feat: Introduce GameConfig to centralize constants for leveling, economy, and inventory, adding new transfer and inventory limits.

src/commands/economy/pay.ts

@@ -2,6 +2,7 @@ import { createCommand } from "@/lib/utils";
 import { SlashCommandBuilder, EmbedBuilder } from "discord.js";
 import { economyService } from "@/modules/economy/economy.service";
 import { userService } from "@/modules/user/user.service";
+import { GameConfig } from "@/config/game";
 
 export const pay = createCommand({
     data: new SlashCommandBuilder()
@@ -26,6 +27,11 @@ export const pay = createCommand({
         const senderId = interaction.user.id;
         const receiverId = targetUser.id;
 
+        if (amount < GameConfig.economy.transfers.minAmount) {
+            await interaction.editReply({ content: `❌ Amount must be at least ${GameConfig.economy.transfers.minAmount}.` });
+            return;
+        }
+
         if (senderId === receiverId) {
             await interaction.editReply({ content: "❌ You cannot pay yourself." });
             return;

src/config/game.ts

@@ -0,0 +1,29 @@
+export const GameConfig = {
+    leveling: {
+        // Curve: Base * (Level ^ Exponent)
+        base: 100,
+        exponent: 2.5,
+
+        chat: {
+            cooldownMs: 60000, // 1 minute
+            minXp: 15,
+            maxXp: 25,
+        }
+    },
+    economy: {
+        daily: {
+            amount: 100n,
+            streakBonus: 10n,
+            cooldownMs: 24 * 60 * 60 * 1000, // 24 hours
+        },
+        transfers: {
+            // Future use
+            allowSelfTransfer: false,
+            minAmount: 1n,
+        }
+    },
+    inventory: {
+        maxStackSize: 999n,
+        maxSlots: 50,
+    }
+} as const;

src/modules/economy/economy.service.ts

@@ -1,10 +1,7 @@
 import { users, transactions, cooldowns } from "@/db/schema";
 import { eq, sql, and } from "drizzle-orm";
 import { DrizzleClient } from "@/lib/DrizzleClient";
-
+import { GameConfig } from "@/config/game";
-const DAILY_REWARD_AMOUNT = 100n;
-const STREAK_BONUS = 10n;
-const DAILY_COOLDOWN = 24 * 60 * 60 * 1000; // 24 hours in ms
 
 export const economyService = {
     transfer: async (fromUserId: string, toUserId: string, amount: bigint, tx?: any) => {
@@ -112,9 +109,9 @@ export const economyService = {
                 streak = 1;
             }
 
-            const bonus = (BigInt(streak) - 1n) * STREAK_BONUS;
+            const bonus = (BigInt(streak) - 1n) * GameConfig.economy.daily.streakBonus;
 
-            const totalReward = DAILY_REWARD_AMOUNT + bonus;
+            const totalReward = GameConfig.economy.daily.amount + bonus;
 
             // Update User w/ Economy Service (reuse modifyUserBalance if we split it out, but here manual is fine for atomic combined streak update)
             // Actually, we can just update directly here as we are already refining specific fields like streak.
@@ -127,7 +124,7 @@ export const economyService = {
                 .where(eq(users.id, BigInt(userId)));
 
             // Set new cooldown (now + 24h)
-            const nextReadyAt = new Date(now.getTime() + DAILY_COOLDOWN);
+            const nextReadyAt = new Date(now.getTime() + GameConfig.economy.daily.cooldownMs);
 
             await txFn.insert(cooldowns)
                 .values({

src/modules/inventory/inventory.service.ts

@@ -1,8 +1,9 @@
 
 import { inventory, items, users } from "@/db/schema";
-import { eq, and, sql } from "drizzle-orm";
+import { eq, and, sql, count } from "drizzle-orm";
 import { DrizzleClient } from "@/lib/DrizzleClient";
 import { economyService } from "@/modules/economy/economy.service";
+import { GameConfig } from "@/config/game";
 
 export const inventoryService = {
     addItem: async (userId: string, itemId: number, quantity: bigint = 1n, tx?: any) => {
@@ -16,9 +17,14 @@ export const inventoryService = {
             });
 
