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 b0674eeea341a725ed774c5de040fe173a6fb833..c985f302812be364c07866727c9d2c2714bec249 100644
--- a/src/main/java/net/minecraft/world/entity/npc/Villager.java
+++ b/src/main/java/net/minecraft/world/entity/npc/Villager.java
@@ -534,7 +534,7 @@ 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 8a9a701baabdaf066cd9b28c05430f673fcafb4e..17cc3237c7fc8ceda136b2371fabf6f004a991aa 100644
--- a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
+++ b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
@@ -132,7 +132,12 @@ 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 75f83aa35fb5ac24f6c51e2315b322d96c69050e..eb021d6673ea37fd59ad3644995eb9ecc394b506 100644
--- a/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
+++ b/src/main/java/org/purpurmc/purpur/PurpurWorldConfig.java
@@ -2680,6 +2680,7 @@ 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);
@@ -2702,6 +2703,7 @@ 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;