Use kv datastore for auth (#272)

app/signup/actions.ts

@@ -1,15 +1,50 @@
 'use server'
 
 import { signIn } from '@/auth'
-import { db } from '@vercel/postgres'
-import { getStringFromBuffer } from '@/lib/utils'
+import { ResultCode, getStringFromBuffer } from '@/lib/utils'
 import { z } from 'zod'
-import { AuthResult } from '@/lib/types'
+import { kv } from '@vercel/kv'
+import { getUser } from '../login/actions'
+import { AuthError } from 'next-auth'
+
+export async function createUser(
+  email: string,
+  hashedPassword: string,
+  salt: string
+) {
+  const existingUser = await getUser(email)
+
+  if (existingUser) {
+    return {
+      type: 'error',
+      resultCode: ResultCode.UserAlreadyExists
+    }
+  } else {
+    const user = {
+      id: crypto.randomUUID(),
+      email,
+      password: hashedPassword,
+      salt
+    }
+
+    await kv.hmset(`user:${email}`, user)
+
+    return {
+      type: 'success',
+      resultCode: ResultCode.UserCreated
+    }
+  }
+}
+
+interface Result {
+  type: string
+  resultCode: ResultCode
+}
 
 export async function signup(
-  _prevState: AuthResult | undefined,
+  _prevState: Result | undefined,
   formData: FormData
-) {
+): Promise<Result | undefined> {
   const email = formData.get('email') as string
   const password = formData.get('password') as string
 
@@ -34,42 +69,43 @@ export async function signup(
     )
     const hashedPassword = getStringFromBuffer(hashedPasswordBuffer)
 
-    const client = await db.connect()
-
     try {
-      await client.sql`
-              INSERT INTO users (email, password, salt)
-              VALUES (${email}, ${hashedPassword}, ${salt})
-              ON CONFLICT (id) DO NOTHING;
-            `
+      const result = await createUser(email, hashedPassword, salt)
 
-      await signIn('credentials', {
-        email,
-        password,
-        redirect: false
-      })
+      if (result.resultCode === ResultCode.UserCreated) {
+        await signIn('credentials', {
+          email,
+          password,
+          redirect: false
+        })
+      }
 
-      return { type: 'success', message: 'Account created!' }
+      return result
     } catch (error) {
-      const { message } = error as Error
-
-      if (
-        message.startsWith('duplicate key value violates unique constraint')
-      ) {
-        return { type: 'error', message: 'User already exists! Please log in.' }
+      if (error instanceof AuthError) {
+        switch (error.type) {
+          case 'CredentialsSignin':
+            return {
+              type: 'error',
+              resultCode: ResultCode.InvalidCredentials
+            }
+          default:
+            return {
+              type: 'error',
+              resultCode: ResultCode.UnknownError
+            }
+        }
       } else {
         return {
           type: 'error',
-          message: 'Something went wrong! Please try again.'
+          resultCode: ResultCode.UnknownError
         }
       }
-    } finally {
-      client.release()
     }
   } else {
     return {
       type: 'error',
-      message: 'Invalid entries, please try again!'
+      resultCode: ResultCode.InvalidCredentials
     }
   }
 }