/**
 * Sliding window rate limiter — in-memory, resets on Gate restart.
 *
 * Tracks request timestamps per credential and enforces configurable
 * rate limits like "100/min", "1000/hour", "10/sec".
 *
 * This is intentionally simple for v0.2. A persistent rate limiter
 * backed by Redis or SQLite is planned for later phases.
 */
export interface RateLimit {
    /** Maximum number of requests in the window */
    maxRequests: number;
    /** Window size in milliseconds */
    windowMs: number;
}
export interface RateLimitResult {
    allowed: boolean;
    /** Seconds until the client should retry (only set when blocked) */
    retryAfterSeconds?: number;
    /** How many requests remain in the current window */
    remaining: number;
    /** Total limit for the window */
    limit: number;
}
/**
 * Parse a rate limit string like "100/min" into a structured RateLimit.
 *
 * Supported formats:
 *   - "100/min" or "100/minute"
 *   - "1000/hour" or "1000/hr"
 *   - "10/sec" or "10/second"
 *   - "5000/day"
 */
export declare function parseRateLimit(input: string): RateLimit;
/**
 * Format a RateLimit back to a human-readable string.
 */
export declare function formatRateLimit(limit: RateLimit): string;
export declare class RateLimiter {
    /**
     * Map from credential ID → array of request timestamps (epoch ms).
     * Timestamps outside the window are pruned on each check.
     */
    private windows;
    /**
     * Check if a request for the given credential is allowed under its rate limit.
     * Records the request timestamp if allowed.
     */
    check(credentialId: string, limit: RateLimit): RateLimitResult;
    /**
     * Reset rate limit state for a specific credential (e.g. after rotation).
     */
    reset(credentialId: string): void;
    /**
     * Clear all rate limit state.
     */
    clear(): void;
}
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