allow to enable/disable email sigin via env variable

website/src/pages/api/auth/[...nextauth].ts

@@ -165,6 +165,10 @@ export default function auth(req: NextApiRequest, res: NextApiResponse) {
           return true;
         }
 
+        if (account.provider === "email" && !boolean(process.env.NEXT_PUBLIC_ENABLE_EMAIL_SIGNIN)) {
+          return false;
+        }
+
         const captcha = req.body.captcha;
 
         const res = await checkCaptcha(captcha, getIp(req));

website/src/pages/auth/signin.tsx

@@ -80,7 +80,9 @@ function Signin({ providers }: SigninProps) {
       <AuthLayout>
         <Stack spacing="2">
           {credentials && <DebugSigninForm providerId={credentials.id} bgColorClass={bgColorClass} />}
-          {email && <EmailSignInForm providerId={email.id}></EmailSignInForm>}
+          {email && boolean(process.env.NEXT_PUBLIC_ENABLE_EMAIL_SIGNIN) && (
+            <EmailSignInForm providerId={email.id}></EmailSignInForm>
+          )}
           {discord && (
             <Button
               bg={buttonBgColor}