[ENG-337] - Create Similarity Ranking Route (#185)

* Add similarity rank API route with error handling and input validation

* Enhance input validation in similarity rank API route to ensure embedding and subsetRoamUids are arrays before processing

Author: mdroidian

apps/website/app/api/supabase/similarity-rank/route.ts

@@ -0,0 +1,45 @@
+import { NextResponse, NextRequest } from "next/server";
+import { createClient } from "~/utils/supabase/server";
+import {
+  createApiResponse,
+  handleRouteError,
+  defaultOptionsHandler,
+  asPostgrestFailure,
+} from "~/utils/supabase/apiUtils";
+
+type SimilarityRankInput = {
+  embedding: number[];
+  subsetRoamUids: string[];
+};
+
+export const POST = async (request: NextRequest): Promise<NextResponse> => {
+  try {
+    const body: SimilarityRankInput = await request.json();
+    const { embedding, subsetRoamUids } = body;
+
+    if (
+      !Array.isArray(embedding) ||
+      !Array.isArray(subsetRoamUids) ||
+      !subsetRoamUids.length
+    ) {
+      return createApiResponse(
+        request,
+        asPostgrestFailure(
+          "Missing required fields: embedding and subsetRoamUids",
+          "invalid",
+        ),
+      );
+    }
+    const supabase = await createClient();
+    const response = await supabase.rpc("match_embeddings_for_subset_nodes", {
+      p_query_embedding: JSON.stringify(embedding),
+      p_subset_roam_uids: subsetRoamUids,
+    });
+
+    return createApiResponse(request, response);
+  } catch (e: unknown) {
+    return handleRouteError(request, e, "/api/supabase/similarity-rank");
+  }
+};
+
+export const OPTIONS = defaultOptionsHandler;