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

src/modules/class/class.service.ts

@@ -0,0 +1,63 @@
+
+import { classes, users } from "@/db/schema";
+import { eq, sql } from "drizzle-orm";
+import { DrizzleClient } from "@/lib/DrizzleClient";
+
+export const classService = {
+    getAllClasses: async () => {
+        return await DrizzleClient.query.classes.findMany();
+    },
+
+    assignClass: async (userId: string, classId: bigint, tx?: any) => {
+        const execute = async (txFn: any) => {
+            const cls = await txFn.query.classes.findFirst({
+                where: eq(classes.id, classId),
+            });
+
+            if (!cls) throw new Error("Class not found");
+
+            const [user] = await txFn.update(users)
+                .set({ classId: classId })
+                .where(eq(users.id, BigInt(userId)))
+                .returning();
+
+            return user;
+        };
+        return tx ? await execute(tx) : await DrizzleClient.transaction(execute);
+    },
+
+    modifyClassBalance: async (classId: bigint, amount: bigint, tx?: any) => {
+        const execute = async (txFn: any) => {
+            const cls = await txFn.query.classes.findFirst({
+                where: eq(classes.id, classId),
+            });
+
+            if (!cls) throw new Error("Class not found");
+
+            if (amount < 0n && (cls.balance ?? 0n) < -amount) {
+                throw new Error("Insufficient class funds");
+            }
+
+            const [updatedClass] = await txFn.update(classes)
+                .set({
+                    balance: sql`${classes.balance} + ${amount}`,
+                })
+                .where(eq(classes.id, classId))
+                .returning();
+
+            return updatedClass;
+        };
+        return tx ? await execute(tx) : await DrizzleClient.transaction(execute);
+    },
+
+    updateClass: async (id: bigint, data: Partial<typeof classes.$inferInsert>, tx?: any) => {
+        const execute = async (txFn: any) => {
+            const [updatedClass] = await txFn.update(classes)
+                .set(data)
+                .where(eq(classes.id, id))
+                .returning();
+            return updatedClass;
+        };
+        return tx ? await execute(tx) : await DrizzleClient.transaction(execute);
+    }
+};