From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <blake.galbreath@gmail.com>
Date: Sat, 11 Jul 2020 19:41:34 -0500
Subject: [PATCH] Entity lifespan


diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index a2381960e213ade5ade22ad180666e4b74185beb..7c55d86901eb591554703e6c83bdfb67dfded0b1 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -2751,6 +2751,7 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
             AABB axisalignedbb = entity.getBoundingBox();
 
             if (this.player.canInteractWithEntity(axisalignedbb, 1.0D)) {
+                if (entity instanceof Mob mob) mob.ticksSinceLastInteraction = 0; // Purpur
                 packet.dispatch(new ServerboundInteractPacket.Handler() {
                     private void performInteraction(InteractionHand enumhand, ServerGamePacketListenerImpl.EntityInteraction playerconnection_a, PlayerInteractEntityEvent event) { // CraftBukkit
                         ItemStack itemstack = ServerGamePacketListenerImpl.this.player.getItemInHand(enumhand);
diff --git a/src/main/java/net/minecraft/world/entity/Mob.java b/src/main/java/net/minecraft/world/entity/Mob.java
index 28ff18c341703148e880e4d4a64b73daa136c32a..1ebc4a8a54081ac9b3ba01e651d611f0237a8970 100644
--- a/src/main/java/net/minecraft/world/entity/Mob.java
+++ b/src/main/java/net/minecraft/world/entity/Mob.java
@@ -146,6 +146,7 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
     private BlockPos restrictCenter;
     private float restrictRadius;
 
+    public int ticksSinceLastInteraction; // Purpur
     public boolean aware = true; // CraftBukkit
 
     protected Mob(EntityType<? extends Mob> type, Level world) {
@@ -333,6 +334,7 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
                 entityliving = null;
             }
         }
+        if (entityliving instanceof ServerPlayer) this.ticksSinceLastInteraction = 0; // Purpur
         this.target = entityliving;
         return true;
         // CraftBukkit end
@@ -375,8 +377,28 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
         }
 
         this.level().getProfiler().pop();
+        incrementTicksSinceLastInteraction(); // Purpur
     }
 
+    // Purpur start
+    private void incrementTicksSinceLastInteraction() {
+        ++this.ticksSinceLastInteraction;
+        if (getRider() != null) {
+            this.ticksSinceLastInteraction = 0;
+            return;
+        }
+        if (this.level().purpurConfig.entityLifeSpan <= 0) {
+            return; // feature disabled
+        }
+        if (!this.removeWhenFarAway(0) || isPersistenceRequired() || requiresCustomPersistence() || hasCustomName()) {
+            return; // mob persistent
+        }
+        if (this.ticksSinceLastInteraction > this.level().purpurConfig.entityLifeSpan) {
+            this.discard(org.bukkit.event.entity.EntityRemoveEvent.Cause.DISCARD);
+        }
+    }
+    // Purpur end
+
     @Override
     protected void playHurtSound(DamageSource damageSource) {
         this.resetAmbientSoundTime();
@@ -551,6 +573,7 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
         }
 
         nbt.putBoolean("Bukkit.Aware", this.aware); // CraftBukkit
+        nbt.putInt("Purpur.ticksSinceLastInteraction", this.ticksSinceLastInteraction); // Purpur
     }
 
     @Override
@@ -628,6 +651,11 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
             this.aware = nbt.getBoolean("Bukkit.Aware");
         }
         // CraftBukkit end
+        // Purpur start
+        if (nbt.contains("Purpur.ticksSinceLastInteraction")) {
+            this.ticksSinceLastInteraction = nbt.getInt("Purpur.ticksSinceLastInteraction");
+        }
+        // Purpur end
     }
 
     @Override
@@ -1751,6 +1779,7 @@ public abstract class Mob extends LivingEntity implements EquipmentUser, Leashab
             this.playAttackSound();
         }
 
+        if (target instanceof ServerPlayer) this.ticksSinceLastInteraction = 0; // Purpur
         return flag;
     }
 
diff --git a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
index a922ae826a3c542094eacd551a9aa04cd81fd02b..f601c4b0c40706a241ca2906f07dfcd869afe9cd 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -125,6 +125,11 @@ public class PurpurWorldConfig {
         elytraDamagePerTridentBoost = getInt("gameplay-mechanics.elytra.damage-per-boost.trident", elytraDamagePerTridentBoost);
     }
 
+    public int entityLifeSpan = 0;
+    private void entitySettings() {
+        entityLifeSpan = getInt("gameplay-mechanics.entity-lifespan", entityLifeSpan);
+    }
+
     public List<Item> itemImmuneToCactus = new ArrayList<>();
     public List<Item> itemImmuneToExplosion = new ArrayList<>();
     public List<Item> itemImmuneToFire = new ArrayList<>();