/**
 * Reranker - Rerank search results for improved relevance
 * Inspired by mastra's rerank module
 */
export interface RerankResult {
    id: string;
    score: number;
    content: string;
    metadata?: Record<string, any>;
    originalRank: number;
    newRank: number;
}
export interface RerankConfig {
    model?: string;
    topK?: number;
    threshold?: number;
}
/**
 * Abstract base class for rerankers
 */
export declare abstract class BaseReranker {
    readonly name: string;
    constructor(name: string);
    abstract rerank(query: string, documents: Array<{
        id: string;
        content: string;
        metadata?: Record<string, any>;
    }>, config?: RerankConfig): Promise<RerankResult[]>;
}
/**
 * Cohere Reranker - Uses Cohere's rerank API
 */
export declare class CohereReranker extends BaseReranker {
    private apiKey;
    private model;
    constructor(config?: {
        apiKey?: string;
        model?: string;
    });
    rerank(query: string, documents: Array<{
        id: string;
        content: string;
        metadata?: Record<string, any>;
    }>, config?: RerankConfig): Promise<RerankResult[]>;
}
/**
 * Cross-Encoder Reranker - Uses sentence similarity for reranking
 * This is a simple implementation using cosine similarity
 */
export declare class CrossEncoderReranker extends BaseReranker {
    private embedFn?;
    constructor(config?: {
        embedFn?: (texts: string[]) => Promise<number[][]>;
    });
    rerank(query: string, documents: Array<{
        id: string;
        content: string;
        metadata?: Record<string, any>;
    }>, config?: RerankConfig): Promise<RerankResult[]>;
    private keywordRerank;
    private cosineSimilarity;
}
/**
 * LLM Reranker - Uses an LLM to score relevance
 */
export declare class LLMReranker extends BaseReranker {
    private generateFn;
    constructor(config: {
        generateFn: (prompt: string) => Promise<string>;
    });
    rerank(query: string, documents: Array<{
        id: string;
        content: string;
        metadata?: Record<string, any>;
    }>, config?: RerankConfig): Promise<RerankResult[]>;
}
export declare function createCohereReranker(config?: {
    apiKey?: string;
    model?: string;
}): CohereReranker;
export declare function createCrossEncoderReranker(config?: {
    embedFn?: (texts: string[]) => Promise<number[][]>;
}): CrossEncoderReranker;
export declare function createLLMReranker(config: {
    generateFn: (prompt: string) => Promise<string>;
}): LLMReranker;