refactor: replace next-auth with better-auth core and client

src/app/api/auth/[...all]/route.ts

@@ -0,0 +1,4 @@
+import { auth } from "@/auth";
+import { toNextJsHandler } from "better-auth/next-js";
+
+export const { GET, POST } = toNextJsHandler(auth);

src/app/api/auth/[...nextauth]/route.ts

@@ -1,2 +0,0 @@
-import { handlers } from "@/auth";
-export const { GET, POST } = handlers;

src/auth.ts

@@ -1,35 +1,26 @@
-import NextAuth, { NextAuthConfig, NextAuthResult } from "next-auth";
-import Authentik from "next-auth/providers/authentik";
-import type { Provider } from "next-auth/providers";
-import { DrizzleAdapter } from "@auth/drizzle-adapter";
+import { betterAuth } from "better-auth";
+import { drizzleAdapter } from "better-auth/adapters/drizzle";
+import { genericOAuth } from "better-auth/plugins";
 import { db } from "@/db/index";
+import * as schema from "@/db/schema";
 
-const providers: Provider[] = [
-	Authentik({
-		clientId: process.env.AUTH_AUTHENTIK_CLIENT_ID,
-		clientSecret: process.env.AUTH_AUTHENTIK_CLIENT_SECRET,
-		issuer: process.env.AUTH_AUTHENTIK_ISSUER,
+export const auth = betterAuth({
+	baseURL: process.env.BETTER_AUTH_URL,
+	database: drizzleAdapter(db, {
+		provider: "pg",
+		schema,
 	}),
-];
-
-export const providerMap = providers.map((provider) => {
-	if (typeof provider === "function") {
-		const providerData = provider();
-		return { id: providerData.id, name: providerData.name };
-	} else {
-		return { id: provider.id, name: provider.name };
-	}
-});
-
-const config = {
-	adapter: DrizzleAdapter(db),
-	providers,
-	pages: {
-		signIn: "/auth/signin",
-		signOut: "/auth/signout",
-		error: "/auth/error",
+	plugins: [
+		genericOAuth({
+			config: [
+				{
+					providerId: "authentik",
+					clientId: process.env.AUTH_AUTHENTIK_CLIENT_ID!,
+					clientSecret: process.env.AUTH_AUTHENTIK_CLIENT_SECRET!,
+					discoveryUrl: `${process.env.AUTH_AUTHENTIK_ISSUER}/.well-known/openid-configuration`,
+					scopes: ["openid", "email", "profile"],
 				},
-	trustHost: true,
-} satisfies NextAuthConfig;
-export const { handlers, signIn, signOut, auth }: NextAuthResult =
-	NextAuth(config);
+			],
+		}),
+	],
+});

src/lib/auth-client.ts

@@ -0,0 +1,5 @@
+import { createAuthClient } from "better-auth/react";
+
+export const authClient = createAuthClient();
+
+export const { useSession, signIn, signOut } = authClient;