Question might work?

src/main/java/com/wurmonline/server/questions/ShopQuestion.java

@@ -2,28 +2,115 @@ package com.wurmonline.server.questions;
 
 import com.wurmonline.server.NoSuchPlayerException;
 import com.wurmonline.server.Players;
+import com.wurmonline.server.players.Player;
 import mod.treestar.shopmod.ShopService;
+import mod.treestar.shopmod.datamodels.ShopCategory;
+import mod.treestar.shopmod.datamodels.ShopItem;
 
+import java.util.List;
 import java.util.Properties;
+import java.util.stream.Collectors;
 
 public class ShopQuestion extends Question {
     private static final int SHOP_QUESTION_ID = 90001;
 
     private ShopService shopService;
+    private int selectedCategoryId = -1;
 
     public ShopQuestion(long responderId, String shopName, ShopService shopService) throws NoSuchPlayerException {
         super(Players.getInstance().getPlayer(responderId), shopName, null, SHOP_QUESTION_ID, responderId);
         this.shopService = shopService;
+        List<ShopCategory> categories = shopService.getCategories();
+        if (!categories.isEmpty()) {
+            selectedCategoryId = categories.get(0).getId();
+        }
     }
 
     @Override
     public void answer(Properties properties) {
         super.answer(properties);
+        List<ShopCategory> categories = shopService.getCategories();
+
+        // Update category selection if present
+        String categoryIndex = properties.getProperty("category");
+        if (categoryIndex != null && !categories.isEmpty()) {
+            try {
+                int idx = Integer.parseInt(categoryIndex);
+                if (idx >= 0 && idx < categories.size()) {
+                    selectedCategoryId = categories.get(idx).getId();
+                }
+            } catch (NumberFormatException ignored) { }
+        }
+
+        // If purchase not requested, refresh UI with selected category
+        if (!properties.containsKey("submit")) {
+            sendQuestion();
+            return;
+        }
+
+        String itemIdStr = properties.getProperty("itemid");
+        if (itemIdStr == null) {
+            getResponder().getCommunicator().sendNormalServerMessage("No item selected.");
+            return;
+        }
+        int itemId;
+        try {
+            itemId = Integer.parseInt(itemIdStr);
+        } catch (NumberFormatException e) {
+            getResponder().getCommunicator().sendNormalServerMessage("Invalid item selected.");
+            return;
+        }
+        ShopService.PurchaseResult result = shopService.purchaseItem((Player)getResponder(), itemId);
+        if (result.isSuccess()) {
+            getResponder().getCommunicator().sendSafeServerMessage(result.getMessage());
+        } else {
+            getResponder().getCommunicator().sendNormalServerMessage(result.getMessage());
+        }
     }
 
     @Override
     public void sendQuestion() {
-        super.sendQuestion();
+        List<ShopCategory> categories = shopService.getCategories();
+        if (categories.isEmpty()) {
+            getResponder().getCommunicator().sendNormalServerMessage("No shop categories are available.");
+            return;
+        }
+        if (selectedCategoryId == -1 || categories.stream().noneMatch(c -> c.getId() == selectedCategoryId)) {
+            selectedCategoryId = categories.get(0).getId();
+        }
+        int defaultCategoryIndex = 0;
+        for (int i = 0; i < categories.size(); i++) {
+            if (categories.get(i).getId() == selectedCategoryId) {
+                defaultCategoryIndex = i;
+                break;
+            }
+        }
+
+        List<ShopItem> items = shopService.getItems().stream()
+                .filter(i -> i.getCategoryId() == selectedCategoryId)
+                .collect(Collectors.toList());
+        if (items.isEmpty()) {
+            getResponder().getCommunicator().sendNormalServerMessage("No shop items are available.");
+            return;
+        }
+        StringBuilder bml = new StringBuilder();
+        bml.append("border{center{heading{text=\"").append(escape(title)).append("\"}}");
+        if (categories.size() > 1) {
+            bml.append("harray{label{text=\"Category\"};dropdown{id=\"category\";options=\"")
+                    .append(categories.stream().map(c -> escape(c.getName())).collect(Collectors.joining(",")))
+                    .append("\";default=\"").append(defaultCategoryIndex).append("\"}}");
+        }
+        bml.append("center{scroll{table{rows=\"");
+        for (ShopItem item : items) {
+            bml.append("label{text=\"").append(escape(item.getName())).append("\"};");
+            bml.append("label{text=\"").append(escape(item.getDescription())).append("\"};");
+            bml.append("label{text=\"").append(escape(item.getPriceDisplay())).append("\"};");
+            bml.append("radio{group=\"itemid\";id=\"").append(item.getId()).append("\"};");
+        }
+        bml.append("\"}}}");
+        bml.append("harray{button{id=\"submit\";text=\"Purchase\"};button{id=\"cancel\";text=\"Cancel\"}}");
+        bml.append("}");
+        getResponder().getCommunicator().sendBml(400, 400, true, true, bml.toString(), 200, 200, 200, title);
     }
 
