refactor(api): sync dev and auth0 plugins (#57136)

api/src/plugins/auth-dev.ts

@@ -0,0 +1,48 @@
+import type { FastifyPluginCallbackTypebox } from '@fastify/type-provider-typebox';
+import type { FastifyReply, FastifyRequest } from 'fastify';
+import {
+  getRedirectParams,
+  getPrefixedLandingPath,
+  haveSamePath
+} from '../utils/redirection';
+import { findOrCreateUser } from '../routes/helpers/auth-helpers';
+import { createAccessToken } from '../utils/tokens';
+
+const trimTrailingSlash = (str: string) =>
+  str.endsWith('/') ? str.slice(0, -1) : str;
+
+async function handleRedirects(req: FastifyRequest, reply: FastifyReply) {
+  const params = getRedirectParams(req);
+  const { origin, pathPrefix } = params;
+  const returnTo = trimTrailingSlash(params.returnTo);
+  const landingUrl = getPrefixedLandingPath(origin, pathPrefix);
+
+  return await reply.redirect(
+    haveSamePath(landingUrl, returnTo) ? `${returnTo}/learn` : returnTo
+  );
+}
+
+/**
+ * Fastify plugin for dev authentication.
+ *
+ * @param fastify - The Fastify instance.
+ * @param _options - The plugin options.
+ * @param done - The callback function.
+ */
+export const devAuth: FastifyPluginCallbackTypebox = (
+  fastify,
+  _options,
+  done
+) => {
+  fastify.get('/signin', async (req, reply) => {
+    const email = 'foo@bar.com';
+
+    const { id } = await findOrCreateUser(fastify, email);
+
+    reply.setAccessTokenCookie(createAccessToken(id));
+
+    await handleRedirects(req, reply);
+  });
+
+  done();
+};