/**
 * Token Bucket Rate Limiter
 *
 * Implements a token bucket algorithm for rate limiting API requests.
 * Supports both request-based and token-based limits.
 */
import type { RateLimiterConfig, RateLimiterStats, RateLimiter, AcquireResult } from './types.js';
/**
 * Token bucket rate limiter implementation
 *
 * Uses the token bucket algorithm:
 * - Tokens are added at a constant rate (refill rate)
 * - Each request consumes tokens
 * - If insufficient tokens, request waits or fails
 *
 * @example
 * ```typescript
 * const limiter = new TokenBucketRateLimiter({
 *   requestsPerMinute: 60,
 *   tokensPerMinute: 100000,
 *   maxConcurrent: 5,
 * });
 *
 * // Before making a request
 * await limiter.acquire(1000); // estimated tokens
 *
 * try {
 *   const result = await makeRequest();
 *   limiter.reportUsage(actualTokens);
 * } finally {
 *   limiter.release();
 * }
 * ```
 */
export declare class TokenBucketRateLimiter implements RateLimiter {
    private readonly config;
    private requestTokens;
    private lastRequestRefill;
    private llmTokens;
    private lastTokenRefill;
    private concurrent;
    private totalRequests;
    private totalTokens;
    private rateLimitHits;
    private totalWaitTimeMs;
    private waiters;
    constructor(config?: RateLimiterConfig);
    /**
     * Acquire permission to make a request
     */
    acquire(estimatedTokens?: number): Promise<AcquireResult>;
    /**
     * Release a concurrent request slot
     */
    release(): void;
    /**
     * Report actual token usage
     */
    reportUsage(tokens: number): void;
    /**
     * Get current statistics
     */
    getStats(): RateLimiterStats;
    /**
     * Reset the rate limiter
     */
    reset(): void;
    /**
     * Check if a request can be made immediately
     */
    canAcquire(estimatedTokens?: number): boolean;
    /**
     * Refill token buckets based on elapsed time
     */
    private refill;
    /**
     * Check if can acquire without refilling
     */
    private canAcquireNow;
    /**
     * Actually acquire the tokens
     */
    private doAcquire;
    /**
     * Estimate wait time until tokens are available
     */
    private estimateWaitTime;
    /**
     * Wait and try to acquire
     */
    private waitAndAcquire;
    /**
     * Process waiting requests
     */
    private processWaiters;
}
/**
 * Create a rate limiter with the given configuration
 */
export declare function createRateLimiter(config?: RateLimiterConfig): RateLimiter;
/**
 * Create a no-op rate limiter (for testing or unlimited access)
 */
export declare function createNoopRateLimiter(): RateLimiter;