fuzzy search on search page

packages/app/src/Hooks/useProfileSearch.tsx

@@ -0,0 +1,72 @@
+import { unixNow } from "@snort/shared";
+import { socialGraphInstance } from "@snort/system";
+import { useMemo } from "react";
+
+import fuzzySearch from "@/Db/FuzzySearch";
+import useTimelineFeed, { TimelineFeedOptions, TimelineSubject } from "@/Feed/TimelineFeed";
+
+export default function useProfileSearch(search: string) {
+  const options: TimelineFeedOptions = useMemo(
+    () => ({
+      method: "LIMIT_UNTIL",
+      window: undefined,
+      now: unixNow(),
+    }),
+    [],
+  );
+
+  const subject: TimelineSubject = useMemo(
+    () => ({
+      type: "profile_keyword",
+      discriminator: search,
+      items: search ? [search] : [],
+      relay: undefined,
+      streams: false,
+    }),
+    [search],
+  );
+
+  const { main } = useTimelineFeed(subject, options);
+
+  const results = useMemo(() => {
+    const searchString = search.trim();
+    const fuseResults = fuzzySearch.search(searchString);
+
+    const followDistanceNormalizationFactor = 3;
+    const seenIds = new Set();
+
+    const combinedResults = fuseResults
+      .map(result => {
+        const fuseScore = result.score === undefined ? 1 : result.score;
+        const followDistance =
+          socialGraphInstance.getFollowDistance(result.item.pubkey) / followDistanceNormalizationFactor;
+
+        const startsWithSearchString = [result.item.name, result.item.display_name, result.item.nip05].some(
+          field => field && field.toLowerCase?.().startsWith(searchString.toLowerCase()),
+        );
+
+        const boostFactor = startsWithSearchString ? 0.25 : 1;
+
+        const weightForFuseScore = 0.8;
+        const weightForFollowDistance = 0.2;
+
+        const combinedScore = (fuseScore * weightForFuseScore + followDistance * weightForFollowDistance) * boostFactor;
+
+        return { ...result, combinedScore };
+      })
+      // Sort by combined score, lower is better
+      .sort((a, b) => a.combinedScore - b.combinedScore)
+      .filter(r => {
+        // for some reason we get duplicates even though fuzzySearch should be removing existing profile on update
+        if (seenIds.has(r.item.pubkey)) {
+          return false;
+        }
+        seenIds.add(r.item.pubkey);
+        return true;
+      });
+
+    return combinedResults.map(r => r.item);
+  }, [search, main]);
+
+  return results;
+}