PaperMC/paper-server/patches/sources/net/minecraft/world/entity/LivingEntity.java.patch

--- a/net/minecraft/world/entity/LivingEntity.java
+++ b/net/minecraft/world/entity/LivingEntity.java
@@ -42,6 +_,8 @@
 import net.minecraft.core.particles.ParticleOptions;
 import net.minecraft.core.particles.ParticleTypes;
 import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.FloatTag;
+import net.minecraft.nbt.IntTag;
 import net.minecraft.nbt.ListTag;
 import net.minecraft.nbt.NbtOps;
 import net.minecraft.nbt.Tag;
@@ -136,6 +_,29 @@
 import net.minecraft.world.scores.Scoreboard;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.LinkedList;
+import java.util.UUID;
+import net.minecraft.world.item.component.Consumable;
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.attribute.CraftAttributeMap;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.craftbukkit.inventory.CraftItemStack;
+import org.bukkit.event.entity.ArrowBodyCountChangeEvent;
+import org.bukkit.event.entity.EntityDamageEvent;
+import org.bukkit.event.entity.EntityDamageEvent.DamageModifier;
+import org.bukkit.event.entity.EntityKnockbackEvent;
+import org.bukkit.event.entity.EntityPotionEffectEvent;
+import org.bukkit.event.entity.EntityRegainHealthEvent;
+import org.bukkit.event.entity.EntityRemoveEvent;
+import org.bukkit.event.entity.EntityResurrectEvent;
+import org.bukkit.event.entity.EntityTeleportEvent;
+import org.bukkit.event.player.PlayerItemConsumeEvent;
+// CraftBukkit end
+
 public abstract class LivingEntity extends Entity implements Attackable {
     private static final Logger LOGGER = LogUtils.getLogger();
     private static final String TAG_ACTIVE_EFFECTS = "active_effects";
@@ -266,11 +_,36 @@
         EquipmentSlot.class
     );
     protected float appliedScale = 1.0F;
+    // CraftBukkit start
+    public int expToDrop;
+    public ArrayList<DefaultDrop> drops = new ArrayList<>(); // Paper - Restore vanilla drops behavior
+    public final org.bukkit.craftbukkit.attribute.CraftAttributeMap craftAttributes;
+    public boolean collides = true;
+    public Set<UUID> collidableExemptions = new HashSet<>();
+    public boolean bukkitPickUpLoot;
+    public org.bukkit.craftbukkit.entity.CraftLivingEntity getBukkitLivingEntity() { return (org.bukkit.craftbukkit.entity.CraftLivingEntity) super.getBukkitEntity(); } // Paper
+    public boolean silentDeath = false; // Paper - mark entity as dying silently for cancellable death event
+    public net.kyori.adventure.util.TriState frictionState = net.kyori.adventure.util.TriState.NOT_SET; // Paper - Friction API
+
+    @Override
+    public float getBukkitYaw() {
+        return this.getYHeadRot();
+    }
+    // CraftBukkit end
+    // Spigot start
+    public void inactiveTick()
+    {
+        super.inactiveTick();
+        ++this.noActionTime; // Above all the floats
+    }
+    // Spigot end
 
     protected LivingEntity(EntityType<? extends LivingEntity> entityType, Level level) {
         super(entityType, level);
         this.attributes = new AttributeMap(DefaultAttributes.getSupplier(entityType));
-        this.setHealth(this.getMaxHealth());
+        this.craftAttributes = new CraftAttributeMap(this.attributes); // CraftBukkit
+        // CraftBukkit - this.setHealth(this.getMaxHealth()) inlined and simplified to skip the instanceof check for Player, as getBukkitEntity() is not initialized in constructor
+        this.entityData.set(LivingEntity.DATA_HEALTH_ID, (float) this.getAttribute(Attributes.MAX_HEALTH).getValue());
         this.blocksBuilding = true;
         this.rotA = (float)((Math.random() + 1.0) * 0.01F);
         this.reapplyPosition();
@@ -360,7 +_,13 @@
                 float f = Mth.ceil(this.fallDistance - attributeValue);
                 double min = Math.min((double)(0.2F + f / 15.0F), 2.5);
                 int i = (int)(150.0 * min);
-                serverLevel.sendParticles(new BlockParticleOption(ParticleTypes.BLOCK, state), x, y1, z, i, 0.0, 0.0, 0.0, 0.15F);
+                // CraftBukkit start - visiblity api
+                if (this instanceof ServerPlayer) {
+                    serverLevel.sendParticlesSource((ServerPlayer) this, new BlockParticleOption(ParticleTypes.BLOCK, state), false, false, x, y1, z, i, 0.0, 0.0, 0.0, 0.15F);
+                } else {
+                    serverLevel.sendParticles(new BlockParticleOption(ParticleTypes.BLOCK, state), x, y1, z, i, 0.0, 0.0, 0.0, 0.15F);
+                }
+                // CraftBukkit end
             }
         }
 
@@ -566,7 +_,7 @@
         this.deathTime++;
         if (this.deathTime >= 20 && !this.level().isClientSide() && !this.isRemoved()) {
             this.level().broadcastEntityEvent(this, (byte)60);
-            this.remove(Entity.RemovalReason.KILLED);
+            this.remove(Entity.RemovalReason.KILLED, EntityRemoveEvent.Cause.DEATH); // CraftBukkit - add Bukkit remove cause
         }
     }
 
@@ -658,7 +_,7 @@
     }
 
     public boolean shouldDiscardFriction() {
-        return this.discardFriction;
+        return !this.frictionState.toBooleanOrElse(!this.discardFriction); // Paper - Friction API
     }
 
     public void setDiscardFriction(boolean discardFriction) {
@@ -670,11 +_,16 @@
     }
 
     public void onEquipItem(EquipmentSlot slot, ItemStack oldItem, ItemStack newItem) {
+        // CraftBukkit start
+        this.onEquipItem(slot, oldItem, newItem, false);
+    }
+    public void onEquipItem(EquipmentSlot slot, ItemStack oldItem, ItemStack newItem, boolean silent) {
+        // CraftBukkit end
         if (!this.level().isClientSide() && !this.isSpectator()) {
             boolean flag = newItem.isEmpty() && oldItem.isEmpty();
             if (!flag && !ItemStack.isSameItemSameComponents(oldItem, newItem) && !this.firstTick) {
                 Equippable equippable = newItem.get(DataComponents.EQUIPPABLE);
-                if (!this.isSilent() && equippable != null && slot == equippable.slot()) {
+                if (!this.isSilent() && equippable != null && slot == equippable.slot() && !silent) { // CraftBukkit
                     this.level()
                         .playSeededSound(
                             null, this.getX(), this.getY(), this.getZ(), equippable.equipSound(), this.getSoundSource(), 1.0F, 1.0F, this.random.nextLong()
@@ -690,11 +_,18 @@
 
     @Override
     public void remove(Entity.RemovalReason reason) {
+        // CraftBukkit start - add Bukkit remove cause
+        this.remove(reason, null);
+    }
+
+    @Override
+    public void remove(Entity.RemovalReason reason, EntityRemoveEvent.Cause eventCaue) {
+        // CraftBukkit end
         if ((reason == Entity.RemovalReason.KILLED || reason == Entity.RemovalReason.DISCARDED) && this.level() instanceof ServerLevel serverLevel) {
             this.triggerOnDeathMobEffects(serverLevel, reason);
         }
 
-        super.remove(reason);
+        super.remove(reason, eventCaue); // CraftBukkit
         this.brain.clearMemories();
     }
 
@@ -703,11 +_,17 @@
             mobEffectInstance.onMobRemoved(level, this, removalReason);
         }
 
+        this.removeAllEffects(org.bukkit.event.entity.EntityPotionEffectEvent.Cause.DEATH); // CraftBukkit
         this.activeEffects.clear();
     }
 
     @Override
     public void addAdditionalSaveData(CompoundTag compound) {
+        // Paper start - Friction API
+        if (this.frictionState != net.kyori.adventure.util.TriState.NOT_SET) {
+            compound.putString("Paper.FrictionState", this.frictionState.toString());
+        }
+        // Paper end - Friction API
         compound.putFloat("Health", this.getHealth());
         compound.putShort("HurtTime", (short)this.hurtTime);
         compound.putInt("HurtByTimestamp", this.lastHurtByMobTimestamp);
@@ -736,7 +_,23 @@
 
     @Override
     public void readAdditionalSaveData(CompoundTag compound) {
-        this.internalSetAbsorptionAmount(compound.getFloat("AbsorptionAmount"));
+        // Paper start - Check for NaN
+        float absorptionAmount = compound.getFloat("AbsorptionAmount");
+        if (Float.isNaN(absorptionAmount)) {
+            absorptionAmount = 0;
+        }
+        this.internalSetAbsorptionAmount(absorptionAmount);
+        // Paper end - Check for NaN
+        // Paper start - Friction API
+        if (compound.contains("Paper.FrictionState")) {
+            String frictionState = compound.getString("Paper.FrictionState");
+            try {
+                this.frictionState = net.kyori.adventure.util.TriState.valueOf(frictionState);
+            } catch (Exception ignored) {
+                LOGGER.error("Unknown friction state " + frictionState + " for " + this);
+            }
+        }
+        // Paper end - Friction API
         if (compound.contains("attributes", 9) && this.level() != null && !this.level().isClientSide) {
             this.getAttributes().load(compound.getList("attributes", 10));
         }
@@ -753,6 +_,16 @@
             }
         }
 
