
+    private float damageThisTick;
+
+    public ChangelingFeedingSpell(CustomisedSpellType<?> type) {
+        super(type);
+        setHidden(true);
+    }
+
+    public ChangelingFeedingSpell(List<LivingEntity> feedTarget, float healthToDrain, int foodToDrain) {
+        this(SpellType.FEED.withTraits());
+        this.targets = feedTarget.stream().map(EntityReference::new).collect(Collectors.toList() /* make mutable */);
+        this.healthToDrain = healthToDrain;
+        this.foodToDrain = foodToDrain;
+    }
+
+    @Override
+    public boolean tick(Caster<?> source, Situation situation) {
+        if (!(source instanceof Pony changeling) || situation != Situation.BODY || !source.canUse(Abilities.FEED)) {
+            return false;
+        }
+
+        PlayerEntity player = changeling.asEntity();
+        if (!canFeed(changeling)) {
+            changeling.playSound(USounds.Vanilla.ENTITY_PLAYER_BURP, 1, (float)player.getWorld().random.nextTriangular(1F, 0.2F));
+            return false;
+        }
+
+        float tickDrain = Math.min(0.05F, healthToDrain);
+        damageThisTick += tickDrain;
+
+        if (damageThisTick > 1) {
+            damageThisTick--;
+
+            float healAmount = drain(changeling, 1);
+            float foodAmount = Math.min(healAmount / 3F, foodToDrain);
+            if (foodAmount > 0) {
+                healAmount -= foodAmount;
+            }
+
+            foodAmount = MathHelper.clamp(foodAmount, 0, foodToDrain);
+            healAmount = MathHelper.clamp(healAmount, 0, healthToDrain);
+
+            int shanks = MathHelper.floor(foodAmount);
+            player.getHungerManager().add(shanks, foodAmount - shanks);
+            player.heal(healAmount);
+
+            if (!canFeed(changeling)) {
+                changeling.playSound(USounds.Vanilla.ENTITY_PLAYER_BURP, 1, (float)player.getWorld().random.nextTriangular(1F, 0.2F));
+            } else {
+                changeling.playSound(USounds.ENTITY_PLAYER_CHANGELING_FEED, 0.1F, changeling.getRandomPitch());
+            }
+
+            foodToDrain -= foodAmount;
+            healthToDrain -= healAmount;
+        }
+
+        return !targets.isEmpty() && (healthToDrain > 0 || foodToDrain > 0);
+    }
+
+    private float drain(Pony changeling, float max) {
+        List<EntityReference<LivingEntity>> targets = this.targets;
+        while (!targets.isEmpty()) {
+            int index = MathHelper.clamp(nextTargetIndex, 0, targets.size());
+            LivingEntity l = targets.get(index).getOrEmpty(changeling.asWorld()).orElse(null);
+            if (l != null && !l.isRemoved() && l.distanceTo(changeling.asEntity()) < 4) {
+                nextTargetIndex = (nextTargetIndex + 1) % targets.size();
+                return drainFrom(changeling, l, max);
+            } else {
+                targets.remove(index);
+            }
+        }
+        return 0;
+    }
+
+    public float drainFrom(Pony changeling, LivingEntity living, float damage) {
+        DamageSource d = changeling.damageOf(UDamageTypes.LOVE_DRAINING, changeling);
+
+        if (damage > 0) {
+            living.damage(d, damage);
+        }
+
+        ParticleUtils.spawnParticles(UParticles.CHANGELING_MAGIC, living, 7);
+        ParticleUtils.spawnParticles(new FollowingParticleEffect(UParticles.HEALTH_DRAIN, changeling.asEntity(), 0.2F), living, 1);
+
+        if (changeling.asEntity().hasStatusEffect(StatusEffects.NAUSEA)) {
+            StatusEffectInstance effect = changeling.asEntity().getStatusEffect(StatusEffects.NAUSEA);
+            changeling.asEntity().removeStatusEffect(StatusEffects.NAUSEA);
+            living.addStatusEffect(effect);
+        } else if (changeling.asWorld().random.nextInt(2300) == 0) {
+            living.addStatusEffect(new StatusEffectInstance(StatusEffects.WITHER, 20, 1));
+        }
+
+        if (living instanceof PlayerEntity) {
+            damage ++;
+            damage *= 1.6F;
+
+            if (!changeling.asEntity().hasStatusEffect(StatusEffects.HEALTH_BOOST)) {
+                changeling.asEntity().addStatusEffect(new StatusEffectInstance(StatusEffects.HEALTH_BOOST, 13000, 1));
+            }
+        }
+
+        return damage;
+    }
+
+    public static boolean canFeed(Pony player) {
+        return player.asEntity().getHealth() < player.asEntity().getMaxHealth()
+            || player.asEntity().canConsume(false);
+    }
+
+    @Override
+    public void toNBT(NbtCompound compound) {
+        super.toNBT(compound);
+        compound.putFloat("healthToDrain", healthToDrain);
+        compound.putInt("foodToDrain", foodToDrain);
+        compound.putFloat("damageThisTick", damageThisTick);
+        compound.put("targets", EntityReference.<LivingEntity>getSerializer().writeAll(targets));
+    }
+
+    @Override
+    public void fromNBT(NbtCompound compound) {
+        super.fromNBT(compound);
+        healthToDrain = compound.getFloat("healthToDrain");
+        foodToDrain = compound.getInt("foodToDrain");
+        damageThisTick = compound.getFloat("damageThisTick");
+        targets = compound.contains("targets", NbtElement.LIST_TYPE)
+                ? EntityReference.<LivingEntity>getSerializer().readAll(compound.getList("targets", NbtElement.COMPOUND_TYPE)).toList()
+                : List.of();
+    }
+}

