update shop costs

backend/internal/handler/game.go

@@ -1007,12 +1007,15 @@ func (h *GameHandler) InitHero(w http.ResponseWriter, r *http.Request) {
 
 	if hero == nil {
 		townsWithNPCs := h.buildTownsWithNPCs(r.Context())
+		pCost, hCost := tuning.EffectiveNPCShopCosts()
 		writeJSON(w, http.StatusOK, map[string]any{
 			"hero":          nil,
 			"needsName":     true,
 			"offlineReport": nil,
 			"mapRef":        h.world.RefForLevel(1),
 			"towns":         townsWithNPCs,
+			"npcCostPotion": pCost,
+			"npcCostHeal":   hCost,
 		})
 		return
 	}
@@ -1069,6 +1072,7 @@ func (h *GameHandler) InitHero(w http.ResponseWriter, r *http.Request) {
 
 	// Build towns with NPCs for the frontend map.
 	townsWithNPCs := h.buildTownsWithNPCs(r.Context())
+	pCost, hCost := tuning.EffectiveNPCShopCosts()
 
 	writeJSON(w, http.StatusOK, map[string]any{
 		"hero":          hero,
@@ -1076,6 +1080,8 @@ func (h *GameHandler) InitHero(w http.ResponseWriter, r *http.Request) {
 		"offlineReport": report,
 		"mapRef":        h.world.RefForLevel(hero.Level),
 		"towns":         townsWithNPCs,
+		"npcCostPotion": pCost,
+		"npcCostHeal":   hCost,
 	})
 }
 

backend/internal/handler/npc.go

@@ -187,20 +187,20 @@ func (h *NPCHandler) InteractNPC(w http.ResponseWriter, r *http.Request) {
 		}
 
 	case "merchant":
-		cfg := tuning.Get()
+		potionCost, _ := tuning.EffectiveNPCShopCosts()
 		actions = append(actions, model.NPCInteractAction{
 			ActionType:  "shop_item",
 			ItemName:    "Healing Potion",
-			ItemCost:    cfg.NPCCostPotion,
+			ItemCost:    potionCost,
 			Description: "Restores health. Always handy in a pinch.",
 		})
 
 	case "healer":
-		cfg := tuning.Get()
+		_, healCost := tuning.EffectiveNPCShopCosts()
 		actions = append(actions, model.NPCInteractAction{
 			ActionType:  "heal",
 			ItemName:    "Full Heal",
-			ItemCost:    cfg.NPCCostHeal,
+			ItemCost:    healCost,
 			Description: "Restore hero to full HP.",
 		})
 	}
@@ -593,7 +593,7 @@ func (h *NPCHandler) HealHero(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	healCost := tuning.Get().NPCCostHeal
+	_, healCost := tuning.EffectiveNPCShopCosts()
 	if hero.Gold < healCost {
 		writeJSON(w, http.StatusBadRequest, map[string]string{
 			"error": fmt.Sprintf("not enough gold (need %d, have %d)", healCost, hero.Gold),
@@ -643,7 +643,7 @@ func (h *NPCHandler) BuyPotion(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	potionCost := tuning.Get().NPCCostPotion
+	potionCost, _ := tuning.EffectiveNPCShopCosts()
 	if hero.Gold < potionCost {
 		writeJSON(w, http.StatusBadRequest, map[string]string{
 			"error": fmt.Sprintf("not enough gold (need %d, have %d)", potionCost, hero.Gold),

backend/internal/tuning/runtime.go

@@ -361,6 +361,21 @@ func Get() Values {
 	return *p
 }
 
+// EffectiveNPCShopCosts returns potion and full-heal prices from runtime tuning (DB-merged JSON),
+// falling back to defaults when unset or non-positive.
+func EffectiveNPCShopCosts() (potionCost, healCost int64) {
+	cfg := Get()
+	potionCost = cfg.NPCCostPotion
+	if potionCost <= 0 {
+		potionCost = DefaultValues().NPCCostPotion
+	}
+	healCost = cfg.NPCCostHeal
+	if healCost <= 0 {
+		healCost = DefaultValues().NPCCostHeal
+	}
+	return potionCost, healCost
+}
+
 func Set(v Values) {
 	current.Store(&v)
 }

frontend/src/App.tsx

@@ -29,6 +29,8 @@ import {
   buyPotion,
   healAtNPC,
   requestRevive,
+  defaultNpcShopCosts,
+  npcShopCostsFromInit,
 } from './network/api';
 import type { HeroResponse, Achievement } from './network/api';
 import type { AdventureLogEntry, Town, HeroQuest, NPC, TownData, EquipmentItem, BuildingData } from './game/types';
@@ -340,6 +342,7 @@ export function App() {
 