+        // CraftBukkit start
+        if (compound.contains("Bukkit.MaxHealth")) {
+            Tag maxHealthTag = compound.get("Bukkit.MaxHealth");
+            if (maxHealthTag.getId() == 5) {
+                this.getAttribute(Attributes.MAX_HEALTH).setBaseValue(((FloatTag) maxHealthTag).getAsDouble());
+            } else if (maxHealthTag.getId() == 3) {
+                this.getAttribute(Attributes.MAX_HEALTH).setBaseValue(((IntTag) maxHealthTag).getAsDouble());
+            }
+        }
+        // CraftBukkit end
         if (compound.contains("Health", 99)) {
             this.setHealth(compound.getFloat("Health"));
         }
@@ -764,6 +_,7 @@
             String string = compound.getString("Team");
             Scoreboard scoreboard = this.level().getScoreboard();
             PlayerTeam playerTeam = scoreboard.getPlayerTeam(string);
+            if (!this.level().paperConfig().scoreboards.allowNonPlayerEntitiesOnScoreboards && !(this instanceof net.minecraft.world.entity.player.Player)) { playerTeam = null; } // Paper - Perf: Disable Scoreboards for non players by default
             boolean flag = playerTeam != null && scoreboard.addPlayerToTeam(this.getStringUUID(), playerTeam);
             if (!flag) {
                 LOGGER.warn("Unable to add mob to team \"{}\" (that team probably doesn't exist)", string);
@@ -776,11 +_,13 @@
 
         if (compound.contains("SleepingX", 99) && compound.contains("SleepingY", 99) && compound.contains("SleepingZ", 99)) {
             BlockPos blockPos = new BlockPos(compound.getInt("SleepingX"), compound.getInt("SleepingY"), compound.getInt("SleepingZ"));
+            if (this.position().distanceToSqr(blockPos.getX(), blockPos.getY(), blockPos.getZ()) < 16 * 16) { // Paper - The sleeping pos will always also set the actual pos, so a desync suggests something is wrong
             this.setSleepingPos(blockPos);
             this.entityData.set(DATA_POSE, Pose.SLEEPING);
             if (!this.firstTick) {
                 this.setPosToBed(blockPos);
             }
+            } // Paper - The sleeping pos will always also set the actual pos, so a desync suggests something is wrong
         }
 
         if (compound.contains("Brain", 10)) {
@@ -788,15 +_,44 @@
         }
     }
 
+    // CraftBukkit start
+    private boolean isTickingEffects = false;
+    private List<ProcessableEffect> effectsToProcess = Lists.newArrayList();
+
+    private static class ProcessableEffect {
+
+        private Holder<MobEffect> type;
+        private MobEffectInstance effect;
+        private final EntityPotionEffectEvent.Cause cause;
+
+        private ProcessableEffect(MobEffectInstance effect, EntityPotionEffectEvent.Cause cause) {
+            this.effect = effect;
+            this.cause = cause;
+        }
+
+        private ProcessableEffect(Holder<MobEffect> type, EntityPotionEffectEvent.Cause cause) {
+            this.type = type;
+            this.cause = cause;
+        }
+    }
+    // CraftBukkit end
+
     protected void tickEffects() {
         Iterator<Holder<MobEffect>> iterator = this.activeEffects.keySet().iterator();
 
+        this.isTickingEffects = true; // CraftBukkit
         try {
             while (iterator.hasNext()) {
                 Holder<MobEffect> holder = iterator.next();
                 MobEffectInstance mobEffectInstance = this.activeEffects.get(holder);
                 if (!mobEffectInstance.tick(this, () -> this.onEffectUpdated(mobEffectInstance, true, null))) {
                     if (!this.level().isClientSide) {
+                        // CraftBukkit start
+                        EntityPotionEffectEvent event = CraftEventFactory.callEntityPotionEffectChangeEvent(this, mobEffectInstance, null, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.EXPIRATION);
+                        if (event.isCancelled()) {
+                            continue;
+                        }
+                        // CraftBukkit end
                         iterator.remove();
                         this.onEffectsRemoved(List.of(mobEffectInstance));
                     }
@@ -807,6 +_,17 @@
         } catch (ConcurrentModificationException var6) {
         }
 
+        // CraftBukkit start
+        this.isTickingEffects = false;
+        for (ProcessableEffect effect : this.effectsToProcess) {
+            if (effect.effect != null) {
+                this.addEffect(effect.effect, effect.cause);
+            } else {
+                this.removeEffect(effect.type, effect.cause);
+            }
+        }
+        this.effectsToProcess.clear();
+        // CraftBukkit end
         if (this.effectsDirty) {
             if (!this.level().isClientSide) {
                 this.updateInvisibilityStatus();
@@ -912,15 +_,33 @@
     }
 
     public boolean removeAllEffects() {
+        // CraftBukkit start
+        return this.removeAllEffects(org.bukkit.event.entity.EntityPotionEffectEvent.Cause.UNKNOWN);
+    }
+    public boolean removeAllEffects(EntityPotionEffectEvent.Cause cause) {
+        // CraftBukkit end
         if (this.level().isClientSide) {
             return false;
         } else if (this.activeEffects.isEmpty()) {
             return false;
         } else {
-            Map<Holder<MobEffect>, MobEffectInstance> map = Maps.newHashMap(this.activeEffects);
-            this.activeEffects.clear();
-            this.onEffectsRemoved(map.values());
-            return true;
+            // CraftBukkit start
+            List<MobEffectInstance> toRemove = new LinkedList<>();
+            Iterator<MobEffectInstance> iterator = this.activeEffects.values().iterator();
+            while (iterator.hasNext()) {
+                MobEffectInstance effect = iterator.next();
+                EntityPotionEffectEvent event = CraftEventFactory.callEntityPotionEffectChangeEvent(this, effect, null, cause, EntityPotionEffectEvent.Action.CLEARED);
+                if (event.isCancelled()) {
+                    continue;
+                }
+
+                iterator.remove();
+                toRemove.add(effect);
+            }
+
+            this.onEffectsRemoved(toRemove);
+            return !toRemove.isEmpty();
+            // CraftBukkit end
         }
     }
 
@@ -942,21 +_,57 @@
     }
 
     public final boolean addEffect(MobEffectInstance effectInstance) {
-        return this.addEffect(effectInstance, null);
+        return this.addEffect(effectInstance, (Entity) null); // CraftBukkit
+    }
+
+    // CraftBukkit start
+    public boolean addEffect(MobEffectInstance effectInstance, EntityPotionEffectEvent.Cause cause) {
+        return this.addEffect(effectInstance, (Entity) null, cause);
     }
 
     public boolean addEffect(MobEffectInstance effectInstance, @Nullable Entity entity) {
+        return this.addEffect(effectInstance, entity, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.UNKNOWN);
+    }
+
+    public boolean addEffect(MobEffectInstance effectInstance, @Nullable Entity entity, EntityPotionEffectEvent.Cause cause) {
+        // Paper start - Don't fire sync event during generation
+        return this.addEffect(effectInstance, entity, cause, true);
+    }
+    public boolean addEffect(MobEffectInstance effectInstance, @Nullable Entity entity, EntityPotionEffectEvent.Cause cause, boolean fireEvent) {
+        // Paper end - Don't fire sync event during generation
+        // org.spigotmc.AsyncCatcher.catchOp("effect add"); // Spigot // Paper - move to API
+        if (this.isTickingEffects) {
+            this.effectsToProcess.add(new ProcessableEffect(effectInstance, cause));
+            return true;
+        }
+        // CraftBukkit end
         if (!this.canBeAffected(effectInstance)) {
             return false;
         } else {
             MobEffectInstance mobEffectInstance = this.activeEffects.get(effectInstance.getEffect());
             boolean flag = false;
+            // CraftBukkit start
+            boolean override = false;
+            if (mobEffectInstance != null) {
+                override = new MobEffectInstance(mobEffectInstance).update(effectInstance);
+            }
+
+            if (fireEvent) { // Paper - Don't fire sync event during generation
+            EntityPotionEffectEvent event = CraftEventFactory.callEntityPotionEffectChangeEvent(this, mobEffectInstance, effectInstance, cause, override);
+            override = event.isOverride(); // Paper - Don't fire sync event during generation
+            if (event.isCancelled()) {
+                return false;
+            }
+            } // Paper - Don't fire sync event during generation
+            // CraftBukkit end
             if (mobEffectInstance == null) {
                 this.activeEffects.put(effectInstance.getEffect(), effectInstance);
                 this.onEffectAdded(effectInstance, entity);
                 flag = true;
                 effectInstance.onEffectAdded(this);
-            } else if (mobEffectInstance.update(effectInstance)) {
+                // CraftBukkit start
+            } else if (override) { // Paper - Don't fire sync event during generation
+                mobEffectInstance.update(effectInstance);
                 this.onEffectUpdated(mobEffectInstance, true, entity);
                 flag = true;
             }
@@ -995,11 +_,37 @@
 
     @Nullable
     public MobEffectInstance removeEffectNoUpdate(Holder<MobEffect> effect) {
-        return this.activeEffects.remove(effect);
+        // CraftBukkit start
+        return this.removeEffectNoUpdate(effect, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.UNKNOWN);
+    }
+
+    @Nullable
+    public MobEffectInstance removeEffectNoUpdate(Holder<MobEffect> effect, EntityPotionEffectEvent.Cause cause) {
+        if (this.isTickingEffects) {
+            this.effectsToProcess.add(new ProcessableEffect(effect, cause));
+            return null;
+        }
+
+        MobEffectInstance effectInstance = this.activeEffects.get(effect);
+        if (effectInstance == null) {
+            return null;
+        }
+
+        EntityPotionEffectEvent event = CraftEventFactory.callEntityPotionEffectChangeEvent(this, effectInstance, null, cause);
+        if (event.isCancelled()) {
+            return null;
+        }
+
+        return this.activeEffects.remove(effectInstance);
     }
 
     public boolean removeEffect(Holder<MobEffect> effect) {
-        MobEffectInstance mobEffectInstance = this.removeEffectNoUpdate(effect);
+        return this.removeEffect(effect, org.bukkit.event.entity.EntityPotionEffectEvent.Cause.UNKNOWN);
+    }
+
+    public boolean removeEffect(Holder<MobEffect> effect, EntityPotionEffectEvent.Cause cause) {
+        MobEffectInstance mobEffectInstance = this.removeEffectNoUpdate(effect, cause);
+        // CraftBukkit end
         if (mobEffectInstance != null) {
             this.onEffectsRemoved(List.of(mobEffectInstance));
             return true;
@@ -1080,17 +_,62 @@
     }
 
     public void heal(float healAmount) {
+        // CraftBukkit start - Delegate so we can handle providing a reason for health being regained
+        this.heal(healAmount, EntityRegainHealthEvent.RegainReason.CUSTOM);
+    }
+
+    public void heal(float healAmount, EntityRegainHealthEvent.RegainReason regainReason) {
+        // Paper start - Forward
+        this.heal(healAmount, regainReason, false);
+    }
+
+    public void heal(float healAmount, EntityRegainHealthEvent.RegainReason regainReason, boolean isFastRegen) {
+        // Paper end - Forward
         float health = this.getHealth();
         if (health > 0.0F) {
-            this.setHealth(health + healAmount);
+            EntityRegainHealthEvent event = new EntityRegainHealthEvent(this.getBukkitEntity(), healAmount, regainReason, isFastRegen); // Paper
+            // Suppress during worldgen
+            if (this.valid) {
+                this.level().getCraftServer().getPluginManager().callEvent(event);
+            }
+
+            if (!event.isCancelled()) {
+                this.setHealth((float) (this.getHealth() + event.getAmount()));
+            }
+            // CraftBukkit end
         }
     }
 
     public float getHealth() {
+        // CraftBukkit start - Use unscaled health
+        if (this instanceof ServerPlayer serverPlayer) {
+            return (float) serverPlayer.getBukkitEntity().getHealth();
+        }
+        // CraftBukkit end
         return this.entityData.get(DATA_HEALTH_ID);
     }
 
     public void setHealth(float health) {
+        // Paper start - Check for NaN
+        if (Float.isNaN(health)) { health = getMaxHealth(); if (this.valid) {
+            System.err.println("[NAN-HEALTH] " + getScoreboardName() + " had NaN health set");
+        } } // Paper end - Check for NaN
+        // CraftBukkit start - Handle scaled health
+        if (this instanceof ServerPlayer) {
+            org.bukkit.craftbukkit.entity.CraftPlayer player = ((ServerPlayer) this).getBukkitEntity();
+            // Squeeze
+            if (health < 0.0F) {
+                player.setRealHealth(0.0D);
+            } else if (health > player.getMaxHealth()) {
+                player.setRealHealth(player.getMaxHealth());
+            } else {
+                player.setRealHealth(health);
+            }
+
+            player.updateScaledHealth(false);
+            return;
+        }
+        // CraftBukkit end
         this.entityData.set(DATA_HEALTH_ID, Mth.clamp(health, 0.0F, this.getMaxHealth()));
     }
 
