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 903016cc402bc688f4fd92f339b242db6dfe3841..0d817148dedd9919e6e1dd0c38c96a57ad919ced 100644
--- a/src/main/java/net/minecraft/world/entity/npc/Villager.java
+++ b/src/main/java/net/minecraft/world/entity/npc/Villager.java
@@ -545,7 +545,7 @@ 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 28bdcb14cb5b458d3c990fcf343ef97f08e4f3c6..48167334162443365bb8a6d082a51b2c626ab3d8 100644
--- a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
+++ b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
@@ -134,7 +134,12 @@ public class MerchantOffer {
     }
 
     public void updateDemand() {
-        this.demand = Math.max(0, this.demand + this.uses - (this.maxUses - this.uses)); // Paper
+        // Purpur start
+        this.updateDemand(0);
+    }
+    public void updateDemand(int minimumDemand) {
+        this.demand = Math.max(minimumDemand, this.demand + this.uses - (this.maxUses - this.uses));
+        // 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 907bf91a92bb3636401296a9e58926221ff8efb0..33235b21d90e488020665b4ff3e3d6a7288cdc5d 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -2737,6 +2737,7 @@ 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);
@@ -2757,6 +2758,7 @@ 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;