   // Wandering NPC encounter state
   const [wanderingNPC, setWanderingNPC] = useState<NPCEncounterEvent | null>(null);
+  const [npcShopCosts, setNpcShopCosts] = useState(defaultNpcShopCosts);
   // Achievements
   const [achievements, setAchievements] = useState<Achievement[]>([]);
   const prevAchievementsRef = useRef<Achievement[]>([]);
@@ -424,6 +427,7 @@ export function App() {
       try {
         const telegramId = getTelegramUserId() ?? 1;
         const initRes = await initHero(telegramId);
+        setNpcShopCosts(npcShopCostsFromInit(initRes));
 
         // Gate game start behind name entry — no hero row until POST /hero/name
         if (initRes.needsName) {
@@ -1067,7 +1071,7 @@ export function App() {
     buyPotion(telegramId)
       .then((hero) => {
         hapticImpact('medium');
-        setToast({ message: t(tr.boughtPotion, { cost: 50 }), color: '#88dd88' });
+        setToast({ message: t(tr.boughtPotion, { cost: npcShopCosts.potionCost }), color: '#88dd88' });
         handleNPCHeroUpdated(hero);
         // Server logs purchase + WS
       })
@@ -1082,7 +1086,7 @@ export function App() {
           }
         }
       });
-  }, [handleNPCHeroUpdated]);
+  }, [handleNPCHeroUpdated, npcShopCosts.potionCost, tr]);
 
   const handleNPCHeal = useCallback((npc: NPCData) => {
     const telegramId = getTelegramUserId() ?? 1;
@@ -1237,6 +1241,8 @@ export function App() {
         <NPCInteraction
           npc={nearestNPC}
           heroGold={gameState.hero?.gold ?? 0}
+          potionCost={npcShopCosts.potionCost}
+          healCost={npcShopCosts.healCost}
           onViewQuests={handleNPCViewQuests}
           onBuyPotion={handleNPCBuyPotion}
           onHeal={handleNPCHeal}
@@ -1250,6 +1256,8 @@ export function App() {
           npc={selectedNPC}
           heroQuests={heroQuests}
           heroGold={gameState.hero?.gold ?? 0}
+          potionCost={npcShopCosts.potionCost}
+          healCost={npcShopCosts.healCost}
           onClose={() => setSelectedNPC(null)}
           onQuestsChanged={refreshHeroQuests}
           onHeroUpdated={handleNPCHeroUpdated}

frontend/src/network/api.ts

@@ -186,6 +186,25 @@ export interface InitHeroResponse {
   offlineReport: OfflineReport | null;
   mapRef: MapRefResponse;
   needsName?: boolean;
+  /** Runtime tuning: merchant potion price (from DB / runtime_config). */
+  npcCostPotion?: number;
+  /** Runtime tuning: healer full heal price (from DB / runtime_config). */
+  npcCostHeal?: number;
+}
+
+/** Matches server defaults when init omits costs (must stay in sync with tuning.DefaultValues). */
+export function defaultNpcShopCosts(): { potionCost: number; healCost: number } {
+  return { potionCost: 50, healCost: 100 };
+}
+
+export function npcShopCostsFromInit(res: InitHeroResponse): { potionCost: number; healCost: number } {
+  const d = defaultNpcShopCosts();
+  const p = res.npcCostPotion;
+  const h = res.npcCostHeal;
+  return {
+    potionCost: typeof p === 'number' && p > 0 ? p : d.potionCost,
+    healCost: typeof h === 'number' && h > 0 ? h : d.healCost,
+  };
 }
 
 /** Initialize or retrieve a hero from the backend (creates on first call) */

frontend/src/ui/NPCDialog.tsx

@@ -12,6 +12,8 @@ interface NPCDialogProps {
   npc: NPC;
   heroQuests: HeroQuest[];
   heroGold: number;
+  potionCost: number;
+  healCost: number;
   onClose: () => void;
   onQuestsChanged: () => void;
   onHeroUpdated: (hero: HeroResponse) => void;
@@ -228,17 +230,14 @@ function questTypeIcon(type: string): string {
   }
 }
 
-// ---- Constants ----
-
-const POTION_COST = 50;
-const HEAL_COST = 30;
-
 // ---- Component ----
 
 export function NPCDialog({
   npc,
   heroQuests,
   heroGold,
+  potionCost,
+  healCost,
   onClose,
   onQuestsChanged,
   onHeroUpdated,
@@ -308,24 +307,24 @@ export function NPCDialog({
   );
 
   const handleBuyPotion = useCallback(() => {
-    if (heroGold < POTION_COST) {
+    if (heroGold < potionCost) {
       onToast(tr.notEnoughGold, '#ff4444');
       return;
     }
     buyPotion(telegramId)
       .then((hero) => {
         hapticImpact('medium');
-        onToast(t(tr.boughtPotion, { cost: POTION_COST }), '#88dd88');
+        onToast(t(tr.boughtPotion, { cost: potionCost }), '#88dd88');
         onHeroUpdated(hero);
       })
       .catch((err) => {
         console.warn('[NPCDialog] Failed to buy potion:', err);
         onToast(tr.failedToBuyPotion, '#ff4444');
       });
-  }, [telegramId, heroGold, onHeroUpdated, onToast]);
+  }, [telegramId, heroGold, potionCost, onHeroUpdated, onToast, tr]);
 
