/**
 * Time Decay Algorithm
 *
 * Score = Confidence × Decay Factor
 * Decay Factor = 0.5^(days / half-life)
 *
 * Default half-life: 90 days
 */
import type { MetaPattern } from '../core/schema.js';
/**
 * Apply time decay to pattern score
 *
 * Uses exponential decay with configurable half-life (default 90 days).
 * Older patterns naturally fade away.
 *
 * @param pattern - Pattern to apply decay to
 * @param halfLifeDays - Half-life in days (default 90)
 * @returns Decayed score
 */
export declare function applyDecay(pattern: MetaPattern, halfLifeDays?: number): number;
/**
 * Apply decay to all patterns and update scores
 *
 * @param patterns - Patterns to apply decay to
 * @param halfLifeDays - Half-life in days (default 90)
 * @returns Updated patterns with decayed scores
 */
export declare function applyDecayToAll(patterns: MetaPattern[], halfLifeDays?: number): MetaPattern[];
/**
 * Get decay factor for a pattern
 *
 * @param daysSinceLastSeen - Days since pattern was last seen
 * @param halfLifeDays - Half-life in days
 * @returns Decay factor [0, 1]
 */
export declare function getDecayFactor(daysSinceLastSeen: number, halfLifeDays: number): number;
/**
 * Estimate when a pattern will decay below threshold
 *
 * @param currentScore - Current score
 * @param threshold - Target threshold
 * @param halfLifeDays - Half-life in days
 * @returns Days until below threshold
 */
export declare function daysUntilBelowThreshold(currentScore: number, threshold: number, halfLifeDays: number): number;
//# sourceMappingURL=decay.d.ts.map