@@ -1102,7 +_,7 @@
     public boolean hurtServer(ServerLevel level, DamageSource damageSource, float amount) {
         if (this.isInvulnerableTo(level, damageSource)) {
             return false;
-        } else if (this.isDeadOrDying()) {
+        } else if (this.isRemoved() || this.dead || this.getHealth() <= 0.0F) { // CraftBukkit - Don't allow entities that got set to dead/killed elsewhere to get damaged and die
             return false;
         } else if (damageSource.is(DamageTypeTags.IS_FIRE) && this.hasEffect(MobEffects.FIRE_RESISTANCE)) {
             return false;
@@ -1116,10 +_,11 @@
                 amount = 0.0F;
             }
 
-            float f = amount;
-            boolean flag = false;
+            float f = amount; final float originalAmount = amount; // Paper - revert to vanilla #hurt - OBFHELPER
+            boolean flag = amount > 0.0F && this.isDamageSourceBlocked(damageSource); // Copied from below;
             float f1 = 0.0F;
-            if (amount > 0.0F && this.isDamageSourceBlocked(damageSource)) {
+            // CraftBukkit - Moved into handleEntityDamage(DamageSource, float) for get f and actuallyHurt(DamageSource, float, EntityDamageEvent) for handle damage
+            if (false && amount > 0.0F && this.isDamageSourceBlocked(damageSource)) {
                 this.hurtCurrentlyUsedShield(amount);
                 f1 = amount;
                 amount = 0.0F;
@@ -1130,33 +_,56 @@
                 flag = true;
             }
 
-            if (damageSource.is(DamageTypeTags.IS_FREEZING) && this.getType().is(EntityTypeTags.FREEZE_HURTS_EXTRA_TYPES)) {
+            // CraftBukkit - Moved into handleEntityDamage(DamageSource, float) for get f
+            if (false && damageSource.is(DamageTypeTags.IS_FREEZING) && this.getType().is(EntityTypeTags.FREEZE_HURTS_EXTRA_TYPES)) {
                 amount *= 5.0F;
             }
 
-            if (damageSource.is(DamageTypeTags.DAMAGES_HELMET) && !this.getItemBySlot(EquipmentSlot.HEAD).isEmpty()) {
+            // CraftBukkit - Moved into handleEntityDamage(DamageSource, float) for get f and actuallyHurt(DamageSource, float, EntityDamageEvent) for handle damage
+            if (false && damageSource.is(DamageTypeTags.DAMAGES_HELMET) && !this.getItemBySlot(EquipmentSlot.HEAD).isEmpty()) {
                 this.hurtHelmet(damageSource, amount);
                 amount *= 0.75F;
             }
 
+            EntityDamageEvent event; // CraftBukkit // Paper - move this into the actual invuln check....
             this.walkAnimation.setSpeed(1.5F);
             if (Float.isNaN(amount) || Float.isInfinite(amount)) {
                 amount = Float.MAX_VALUE;
             }
 
             boolean flag1 = true;
-            if (this.invulnerableTime > 10.0F && !damageSource.is(DamageTypeTags.BYPASSES_COOLDOWN)) {
+            if (this.invulnerableTime > (float) this.invulnerableDuration / 2.0F && !damageSource.is(DamageTypeTags.BYPASSES_COOLDOWN)) { // CraftBukkit - restore use of maxNoDamageTicks
                 if (amount <= this.lastHurt) {
                     return false;
                 }
 
-                this.actuallyHurt(level, damageSource, amount - this.lastHurt);
+                // Paper start - only call damage event when actuallyHurt will be called - move call logic down
+                event = this.handleEntityDamage(damageSource, amount, this.lastHurt); // Paper - fix invulnerability reduction in EntityDamageEvent - pass lastDamage reduction
+                amount = computeAmountFromEntityDamageEvent(event);
+                // Paper end - only call damage event when actuallyHurt will be called - move call logic down
+
+                // CraftBukkit start
+                if (!this.actuallyHurt(level, damageSource, (float) event.getFinalDamage(), event)) { // Paper - fix invulnerability reduction in EntityDamageEvent - no longer subtract lastHurt, that is part of the damage event calc now
+                    return false;
+                }
+                if (this instanceof ServerPlayer && event.getDamage() == 0 && originalAmount == 0) return false; // Paper - revert to vanilla damage - players are not affected by damage that is 0 - skip damage if the vanilla damage is 0 and was not modified by plugins in the event.
+                // CraftBukkit end
                 this.lastHurt = amount;
                 flag1 = false;
             } else {
+                // Paper start - only call damage event when actuallyHurt will be called - move call logic down
+                event = this.handleEntityDamage(damageSource, amount, 0); // Paper - fix invulnerability reduction in EntityDamageEvent - pass lastDamage reduction (none in this branch)
+                amount = computeAmountFromEntityDamageEvent(event);
+                // Paper end - only call damage event when actuallyHurt will be called - move call logic down
+                // CraftBukkit start
+                if (!this.actuallyHurt(level, damageSource, (float) event.getFinalDamage(), event)) {
+                    return false;
+                }
+                if (this instanceof ServerPlayer && event.getDamage() == 0 && originalAmount == 0) return false; // Paper - revert to vanilla damage - players are not affected by damage that is 0 - skip damage if the vanilla damage is 0 and was not modified by plugins in the event.
                 this.lastHurt = amount;
-                this.invulnerableTime = 20;
-                this.actuallyHurt(level, damageSource, amount);
+                this.invulnerableTime = this.invulnerableDuration; // CraftBukkit - restore use of maxNoDamageTicks
+                // this.actuallyHurt(level, damageSource, amount);
+                // CraftBukkit end
                 this.hurtDuration = 10;
                 this.hurtTime = this.hurtDuration;
             }
@@ -1170,7 +_,7 @@
                     level.broadcastDamageEvent(this, damageSource);
                 }
 
-                if (!damageSource.is(DamageTypeTags.NO_IMPACT) && (!flag || amount > 0.0F)) {
+                if (!damageSource.is(DamageTypeTags.NO_IMPACT) && !flag) { // CraftBukkit - Prevent marking hurt if the damage is blocked
                     this.markHurt();
                 }
 
@@ -1186,7 +_,7 @@
                         d1 = damageSource.getSourcePosition().z() - this.getZ();
                     }
 
-                    this.knockback(0.4F, d, d1);
+                    this.knockback(0.4F, d, d1, damageSource.getDirectEntity(), damageSource.getDirectEntity() == null ? io.papermc.paper.event.entity.EntityKnockbackEvent.Cause.DAMAGE : io.papermc.paper.event.entity.EntityKnockbackEvent.Cause.ENTITY_ATTACK); // CraftBukkit // Paper - knockback events
                     if (!flag) {
                         this.indicateDamage(d, d1);
                     }
@@ -1195,17 +_,18 @@
 
             if (this.isDeadOrDying()) {
                 if (!this.checkTotemDeathProtection(damageSource)) {
-                    if (flag1) {
-                        this.makeSound(this.getDeathSound());
-                    }
+                    // Paper start - moved into CraftEventFactory event caller for cancellable death event
+                    this.silentDeath = !flag1; // mark entity as dying silently
+                    // Paper end
 
                     this.die(damageSource);
+                    this.silentDeath = false; // Paper - cancellable death event - reset to default
                 }
             } else if (flag1) {
                 this.playHurtSound(damageSource);
             }
 
-            boolean flag2 = !flag || amount > 0.0F;
+            boolean flag2 = !flag; // CraftBukkit - Ensure to return false if damage is blocked
             if (flag2) {
                 this.lastDamageSource = damageSource;
                 this.lastDamageStamp = this.level().getGameTime();
@@ -1259,12 +_,24 @@
         }
     }
 
+    // Paper start - only call damage event when actuallyHurt will be called - move out amount computation logic
+    private float computeAmountFromEntityDamageEvent(final EntityDamageEvent event) {
+        // Taken from hurt()'s craftbukkit diff.
+        float amount = 0;
+        amount += (float) event.getDamage(DamageModifier.BASE);
+        amount += (float) event.getDamage(DamageModifier.BLOCKING);
+        amount += (float) event.getDamage(DamageModifier.FREEZING);
+        amount += (float) event.getDamage(DamageModifier.HARD_HAT);
+        return amount;
+    }
+    // Paper end - only call damage event when actuallyHurt will be called - move out amount computation logic
+
     protected void blockUsingShield(LivingEntity attacker) {
         attacker.blockedByShield(this);
     }
 
     protected void blockedByShield(LivingEntity defender) {
-        defender.knockback(0.5, defender.getX() - this.getX(), defender.getZ() - this.getZ());
+        defender.knockback(0.5, defender.getX() - this.getX(), defender.getZ() - this.getZ(), this, io.papermc.paper.event.entity.EntityKnockbackEvent.Cause.SHIELD_BLOCK); // CraftBukkit // Paper - fix attacker & knockback events
     }
 
     private boolean checkTotemDeathProtection(DamageSource damageSource) {
@@ -1274,18 +_,37 @@
             ItemStack itemStack = null;
             DeathProtection deathProtection = null;
 
+            // CraftBukkit start
+            InteractionHand hand = null;
+            ItemStack itemInHand = ItemStack.EMPTY;
             for (InteractionHand interactionHand : InteractionHand.values()) {
-                ItemStack itemInHand = this.getItemInHand(interactionHand);
+                itemInHand = this.getItemInHand(interactionHand);
                 deathProtection = itemInHand.get(DataComponents.DEATH_PROTECTION);
                 if (deathProtection != null) {
+                    hand = interactionHand; // CraftBukkit
                     itemStack = itemInHand.copy();
-                    itemInHand.shrink(1);
+                    // itemInHand.shrink(1); // CraftBukkit
                     break;
                 }
             }
 
