From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Max Lee <max@themoep.de>
Date: Thu, 27 May 2021 14:52:30 -0700
Subject: [PATCH] Fix invulnerable end crystals

MC-108513

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 7777ff1677a207adfb48f2f227b854cfcade0373..43ab68f1822e92973e57a40f63376b467df3bdc7 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -747,5 +747,10 @@ public class PaperWorldConfig {
     private void fixItemsMergingThroughWalls() {
         fixItemsMergingThroughWalls = getBoolean("fix-items-merging-through-walls", fixItemsMergingThroughWalls);
     }
+
+    public boolean fixInvulnerableEndCrystalExploit = true;
+    private void fixInvulnerableEndCrystalExploit() {
+        fixInvulnerableEndCrystalExploit = getBoolean("unsupported-settings.fix-invulnerable-end-crystal-exploit", fixInvulnerableEndCrystalExploit);
+    }
 }
 
diff --git a/src/main/java/net/minecraft/world/entity/boss/enderdragon/EndCrystal.java b/src/main/java/net/minecraft/world/entity/boss/enderdragon/EndCrystal.java
index 2c4c1fc2a2afe88864b72d86708a3ddb6a1f50a0..567a9755e7ef0d6bf1803a3ba8460fb7de2e66b1 100644
--- a/src/main/java/net/minecraft/world/entity/boss/enderdragon/EndCrystal.java
+++ b/src/main/java/net/minecraft/world/entity/boss/enderdragon/EndCrystal.java
@@ -31,6 +31,7 @@ public class EndCrystal extends Entity {
     private static final EntityDataAccessor<Optional<BlockPos>> DATA_BEAM_TARGET = SynchedEntityData.defineId(EndCrystal.class, EntityDataSerializers.OPTIONAL_BLOCK_POS);
     private static final EntityDataAccessor<Boolean> DATA_SHOW_BOTTOM = SynchedEntityData.defineId(EndCrystal.class, EntityDataSerializers.BOOLEAN);
     public int time;
+    public boolean generatedByDragonFight = false; // Paper - Fix invulnerable end crystals
 
     public EndCrystal(EntityType<? extends EndCrystal> type, Level world) {
         super(type, world);
@@ -67,6 +68,17 @@ public class EndCrystal extends Entity {
                 }
                 // CraftBukkit end
             }
+            // Paper start - Fix invulnerable end crystals
+            if (this.level.paperConfig.fixInvulnerableEndCrystalExploit && this.generatedByDragonFight && this.isInvulnerable()) {
+                if ((this.origin.getWorld() != null && !((ServerLevel) this.level).uuid.equals(this.origin.getWorld().getUID()))
+                    || ((ServerLevel) this.level).dragonFight() == null
+                    || ((ServerLevel) this.level).dragonFight().respawnStage == null
+                    || ((ServerLevel) this.level).dragonFight().respawnStage.ordinal() > net.minecraft.world.level.dimension.end.DragonRespawnAnimation.SUMMONING_DRAGON.ordinal()) {
+                    this.setInvulnerable(false);
+                    this.setBeamTarget(null);
+                }
+            }
+            // Paper end
         }
 
     }
@@ -78,6 +90,7 @@ public class EndCrystal extends Entity {
         }
 
         nbt.putBoolean("ShowBottom", this.showsBottom());
+        if (this.generatedByDragonFight) nbt.putBoolean("Paper.GeneratedByDragonFight", this.generatedByDragonFight); // Paper - Fix invulnerable end crystals
     }
 
     @Override
@@ -89,6 +102,7 @@ public class EndCrystal extends Entity {
         if (nbt.contains("ShowBottom", 1)) {
             this.setShowBottom(nbt.getBoolean("ShowBottom"));
         }
+        if (nbt.contains("Paper.GeneratedByDragonFight", 1)) this.generatedByDragonFight = nbt.getBoolean("Paper.GeneratedByDragonFight"); // Paper - Fix invulnerable end crystals
 
     }
 
diff --git a/src/main/java/net/minecraft/world/level/levelgen/feature/SpikeFeature.java b/src/main/java/net/minecraft/world/level/levelgen/feature/SpikeFeature.java
index 1e53d4bef86349eaa1356444a80ae92d4311ccce..c03bf5bdb67b00c75f9fcfead882c4d944282244 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/feature/SpikeFeature.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/feature/SpikeFeature.java
@@ -99,6 +99,7 @@ public class SpikeFeature extends Feature<SpikeConfiguration> {
         endCrystal.setBeamTarget(config.getCrystalBeamTarget());
         endCrystal.setInvulnerable(config.isCrystalInvulnerable());
         endCrystal.moveTo((double)spike.getCenterX() + 0.5D, (double)(spike.getHeight() + 1), (double)spike.getCenterZ() + 0.5D, random.nextFloat() * 360.0F, 0.0F);
+        endCrystal.generatedByDragonFight = true; // Paper
         world.addFreshEntity(endCrystal);
         this.setBlock(world, new BlockPos(spike.getCenterX(), spike.getHeight(), spike.getCenterZ()), Blocks.BEDROCK.defaultBlockState());
     }