/**
 * Transposition Table for js-chess-engine v2
 *
 * Stores previously evaluated positions to avoid re-computation.
 * Uses Zobrist hashing for position identification.
 */
import { InternalMove } from '../types';
import { Score } from '../types/ai.types';
/**
 * Get recommended TT size for a given AI level and environment
 *
 * NOTE: TT size directly affects AI strength. Larger TT = better move ordering
 * and fewer re-searches, which improves play quality at higher depths.
 *
 * @param level - AI difficulty level (1-5)
 * @returns Recommended TT size in MB
 */
export declare function getRecommendedTTSize(level: number): number;
/**
 * Types of transposition table entries
 */
export declare enum TTEntryType {
    EXACT = 0,// Exact score
    LOWER_BOUND = 1,// Alpha cutoff (fail-high)
    UPPER_BOUND = 2
}
/**
 * Transposition table entry
 */
export interface TTEntry {
    zobristHash: bigint;
    depth: number;
    score: Score;
    type: TTEntryType;
    bestMove: InternalMove | null;
    age: number;
}
/**
 * Transposition Table
 *
 * Implements a hash table with replacement strategy for storing
 * previously evaluated positions.
 */
export declare class TranspositionTable {
    private table;
    private size;
    private currentAge;
    private hits;
    private misses;
    /**
     * Create a new transposition table
     *
     * @param sizeMB - Size in megabytes (default: 16MB)
     */
    constructor(sizeMB?: number);
    /**
     * Store a position in the transposition table
     *
     * @param zobristHash - Position hash
     * @param depth - Search depth
     * @param score - Position score
     * @param type - Entry type
     * @param bestMove - Best move found
     */
    store(zobristHash: bigint, depth: number, score: Score, type: TTEntryType, bestMove: InternalMove | null, ply?: number): void;
    /**
     * Probe the transposition table
     *
     * @param zobristHash - Position hash
     * @param depth - Current search depth
     * @param alpha - Alpha bound
     * @param beta - Beta bound
     * @returns Entry if found and usable, null otherwise
     */
    probe(zobristHash: bigint, depth: number, alpha: Score, beta: Score, ply?: number): TTEntry | null;
    /**
     * Get best move from transposition table (for move ordering)
     *
     * @param zobristHash - Position hash
     * @returns Best move if found, null otherwise
     */
    getBestMove(zobristHash: bigint): InternalMove | null;
    /**
     * Clear the transposition table
     */
    clear(): void;
    /**
     * Increment search age (call at start of new search)
     */
    newSearch(): void;
    /**
     * Get index for a hash value
     *
     * @param hash - Zobrist hash
     * @returns Table index
     */
    private getIndex;
    /**
     * Get cache statistics
     *
     * @returns Statistics object
     */
    getStats(): {
        hits: number;
        misses: number;
        hitRate: number;
        size: number;
    };
}
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