feat(api): upgrade zod to v4 and implement api docs and client generation

src/lib/auth/login.ts

@@ -1,7 +1,7 @@
 'use server';
 
-import { z } from 'zod';
-import { loginSchema } from '@/lib/validation/user';
+import { z } from 'zod/v4';
+import { loginSchema } from './validation';
 import { signIn } from '@/auth';
 
 export async function loginAction(data: z.infer<typeof loginSchema>) {

src/lib/auth/register.ts

@@ -1,46 +1,24 @@
 'use server';
 
-import type { z } from 'zod';
+import type { z } from 'zod/v4';
 import bcrypt from 'bcryptjs';
-import { registerSchema } from '@/lib/validation/user';
+import { registerServerSchema } from './validation';
 import { prisma } from '@/prisma';
 
-export async function registerAction(data: z.infer<typeof registerSchema>) {
+export async function registerAction(
+  data: z.infer<typeof registerServerSchema>,
+) {
   try {
-    const result = await registerSchema.safeParseAsync(data);
+    const result = await registerServerSchema.safeParseAsync(data);
 
     if (!result.success) {
       return {
-        error: result.error.errors[0].message,
+        error: result.error.issues[0].message,
       };
     }
 
     const { email, password, firstName, lastName, username } = result.data;
 
-    const user = await prisma.user.findUnique({
-      where: {
-        email,
-      },
-    });
-
-    if (user) {
-      return {
-        error: 'User already exist with this email',
-      };
-    }
-
-    const existingUsername = await prisma.user.findUnique({
-      where: {
-        name: username,
-      },
-    });
-
-    if (existingUsername) {
-      return {
-        error: 'Username already exists',
-      };
-    }
-
     const passwordHash = await bcrypt.hash(password, 10);
 
     await prisma.$transaction(async (tx) => {

src/lib/auth/validation.ts

@@ -0,0 +1,53 @@
+import zod from 'zod/v4';
+import {
+  emailSchema,
+  firstNameSchema,
+  lastNameSchema,
+  newUserEmailServerSchema,
+  newUserNameServerSchema,
+  passwordSchema,
+  userNameSchema,
+} from '@/app/api/user/validation';
+
+// ----------------------------------------
+//
+// Login Validation
+//
+// ----------------------------------------
+export const loginSchema = zod.object({
+  email: emailSchema.or(userNameSchema),
+  password: zod.string().min(1, 'Password is required'),
+});
+
+// ----------------------------------------
+//
+// Register Validation
+//
+// ----------------------------------------
+export const registerServerSchema = zod
+  .object({
+    firstName: firstNameSchema,
+    lastName: lastNameSchema,
+    email: newUserEmailServerSchema,
+    password: passwordSchema,
+    confirmPassword: passwordSchema,
+    username: newUserNameServerSchema,
+  })
+  .refine((data) => data.password === data.confirmPassword, {
+    message: 'Passwords do not match',
+    path: ['confirmPassword'],
+  });
+
+export const registerSchema = zod
+  .object({
+    firstName: firstNameSchema,
+    lastName: lastNameSchema,
+    email: emailSchema,
+    password: passwordSchema,
+    confirmPassword: passwordSchema,
+    username: userNameSchema,
+  })
+  .refine((data) => data.password === data.confirmPassword, {
+    message: 'Passwords do not match',
+    path: ['confirmPassword'],
+  });