import "server-only";
import { sql, type SQL } from "drizzle-orm";

/**
 * Build a Drizzle WHERE fragment that fuzzy-matches `column` against `query`
 * using pg_trgm's similarity operator. Returns `true` (no filter) when query is
 * empty so callers can compose unconditionally.
 *
 * Caller must ensure a `gin_trgm_ops` index exists on the column.
 */
export function trigramMatch(column: SQL, query: string | null | undefined): SQL {
  const q = (query ?? "").trim();
  if (!q) return sql`true`;
  return sql`${column} % ${q}`;
}

/** Order-by fragment that ranks rows by similarity descending. */
export function trigramRank(column: SQL, query: string | null | undefined): SQL {
  const q = (query ?? "").trim();
  if (!q) return sql`1`;
  return sql`similarity(${column}, ${q}) DESC`;
}