-            if (itemStack != null) {
-                if (this instanceof ServerPlayer serverPlayer) {
+            org.bukkit.inventory.EquipmentSlot handSlot = (hand != null) ? org.bukkit.craftbukkit.CraftEquipmentSlot.getHand(hand) : null;
+            EntityResurrectEvent event = new EntityResurrectEvent((org.bukkit.entity.LivingEntity) this.getBukkitEntity(), handSlot);
+            event.setCancelled(itemStack == null);
+            this.level().getCraftServer().getPluginManager().callEvent(event);
+
+            if (!event.isCancelled()) {
+                if (!itemStack.isEmpty() && itemStack != null) { // Paper - only reduce item if actual totem was found
+                    itemStack.shrink(1);
+                }
+                // Paper start - fix NPE when pre-cancelled EntityResurrectEvent is uncancelled
+                // restore the previous behavior in that case by defaulting to vanillas totem of undying efect
+                if (deathProtection == null) {
+                    deathProtection = DeathProtection.TOTEM_OF_UNDYING;
+                }
+                // Paper end - fix NPE when pre-cancelled EntityResurrectEvent is uncancelled
+                if (itemStack != null && this instanceof ServerPlayer serverPlayer) {
+                    // CraftBukkit end
                     serverPlayer.awardStat(Stats.ITEM_USED.get(itemStack.getItem()));
                     CriteriaTriggers.USED_TOTEM.trigger(serverPlayer, itemStack);
                     this.gameEvent(GameEvent.ITEM_INTERACT_FINISH);
@@ -1364,6 +_,7 @@
         if (!this.isRemoved() && !this.dead) {
             Entity entity = damageSource.getEntity();
             LivingEntity killCredit = this.getKillCredit();
+            /* // Paper - move down to make death event cancellable - this is the awardKillScore below
             if (killCredit != null) {
                 killCredit.awardKillScore(this, damageSource);
             }
@@ -1373,68 +_,145 @@
             }
 
             if (!this.level().isClientSide && this.hasCustomName()) {
-                LOGGER.info("Named entity {} died: {}", this, this.getCombatTracker().getDeathMessage().getString());
+                if (org.spigotmc.SpigotConfig.logNamedDeaths) LivingEntity.LOGGER.info("Named entity {} died: {}", this, this.getCombatTracker().getDeathMessage().getString()); // Spigot
             }
+            */ // Paper - move down to make death event cancellable - this is the awardKillScore below
 
             this.dead = true;
-            this.getCombatTracker().recheckStatus();
+            // Paper - moved into if below
             if (this.level() instanceof ServerLevel serverLevel) {
-                if (entity == null || entity.killedEntity(serverLevel, this)) {
+                // Paper - move below into if for onKill
+                // Paper start
+                org.bukkit.event.entity.EntityDeathEvent deathEvent = this.dropAllDeathLoot(serverLevel, damageSource);
+                if (deathEvent == null || !deathEvent.isCancelled()) {
+                    //if (entityliving != null) { // Paper - Fix item duplication and teleport issues; moved to be run earlier in #dropAllDeathLoot before destroying the drop items in CraftEventFactory#callEntityDeathEvent
+                    //    entityliving.awardKillScore(this, damageSource);
+                    //}
+                    // Paper start - clear equipment if event is not cancelled
+                    if (this instanceof Mob) {
+                        for (EquipmentSlot slot : this.clearedEquipmentSlots) {
+                            this.setItemSlot(slot, ItemStack.EMPTY);
+                        }
+                        this.clearedEquipmentSlots.clear();
+                    }
+                    // Paper end
+
+                    if (this.isSleeping()) {
+                        this.stopSleeping();
+                    }
+
+                    if (!this.level().isClientSide && this.hasCustomName()) {
+                        if (org.spigotmc.SpigotConfig.logNamedDeaths) LivingEntity.LOGGER.info("Named entity {} died: {}", this, this.getCombatTracker().getDeathMessage().getString()); // Spigot
+                    }
+
+                    this.getCombatTracker().recheckStatus();
+                    if (entity != null) {
+                        entity.killedEntity((ServerLevel) this.level(), this);
+                    }
                     this.gameEvent(GameEvent.ENTITY_DIE);
-                    this.dropAllDeathLoot(serverLevel, damageSource);
+                } else {
+                    this.dead = false;
+                    this.setHealth((float) deathEvent.getReviveHealth());
+                }
+                // Paper end
                     this.createWitherRose(killCredit);
                 }
 
+            // Paper start
+            if (this.dead) { // Paper
                 this.level().broadcastEntityEvent(this, (byte)3);
-            }
 
             this.setPose(Pose.DYING);
+            }
+            // Paper end
         }
     }
 
     protected void createWitherRose(@Nullable LivingEntity entitySource) {
         if (this.level() instanceof ServerLevel serverLevel) {
             boolean var6 = false;
-            if (entitySource instanceof WitherBoss) {
+            if (this.dead && entitySource instanceof WitherBoss) { // Paper
                 if (serverLevel.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) {
                     BlockPos blockPos = this.blockPosition();
                     BlockState blockState = Blocks.WITHER_ROSE.defaultBlockState();
                     if (this.level().getBlockState(blockPos).isAir() && blockState.canSurvive(this.level(), blockPos)) {
                         this.level().setBlock(blockPos, blockState, 3);
-                        var6 = true;
+                        // CraftBukkit start - call EntityBlockFormEvent for Wither Rose
+                        var6 = org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this.level(), blockPos, blockState, 3, this);
+                        // CraftBukkit end
                     }
                 }
 
                 if (!var6) {
                     ItemEntity itemEntity = new ItemEntity(this.level(), this.getX(), this.getY(), this.getZ(), new ItemStack(Items.WITHER_ROSE));
+                    // CraftBukkit start
+                    org.bukkit.event.entity.EntityDropItemEvent event = new org.bukkit.event.entity.EntityDropItemEvent(this.getBukkitEntity(), (org.bukkit.entity.Item) itemEntity.getBukkitEntity());
+                    CraftEventFactory.callEvent(event);
+                    if (event.isCancelled()) {
+                        return;
+                    }
+                    // CraftBukkit end
                     this.level().addFreshEntity(itemEntity);
                 }
             }
         }
     }
 
-    protected void dropAllDeathLoot(ServerLevel level, DamageSource damageSource) {
+    // Paper start
+    protected boolean clearEquipmentSlots = true;
+    protected Set<EquipmentSlot> clearedEquipmentSlots = new java.util.HashSet<>();
+    protected org.bukkit.event.entity.EntityDeathEvent dropAllDeathLoot(ServerLevel level, DamageSource damageSource) {
+        // Paper end
         boolean flag = this.lastHurtByPlayerTime > 0;
+        this.dropEquipment(level); // CraftBukkit - from below
         if (this.shouldDropLoot() && level.getGameRules().getBoolean(GameRules.RULE_DOMOBLOOT)) {
             this.dropFromLootTable(level, damageSource, flag);
+            // Paper start
+            final boolean prev = this.clearEquipmentSlots;
+            this.clearEquipmentSlots = false;
+            this.clearedEquipmentSlots.clear();
+            // Paper end
             this.dropCustomDeathLoot(level, damageSource, flag);
+            this.clearEquipmentSlots = prev; // Paper
         }
 
-        this.dropEquipment(level);
+        // CraftBukkit start - Call death event // Paper start - call advancement triggers with correct entity equipment
+        org.bukkit.event.entity.EntityDeathEvent deathEvent = CraftEventFactory.callEntityDeathEvent(this, damageSource, this.drops, () -> {
+            final LivingEntity entityliving = this.getKillCredit();
+            if (entityliving != null) {
+                entityliving.awardKillScore(this, damageSource);
+            }
+        }); // Paper end
+        this.postDeathDropItems(deathEvent); // Paper
+        this.drops = new ArrayList<>();
+        // this.dropEquipment(level); // CraftBukkit - moved up
+        // CraftBukkit end
         this.dropExperience(level, damageSource.getEntity());
+        return deathEvent; // Paper
     }
 
     protected void dropEquipment(ServerLevel level) {
     }
+    protected void postDeathDropItems(org.bukkit.event.entity.EntityDeathEvent event) {} // Paper - method for post death logic that cannot be ran before the event is potentially cancelled
 
-    protected void dropExperience(ServerLevel level, @Nullable Entity entity) {
+    protected int getExpReward(ServerLevel level, @Nullable Entity entity) { // CraftBukkit
         if (!this.wasExperienceConsumed()
             && (
                 this.isAlwaysExperienceDropper()
                     || this.lastHurtByPlayerTime > 0 && this.shouldDropExperience() && level.getGameRules().getBoolean(GameRules.RULE_DOMOBLOOT)
             )) {
-            ExperienceOrb.award(level, this.position(), this.getExperienceReward(level, entity));
-        }
+            return this.getExperienceReward(level, entity); // CraftBukkit
+        }
+        return 0; // CraftBukkit
+    }
+
+    protected void dropExperience(ServerLevel level, @Nullable Entity entity) {
+        // CraftBukkit start - Update getExpReward() above if the removed if() changes!
+        if (!(this instanceof net.minecraft.world.entity.boss.enderdragon.EnderDragon)) { // CraftBukkit - SPIGOT-2420: Special case ender dragon will drop the xp over time
+            ExperienceOrb.award(level, this.position(), this.expToDrop, this instanceof ServerPlayer ? org.bukkit.entity.ExperienceOrb.SpawnReason.PLAYER_DEATH : org.bukkit.entity.ExperienceOrb.SpawnReason.ENTITY_DEATH, entity, this); // Paper
+            this.expToDrop = 0;
+        }
+        // CraftBukkit end
     }
 
     protected void dropCustomDeathLoot(ServerLevel level, DamageSource damageSource, boolean recentlyHit) {
@@ -1513,9 +_,14 @@
     }
 
     public void knockback(double strength, double x, double z) {
+        // CraftBukkit start - EntityKnockbackEvent
+        this.knockback(strength, x, z, null, io.papermc.paper.event.entity.EntityKnockbackEvent.Cause.UNKNOWN); // Paper - knockback events
+    }
+
+    public void knockback(double strength, double x, double z, @Nullable Entity attacker, io.papermc.paper.event.entity.EntityKnockbackEvent.Cause eventCause) { // Paper - knockback events
         strength *= 1.0 - this.getAttributeValue(Attributes.KNOCKBACK_RESISTANCE);
-        if (!(strength <= 0.0)) {
-            this.hasImpulse = true;
+        if (true || !(strength <= 0.0)) { // CraftBukkit - Call event even when force is 0
+            // this.hasImpulse = true; // CraftBukkit - Move down
             Vec3 deltaMovement = this.getDeltaMovement();
 
             while (x * x + z * z < 1.0E-5F) {
@@ -1524,11 +_,22 @@
             }
 
             Vec3 vec3 = new Vec3(x, 0.0, z).normalize().scale(strength);
-            this.setDeltaMovement(
+            // Paper start - knockback events
+            Vec3 finalVelocity = new Vec3(
                 deltaMovement.x / 2.0 - vec3.x,
                 this.onGround() ? Math.min(0.4, deltaMovement.y / 2.0 + strength) : deltaMovement.y,
                 deltaMovement.z / 2.0 - vec3.z
             );
+            Vec3 diff = finalVelocity.subtract(deltaMovement);
+            io.papermc.paper.event.entity.EntityKnockbackEvent event = CraftEventFactory.callEntityKnockbackEvent((org.bukkit.craftbukkit.entity.CraftLivingEntity) this.getBukkitEntity(), attacker, attacker, eventCause, strength, diff);
+            // Paper end - knockback events
+            if (event.isCancelled()) {
+                return;
+            }
+
+            this.hasImpulse = true;
+            this.setDeltaMovement(deltaMovement.add(event.getKnockback().getX(), event.getKnockback().getY(), event.getKnockback().getZ())); // Paper - knockback events
+            // CraftBukkit end
         }
     }
 
