From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <Blake.Galbreath@GMail.com>
Date: Thu, 3 Dec 2020 17:56:18 -0600
Subject: [PATCH] Lobotomize stuck villagers


diff --git a/src/main/java/net/minecraft/world/entity/npc/Villager.java b/src/main/java/net/minecraft/world/entity/npc/Villager.java
index 59bfaf90d448223c5aee9b18d2915539f54f0d4b..b5db8212aa6b20fbaa8ea7dbcd14c9cc13460fe0 100644
--- a/src/main/java/net/minecraft/world/entity/npc/Villager.java
+++ b/src/main/java/net/minecraft/world/entity/npc/Villager.java
@@ -140,6 +140,8 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
         return villageplacetype == PoiType.MEETING;
     });
     private final int brainTickOffset; // Purpur
+    private boolean isLobotomized = false; public boolean isLobotomized() { return this.isLobotomized; } // Purpur
+    private int notLobotomizedCount = 0; // Purpur
 
     public long nextGolemPanic = -1; // Pufferfish
 
@@ -198,6 +200,47 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
     protected boolean isAlwaysExperienceDropper() {
         return this.level.purpurConfig.villagerAlwaysDropExp;
     }
+
+    private boolean checkLobotomized() {
+        int interval = this.level.purpurConfig.villagerLobotomizeCheckInterval;
+        if (this.notLobotomizedCount > 3) {
+            // check half as often if not lobotomized for the last 3+ consecutive checks
+            interval *= 2;
+        }
+        if ((this.level.getGameTime() + brainTickOffset) % interval == 0) {
+            // offset Y for short blocks like dirt_path/farmland
+            this.isLobotomized = !canTravelFrom(new BlockPos(getX(), getY() + 0.0625D, getZ()));
+
+            if (this.isLobotomized) {
+                this.notLobotomizedCount = 0;
+            } else {
+                this.notLobotomizedCount++;
+            }
+        }
+        return this.isLobotomized;
+    }
+
+    private boolean canTravelFrom(BlockPos pos) {
+        return canTravelTo(pos.east()) || canTravelTo(pos.west()) || canTravelTo(pos.north()) || canTravelTo(pos.south());
+    }
+
+    private boolean canTravelTo(BlockPos pos) {
+        BlockState state = this.level.getBlockStateIfLoaded(pos);
+        if (state == null) {
+            // chunk not loaded
+            return false;
+        }
+        net.minecraft.world.level.block.Block bottom = state.getBlock();
+        if (bottom instanceof net.minecraft.world.level.block.FenceBlock ||
+                bottom instanceof net.minecraft.world.level.block.FenceGateBlock ||
+                bottom instanceof net.minecraft.world.level.block.WallBlock) {
+            // bottom block is too tall to get over
+            return false;
+        }
+        net.minecraft.world.level.block.Block top = level.getBlockState(pos.above()).getBlock();
+        // only if both blocks have no collision
+        return !bottom.hasCollision && !top.hasCollision;
+    }
     // Purpur end
 
     @Override
@@ -295,6 +338,15 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
     protected void customServerAiStep() { mobTick(false); }
     protected void mobTick(boolean inactive) {
         this.level.getProfiler().push("villagerBrain");
+        // Purpur start
+        if (this.level.purpurConfig.villagerLobotomizeEnabled) {
+            // treat as inactive if lobotomized
+            inactive = inactive || checkLobotomized();
+        } else {
+            // clean up state for API
+            this.isLobotomized = false;
+        }
+        // Purpur end
         // Pufferfish start
         if (!inactive) {
             // Purpur start
@@ -305,6 +357,12 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
             this.getBrain().tick((ServerLevel) this.level, this); // Paper
          }
         // Pufferfish end
+        // Purpur start
+        else if (this.isLobotomized && shouldRestock()) {
+            // make sure we restock if needed when lobotomized
+            restock();
+        }
+        // Purpur end
         this.level.getProfiler().pop();
         if (this.assignProfessionWhenSpawned) {
             this.assignProfessionWhenSpawned = false;
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java
index dbc1ea96223675fbe03585598a9c7f51acc61d2e..dde09a8495270d9038f55974e252576095259ca9 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java
@@ -187,4 +187,11 @@ public class CraftVillager extends CraftAbstractVillager implements Villager {
         getHandle().getGossips().getReputations().clear();
     }
     // Paper end
+
+    // Purpur start
+    @Override
+    public boolean isLobotomized() {
+        return getHandle().isLobotomized();
+    }
+    // Purpur end
 }
diff --git a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
index e4e75914042b6e1024662ef59b2190865a879759..973cec1676fe533a8e4aa268aa15dda135d43367 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -2666,6 +2666,8 @@ public class PurpurWorldConfig {
     public boolean villagerAllowTrading = true;
     public boolean villagerAlwaysDropExp = false;
     public int villagerMinimumDemand = 0;
+    public boolean villagerLobotomizeEnabled = false;
+    public int villagerLobotomizeCheckInterval = 100;
     private void villagerSettings() {
         villagerRidable = getBoolean("mobs.villager.ridable", villagerRidable);
         villagerRidableInWater = getBoolean("mobs.villager.ridable-in-water", villagerRidableInWater);
@@ -2691,6 +2693,17 @@ public class PurpurWorldConfig {
         villagerAllowTrading = getBoolean("mobs.villager.allow-trading", villagerAllowTrading);
         villagerAlwaysDropExp = getBoolean("mobs.villager.always-drop-exp", villagerAlwaysDropExp);
         villagerMinimumDemand = getInt("mobs.villager.minimum-demand", villagerMinimumDemand);
+        if (PurpurConfig.version < 9) {
+            boolean oldValue = getBoolean("mobs.villager.lobotomize-1x1", villagerLobotomizeEnabled);
+            set("mobs.villager.lobotomize.enabled", oldValue);
+            set("mobs.villager.lobotomize-1x1", null);
+        }
+        if (PurpurConfig.version < 27) {
+            int oldValue = getInt("mobs.villager.lobotomize.check-interval", villagerLobotomizeCheckInterval);
+            set("mobs.villager.lobotomize.check-interval", oldValue == 60 ? 100 : oldValue);
+        }
+        villagerLobotomizeEnabled = getBoolean("mobs.villager.lobotomize.enabled", villagerLobotomizeEnabled);
+        villagerLobotomizeCheckInterval = getInt("mobs.villager.lobotomize.check-interval", villagerLobotomizeCheckInterval);
     }
 
     public boolean vindicatorRidable = false;