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

@@ -11,6 +11,7 @@ import com.minelittlepony.unicopia.Affinity;
 import com.minelittlepony.unicopia.Unicopia;
 import com.minelittlepony.unicopia.ability.magic.Affine;
 import com.minelittlepony.unicopia.ability.magic.SpellPredicate;
+import com.minelittlepony.unicopia.ability.magic.spell.ChangelingFeedingSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.DispersableDisguiseSpell;
 import com.minelittlepony.unicopia.ability.magic.spell.RainboomAbilitySpell;
 import com.minelittlepony.unicopia.ability.magic.spell.PlaceableSpell;
@@ -49,6 +50,7 @@ public final class SpellType<T extends Spell> implements Affine, SpellPredicate<
     public static final SpellType<ThrowableSpell> THROWN_SPELL = register("thrown", Affinity.NEUTRAL, 0, false, SpellTraits.EMPTY, ThrowableSpell::new);
 
     public static final SpellType<DispersableDisguiseSpell> CHANGELING_DISGUISE = register("disguise", Affinity.BAD, 0x19E48E, false, SpellTraits.EMPTY, DispersableDisguiseSpell::new);
+    public static final SpellType<ChangelingFeedingSpell> FEED = register("feed", Affinity.BAD, 0xBDBDF9, false, SpellTraits.EMPTY, ChangelingFeedingSpell::new);
     public static final SpellType<RainboomAbilitySpell> RAINBOOM = register("rainboom", Affinity.GOOD, 0xBDBDF9, false, SpellTraits.EMPTY, RainboomAbilitySpell::new);
     public static final SpellType<RageAbilitySpell> RAGE = register("rage", Affinity.GOOD, 0xBDBDF9, false, SpellTraits.EMPTY, RageAbilitySpell::new);
     public static final SpellType<TimeControlAbilitySpell> TIME_CONTROL = register("time_control", Affinity.GOOD, 0xBDBDF9, false, SpellTraits.EMPTY, TimeControlAbilitySpell::new);

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

@@ -11,7 +11,6 @@ import org.jetbrains.annotations.Nullable;
 import com.minelittlepony.unicopia.ability.magic.Caster;
 import com.minelittlepony.unicopia.ability.magic.Levelled;
 import com.minelittlepony.unicopia.util.NbtSerialisable;
-
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.nbt.NbtCompound;
@@ -31,6 +30,13 @@ import net.minecraft.world.World;
  * @param <T> The type of the entity this reference points to.
  */
 public class EntityReference<T extends Entity> implements NbtSerialisable {
+    private static final Serializer<?> SERIALIZER = Serializer.of(EntityReference::new);
+
+    @SuppressWarnings("unchecked")
+    public static <T extends Entity> Serializer<EntityReference<T>> getSerializer() {
+        return (Serializer<EntityReference<T>>)SERIALIZER;
+    }
+
     @Nullable
     private EntityValues<T> reference;
 

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

@@ -128,9 +128,9 @@ public class CrystalHeartItem extends Item implements FloatingArtefactEntity.Art
                     LivingEntity living = (LivingEntity)e;
 
                     if (e instanceof PlayerEntity
-                            || (living instanceof TameableEntity && ((TameableEntity)living).isTamed())
+                            || (e instanceof TameableEntity t && t.isTamed())
-                            || (living instanceof Saddleable && ((Saddleable)living).isSaddled())
+                            || (e instanceof Saddleable s && s.isSaddled())
-                            || (living instanceof MerchantEntity)) {
+                            || (e instanceof MerchantEntity)) {
                         if (living.getHealth() < living.getMaxHealth()) {
                             outputs.add(living);
                         }
@@ -149,19 +149,8 @@ public class CrystalHeartItem extends Item implements FloatingArtefactEntity.Art
                     return;
                 }
 
-                float gives;
+                float gives = supply > demand ? supply / demand : 1;
-                float takes;
+                float takes = demand > supply ? demand / supply : 1;
-
-                if (supply > demand) {
-                    gives = supply / demand;
-                    takes = 1;
-                } else if (demand > supply) {
-                    takes = demand / supply;
-                    gives = 1;
-                } else {
-                    gives = 1;
-                    takes = 1;
-                }
 
                 inputs.forEach(input -> {
                     input.damage(entity.damageOf(UDamageTypes.LIFE_DRAINING), takes);

src/main/java/com/minelittlepony/unicopia/util/NbtSerialisable.java

@@ -97,7 +97,7 @@ public interface NbtSerialisable {
             return read((NbtCompound)element);
         }
 
-        default NbtList writeAll(Collection<T> ts) {
+        default NbtList writeAll(Collection<? extends T> ts) {
             NbtList list = new NbtList();
             ts.stream().map(this::write).forEach(list::add);
             return list;