feat: Introduce new modules for class, inventory, leveling, and quests with expanded schema, refactor user service, and add verification scripts.

src/modules/leveling/leveling.service.ts

@@ -0,0 +1,58 @@
+import { users } from "@/db/schema";
+import { eq, sql } from "drizzle-orm";
+import { DrizzleClient } from "@/lib/DrizzleClient";
+
+// Simple configurable curve: Base * (Level ^ Exponent)
+const XP_BASE = 1000;
+const XP_EXPONENT = 1.5;
+
+export const levelingService = {
+    // Calculate XP required for a specific level
+    getXpForLevel: (level: number) => {
+        return Math.floor(XP_BASE * Math.pow(level, XP_EXPONENT));
+    },
+
+    addXp: async (id: string, amount: bigint, tx?: any) => {
+        const execute = async (txFn: any) => {
+            // Get current state
+            const user = await txFn.query.users.findFirst({
+                where: eq(users.id, BigInt(id)),
+            });
+
+            if (!user) throw new Error("User not found");
+
+            let newXp = (user.xp ?? 0n) + amount;
+            let currentLevel = user.level ?? 1;
+            let levelUp = false;
+
+            // Check for level up loop
+            let xpForNextLevel = BigInt(levelingService.getXpForLevel(currentLevel));
+
+            while (newXp >= xpForNextLevel) {
+                newXp -= xpForNextLevel;
+                currentLevel++;
+                levelUp = true;
+                xpForNextLevel = BigInt(levelingService.getXpForLevel(currentLevel));
+            }
+
+            // Update user
+            const [updatedUser] = await txFn.update(users)
+                .set({
+                    xp: newXp,
+                    level: currentLevel,
+                })
+                .where(eq(users.id, BigInt(id)))
+                .returning();
+
+            return { user: updatedUser, levelUp, currentLevel };
+        }
+
+        if (tx) {
+            return await execute(tx);
+        } else {
+            return await DrizzleClient.transaction(async (t) => {
+                return await execute(t);
+            })
+        }
+    },
+};