Added math stuff to calculate price based on points (thanks everett)

src/main/java/com/alttd/GUI/windows/BuyGUI.java

@@ -3,6 +3,7 @@ package com.alttd.GUI.windows;
 import com.alttd.GUI.GUIMerchant;
 import com.alttd.VillagerUI;
 import com.alttd.config.Config;
+import com.alttd.config.WorthConfig;
 import com.alttd.events.SpawnShopEvent;
 import com.alttd.objects.EconUser;
 import com.alttd.objects.Price;
@@ -39,7 +40,10 @@ public class BuyGUI extends GUIMerchant {
     private void buy(VillagerType villagerType, Player player, Material material, int amount, Price price) {
         Economy econ = VillagerUI.getInstance().getEconomy();
         double balance = econ.getBalance(player);
-        double cost = price.getPrice(amount);
+        int trans_pts = (int) (Math.floor(price.getPrice(amount)/ WorthConfig.POINT_MOD) * amount);
+        EconUser econUser = EconUser.users.get(player.getUniqueId());
+        int oldPoints = econUser.getPointsMap().get(villagerType.getName());
+        double cost = price.calculatePriceThing(oldPoints, trans_pts);
 
         if (balance < cost) {
             player.sendMessage(MiniMessage.get().parse(Config.NOT_ENOUGH_MONEY,
@@ -47,11 +51,9 @@ public class BuyGUI extends GUIMerchant {
                     Template.of("price", String.valueOf(price))));
             return;
         }
-        EconUser econUser = EconUser.users.get(player.getUniqueId());
-        int oldPoints = econUser.getPointsMap().get(villagerType.getName());
 
         econ.withdrawPlayer(player, cost);
-        econUser.addPoints(villagerType.getName(), price.getPoints());
+        econUser.addPoints(villagerType.getName(), trans_pts);
         player.sendMessage(MiniMessage.get().parse(Config.PURCHASED_ITEM,
                 Template.of("amount", String.valueOf(amount)),
                 Template.of("item", material.toString()),

src/main/java/com/alttd/GUI/windows/SellGUI.java

@@ -3,6 +3,7 @@ package com.alttd.GUI.windows;
 import com.alttd.GUI.GUIMerchant;
 import com.alttd.VillagerUI;
 import com.alttd.config.Config;
+import com.alttd.config.WorthConfig;
 import com.alttd.events.SpawnShopEvent;
 import com.alttd.objects.EconUser;
 import com.alttd.objects.Price;
@@ -39,9 +40,10 @@ public class SellGUI extends GUIMerchant {
 
     private void sell(VillagerType villagerType, Player player, Material material, int amount, Price price) {
         Economy econ = VillagerUI.getInstance().getEconomy();
-        double cost = price.getPrice(amount);
         EconUser econUser = EconUser.users.get(player.getUniqueId());
         int oldPoints = econUser.getPointsMap().get(villagerType.getName());
+        int trans_pts = (int) (Math.floor(price.getPrice(amount)/ WorthConfig.POINT_MOD) * amount);
+        double cost = price.calculatePriceThing(oldPoints, trans_pts);
 
         econ.depositPlayer(player, cost);
         econUser.addPoints(villagerType.getName(), -price.getPoints());

src/main/java/com/alttd/config/VillagerConfig.java

@@ -1,12 +1,8 @@
 package com.alttd.config;
 
-import com.alttd.VillagerUI;
 import com.alttd.objects.LoadedVillagers;
 import com.alttd.objects.VillagerType;
 import com.alttd.util.Logger;
-import org.bukkit.configuration.ConfigurationSection;
-
-import java.util.Set;
 import java.util.UUID;
 
 public class VillagerConfig extends AbstractConfig {

src/main/java/com/alttd/config/WorthConfig.java

@@ -46,4 +46,9 @@ public class WorthConfig extends AbstractConfig {
             prices.put(Material.getMaterial(key), new Price(Utilities.round(worth.getDouble(key), 2)));
         }
     }
+
+    public static int POINT_MOD = 4;
+    private static void loadOtherStuff() {
+        POINT_MOD = config.getInt("point-mod", POINT_MOD);
+    }
 }

src/main/java/com/alttd/events/VillagerInteract.java

@@ -5,6 +5,7 @@ import com.alttd.VillagerUI;
 import com.alttd.config.Config;
 import com.alttd.objects.LoadedVillagers;
 import com.alttd.objects.VillagerType;
+import net.kyori.adventure.text.minimessage.MiniMessage;
 import org.bukkit.entity.Villager;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
@@ -23,7 +24,7 @@ public class VillagerInteract implements Listener {
             return;
 
         if (!event.getPlayer().hasPermission(loadedVillager.getPermission())) {
-            event.getPlayer().sendMessage(Config.NO_PERMISSION); //TODO more specific message?
+            event.getPlayer().sendMessage(MiniMessage.get().parse(Config.NO_PERMISSION)); //TODO more specific message?
             return;
         }
         new BukkitRunnable() {

src/main/java/com/alttd/objects/Price.java

@@ -3,11 +3,17 @@ package com.alttd.objects;
 import com.alttd.config.Config;
 import com.alttd.util.Logger;
 import com.alttd.util.Utilities;
+import org.apache.commons.math3.analysis.function.StepFunction;
+import org.apache.commons.math3.analysis.integration.TrapezoidIntegrator;
 
 public final class Price {
     private final double price;
     private final int points;
 
+    double x_mult[] = {0, 500, 2000, 4000};
+    double y_mult[] = {1.0, 1.5, 2.5, 5.0};
+    StepFunction multiplierModel = new StepFunction(x_mult, y_mult);
+
     public Price(double price) {
         this.price = price;
         for (int key : Config.pointsRangeMap.keySet()) {
@@ -28,6 +34,12 @@ public final class Price {
         return (Utilities.round(price * multiplier, 2));
     }
 
+    public double calculatePriceThing(int oldPoints, int transPts) {
+        // Compute numerical integration to determine price
+        TrapezoidIntegrator trapez = new TrapezoidIntegrator();
+        return (price * trapez.integrate(10, multiplierModel, oldPoints, oldPoints + transPts));
+    }
+
     public int getPoints() {
         return (points);
     }