add authentication with next-auth

dashboard-app-course/app/lib/actions.ts

@@ -4,9 +4,30 @@ import { z } from 'zod';
 import { revalidatePath } from 'next/cache';
 import { redirect } from 'next/navigation';
 import postgres from 'postgres';
+import { signIn } from '@/auth';
+import { AuthError } from 'next-auth';
 
 const sql = postgres(process.env.POSTGRES_URL!, {ssl: 'require'});
 
+export async function authenticate(
+    prevState: string | undefined,
+    formData: FormData,
+){
+    try{
+        await signIn('credentials', formData)
+    } catch(error){
+        if(error instanceof AuthError){
+            switch(error.type){
+                case 'CredentialsSignIn':
+                    return 'Invalid credentials.';
+                default:
+                    return 'Something went wrong.';
+            }
+        }
+        throw error;
+    }
+}
+
 const FormSchema = z.object({
     id: z.string(),
     customerId: z.string({