import type { Card } from "../db/schema.js";
export interface SearchResult {
    card: Card;
    score: number;
    source: "semantic" | "keyword" | "both";
}
/**
 * Checks the metrics table for a recent query whose embedding has cosine
 * similarity > 0.92 with the current query. If found, returns the same
 * cards that were served for that query (a semantic cache hit).
 */
export declare function checkCache(query: string): Promise<SearchResult[] | null>;
/**
 * Reciprocal Rank Fusion score across multiple retrieval lists.
 * Standard RRF formula: Σ 1/(k + rank_i), k=60 per Cormack et al. (2009).
 * A card appearing in two lists at rank 0 scores ~0.033 (vs 0.016 for one).
 */
export declare function computeRrfScore(ranks: number[], k?: number): number;
/**
 * Score-weighted RRF: blends the standard rank-based RRF with normalized raw
 * scores (cosine similarity for semantic, normalized BM25 for keyword).
 *
 * Pure RRF ignores that rank-0 distance=0.05 is a much stronger match than
 * rank-0 distance=0.40. This blend adds a small score-proportional bonus
 * (weight=0.25) on top of the rank signal (weight=0.75), preserving the
 * rank ordering while rewarding strong confidence matches.
 *
 * @param ranks - 0-based rank positions from each retrieval list
 * @param normalizedScores - scores in [0,1] where 1 = best (cosine similarity or normalized BM25)
 */
export declare function computeWeightedRrfScore(ranks: number[], normalizedScores: number[], k?: number): number;
/**
 * Runs semantic and keyword search in parallel, then fuses results with:
 *  - Semantic weight: 0.7, keyword weight: 0.3
 *  - 1.2x boost for cards appearing in both result sets
 *  - Card-type multiplier (hubs penalized at 0.4x)
 *  - Usage-count logarithmic boost
 *  - Specificity_score boost (populated after centroid computation)
 *  - Repo-affinity multiplier (text signals + embedding-based classifier)
 *
 * @param semanticQuery - optional override for the query used in semantic
 *   search only (BM25 always uses the original query). Used for prefix-
 *   boosted embeddings in codeprism_context.
 */
export declare function hybridSearch(query: string, options?: {
    branch?: string;
    limit?: number;
    semanticQuery?: string;
    skipUsageUpdate?: boolean;
}): Promise<SearchResult[]>;
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