/**
 * @fileoverview Circuit breaker implementation for fault tolerance
 * This module implements the circuit breaker pattern to prevent cascade failures.
 */
/**
 * Circuit breaker states
 * @enum
 * @public
 */
export declare enum CircuitState {
    /** Normal operation - requests pass through */
    CLOSED = "closed",
    /** Circuit is open - requests fail immediately */
    OPEN = "open",
    /** Testing if service has recovered */
    HALF_OPEN = "half-open"
}
/**
 * Circuit breaker configuration
 * @interface
 * @public
 */
export interface CircuitBreakerConfig {
    /** Number of failures before opening circuit */
    failureThreshold: number;
    /** Time window for counting failures (ms) */
    failureWindow: number;
    /** Time to wait before attempting recovery (ms) */
    recoveryTimeout: number;
    /** Number of successful requests needed to close from half-open */
    successThreshold: number;
    /** Maximum number of test requests in half-open state */
    halfOpenMaxAttempts: number;
}
/**
 * Circuit breaker statistics
 * @interface
 * @public
 */
export interface CircuitBreakerStats {
    /** Current circuit state */
    state: CircuitState;
    /** Number of failures in current window */
    failureCount: number;
    /** Number of successful requests */
    successCount: number;
    /** Total requests processed */
    totalRequests: number;
    /** Time when circuit was last opened */
    lastOpenTime?: number;
    /** Time when circuit was last closed */
    lastCloseTime?: number;
    /** Success rate percentage */
    successRate: number;
}
/**
 * Circuit breaker implementation
 * @class
 * @public
 */
export declare class CircuitBreaker {
    private state;
    private failures;
    private successes;
    private lastStateChange;
    private halfOpenAttempts;
    private totalRequests;
    private readonly config;
    private readonly name;
    /**
     * Creates a new circuit breaker instance
     * @param name The name of this circuit breaker (for logging)
     * @param config Optional configuration overrides
     */
    constructor(name: string, config?: Partial<CircuitBreakerConfig>);
    /**
     * Check if a request should be allowed through
     * @returns True if the request can proceed
     * @public
     */
    canRequest(): boolean;
    /**
     * Record a successful request
     * @public
     */
    recordSuccess(): void;
    /**
     * Record a failed request
     * @public
     */
    recordFailure(): void;
    /**
     * Get current circuit breaker statistics
     * @returns The current statistics
     * @public
     */
    getStats(): CircuitBreakerStats;
    /**
     * Reset the circuit breaker to closed state
     * @public
     */
    reset(): void;
    /**
     * Get the current state
     * @returns The current circuit state
     * @public
     */
    getState(): CircuitState;
    /**
     * Transition to a new state
     * @param newState The new state to transition to
     * @private
     */
    private transitionTo;
    /**
     * Clean up old entries outside the time window
     * @private
     */
    private cleanupOldEntries;
    /**
     * Get the count of recent failures within the time window
     * @returns The number of recent failures
     * @private
     */
    private getRecentFailureCount;
    /**
     * Get the count of recent successes within the time window
     * @returns The number of recent successes
     * @private
     */
    private getRecentSuccessCount;
}
/**
 * Circuit breaker manager for managing multiple circuit breakers
 * @class
 * @public
 */
export declare class CircuitBreakerManager {
    private static instance;
    private breakers;
    /**
     * Get the singleton instance
     * @returns The circuit breaker manager instance
     * @public
     */
    static getInstance(): CircuitBreakerManager;
    /**
     * Get or create a circuit breaker for an endpoint
     * @param endpoint The endpoint name
     * @param config Optional configuration overrides
     * @returns The circuit breaker instance
     * @public
     */
    getBreaker(endpoint: string, config?: Partial<CircuitBreakerConfig>): CircuitBreaker;
    /**
     * Get statistics for all circuit breakers
     * @returns Map of endpoint to statistics
     * @public
     */
    getAllStats(): Map<string, CircuitBreakerStats>;
    /**
     * Reset all circuit breakers
     * @public
     */
    resetAll(): void;
    /**
     * Clear all circuit breakers (for testing)
     * @public
     */
    clear(): void;
}