@@ -1584,6 +_,20 @@
         return new LivingEntity.Fallsounds(SoundEvents.GENERIC_SMALL_FALL, SoundEvents.GENERIC_BIG_FALL);
     }
 
+    // CraftBukkit start - Add delegate methods
+    public SoundEvent getHurtSound0(DamageSource damagesource) {
+        return this.getHurtSound(damagesource);
+    }
+
+    public SoundEvent getDeathSound0() {
+        return this.getDeathSound();
+    }
+
+    public SoundEvent getFallDamageSound0(int fallHeight) {
+        return this.getFallDamageSound(fallHeight);
+    }
+    // CraftBukkit end
+
     public Optional<BlockPos> getLastClimbablePos() {
         return this.lastClimbablePos;
     }
@@ -1617,7 +_,7 @@
 
     @Override
     public boolean isAlive() {
-        return !this.isRemoved() && this.getHealth() > 0.0F;
+        return !this.isRemoved() && this.getHealth() > 0.0F && !this.dead; // Paper - Check this.dead
     }
 
     public boolean isLookingAtMe(LivingEntity entity, double tolerance, boolean scaleByDistance, boolean visual, double... yValues) {
@@ -1651,9 +_,14 @@
         boolean flag = super.causeFallDamage(fallDistance, multiplier, source);
         int i = this.calculateFallDamage(fallDistance, multiplier);
         if (i > 0) {
+            // CraftBukkit start
+            if (!this.hurtServer((ServerLevel) this.level(), source, (float) i)) {
+                return true;
+            }
+            // CraftBukkit end
             this.playSound(this.getFallDamageSound(i), 1.0F, 1.0F);
             this.playBlockFallSound();
-            this.hurt(source, i);
+            // this.hurt(source, i); // CraftBukkit - moved up
             return true;
         } else {
             return flag;
@@ -1718,7 +_,7 @@
 
     protected float getDamageAfterArmorAbsorb(DamageSource damageSource, float damageAmount) {
         if (!damageSource.is(DamageTypeTags.BYPASSES_ARMOR)) {
-            this.hurtArmor(damageSource, damageAmount);
+            // this.hurtArmor(damageSource, damageAmount); // CraftBukkit - actuallyHurt(DamageSource, float, EntityDamageEvent) for damage handling
             damageAmount = CombatRules.getDamageAfterAbsorb(
                 this, damageAmount, damageSource, this.getArmorValue(), (float)this.getAttributeValue(Attributes.ARMOR_TOUGHNESS)
             );
@@ -1731,7 +_,8 @@
         if (damageSource.is(DamageTypeTags.BYPASSES_EFFECTS)) {
             return damageAmount;
         } else {
-            if (this.hasEffect(MobEffects.DAMAGE_RESISTANCE) && !damageSource.is(DamageTypeTags.BYPASSES_RESISTANCE)) {
+            // CraftBukkit - Moved to handleEntityDamage(DamageSource, float)
+            if (false && this.hasEffect(MobEffects.DAMAGE_RESISTANCE) && !damageSource.is(DamageTypeTags.BYPASSES_RESISTANCE)) {
                 int i = (this.getEffect(MobEffects.DAMAGE_RESISTANCE).getAmplifier() + 1) * 5;
                 int i1 = 25 - i;
                 float f = damageAmount * i1;
@@ -1768,24 +_,212 @@
         }
     }
 
-    protected void actuallyHurt(ServerLevel level, DamageSource damageSource, float amount) {
+    // CraftBukkit start
+    private EntityDamageEvent handleEntityDamage(final DamageSource damagesource, float amount, final float invulnerabilityRelatedLastDamage) { // Paper - fix invulnerability reduction in EntityDamageEvent
+        float originalDamage = amount;
+        // Paper start - fix invulnerability reduction in EntityDamageEvent
+        final com.google.common.base.Function<Double, Double> invulnerabilityReductionEquation = d -> {
+            if (invulnerabilityRelatedLastDamage == 0) return 0D; // no last damage, no reduction
+            // last damage existed, this means the reduction *technically* is (new damage - last damage).
+            // If the event damage was changed to something less than invul damage, hard lock it at 0.
+            if (d < invulnerabilityRelatedLastDamage) return 0D;
+            return (double) -invulnerabilityRelatedLastDamage;
+        };
+        final float originalInvulnerabilityReduction = invulnerabilityReductionEquation.apply((double) amount).floatValue();
+        amount += originalInvulnerabilityReduction;
+        // Paper end - fix invulnerability reduction in EntityDamageEvent
+
+        com.google.common.base.Function<Double, Double> freezing = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                if (damagesource.is(DamageTypeTags.IS_FREEZING) && LivingEntity.this.getType().is(EntityTypeTags.FREEZE_HURTS_EXTRA_TYPES)) {
+                    return -(f - (f * 5.0F));
+                }
+                return -0.0;
+            }
+        };
+        float freezingModifier = freezing.apply((double) amount).floatValue();
+        amount += freezingModifier;
+
+        com.google.common.base.Function<Double, Double> hardHat = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                if (damagesource.is(DamageTypeTags.DAMAGES_HELMET) && !LivingEntity.this.getItemBySlot(EquipmentSlot.HEAD).isEmpty()) {
+                    return -(f - (f * 0.75F));
+                }
+                return -0.0;
+            }
+        };
+        float hardHatModifier = hardHat.apply((double) amount).floatValue();
+        amount += hardHatModifier;
+
+        com.google.common.base.Function<Double, Double> blocking = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                return -((LivingEntity.this.isDamageSourceBlocked(damagesource)) ? f : 0.0);
+            }
+        };
+        float blockingModifier = blocking.apply((double) amount).floatValue();
+        amount += blockingModifier;
+
+        com.google.common.base.Function<Double, Double> armor = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                return -(f - LivingEntity.this.getDamageAfterArmorAbsorb(damagesource, f.floatValue()));
+            }
+        };
+        float armorModifier = armor.apply((double) amount).floatValue();
+        amount += armorModifier;
+
+        com.google.common.base.Function<Double, Double> resistance = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                if (!damagesource.is(DamageTypeTags.BYPASSES_EFFECTS) && LivingEntity.this.hasEffect(MobEffects.DAMAGE_RESISTANCE) && !damagesource.is(DamageTypeTags.BYPASSES_RESISTANCE)) {
+                    int i = (LivingEntity.this.getEffect(MobEffects.DAMAGE_RESISTANCE).getAmplifier() + 1) * 5;
+                    int j = 25 - i;
+                    float f1 = f.floatValue() * (float) j;
+
+                    return -(f - Math.max(f1 / 25.0F, 0.0F));
+                }
+                return -0.0;
+            }
+        };
+        float resistanceModifier = resistance.apply((double) amount).floatValue();
+        amount += resistanceModifier;
+
+        com.google.common.base.Function<Double, Double> magic = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                return -(f - LivingEntity.this.getDamageAfterMagicAbsorb(damagesource, f.floatValue()));
+            }
+        };
+        float magicModifier = magic.apply((double) amount).floatValue();
+        amount += magicModifier;
+
+        com.google.common.base.Function<Double, Double> absorption = new com.google.common.base.Function<Double, Double>() {
+            @Override
+            public Double apply(Double f) {
+                return -(Math.max(f - Math.max(f - LivingEntity.this.getAbsorptionAmount(), 0.0F), 0.0F));
+            }
+        };
+        float absorptionModifier = absorption.apply((double) amount).floatValue();
+
+        // Paper start - fix invulnerability reduction in EntityDamageEvent
+        return CraftEventFactory.handleLivingEntityDamageEvent(this, damagesource, originalDamage, freezingModifier, hardHatModifier, blockingModifier, armorModifier, resistanceModifier, magicModifier, absorptionModifier, freezing, hardHat, blocking, armor, resistance, magic, absorption, (damageModifierDoubleMap, damageModifierFunctionMap) -> {
+            damageModifierFunctionMap.put(DamageModifier.INVULNERABILITY_REDUCTION, invulnerabilityReductionEquation);
+            damageModifierDoubleMap.put(DamageModifier.INVULNERABILITY_REDUCTION, (double) originalInvulnerabilityReduction);
+        });
+        // Paper end - fix invulnerability reduction in EntityDamageEvent
+    }
+
+    protected boolean actuallyHurt(ServerLevel level, final DamageSource damageSource, float amount, final EntityDamageEvent event) { // void -> boolean, add final
         if (!this.isInvulnerableTo(level, damageSource)) {
-            amount = this.getDamageAfterArmorAbsorb(damageSource, amount);
-            amount = this.getDamageAfterMagicAbsorb(damageSource, amount);
-            float var10 = Math.max(amount - this.getAbsorptionAmount(), 0.0F);
-            this.setAbsorptionAmount(this.getAbsorptionAmount() - (amount - var10));
-            float f1 = amount - var10;
+            if (event.isCancelled()) {
+                return false;
+            }
+
+            if (damageSource.getEntity() instanceof net.minecraft.world.entity.player.Player) {
+                // Paper start - PlayerAttackEntityCooldownResetEvent
+                //((net.minecraft.world.entity.player.Player) damagesource.getEntity()).resetAttackStrengthTicker(); // Moved from EntityHuman in order to make the cooldown reset get called after the damage event is fired
+                if (damageSource.getEntity() instanceof ServerPlayer) {
+                    ServerPlayer player = (ServerPlayer) damageSource.getEntity();
+                    if (new com.destroystokyo.paper.event.player.PlayerAttackEntityCooldownResetEvent(player.getBukkitEntity(), this.getBukkitEntity(), player.getAttackStrengthScale(0F)).callEvent()) {
+                        player.resetAttackStrengthTicker();
+                    }
+                } else {
+                    ((net.minecraft.world.entity.player.Player) damageSource.getEntity()).resetAttackStrengthTicker();
+                }
+                // Paper end - PlayerAttackEntityCooldownResetEvent
+            }
+
+            // Resistance
+            if (event.getDamage(DamageModifier.RESISTANCE) < 0) {
+                float f3 = (float) -event.getDamage(DamageModifier.RESISTANCE);
+                if (f3 > 0.0F && f3 < 3.4028235E37F) {
+                    if (this instanceof ServerPlayer) {
+                        ((ServerPlayer) this).awardStat(Stats.DAMAGE_RESISTED, Math.round(f3 * 10.0F));
+                    } else if (damageSource.getEntity() instanceof ServerPlayer) {
+                        ((ServerPlayer) damageSource.getEntity()).awardStat(Stats.DAMAGE_DEALT_RESISTED, Math.round(f3 * 10.0F));
+                    }
+                }
+            }
+
+            // Apply damage to helmet
+            if (damageSource.is(DamageTypeTags.DAMAGES_HELMET) && !this.getItemBySlot(EquipmentSlot.HEAD).isEmpty()) {
+                this.hurtHelmet(damageSource, amount);
+            }
+
+            // Apply damage to armor
+            if (!damageSource.is(DamageTypeTags.BYPASSES_ARMOR)) {
+                float armorDamage = (float) (event.getDamage() + event.getDamage(DamageModifier.BLOCKING) + event.getDamage(DamageModifier.HARD_HAT));
+                this.hurtArmor(damageSource, armorDamage);
+            }
+
+            // Apply blocking code // PAIL: steal from above
+            if (event.getDamage(DamageModifier.BLOCKING) < 0) {
+                this.hurtCurrentlyUsedShield((float) -event.getDamage(DamageModifier.BLOCKING));
+                Entity entity = damageSource.getDirectEntity();
+
+                if (!damageSource.is(DamageTypeTags.IS_PROJECTILE) && entity instanceof LivingEntity) { // Paper - Fix shield disable inconsistency
+                    this.blockUsingShield((LivingEntity) entity);
+                }
+            }
+
+            boolean human = this instanceof net.minecraft.world.entity.player.Player;
+            float originalDamage = (float) event.getDamage();
+            float absorptionModifier = (float) -event.getDamage(DamageModifier.ABSORPTION);
+            this.setAbsorptionAmount(Math.max(this.getAbsorptionAmount() - absorptionModifier, 0.0F));
+            float f1 = absorptionModifier;
+
+            if (f1 > 0.0F && f1 < 3.4028235E37F && this instanceof Player player) {
+                player.awardStat(Stats.DAMAGE_ABSORBED, Math.round(f1 * 10.0F));
+            }
+            // CraftBukkit end
             if (f1 > 0.0F && f1 < 3.4028235E37F && damageSource.getEntity() instanceof ServerPlayer serverPlayer) {
                 serverPlayer.awardStat(Stats.DAMAGE_DEALT_ABSORBED, Math.round(f1 * 10.0F));
             }
 