     public ShopService getShopService() {
@@ -33,4 +120,8 @@ public class ShopQuestion extends Question {
     public void setShopService(ShopService shopService) {
         this.shopService = shopService;
     }
+
+    private String escape(String value) {
+        return value == null ? "" : value.replace("\"", "''");
+    }
 }

src/main/java/mod/treestar/shopmod/ShopService.java

@@ -1,12 +1,21 @@
 package mod.treestar.shopmod;
 
+import com.wurmonline.server.players.Player;
 import mod.treestar.shopmod.categoryprovider.ShopCategoryProvider;
 import mod.treestar.shopmod.itemprovider.ShopItemProvider;
+import mod.treestar.shopmod.datamodels.ShopCategory;
+import mod.treestar.shopmod.datamodels.ShopItem;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 public class ShopService {
+    private static final Logger logger = Logger.getLogger(ShopService.class.getName());
+
     private List<ShopCategoryProvider> categoryProviders = new ArrayList<>();
     private List<ShopItemProvider> itemProviders = new ArrayList<>();
 
@@ -20,6 +29,59 @@ public class ShopService {
         itemProviders.add(provider);
     }
 
+    public List<ShopCategory> getCategories() {
+        List<ShopCategory> categories = new ArrayList<>();
+        for (ShopCategoryProvider provider : categoryProviders) {
+            List<ShopCategory> provided = provider.getCategories();
+            if (provided != null) {
+                categories.addAll(provided);
+            }
+        }
+        return categories;
+    }
+
+    public List<ShopItem> getItems() {
+        List<ShopItem> items = new ArrayList<>();
+        for (ShopItemProvider provider : itemProviders) {
+            List<ShopItem> provided = provider.getItems();
+            if (provided != null) {
+                items.addAll(provided);
+            }
+        }
+        return items;
+    }
+
+    public ShopItem getItemById(int id) {
+        return getItems().stream().filter(i -> i.getId() == id).findFirst().orElse(null);
+    }
+
+    public PurchaseResult purchaseItem(Player player, int itemId) {
+        ShopItem item = getItemById(itemId);
+        if (item == null) {
+            return PurchaseResult.failure("Item not found.");
+        }
+        if (item.getCurrency() == null) {
+            return PurchaseResult.failure("Item has no currency configured.");
+        }
+        if (item.getPurchaseHandler() == null) {
+            return PurchaseResult.failure("Item has no purchase handler configured.");
+        }
+        if (!item.getCurrency().canPlayerAfford(player)) {
+            return PurchaseResult.failure("You cannot afford this item.");
+        }
+        boolean charged = item.getCurrency().chargePlayer(player);
+        if (!charged) {
+            return PurchaseResult.failure("Charging failed; purchase canceled.");
+        }
+        try {
+            item.getPurchaseHandler().onPurchase(player);
+            return PurchaseResult.success("Purchase successful.");
+        } catch (Exception e) {
+            logger.log(Level.WARNING, "Purchase handler failed for item " + itemId + " for player " + player.getName(), e);
+            return PurchaseResult.failure("An error occurred while delivering the item.");
+        }
+    }
+
 
     public static ShopService getInstance() {
         if(instance == null) {
@@ -34,4 +96,30 @@ public class ShopService {
     public static ShopService create() {
         return new ShopService();
     }
+
+    public static class PurchaseResult {
+        private final boolean success;
+        private final String message;
+
+        private PurchaseResult(boolean success, String message) {
+            this.success = success;
+            this.message = message;
+        }
+
+        public static PurchaseResult success(String message) {
+            return new PurchaseResult(true, message);
+        }
+
+        public static PurchaseResult failure(String message) {
+            return new PurchaseResult(false, message);
+        }
+
+        public boolean isSuccess() {
+            return success;
+        }
+
+        public String getMessage() {
+            return message;
+        }
+    }
 }