/**
 * @module CircuitBreaker
 */
import { type CIRCUIT_BREAKER_STATE } from "../../circuit-breaker/contracts/circuit-breaker-state.contract.js";
/**
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type CircuitBreakerHalfOpenState<TMetrics = unknown> = {
    type: typeof CIRCUIT_BREAKER_STATE.HALF_OPEN;
    metrics: TMetrics;
};
/**
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type CircuitBreakerClosedState<TMetrics = unknown> = {
    type: typeof CIRCUIT_BREAKER_STATE.CLOSED;
    metrics: TMetrics;
};
/**
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type CircuitBreakerTrackState<TMetrics = unknown> = CircuitBreakerClosedState<TMetrics> | CircuitBreakerHalfOpenState<TMetrics>;
/**
 * The constant represents all available state transition when in closed state
 *
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export declare const CLOSED_TRANSITIONS: {
    /**
     * This field indicates that circuit breaker will transition from closed to open state.
     */
    readonly TO_OPEN: "TO_OPEN";
    /**
     * This field indicates that circuite breaker will stay in closed state and not transition.
     */
    readonly NONE: "NONE";
};
/**
 * Indicates all available state transition when in closed state
 *
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type ClosedTransitions = (typeof CLOSED_TRANSITIONS)[keyof typeof CLOSED_TRANSITIONS];
/**
 * The constant represents all available state transition when in half open state
 *
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export declare const HALF_OPEN_TRANSITIONS: {
    /**
     * This field indicates that circuit breaker will transition from half open to open state.
     */
    readonly TO_OPEN: "TO_OPEN";
    /**
     * This field indicates that circuit breaker will transition from half openb to closed state.
     */
    readonly TO_CLOSED: "TO_CLOSED";
    /**
     * This field indicates that circuite breaker will stay in half open state and not transition.
     */
    readonly NONE: "NONE";
};
/**
 * Indicates all available state transition when in half open state
 *
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type HalfOpenTransitions = (typeof HALF_OPEN_TRANSITIONS)[keyof typeof HALF_OPEN_TRANSITIONS];
/**
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type CircuitBreakerTrackSettings<TMetrics = unknown> = {
    currentDate: Date;
    initialMetrics: TMetrics;
};
/**
 * The `ICircuitBreakerPolicy` contract defines the circuite breaker algorithm.
 * Note all the methods here are pure functions, meaning they should return copies and not mutate input data.
 *
 * IMPORT_PATH: `"@daiso-tech/core/circuit-breaker/contracts"`
 * @group Contracts
 */
export type ICircuitBreakerPolicy<TMetrics = unknown> = {
    initialMetrics(): TMetrics;
    /**
     * The `whenClosed` method should use `currentMetrics` and if needed `currentDate` to transition to open state or stay in closed state.
     */
    whenClosed(currentMetrics: TMetrics, currentDate: Date): ClosedTransitions;
    /**
     * The `whenHalfOpened` method should use `currentMetrics` and if needed `currentDate` to transition to open state, closed state or stay in half open state.
     */
    whenHalfOpened(currentMetrics: TMetrics, currentDate: Date): HalfOpenTransitions;
    /**
     * The `trackFailure` method updates the metrics when failure occurs. The metrics will be used `whenClosed` and `whenHalfOpen` methods.
     */
    trackFailure(currentState: CircuitBreakerTrackState<TMetrics>, settings: CircuitBreakerTrackSettings<TMetrics>): TMetrics;
    /**
     * The `trackSuccess` method updates the metrics when success occurs.
     */
    trackSuccess(currentState: CircuitBreakerTrackState<TMetrics>, settings: CircuitBreakerTrackSettings<TMetrics>): TMetrics;
    /**
     * The `isEqual` method should return true only when both metrics are equal.
     * This method is optional, it is only used for optimization purposes.
     */
    isEqual?(metricsA: TMetrics, metricsB: TMetrics): boolean;
};