-            if (var10 != 0.0F) {
-                this.getCombatTracker().recordDamage(damageSource, var10);
-                this.setHealth(this.getHealth() - var10);
-                this.setAbsorptionAmount(this.getAbsorptionAmount() - var10);
+            // CraftBukkit start
+            if (amount > 0 || !human) {
+                if (human) {
+                    // PAIL: Be sure to drag all this code from the EntityHuman subclass each update.
+                    ((net.minecraft.world.entity.player.Player) this).causeFoodExhaustion(damageSource.getFoodExhaustion(), org.bukkit.event.entity.EntityExhaustionEvent.ExhaustionReason.DAMAGED); // CraftBukkit - EntityExhaustionEvent
+                    if (amount < 3.4028235E37F) {
+                        ((net.minecraft.world.entity.player.Player) this).awardStat(Stats.DAMAGE_TAKEN, Math.round(amount * 10.0F));
+                    }
+                }
+                // CraftBukkit end
+                this.getCombatTracker().recordDamage(damageSource, amount);
+                this.setHealth(this.getHealth() - amount);
+                // CraftBukkit start
+                if (!human) {
+                    this.setAbsorptionAmount(this.getAbsorptionAmount() - amount);
+                }
                 this.gameEvent(GameEvent.ENTITY_DAMAGE);
+                return true;
+            } else {
+                // Duplicate triggers if blocking
+                if (event.getDamage(DamageModifier.BLOCKING) < 0) {
+                    if (this instanceof ServerPlayer) {
+                        CriteriaTriggers.ENTITY_HURT_PLAYER.trigger((ServerPlayer) this, damageSource, originalDamage, amount, true); // Paper - fix taken/dealt param order
+                        f1 = (float) -event.getDamage(DamageModifier.BLOCKING);
+                        if (f1 > 0.0F && f1 < 3.4028235E37F) {
+                            ((ServerPlayer) this).awardStat(Stats.DAMAGE_BLOCKED_BY_SHIELD, Math.round(originalDamage * 10.0F));
+                        }
+                    }
+
+                    if (damageSource.getEntity() instanceof ServerPlayer) {
+                        CriteriaTriggers.PLAYER_HURT_ENTITY.trigger((ServerPlayer) damageSource.getEntity(), this, damageSource, originalDamage, amount, true); // Paper - fix taken/dealt param order
+                    }
+
+                    return !io.papermc.paper.configuration.GlobalConfiguration.get().unsupportedSettings.skipVanillaDamageTickWhenShieldBlocked; // Paper - this should always return true, however expose an unsupported setting to flip this to false to enable "shield stunning".
+                } else {
+                    return true; // Paper - return false ONLY if event was cancelled
+                }
+                // CraftBukkit end
             }
         }
+        return true; // CraftBukkit // Paper - return false ONLY if event was cancelled
     }
 
     public CombatTracker getCombatTracker() {
@@ -1814,7 +_,17 @@
     }
 
     public final void setArrowCount(int count) {
-        this.entityData.set(DATA_ARROW_COUNT_ID, count);
+        // CraftBukkit start
+        this.setArrowCount(count, false);
+    }
+
+    public final void setArrowCount(int count, boolean reset) {
+        ArrowBodyCountChangeEvent event = CraftEventFactory.callArrowBodyCountChangeEvent(this, this.getArrowCount(), count, reset);
+        if (event.isCancelled()) {
+            return;
+        }
+        this.entityData.set(DATA_ARROW_COUNT_ID, event.getNewAmount());
+        // CraftBukkit end
     }
 
     public final int getStingerCount() {
@@ -1957,7 +_,7 @@
 
     @Override
     protected void onBelowWorld() {
-        this.hurt(this.damageSources().fellOutOfWorld(), 4.0F);
+        this.hurt(this.damageSources().fellOutOfWorld(), this.level().getWorld().getVoidDamageAmount()); // Paper - use configured void damage amount
     }
 
     protected void updateSwingTime() {
@@ -2052,6 +_,12 @@
 
     public abstract ItemStack getItemBySlot(EquipmentSlot slot);
 
+    // CraftBukkit start
+    public void setItemSlot(EquipmentSlot enumitemslot, ItemStack itemstack, boolean silent) {
+        this.setItemSlot(enumitemslot, itemstack);
+    }
+    // CraftBukkit end
+
     public abstract void setItemSlot(EquipmentSlot slot, ItemStack stack);
 
     public Iterable<ItemStack> getHandSlots() {
@@ -2158,14 +_,27 @@
         return this.hasEffect(MobEffects.JUMP) ? 0.1F * (this.getEffect(MobEffects.JUMP).getAmplifier() + 1.0F) : 0.0F;
     }
 
+    protected long lastJumpTime = 0L; // Paper - Prevent excessive velocity through repeated crits
     @VisibleForTesting
     public void jumpFromGround() {
         float jumpPower = this.getJumpPower();
         if (!(jumpPower <= 1.0E-5F)) {
             Vec3 deltaMovement = this.getDeltaMovement();
+            // Paper start - Prevent excessive velocity through repeated crits
+            long time = System.nanoTime();
+            boolean canCrit = true;
+            if (this instanceof net.minecraft.world.entity.player.Player) {
+                canCrit = false;
+                if (time - this.lastJumpTime > (long)(0.250e9)) {
+                    this.lastJumpTime = time;
+                    canCrit = true;
+                }
+            }
+            // Paper end - Prevent excessive velocity through repeated crits
             this.setDeltaMovement(deltaMovement.x, Math.max((double)jumpPower, deltaMovement.y), deltaMovement.z);
             if (this.isSprinting()) {
                 float f = this.getYRot() * (float) (Math.PI / 180.0);
+                if (canCrit) // Paper - Prevent excessive velocity through repeated crits
                 this.addDeltaMovement(new Vec3(-Mth.sin(f) * 0.2, 0.0, Mth.cos(f) * 0.2));
             }
 
@@ -2425,7 +_,7 @@
     }
 
     protected float getFlyingSpeed() {
-        return this.getControllingPassenger() instanceof Player ? this.getSpeed() * 0.1F : 0.02F;
+        return this.getControllingPassenger() instanceof net.minecraft.world.entity.player.Player ? this.getSpeed() * 0.1F : 0.02F;
     }
 
     public float getSpeed() {
@@ -2471,7 +_,7 @@
                 }
             }
 
-            this.detectEquipmentUpdates();
+            this.detectEquipmentUpdatesPublic(); // CraftBukkit
             if (this.tickCount % 20 == 0) {
                 this.getCombatTracker().recheckStatus();
             }
@@ -2519,37 +_,14 @@
         profilerFiller.pop();
         profilerFiller.push("rangeChecks");
 
-        while (this.getYRot() - this.yRotO < -180.0F) {
-            this.yRotO -= 360.0F;
-        }
-
-        while (this.getYRot() - this.yRotO >= 180.0F) {
-            this.yRotO += 360.0F;
-        }
-
-        while (this.yBodyRot - this.yBodyRotO < -180.0F) {
-            this.yBodyRotO -= 360.0F;
-        }
-
-        while (this.yBodyRot - this.yBodyRotO >= 180.0F) {
-            this.yBodyRotO += 360.0F;
-        }
-
-        while (this.getXRot() - this.xRotO < -180.0F) {
-            this.xRotO -= 360.0F;
-        }
-
-        while (this.getXRot() - this.xRotO >= 180.0F) {
-            this.xRotO += 360.0F;
-        }
-
-        while (this.yHeadRot - this.yHeadRotO < -180.0F) {
-            this.yHeadRotO -= 360.0F;
-        }
-
-        while (this.yHeadRot - this.yHeadRotO >= 180.0F) {
-            this.yHeadRotO += 360.0F;
-        }
+        // Paper start - stop large pitch and yaw changes from crashing the server
+        this.yRotO += Math.round((this.getYRot() - this.yRotO) / 360.0F) * 360.0F;
+
+        this.yBodyRotO += Math.round((this.yBodyRot - this.yBodyRotO) / 360.0F) * 360.0F;
+
+        this.xRotO += Math.round((this.getXRot() - this.xRotO) / 360.0F) * 360.0F;
+
+        this.yHeadRotO += Math.round((this.yHeadRot - this.yHeadRotO) / 360.0F) * 360.0F;
 
         profilerFiller.pop();
         this.animStep += f2;
@@ -2573,7 +_,7 @@
         this.elytraAnimationState.tick();
     }
 