   const handleHeal = useCallback(() => {
-    if (heroGold < HEAL_COST) {
+    if (heroGold < healCost) {
       onToast(tr.notEnoughGold, '#ff4444');
       return;
     }
@@ -339,7 +338,7 @@ export function NPCDialog({
         console.warn('[NPCDialog] Failed to heal:', err);
         onToast(tr.failedToHeal, '#ff4444');
       });
-  }, [telegramId, heroGold, onHeroUpdated, onToast, npc.id]);
+  }, [telegramId, heroGold, healCost, onHeroUpdated, onToast, npc.id, tr]);
 
   // Quests relevant to this NPC
   const npcHeroQuests = heroQuests.filter(
@@ -522,14 +521,14 @@ export function NPCDialog({
                 <div style={sectionTitleStyle}>Shop</div>
                 <button
                   style={
-                    heroGold >= POTION_COST
+                    heroGold >= potionCost
                       ? { ...serviceBtnStyle, backgroundColor: 'rgba(68, 200, 68, 0.2)', color: '#88dd88' }
                       : { ...disabledBtnStyle, backgroundColor: 'rgba(68, 200, 68, 0.1)', color: '#88dd88' }
                   }
                   onClick={handleBuyPotion}
-                  disabled={heroGold < POTION_COST}
+                  disabled={heroGold < potionCost}
                 >
-                  {'\uD83E\uDDEA'} {tr.buyPotion} &mdash; {POTION_COST} {tr.gold}
+                  {'\uD83E\uDDEA'} {tr.buyPotion} &mdash; {potionCost} {tr.gold}
                 </button>
                 <div style={{ fontSize: 11, color: '#666', textAlign: 'center' }}>
                   Your gold: {heroGold}
@@ -543,14 +542,14 @@ export function NPCDialog({
                 <div style={sectionTitleStyle}>Services</div>
                 <button
                   style={
-                    heroGold >= HEAL_COST
+                    heroGold >= healCost
                       ? { ...serviceBtnStyle, backgroundColor: 'rgba(200, 68, 68, 0.2)', color: '#ff8888' }
                       : { ...disabledBtnStyle, backgroundColor: 'rgba(200, 68, 68, 0.1)', color: '#ff8888' }
                   }
                   onClick={handleHeal}
-                  disabled={heroGold < HEAL_COST}
+                  disabled={heroGold < healCost}
                 >
-                  {'\u2764\uFE0F'} {tr.healToFull} &mdash; {HEAL_COST} {tr.gold}
+                  {'\u2764\uFE0F'} {tr.healToFull} &mdash; {healCost} {tr.gold}
                 </button>
                 <div style={{ fontSize: 11, color: '#666', textAlign: 'center' }}>
                   Your gold: {heroGold}

frontend/src/ui/NPCInteraction.tsx

@@ -6,6 +6,8 @@ import type { NPCData } from '../game/types';
 interface NPCInteractionProps {
   npc: NPCData;
   heroGold: number;
+  potionCost: number;
+  healCost: number;
   onViewQuests: (npc: NPCData) => void;
   onBuyPotion: (npc: NPCData) => void;
   onHeal: (npc: NPCData) => void;
@@ -77,9 +79,6 @@ const actionBtnStyle: CSSProperties = {
   textAlign: 'center',
 };
 
-const POTION_COST = 50;
-const HEAL_COST = 30;
-
 // ---- NPC appearance ----
 
 function npcColor(type: string): { bg: string; icon: string; text: string } {
@@ -100,6 +99,8 @@ function npcColor(type: string): { bg: string; icon: string; text: string } {
 export function NPCInteraction({
   npc,
   heroGold,
+  potionCost,
+  healCost,
   onViewQuests,
   onBuyPotion,
   onHeal,
@@ -126,9 +127,9 @@ export function NPCInteraction({
       case 'quest_giver':
         return 'View Quests';
       case 'merchant':
-        return `Buy Potion (${POTION_COST}g)`;
+        return `Buy Potion (${potionCost}g)`;
       case 'healer':
-        return `Heal to Full (${HEAL_COST}g)`;
+        return `Heal to Full (${healCost}g)`;
       default:
         return 'Talk';
     }
@@ -136,8 +137,8 @@ export function NPCInteraction({
 
   const canAfford =
     npc.type === 'quest_giver' ||
-    (npc.type === 'merchant' && heroGold >= POTION_COST) ||
+    (npc.type === 'merchant' && heroGold >= potionCost) ||
-    (npc.type === 'healer' && heroGold >= HEAL_COST);
+    (npc.type === 'healer' && heroGold >= healCost);
 
   return (
     <>