From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Totorewa <76272501+totorewa@users.noreply.github.com>
Date: Fri, 7 Jan 2022 21:34:57 +1300
Subject: [PATCH] Configurable minimum demand for trades

Addresses MC-163962 where villager demand decreases indefinitely. Paper
adds a patch to fix this by preventing demand from going below zero.
This patch adds a config option to allow the minimum demand to instead
be configurable.

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 19a3e88ce5ccdd74b049246eb51eaa0783d03d5d..79184e4721236d4d30f9c516ac0efb56cf06af7d 100644
--- a/src/main/java/net/minecraft/world/entity/npc/Villager.java
+++ b/src/main/java/net/minecraft/world/entity/npc/Villager.java
@@ -547,7 +547,7 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
         while (iterator.hasNext()) {
             MerchantOffer merchantrecipe = (MerchantOffer) iterator.next();
 
-            merchantrecipe.updateDemand();
+            merchantrecipe.updateDemand(this.level().purpurConfig.villagerMinimumDemand); // Purpur
         }
 
     }
diff --git a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
index 02feea12c998f37098b72becf6bfaf6b27d155de..9c89a85d934955c9388cfe1361f13e70e699d279 100644
--- a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
+++ b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
@@ -149,7 +149,12 @@ public class MerchantOffer {
     }
 
     public void updateDemand() {
-        this.demand = Math.max(0, this.demand + this.uses - (this.maxUses - this.uses)); // Paper - Fix MC-163962
+        // Purpur start
+        this.updateDemand(0);
+    }
+    public void updateDemand(int minimumDemand) {
+        this.demand = Math.max(minimumDemand, this.demand + this.uses - (this.maxUses - this.uses)); // Paper - Fix MC-163962
+        // Purpur end
     }
 
     public ItemStack assemble() {
diff --git a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
index bc3b4d6efe2182b634c021ad5772a8a81d4cc2d9..c5eaf27e8983949ede5555da7905fa7bc1bf5700 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -2784,6 +2784,7 @@ public class PurpurWorldConfig {
     public boolean villagerTakeDamageFromWater = false;
     public boolean villagerAllowTrading = true;
     public boolean villagerAlwaysDropExp = false;
+    public int villagerMinimumDemand = 0;
     private void villagerSettings() {
         villagerRidable = getBoolean("mobs.villager.ridable", villagerRidable);
         villagerRidableInWater = getBoolean("mobs.villager.ridable-in-water", villagerRidableInWater);
@@ -2804,6 +2805,7 @@ public class PurpurWorldConfig {
         villagerTakeDamageFromWater = getBoolean("mobs.villager.takes-damage-from-water", villagerTakeDamageFromWater);
         villagerAllowTrading = getBoolean("mobs.villager.allow-trading", villagerAllowTrading);
         villagerAlwaysDropExp = getBoolean("mobs.villager.always-drop-exp", villagerAlwaysDropExp);
+        villagerMinimumDemand = getInt("mobs.villager.minimum-demand", villagerMinimumDemand);
     }
 
     public boolean vindicatorRidable = false;