step 10.15: done

src/game/inventory.js

@@ -0,0 +1,25 @@
+// src/game/inventory.js — Shared inventory helpers.
+// Pure data operations; no DB, no Express.
+
+/**
+ * Grant an item to a character's inventory.
+ * Stackable items merge into one row (increment quantity).
+ * Non-stackable items get one row per unit (quantity 1 each).
+ *
+ * @param {object} s — prepared statements cache (from service's getStmts)
+ * @param {number} characterId
+ * @param {object} item — item row with `stackable` and `id`
+ * @param {number} quantity
+ * @param {number} now — timestamp in ms
+ */
+function grantItem(s, characterId, item, quantity, now) {
+  if (item.stackable) {
+    const row = s.stackRow.get(characterId, item.id);
+    if (row) s.addToStack.run(quantity, row.id);
+    else s.insertInv.run(characterId, item.id, quantity, now);
+  } else {
+    for (let i = 0; i < quantity; i++) s.insertInv.run(characterId, item.id, 1, now);
+  }
+}
+
+module.exports = { grantItem };

src/services/huntService.js

@@ -12,6 +12,7 @@ const { calculateRewards, rollLoot } = require('../game/rewards');
 const { checkLevelUp, applyXpGain } = require('../game/leveling');
 const { computeHp } = require('../game/hp');
 const { getEquipmentBonuses } = require('../game/equipment');
+const { grantItem } = require('../game/inventory');
 
 const MIN_HP_PCT_TO_HUNT = 0.2;
 const DEFEAT_GOLD_LOSS_PCT = 0.10;
@@ -59,17 +60,6 @@ function pickWeightedMonster(monsters, rng) {
   return monsters[monsters.length - 1];
 }
 
-// Stackable items merge into one row per (character, item); others get one row per unit.
-function grantItem(s, characterId, item, quantity, now) {
-  if (item.stackable) {
-    const row = s.stackRow.get(characterId, item.id);
-    if (row) s.addToStack.run(quantity, row.id);
-    else s.insertInv.run(characterId, item.id, quantity, now);
-  } else {
-    for (let i = 0; i < quantity; i++) s.insertInv.run(characterId, item.id, 1, now);
-  }
-}
-
 /**
  * @param {number} characterId
  * @param {number} zoneId

src/services/shopService.js

@@ -5,6 +5,7 @@ const { AppError } = require('../utils/errors');
 const { getEquipmentBonuses } = require('../game/equipment');
 const { calcDerived } = require('../game/stats');
 const { materialSellPrice } = require('../game/rewards');
+const { grantItem } = require('../game/inventory');
 
 // Prepared statements cached per DB handle (WeakMap).
 const stmtCache = new WeakMap();
@@ -41,6 +42,21 @@ function getStmts(db) {
         'SELECT * FROM characters WHERE id = ?'
       ),
 
+      // Get inventory row for stack check (used by shared grantItem).
+      stackRow: db.prepare(
+        'SELECT id FROM inventory WHERE character_id = ? AND item_id = ? AND equipped_slot IS NULL'
+      ),
+
+      // Add to existing stack (used by shared grantItem).
+      addToStack: db.prepare(
+        'UPDATE inventory SET quantity = quantity + ? WHERE id = ?'
+      ),
+
+      // Insert new inventory row (used by shared grantItem).
+      insertInv: db.prepare(
+        'INSERT INTO inventory (character_id, item_id, quantity, acquired_at) VALUES (?, ?, ?, ?)'
+      ),
+
       // Get inventory rows for a character + item (for selling).
       inventoryRows: db.prepare(
         'SELECT * FROM inventory WHERE character_id = ? AND item_id = ? AND quantity >= ?'
@@ -253,21 +269,15 @@ function buyItem(characterId, itemId, quantity) {
   const now = require('../utils/time').now();
 
   // Execute the purchase inside a transaction.
-  const doBuy = db.transaction((cost, ng, cid, iid, qty, acquiredAt) => {
+  const doBuy = db.transaction((ng, cid, itemObj, qty, acquiredAt) => {
     // Deduct gold.
     s.updateGold.run(ng, cid);
 
-    // If stackable and already owned, increment quantity.
-    const existing = s.inventoryRows.get(cid, iid, 1);
-    if (existing && item.stackable) {
-      s.incrementQty.run(qty, cid, iid);
-    } else {
-      // New inventory entry.
-      s.addToInventory.run(cid, iid, qty, acquiredAt);
-    }
+    // Grant item (stackable merges, non-stackable gets one row per unit).
+    grantItem(s, cid, itemObj, qty, acquiredAt);
   });
 
-  doBuy(totalCost, newGold, characterId, itemId, quantity, now);
+  doBuy(newGold, characterId, item, quantity, now);
 
   // Return updated inventory listing.
   return listInventory(characterId);