import { CanActivate, ExecutionContext } from '@nestjs/common';
import { HttpAdapterHost, Reflector } from '@nestjs/core';
import { IRateLimitPluginOptions } from '../../../shared/types';
import { IRateLimitService } from '../../application/ports/rate-limit-service.port';
interface IMetricsService {
    incrementCounter(name: string, labels?: Record<string, string>, value?: number): void;
}
interface ISpan {
    setAttribute(key: string, value: unknown): this;
    addEvent(name: string, attributes?: Record<string, unknown>): this;
    setStatus(status: 'OK' | 'ERROR'): this;
    recordException(error: Error): this;
    end(): void;
}
interface ITracingService {
    startSpan(name: string, options?: {
        kind?: string;
        attributes?: Record<string, unknown>;
    }): ISpan;
}
/**
 * Rate limit guard.
 * Enforces rate limiting based on @RateLimit() decorator configuration.
 */
export declare class RateLimitGuard implements CanActivate {
    private readonly rateLimitService;
    private readonly config;
    private readonly reflector;
    private readonly adapterHost;
    private readonly metrics?;
    private readonly tracing?;
    constructor(rateLimitService: IRateLimitService, config: IRateLimitPluginOptions, reflector: Reflector, adapterHost: HttpAdapterHost, metrics?: IMetricsService | undefined, tracing?: ITracingService | undefined);
    /**
     * Guard activation logic.
     * Checks rate limit and sets response headers.
     */
    canActivate(context: ExecutionContext): Promise<boolean>;
    /**
     * Get rate limit options from decorator metadata.
     * Merges class-level and method-level options.
     */
    private getOptions;
    /**
     * Extract rate limit key from context.
     */
    private extractKey;
    /**
     * Get client IP address.
     */
    private getClientIp;
    /**
     * Get user ID from request.
     */
    private getUserId;
    /**
     * Get API key from request.
     */
    private getApiKey;
    /**
     * Set response headers.
     */
    private setHeaders;
    /**
     * Create error when rate limit exceeded.
     */
    private createError;
    /**
     * Check if rate limiting should be skipped.
     */
    private shouldSkip;
}
export {};
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