port mintlify to fumadocs

proxy.ts

@@ -0,0 +1,45 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { isMarkdownPreferred, rewritePath } from 'fumadocs-core/negotiation';
+import { docsContentRoute } from '@/lib/shared';
+
+// `/some/page.md` (and `.mdx`) -> raw Markdown of the page, like Mintlify
+const { rewrite: rewriteSuffix } = rewritePath(
+  '{/*path}.md',
+  `${docsContentRoute}{/*path}/content.md`,
+);
+const { rewrite: rewriteSuffixMdx } = rewritePath(
+  '{/*path}.mdx',
+  `${docsContentRoute}{/*path}/content.md`,
+);
+const { rewrite: rewriteDocs } = rewritePath('{/*path}', `${docsContentRoute}{/*path}/content.md`);
+
+function normalize(result: string) {
+  // `/index.md` is the home page
+  return result.replace(new RegExp(`^${docsContentRoute}/index/content\\.md$`), `${docsContentRoute}/content.md`);
+}
+
+export default function proxy(request: NextRequest) {
+  const { pathname } = request.nextUrl;
+
+  const suffix = rewriteSuffix(pathname) || rewriteSuffixMdx(pathname);
+  if (suffix) {
+    return NextResponse.rewrite(new URL(normalize(suffix), request.nextUrl));
+  }
+
+  // agents asking for `Accept: text/markdown` get Markdown on the normal URL
+  if (isMarkdownPreferred(request)) {
+    const result = rewriteDocs(pathname === '/' ? '' : pathname);
+    if (result) {
+      return NextResponse.rewrite(new URL(normalize(result), request.nextUrl), {
+        headers: { Vary: 'Accept' },
+      });
+    }
+  }
+
+  return NextResponse.next();
+}
+
+export const config = {
+  // skip Next internals, API routes, generated files and static assets
+  matcher: ['/((?!_next/|api/|og/|llms|images/|logo/|favicon).*)'],
+};