Implement monolith shop discounts

src/main/java/emu/nebula/game/tower/StarTowerModifiers.java

@@ -25,6 +25,10 @@ public class StarTowerModifiers {
     private int shopRerollCount;
     private int shopRerollPrice;
     
+    private boolean shopDiscountTier1;
+    private boolean shopDiscountTier2;
+    private boolean shopDiscountTier3;
+    
     public StarTowerModifiers(StarTowerGame game) {
         this.game = game;
         
@@ -69,6 +73,10 @@ public class StarTowerModifiers {
         if (this.shopRerollCount > 0) {
             this.shopRerollPrice = 100;
         }
+        
+        this.shopDiscountTier1 = this.hasGrowthNode(20202) && game.getDifficulty() >= 3;
+        this.shopDiscountTier2 = this.hasGrowthNode(20502) && game.getDifficulty() >= 4;
+        this.shopDiscountTier3 = this.hasGrowthNode(20802) && game.getDifficulty() >= 5;
     }
     
     public boolean hasGrowthNode(int nodeId) {

src/main/java/emu/nebula/game/tower/StarTowerShopGoods.java

@@ -9,6 +9,7 @@ public class StarTowerShopGoods {
     private int type;
     private int goodsId;
     private int price;
+    private int discount;
     private boolean sold;
     
     public StarTowerShopGoods(int type, int goodsId, int price) {
@@ -21,4 +22,19 @@ public class StarTowerShopGoods {
         this.sold = true;
     }
     
+    public boolean hasDiscount() {
+        return this.getDiscount() > 0;
+    }
+    
+    public void applyDiscount(double percentage) {
+        this.discount = (int) Math.ceil(this.price * (1.0 - percentage));
+    }
+    
+    public int getPrice() {
+        return this.price - this.discount;
+    }
+    
+    public int getDisplayPrice() {
+        return this.price;
+    }
 }

src/main/java/emu/nebula/game/tower/cases/StarTowerHawkerCase.java

@@ -2,6 +2,7 @@ package emu.nebula.game.tower.cases;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import emu.nebula.GameConstants;
 import emu.nebula.game.tower.StarTowerShopGoods;
@@ -10,6 +11,8 @@ import emu.nebula.proto.PublicStarTower.HawkerGoods;
 import emu.nebula.proto.PublicStarTower.StarTowerRoomCase;
 import emu.nebula.proto.StarTowerInteract.StarTowerInteractReq;
 import emu.nebula.proto.StarTowerInteract.StarTowerInteractResp;
+import emu.nebula.util.Utils;
+
 import lombok.Getter;
 
 @Getter
@@ -39,7 +42,42 @@ public class StarTowerHawkerCase extends StarTowerBaseCase {
             this.addGoods(new StarTowerShopGoods(1, 1, 200));
         }
         
-        // TODO apply discounts based on star tower talents
+        // Apply discounts based on star tower talents
+        if (getModifiers().isShopDiscountTier1()) {
+            this.applyDiscount(1.0, 2, 0.8);
+        }
+        if (getModifiers().isShopDiscountTier2()) {
+            this.applyDiscount(0.3, 1, 0.5);
+        }
+        if (getModifiers().isShopDiscountTier3()) {
+            this.applyDiscount(1.0, 1, 0.5);
+        }
+    }
+    
+    private void applyDiscount(double chance, int times, double percentage) {
+        // Check chance
+        double random = Utils.generateRandomDouble();
+        
+        if (random > chance) {
+            return;
+        }
+        
+        // Create goods list
+        var list = this.getGoods().values().stream()
+                .filter(g -> !g.hasDiscount())
+                .collect(Collectors.toList());
+        
+        // Apply discounts
+        for (int i = 0; i < times; i++) {
+            // Sanity check
+            if (list.isEmpty()) {
+                break;
+            }
+            
+            // Get goods and apply discount
+            var goods = Utils.randomElement(list, true);
+            goods.applyDiscount(percentage);
+        }
     }
     
     public void addGoods(StarTowerShopGoods goods) {
@@ -145,9 +183,13 @@ public class StarTowerHawkerCase extends StarTowerBaseCase {
                     .setSid(sid)
                     .setType(goods.getType())
                     .setGoodsId(102) // ?
-                    .setPrice(goods.getPrice())
+                    .setPrice(goods.getDisplayPrice())
                     .setTag(1);
             
+            if (goods.hasDiscount()) {
+                info.setDiscount(goods.getPrice());
+            }
+            
             hawker.addList(info);
         }
         

src/main/java/emu/nebula/util/Utils.java

@@ -179,12 +179,34 @@ public class Utils {
     }
 
     public static <T> T randomElement(List<T> list) {
-        return list.get(ThreadLocalRandom.current().nextInt(0, list.size()));
+        return randomElement(list, false);
+    }
+    
+    public static <T> T randomElement(List<T> list, boolean remove) {
+        int index = ThreadLocalRandom.current().nextInt(0, list.size());
+        var object = list.get(index);
+        
+        if (remove) {
+            list.remove(index);
+        }
+        
+        return object;
     }
     
     public static int randomElement(IntList list) {
         return list.getInt(ThreadLocalRandom.current().nextInt(0, list.size()));
     }
+    
+    public static int randomElement(IntList list, boolean remove) {
+        int index = ThreadLocalRandom.current().nextInt(0, list.size());
+        int object = list.getInt(index);
+        
+        if (remove) {
+            list.removeInt(index);
+        }
+        
+        return object;
+    }
 
     /**
      * Checks if an integer array contains a value