-    public void detectEquipmentUpdates() {
+    public void detectEquipmentUpdatesPublic() { // CraftBukkit
         Map<EquipmentSlot, ItemStack> map = this.collectEquipmentChanges();
         if (map != null) {
             this.handleHandSwap(map);
@@ -2595,6 +_,13 @@
             };
             ItemStack itemBySlot = this.getItemBySlot(equipmentSlot);
             if (this.equipmentHasChanged(itemStack, itemBySlot)) {
+                // Paper start - PlayerArmorChangeEvent
+                if (this instanceof ServerPlayer && equipmentSlot.getType() == EquipmentSlot.Type.HUMANOID_ARMOR) {
+                    final org.bukkit.inventory.ItemStack oldItem = CraftItemStack.asBukkitCopy(itemStack);
+                    final org.bukkit.inventory.ItemStack newItem = CraftItemStack.asBukkitCopy(itemBySlot);
+                    new com.destroystokyo.paper.event.player.PlayerArmorChangeEvent((org.bukkit.entity.Player) this.getBukkitEntity(), com.destroystokyo.paper.event.player.PlayerArmorChangeEvent.SlotType.valueOf(equipmentSlot.name()), oldItem, newItem).callEvent();
+                }
+                // Paper end - PlayerArmorChangeEvent
                 if (map == null) {
                     map = Maps.newEnumMap(EquipmentSlot.class);
                 }
@@ -2664,7 +_,7 @@
                     this.lastBodyItemStack = itemStack;
             }
         });
-        ((ServerLevel)this.level()).getChunkSource().broadcast(this, new ClientboundSetEquipmentPacket(this.getId(), list));
+        ((ServerLevel)this.level()).getChunkSource().broadcast(this, new ClientboundSetEquipmentPacket(this.getId(), list, true)); // Paper - data sanitization
     }
 
     private ItemStack getLastArmorItem(EquipmentSlot slot) {
@@ -2765,8 +_,10 @@
             if (!flag || this.onGround() && !(fluidHeight > fluidJumpThreshold)) {
                 if (!this.isInLava() || this.onGround() && !(fluidHeight > fluidJumpThreshold)) {
                     if ((this.onGround() || flag && fluidHeight <= fluidJumpThreshold) && this.noJumpDelay == 0) {
+                        if (new com.destroystokyo.paper.event.entity.EntityJumpEvent(getBukkitLivingEntity()).callEvent()) { // Paper - Entity Jump API
                         this.jumpFromGround();
                         this.noJumpDelay = 10;
+                        } else { this.setJumping(false); } // Paper - Entity Jump API; setJumping(false) stops a potential loop
                     }
                 } else {
                     this.jumpInLiquid(FluidTags.LAVA);
@@ -2805,7 +_,7 @@
         this.calculateEntityAnimation(this instanceof FlyingAnimal);
         profilerFiller.pop();
         profilerFiller.push("freezing");
-        if (!this.level().isClientSide && !this.isDeadOrDying()) {
+        if (!this.level().isClientSide && !this.isDeadOrDying() && !this.freezeLocked) { // Paper - Freeze Tick Lock API
             int ticksFrozen = this.getTicksFrozen();
             if (this.isInPowderSnow && this.canFreeze()) {
                 this.setTicksFrozen(Math.min(this.getTicksRequiredToFreeze(), ticksFrozen + 1));
@@ -2829,6 +_,20 @@
 
         this.pushEntities();
         profilerFiller.pop();
+        // Paper start - Add EntityMoveEvent
+        if (((ServerLevel) this.level()).hasEntityMoveEvent && !(this instanceof Player)) {
+            if (this.xo != this.getX() || this.yo != this.getY() || this.zo != this.getZ() || this.yRotO != this.getYRot() || this.xRotO != this.getXRot()) {
+                Location from = new Location(this.level().getWorld(), this.xo, this.yo, this.zo, this.yRotO, this.xRotO);
+                Location to = new Location(this.level().getWorld(), this.getX(), this.getY(), this.getZ(), this.getYRot(), this.getXRot());
+                io.papermc.paper.event.entity.EntityMoveEvent event = new io.papermc.paper.event.entity.EntityMoveEvent(this.getBukkitLivingEntity(), from, to.clone());
+                if (!event.callEvent()) {
+                    this.absMoveTo(from.getX(), from.getY(), from.getZ(), from.getYaw(), from.getPitch());
+                } else if (!to.equals(event.getTo())) {
+                    this.absMoveTo(event.getTo().getX(), event.getTo().getY(), event.getTo().getZ(), event.getTo().getYaw(), event.getTo().getPitch());
+                }
+            }
+        }
+        // Paper end - Add EntityMoveEvent
         if (this.level() instanceof ServerLevel serverLevel && this.isSensitiveToWater() && this.isInWaterRainOrBubble()) {
             this.hurtServer(serverLevel, this.damageSources().drown(), 1.0F);
         }
@@ -2842,6 +_,7 @@
         this.checkSlowFallDistance();
         if (!this.level().isClientSide) {
             if (!this.canGlide()) {
+                if (this.getSharedFlag(7) != false && !CraftEventFactory.callToggleGlideEvent(this, false).isCancelled()) // CraftBukkit
                 this.setSharedFlag(7, false);
                 return;
             }
@@ -2881,9 +_,24 @@
         if (!(this.level() instanceof ServerLevel serverLevel)) {
             this.level().getEntities(EntityTypeTest.forClass(Player.class), this.getBoundingBox(), EntitySelector.pushableBy(this)).forEach(this::doPush);
         } else {
-            List<Entity> entities = this.level().getEntities(this, this.getBoundingBox(), EntitySelector.pushableBy(this));
+            // Paper start - don't run getEntities if we're not going to use its result
+            if (!this.isPushable()) {
+                return;
+            }
+
+            net.minecraft.world.scores.Team team = this.getTeam();
+            if (team != null && team.getCollisionRule() == net.minecraft.world.scores.Team.CollisionRule.NEVER) {
+                return;
+            }
+
+            int _int = serverLevel.getGameRules().getInt(GameRules.RULE_MAX_ENTITY_CRAMMING);
+            if (_int <= 0 && this.level().paperConfig().collisions.maxEntityCollisions <= 0) {
+                return;
+            }
+            // Paper end - don't run getEntities if we're not going to use its result
+            List<Entity> entities = this.level().getEntities(this, this.getBoundingBox(), EntitySelector.pushable(this, this.level().paperConfig().collisions.fixClimbingBypassingCrammingRule)); // Paper - Climbing should not bypass cramming gamerule
             if (!entities.isEmpty()) {
-                int _int = serverLevel.getGameRules().getInt(GameRules.RULE_MAX_ENTITY_CRAMMING);
+                // Paper - don't run getEntities if we're not going to use its result; moved up
                 if (_int > 0 && entities.size() > _int - 1 && this.random.nextInt(4) == 0) {
                     int i = 0;
 
@@ -2898,7 +_,16 @@
                     }
                 }
 
+                // Paper start - Cap entity collisions
+                this.numCollisions = Math.max(0, this.numCollisions - this.level().paperConfig().collisions.maxEntityCollisions);
                 for (Entity entity1 : entities) {
+                    if (this.numCollisions >= this.level().paperConfig().collisions.maxEntityCollisions) {
+                        break;
+                    }
+
+                    entity1.numCollisions++;
+                    this.numCollisions++;
+                    // Paper end - Cap entity collisions
                     this.doPush(entity1);
                 }
             }
@@ -2941,9 +_,16 @@
 
     @Override
     public void stopRiding() {
+        // Paper start - Force entity dismount during teleportation
+        this.stopRiding(false);
+    }
+
+    @Override
+    public void stopRiding(boolean suppressCancellation) {
+        // Paper end - Force entity dismount during teleportation
         Entity vehicle = this.getVehicle();
-        super.stopRiding();
-        if (vehicle != null && vehicle != this.getVehicle() && !this.level().isClientSide) {
+        super.stopRiding(suppressCancellation); // Paper - Force entity dismount during teleportation
+        if (vehicle != null && vehicle != this.getVehicle() && !this.level().isClientSide && vehicle.valid) { // Paper - don't process on world gen
             this.dismountVehicle(vehicle);
         }
     }
@@ -3007,7 +_,7 @@
     }
 
     public void onItemPickup(ItemEntity itemEntity) {
-        Entity owner = itemEntity.getOwner();
+        Entity owner = itemEntity.thrower != null ? this.level().getGlobalPlayerByUUID(itemEntity.thrower) : null; // Paper - check global player list where appropriate
         if (owner instanceof ServerPlayer) {
             CriteriaTriggers.THROWN_ITEM_PICKED_UP_BY_ENTITY.trigger((ServerPlayer)owner, itemEntity.getItem(), this);
         }
@@ -3017,7 +_,7 @@
         if (!entity.isRemoved()
             && !this.level().isClientSide
             && (entity instanceof ItemEntity || entity instanceof AbstractArrow || entity instanceof ExperienceOrb)) {
-            ((ServerLevel)this.level()).getChunkSource().broadcast(entity, new ClientboundTakeItemEntityPacket(entity.getId(), this.getId(), amount));
+            ((ServerLevel)this.level()).getChunkSource().broadcastAndSend(this, new ClientboundTakeItemEntityPacket(entity.getId(), this.getId(), amount)); // Paper - broadcast with collector as source
         }
     }
 
@@ -3031,7 +_,8 @@
         } else {
             Vec3 vec3 = new Vec3(this.getX(), this.getEyeY(), this.getZ());
             Vec3 vec31 = new Vec3(entity.getX(), y, entity.getZ());
-            return !(vec31.distanceTo(vec3) > 128.0) && this.level().clip(new ClipContext(vec3, vec31, block, fluid, this)).getType() == HitResult.Type.MISS;
+            // Paper - diff on change - used in CraftLivingEntity#hasLineOfSight(Location) and CraftWorld#lineOfSightExists
+            return !(vec31.distanceToSqr(vec3) > 128.0D * 128.0D) && this.level().clip(new ClipContext(vec3, vec31, block, fluid, this)).getType() == HitResult.Type.MISS; // Paper - Perf: Use distance squared
         }
     }
 
@@ -3051,13 +_,27 @@
 
     @Override
     public boolean isPickable() {
-        return !this.isRemoved();
+        return !this.isRemoved() && this.collides; // CraftBukkit
     }
 
+    // Paper start - Climbing should not bypass cramming gamerule
     @Override
     public boolean isPushable() {
-        return this.isAlive() && !this.isSpectator() && !this.onClimbable();
-    }
+        return this.isCollidable(this.level().paperConfig().collisions.fixClimbingBypassingCrammingRule);
+    }
+
+    @Override
+    public boolean isCollidable(boolean ignoreClimbing) {
+        return this.isAlive() && !this.isSpectator() && (ignoreClimbing || !this.onClimbable()) && this.collides; // CraftBukkit
+        // Paper end - Climbing should not bypass cramming gamerule
+    }
+
+    // CraftBukkit start - collidable API
+    @Override
+    public boolean canCollideWithBukkit(Entity entity) {
+        return this.isPushable() && this.collides != this.collidableExemptions.contains(entity.getUUID());
+    }
+    // CraftBukkit end
 