             if (existing) {
+                const newQuantity = (existing.quantity ?? 0n) + quantity;
+                if (newQuantity > GameConfig.inventory.maxStackSize) {
+                    throw new Error(`Cannot exceed max stack size of ${GameConfig.inventory.maxStackSize}`);
+                }
+
                 const [entry] = await txFn.update(inventory)
                     .set({
-                        quantity: sql`${inventory.quantity} + ${quantity}`,
+                        quantity: newQuantity,
                     })
                     .where(and(
                         eq(inventory.userId, BigInt(userId)),
@@ -27,6 +33,20 @@ export const inventoryService = {
                     .returning();
                 return entry;
             } else {
+                // Check Slot Limit
+                const [inventoryCount] = await txFn
+                    .select({ count: count() })
+                    .from(inventory)
+                    .where(eq(inventory.userId, BigInt(userId)));
+
+                if (inventoryCount.count >= GameConfig.inventory.maxSlots) {
+                    throw new Error(`Inventory full (Max ${GameConfig.inventory.maxSlots} slots)`);
+                }
+
+                if (quantity > GameConfig.inventory.maxStackSize) {
+                    throw new Error(`Cannot exceed max stack size of ${GameConfig.inventory.maxStackSize}`);
+                }
+
                 const [entry] = await txFn.insert(inventory)
                     .values({
                         userId: BigInt(userId),
@@ -105,16 +125,9 @@ export const inventoryService = {
             // Since we are modifying buyItem, we can just inline the item addition or call addItem if we update it.
             // Let's assume we update addItem next. For now, inline the add logic but cleaner.
 
-            const existingInv = await txFn.query.inventory.findFirst({
+            // Add Item using inner logic or self-call if we refactor properly. 
-                where: and(eq(inventory.userId, BigInt(userId)), eq(inventory.itemId, itemId)),
+            // Calling addItem directly within the same transaction scope:
-            });
+            await inventoryService.addItem(userId, itemId, quantity, txFn);
-
-            if (existingInv) {
-                await txFn.update(inventory).set({ quantity: sql`${inventory.quantity} + ${quantity}` })
-                    .where(and(eq(inventory.userId, BigInt(userId)), eq(inventory.itemId, itemId)));
-            } else {
-                await txFn.insert(inventory).values({ userId: BigInt(userId), itemId, quantity });
-            }
 
             return { success: true, item, totalPrice };
         };

src/modules/leveling/leveling.service.ts

@@ -1,18 +1,12 @@
 import { users, cooldowns } from "@/db/schema";
 import { eq, sql, and } from "drizzle-orm";
 import { DrizzleClient } from "@/lib/DrizzleClient";
-
+import { GameConfig } from "@/config/game";
-// Simple configurable curve: Base * (Level ^ Exponent)
-const XP_BASE = 100;
-const XP_EXPONENT = 2.5;
-const CHAT_XP_COOLDOWN_MS = 60000; // 1 minute
-const MIN_CHAT_XP = 15;
-const MAX_CHAT_XP = 25;
 
 export const levelingService = {
     // Calculate XP required for a specific level
     getXpForLevel: (level: number) => {
-        return Math.floor(XP_BASE * Math.pow(level, XP_EXPONENT));
+        return Math.floor(GameConfig.leveling.base * Math.pow(level, GameConfig.leveling.exponent));
     },
 
     // Pure XP addition - No cooldown checks
@@ -77,13 +71,13 @@ export const levelingService = {
             }
 
             // Calculate random XP
-            const amount = BigInt(Math.floor(Math.random() * (MAX_CHAT_XP - MIN_CHAT_XP + 1)) + MIN_CHAT_XP);
+            const amount = BigInt(Math.floor(Math.random() * (GameConfig.leveling.chat.maxXp - GameConfig.leveling.chat.minXp + 1)) + GameConfig.leveling.chat.minXp);
 
             // Add XP
             const result = await levelingService.addXp(id, amount, txFn);
 
             // Update/Set Cooldown
-            const nextReadyAt = new Date(now.getTime() + CHAT_XP_COOLDOWN_MS);
+            const nextReadyAt = new Date(now.getTime() + GameConfig.leveling.chat.cooldownMs);
 
             await txFn.insert(cooldowns)
                 .values({