import { EventEmitter } from 'node:events';
/**
 * Interface for rate limit configuration
 */
export interface IRateLimitConfig {
    maxMessagesPerMinute?: number;
    maxRecipientsPerMessage?: number;
    maxConnectionsPerIP?: number;
    maxErrorsPerIP?: number;
    maxAuthFailuresPerIP?: number;
    blockDuration?: number;
}
/**
 * Interface for hierarchical rate limits
 */
export interface IHierarchicalRateLimits {
    global: IRateLimitConfig;
    patterns?: Record<string, IRateLimitConfig>;
    ips?: Record<string, IRateLimitConfig>;
    domains?: Record<string, IRateLimitConfig>;
    blocks?: Record<string, number>;
}
/**
 * Rate limiter statistics
 */
export interface IRateLimiterStats {
    activeCounters: number;
    totalBlocked: number;
    currentlyBlocked: number;
    byPattern: Record<string, {
        messagesPerMinute: number;
        totalMessages: number;
        totalBlocked: number;
    }>;
    byIp: Record<string, {
        messagesPerMinute: number;
        totalMessages: number;
        totalBlocked: number;
        connections: number;
        errors: number;
        authFailures: number;
        blocked: boolean;
    }>;
}
/**
 * Result of a rate limit check
 */
export interface IRateLimitResult {
    allowed: boolean;
    reason?: string;
    limit?: number;
    current?: number;
    resetIn?: number;
}
/**
 * Unified rate limiter for all email processing modes
 */
export declare class UnifiedRateLimiter extends EventEmitter {
    private config;
    private counters;
    private patternCounters;
    private ipCounters;
    private domainCounters;
    private cleanupInterval?;
    private stats;
    /**
     * Create a new unified rate limiter
     * @param config Rate limit configuration
     */
    constructor(config: IHierarchicalRateLimits);
    /**
     * Start the cleanup interval
     */
    private startCleanupInterval;
    /**
     * Stop the cleanup interval
     */
    stop(): void;
    /**
     * Destroy the rate limiter and clean up all resources
     */
    destroy(): void;
    /**
     * Clean up expired counters and blocks
     */
    private cleanup;
    /**
     * Check if a message is allowed by rate limits
     * @param email Email address
     * @param ip IP address
     * @param recipients Number of recipients
     * @param pattern Matched pattern
     * @param domain Domain name for domain-specific limits
     * @returns Result of rate limit check
     */
    checkMessageLimit(email: string, ip: string, recipients: number, pattern?: string, domain?: string): IRateLimitResult;
    /**
     * Check global message rate limit
     * @param email Email address
     */
    private checkGlobalMessageLimit;
    /**
     * Check pattern-specific message rate limit
     * @param pattern Pattern to check
     */
    private checkPatternMessageLimit;
    /**
     * Check domain-specific message rate limit
     * @param domain Domain to check
     */
    private checkDomainMessageLimit;
    /**
     * Check IP-specific message rate limit
     * @param ip IP address
     */
    private checkIpMessageLimit;
    /**
     * Check recipient limit
     * @param email Email address
     * @param recipients Number of recipients
     * @param pattern Matched pattern
     * @param domain Domain name
     */
    private checkRecipientLimit;
    /**
     * Record a connection from an IP
     * @param ip IP address
     * @returns Result of rate limit check
     */
    recordConnection(ip: string): IRateLimitResult;
    /**
     * Record an error from an IP
     * @param ip IP address
     * @returns True if IP should be blocked
     */
    recordError(ip: string): boolean;
    /**
     * Record an authentication failure from an IP
     * @param ip IP address
     * @returns True if IP should be blocked
     */
    recordAuthFailure(ip: string): boolean;
    /**
     * Block an IP address
     * @param ip IP address to block
     * @param duration Override the default block duration (milliseconds)
     */
    blockIp(ip: string, duration?: number): void;
    /**
     * Unblock an IP address
     * @param ip IP address to unblock
     */
    unblockIp(ip: string): void;
    /**
     * Check if an IP is blocked
     * @param ip IP address to check
     */
    isIpBlocked(ip: string): boolean;
    /**
     * Get the time until a block is released
     * @param ip IP address
     * @returns Milliseconds until release or 0 if not blocked
     */
    getBlockReleaseTime(ip: string): number;
    /**
     * Update rate limiter statistics
     */
    private updateStats;
    /**
     * Get rate limiter statistics
     */
    getStats(): IRateLimiterStats;
    /**
     * Update rate limiter configuration
     * @param config New configuration
     */
    updateConfig(config: Partial<IHierarchicalRateLimits>): void;
    /**
     * Get configuration for debugging
     */
    getConfig(): IHierarchicalRateLimits;
    /**
     * Apply domain-specific rate limits
     * Merges domain limits with existing configuration
     * @param domain Domain name
     * @param limits Rate limit configuration for the domain
     */
    applyDomainLimits(domain: string, limits: IRateLimitConfig): void;
    /**
     * Remove domain-specific rate limits
     * @param domain Domain name
     */
    removeDomainLimits(domain: string): void;
    /**
     * Get domain-specific rate limits
     * @param domain Domain name
     * @returns Domain rate limit config or undefined
     */
    getDomainLimits(domain: string): IRateLimitConfig | undefined;
}