feat: add granular signin disable flags and OIDC auto-redirect (#2857)

apps/remix/app/routes/_unauthenticated+/signin.tsx

@@ -1,8 +1,11 @@
+import { authClient } from '@documenso/auth/client';
 import { getOptionalSession } from '@documenso/auth/server/lib/utils/get-session';
 import {
   IS_GOOGLE_SSO_ENABLED,
   IS_MICROSOFT_SSO_ENABLED,
+  IS_OIDC_AUTO_REDIRECT_DISABLED,
   IS_OIDC_SSO_ENABLED,
+  isSigninEnabledForProvider,
   isSignupEnabledForProvider,
   OIDC_PROVIDER_LABEL,
 } from '@documenso/lib/constants/auth';
@@ -11,6 +14,7 @@ import { Alert, AlertDescription } from '@documenso/ui/primitives/alert';
 import { msg } from '@lingui/core/macro';
 import { useLingui } from '@lingui/react';
 import { Trans } from '@lingui/react/macro';
+import { Loader2Icon } from 'lucide-react';
 import { useEffect, useState } from 'react';
 import { Link, redirect, useSearchParams } from 'react-router';
 
@@ -28,10 +32,20 @@ export async function loader({ request }: Route.LoaderArgs) {
   const { isAuthenticated } = await getOptionalSession(request);
 
   // SSR env variables.
-  const isGoogleSSOEnabled = IS_GOOGLE_SSO_ENABLED;
-  const isMicrosoftSSOEnabled = IS_MICROSOFT_SSO_ENABLED;
-  const isOIDCSSOEnabled = IS_OIDC_SSO_ENABLED;
+  const isEmailPasswordSigninEnabled = isSigninEnabledForProvider('email');
+  const isGoogleSSOEnabled = IS_GOOGLE_SSO_ENABLED && isSigninEnabledForProvider('google');
+  const isMicrosoftSSOEnabled = IS_MICROSOFT_SSO_ENABLED && isSigninEnabledForProvider('microsoft');
+  const isOIDCSSOEnabled = IS_OIDC_SSO_ENABLED && isSigninEnabledForProvider('oidc');
+
+  // Automatically redirect to OIDC when it is the only enabled signin transport,
+  // unless the redirect has been explicitly disabled via env.
+  const isOIDCOnlyTransport =
+    isOIDCSSOEnabled && !isEmailPasswordSigninEnabled && !isGoogleSSOEnabled && !isMicrosoftSSOEnabled;
+
+  const shouldAutoRedirectToOIDC = isOIDCOnlyTransport && !IS_OIDC_AUTO_REDIRECT_DISABLED;
+
   const oidcProviderLabel = OIDC_PROVIDER_LABEL;
+
   const isSignupEnabled =
     isSignupEnabledForProvider('email') ||
     (IS_GOOGLE_SSO_ENABLED && isSignupEnabledForProvider('google')) ||
@@ -47,18 +61,28 @@ export async function loader({ request }: Route.LoaderArgs) {
   }
 
   return {
+    isEmailPasswordSigninEnabled,
     isGoogleSSOEnabled,
     isMicrosoftSSOEnabled,
     isOIDCSSOEnabled,
     isSignupEnabled,
     oidcProviderLabel,
     returnTo,
+    shouldAutoRedirectToOIDC,
   };
 }
 
 export default function SignIn({ loaderData }: Route.ComponentProps) {
-  const { isGoogleSSOEnabled, isMicrosoftSSOEnabled, isOIDCSSOEnabled, isSignupEnabled, oidcProviderLabel, returnTo } =
-    loaderData;
+  const {
+    isEmailPasswordSigninEnabled,
+    isGoogleSSOEnabled,
+    isMicrosoftSSOEnabled,
+    isOIDCSSOEnabled,
+    isSignupEnabled,
+    oidcProviderLabel,
+    returnTo,
+    shouldAutoRedirectToOIDC,
+  } = loaderData;
 
   const { _ } = useLingui();
 
@@ -76,6 +100,27 @@ export default function SignIn({ loaderData }: Route.ComponentProps) {
     setIsEmbeddedRedirect(params.get('embedded') === 'true');
   }, []);
 
+  useEffect(() => {
+    if (!shouldAutoRedirectToOIDC) {
+      return;
+    }
+
+    void authClient.oidc.signIn({ redirectPath: returnTo ?? '/' });
+  }, [shouldAutoRedirectToOIDC, returnTo]);
+
+  if (shouldAutoRedirectToOIDC) {
+    return (
+      <div className="w-screen max-w-lg px-4">
+        <div className="flex flex-col items-center justify-center gap-y-4 py-12">
+          <Loader2Icon className="h-8 w-8 animate-spin text-muted-foreground" />
+          <p className="text-muted-foreground text-sm">
+            <Trans>Redirecting to {oidcProviderLabel || 'OIDC'}...</Trans>
+          </p>
+        </div>
+      </div>
+    );
+  }
+
   return (
     <div className="w-screen max-w-lg px-4">
       <div className="z-10 rounded-xl border border-border bg-neutral-100 p-6 dark:bg-background">
@@ -95,6 +140,7 @@ export default function SignIn({ loaderData }: Route.ComponentProps) {
         <hr className="-mx-6 my-4" />
 
         <SignInForm
+          isEmailPasswordSigninEnabled={isEmailPasswordSigninEnabled}
           isGoogleSSOEnabled={isGoogleSSOEnabled}
           isMicrosoftSSOEnabled={isMicrosoftSSOEnabled}
           isOIDCSSOEnabled={isOIDCSSOEnabled}