Split queries into two steps

src/utils/search_packages.ts

@@ -10,41 +10,68 @@ export type PackageResult = {
   maturity: MaturityValue;
 };
 
-export default async function search_packages(query: string) {
+export async function searchByPrefix(query: string) {
+  const sqlQuery = `
+  SELECT DISTINCT
+    packages.ecosystem,
+    packages.name,
+    scores.health_risk.value AS health_risk,
+    scores.maturity.value AS maturity
+  FROM packages
+  LEFT JOIN scores ON packages.source_url = scores.source_url
+  WHERE lower(packages.name) ILIKE lower(?::VARCHAR) || '%'  -- Prefix matching
+  ORDER BY
+    packages.name
+  LIMIT 100`;
+
+  try {
+    const results = await fetchAll<PackageResult>(sqlQuery, query);
+    console.log("Prefix matching results", results);
+    return results; // Return the filtered results
+  } catch (error) {
+    console.error("Error querying packages by prefix:", error);
+    return [];
+  }
+}
+
+export async function refineWithDamerauLevenshtein(
+  filteredResults: PackageResult[],
+  query: string,
+) {
+  if (filteredResults.length === 0) {
+    return []; // No need to run Damerau-Levenshtein if no prefix matches
+  }
+
   const sqlQuery = `
-  WITH filtered_packages AS (
-    SELECT
-      packages.ecosystem,
-      packages.name,
-      scores.health_risk.value AS health_risk,
-      scores.maturity.value AS maturity,
-      packages.source_url
-    FROM packages
-    LEFT JOIN scores ON packages.source_url = scores.source_url
-    WHERE lower(packages.name) ILIKE lower(?::VARCHAR) || '%'  -- Prefix matching
-    LIMIT 100  -- Limit rows for Damerau-Levenshtein
-  )
   SELECT DISTINCT
     ecosystem,
     name,
     health_risk,
     maturity,
     damerau_levenshtein(lower(name), lower(?::VARCHAR))::int AS name_distance
-  FROM filtered_packages
+  FROM (
+    SELECT * FROM packages WHERE name IN (${filteredResults.map((pkg) => `'${pkg.name}'`).join(", ")})  -- Filter by prefix results
+  ) AS filtered_packages
   ORDER BY
     name_distance,
     name
-  LIMIT 10;`;
+  LIMIT 10`;
 
   try {
     const results = await fetchAll<PackageResult>(sqlQuery, query);
-    console.log("results", results);
-    return results.map((result) => ({
-      ecosystem: result.ecosystem, // Send only the fields needed for search suggestions
-      name: result.name,
-    }));
+    console.log("Damerau-Levenshtein results", results);
+    return results; // Return refined results
   } catch (error) {
-    console.error("Error querying packages:", error);
+    console.error("Error querying packages with Damerau-Levenshtein:", error);
     return [];
   }
 }
+
+export async function search_packages(query: string) {
+  const prefixResults = await searchByPrefix(query);
+  const refinedResults = await refineWithDamerauLevenshtein(
+    prefixResults,
+    query,
+  );
+  return refinedResults;
+}