     @Override
     public float getYHeadRot() {
@@ -3088,7 +_,7 @@
     }
 
     public final void setAbsorptionAmount(float absorptionAmount) {
-        this.internalSetAbsorptionAmount(Mth.clamp(absorptionAmount, 0.0F, this.getMaxAbsorption()));
+        this.internalSetAbsorptionAmount(!Float.isNaN(absorptionAmount) ? Mth.clamp(absorptionAmount, 0.0F, this.getMaxAbsorption()) : 0.0F); // Paper - Check for NaN
     }
 
     protected void internalSetAbsorptionAmount(float absorptionAmount) {
@@ -3115,6 +_,11 @@
         return (this.entityData.get(DATA_LIVING_ENTITY_FLAGS) & 2) > 0 ? InteractionHand.OFF_HAND : InteractionHand.MAIN_HAND;
     }
 
+    // Paper start - Properly cancel usable items
+    public void resyncUsingItem(ServerPlayer serverPlayer) {
+        this.resendPossiblyDesyncedDataValues(java.util.List.of(DATA_LIVING_ENTITY_FLAGS), serverPlayer);
+    }
+    // Paper end - Properly cancel usable items
     private void updatingUsingItem() {
         if (this.isUsingItem()) {
             if (ItemStack.isSameItem(this.getItemInHand(this.getUsedItemHand()), this.useItem)) {
@@ -3154,8 +_,13 @@
     }
 
     public void startUsingItem(InteractionHand hand) {
+        // Paper start - Prevent consuming the wrong itemstack
+        this.startUsingItem(hand, false);
+    }
+    public void startUsingItem(InteractionHand hand, boolean forceUpdate) {
+        // Paper end - Prevent consuming the wrong itemstack
         ItemStack itemInHand = this.getItemInHand(hand);
-        if (!itemInHand.isEmpty() && !this.isUsingItem()) {
+        if (!itemInHand.isEmpty() && !this.isUsingItem() || forceUpdate) { // Paper - Prevent consuming the wrong itemstack
             this.useItem = itemInHand;
             this.useItemRemaining = itemInHand.getUseDuration(this);
             if (!this.level().isClientSide) {
@@ -3220,12 +_,49 @@
                 this.releaseUsingItem();
             } else {
                 if (!this.useItem.isEmpty() && this.isUsingItem()) {
-                    ItemStack itemStack = this.useItem.finishUsingItem(this.level(), this);
+                    this.startUsingItem(this.getUsedItemHand(), true); // Paper - Prevent consuming the wrong itemstack
+                    // CraftBukkit start - fire PlayerItemConsumeEvent
+                    ItemStack itemStack;
+                    PlayerItemConsumeEvent event = null; // Paper
+                    if (this instanceof ServerPlayer serverPlayer) {
+                        org.bukkit.inventory.ItemStack craftItem = CraftItemStack.asBukkitCopy(this.useItem);
+                        org.bukkit.inventory.EquipmentSlot hand = org.bukkit.craftbukkit.CraftEquipmentSlot.getHand(usedItemHand);
+                        event = new PlayerItemConsumeEvent((org.bukkit.entity.Player) this.getBukkitEntity(), craftItem, hand); // Paper
+                        this.level().getCraftServer().getPluginManager().callEvent(event);
+
+                        if (event.isCancelled()) {
+                            // Update client
+                            Consumable consumable = this.useItem.get(DataComponents.CONSUMABLE);
+                            if (consumable != null) {
+                                consumable.cancelUsingItem(serverPlayer, this.useItem);
+                            }
+                            serverPlayer.getBukkitEntity().updateInventory();
+                            serverPlayer.getBukkitEntity().updateScaledHealth();
+                            this.stopUsingItem(); // Paper - event is using an item, clear active item to reset its use
+                            return;
+                        }
+
+                        itemStack = (craftItem.equals(event.getItem())) ? this.useItem.finishUsingItem(this.level(), this) : CraftItemStack.asNMSCopy(event.getItem()).finishUsingItem(this.level(), this);
+                    } else {
+                        itemStack = this.useItem.finishUsingItem(this.level(), this);
+                    }
+                    // Paper start - save the default replacement item and change it if necessary
+                    final ItemStack defaultReplacement = itemStack;
+                    if (event != null && event.getReplacement() != null) {
+                        itemStack = CraftItemStack.asNMSCopy(event.getReplacement());
+                    }
+                    // Paper end
+                    // CraftBukkit end
                     if (itemStack != this.useItem) {
                         this.setItemInHand(usedItemHand, itemStack);
                     }
 
                     this.stopUsingItem();
+                    // Paper start
+                    if (this instanceof ServerPlayer) {
+                        ((ServerPlayer) this).getBukkitEntity().updateInventory();
+                    }
+                    // Paper end
                 }
             }
         }
@@ -3248,6 +_,7 @@
 
     public void releaseUsingItem() {
         if (!this.useItem.isEmpty()) {
+            if (this instanceof ServerPlayer) new io.papermc.paper.event.player.PlayerStopUsingItemEvent((org.bukkit.entity.Player) getBukkitEntity(), useItem.asBukkitMirror(), getTicksUsingItem()).callEvent(); // Paper - Add PlayerStopUsingItemEvent
             this.useItem.releaseUsing(this.level(), this, this.getUseItemRemainingTicks());
             if (this.useItem.useOnRelease()) {
                 this.updatingUsingItem();
@@ -3281,12 +_,69 @@
             if (item.getUseAnimation(this.useItem) != ItemUseAnimation.BLOCK) {
                 return null;
             } else {
-                return item.getUseDuration(this.useItem, this) - this.useItemRemaining < 5 ? null : this.useItem;
+                return item.getUseDuration(this.useItem, this) - this.useItemRemaining < this.getShieldBlockingDelay() ? null : this.useItem; // Paper - Make shield blocking delay configurable
             }
         } else {
             return null;
         }
     }
+
+    // Paper start - Make shield blocking delay configurable
+    public HitResult getRayTrace(int maxDistance, ClipContext.Fluid fluidCollisionOption) {
+        if (maxDistance < 1 || maxDistance > 120) {
+            throw new IllegalArgumentException("maxDistance must be between 1-120");
+        }
+
+        Vec3 start = new Vec3(getX(), getY() + getEyeHeight(), getZ());
+        org.bukkit.util.Vector dir = getBukkitEntity().getLocation().getDirection().multiply(maxDistance);
+        Vec3 end = new Vec3(start.x + dir.getX(), start.y + dir.getY(), start.z + dir.getZ());
+        ClipContext raytrace = new ClipContext(start, end, ClipContext.Block.OUTLINE, fluidCollisionOption, this);
+
+        return this.level().clip(raytrace);
+    }
+
+    public @Nullable net.minecraft.world.phys.EntityHitResult getTargetEntity(int maxDistance) {
+        if (maxDistance < 1 || maxDistance > 120) {
+            throw new IllegalArgumentException("maxDistance must be between 1-120");
+        }
+
+        Vec3 start = this.getEyePosition(1.0F);
+        Vec3 direction = this.getLookAngle();
+        Vec3 end = start.add(direction.x * maxDistance, direction.y * maxDistance, direction.z * maxDistance);
+
+        List<Entity> entityList = this.level().getEntities(this, getBoundingBox().expandTowards(direction.x * maxDistance, direction.y * maxDistance, direction.z * maxDistance).inflate(1.0D, 1.0D, 1.0D), EntitySelector.NO_SPECTATORS.and(Entity::isPickable));
+
+        double distance = 0.0D;
+        net.minecraft.world.phys.EntityHitResult result = null;
+
+        for (Entity entity : entityList) {
+            final double inflationAmount = (double) entity.getPickRadius();
+            AABB aabb = entity.getBoundingBox().inflate(inflationAmount, inflationAmount, inflationAmount);
+            Optional<Vec3> rayTraceResult = aabb.clip(start, end);
+
+            if (rayTraceResult.isPresent()) {
+                Vec3 rayTrace = rayTraceResult.get();
+                double distanceTo = start.distanceToSqr(rayTrace);
+                if (distanceTo < distance || distance == 0.0D) {
+                    result = new net.minecraft.world.phys.EntityHitResult(entity, rayTrace);
+                    distance = distanceTo;
+                }
+            }
+        }
+
+        return result;
+    }
+
+    public int shieldBlockingDelay = this.level().paperConfig().misc.shieldBlockingDelay;
+
+    public int getShieldBlockingDelay() {
+        return shieldBlockingDelay;
+    }
+
+    public void setShieldBlockingDelay(int shieldBlockingDelay) {
+        this.shieldBlockingDelay = shieldBlockingDelay;
+    }
+    // Paper end - Make shield blocking delay configurable
 
     public boolean isSuppressingSlidingDownLadder() {
         return this.isShiftKeyDown();
@@ -3306,6 +_,12 @@
     }
 
     public boolean randomTeleport(double x, double y, double z, boolean broadcastTeleport) {
+        // CraftBukkit start
+        return this.randomTeleport(x, y, z, broadcastTeleport, org.bukkit.event.player.PlayerTeleportEvent.TeleportCause.UNKNOWN).orElse(false);
+    }
+
+    public Optional<Boolean> randomTeleport(double x, double y, double z, boolean broadcastTeleport, org.bukkit.event.player.PlayerTeleportEvent.TeleportCause cause) {
+        // CraftBukkit end
         double x1 = this.getX();
         double y1 = this.getY();
         double z1 = this.getZ();
@@ -3328,16 +_,39 @@
             }
 
             if (flag1) {
-                this.teleportTo(x, d, z);
+                // CraftBukkit start - Teleport event
+                // first set position, to check if the place to teleport is valid
+                this.setPos(x, d, z);
                 if (level.noCollision(this) && !level.containsAnyLiquid(this.getBoundingBox())) {
                     flag = true;
                 }
+                // now revert and call event if the teleport place is valid
+                this.setPos(x1, y1, z1);
+
+                if (flag) {
+                    if (!(this instanceof ServerPlayer)) {
+                        EntityTeleportEvent teleport = new EntityTeleportEvent(this.getBukkitEntity(), new Location(this.level().getWorld(), x1, y1, z1), new Location(this.level().getWorld(), x, d, z));
+                        this.level().getCraftServer().getPluginManager().callEvent(teleport);
+                        if (!teleport.isCancelled() && teleport.getTo() != null) { // Paper
+                            Location to = teleport.getTo();
+                            this.teleportTo(to.getX(), to.getY(), to.getZ());
+                        } else {
+                            return Optional.empty();
+                        }
+                    } else {
+                        // player teleport event is called in the underlining code
+                        if (!((ServerPlayer) this).connection.teleport(x, d, z, this.getYRot(), this.getXRot(), cause)) {
+                            return Optional.empty();
+                        }
+                    }
+                }
+                // CraftBukkit end
             }
         }
 
         if (!flag) {
-            this.teleportTo(x1, y1, z1);
-            return false;
+            // this.teleportTo(x1, y1, z1); // CraftBukkit - already set the location back
+            return Optional.of(false); // CraftBukkit
         } else {
             if (broadcastTeleport) {
                 level.broadcastEntityEvent(this, (byte)46);
@@ -3347,7 +_,7 @@
                 pathfinderMob.getNavigation().stop();
             }
 
-            return true;
+            return Optional.of(true); // CraftBukkit
         }
     }