import { type Step } from "./engine.ts";
import type { Event, Run, ScenarioInfo, Spec, World } from "./spec.ts";
/** Most events one settle runs: left alone, a retry loop never ends by itself. */
export declare const SETTLE_LIMIT = 200;
export declare class Runner {
    readonly spec: Spec;
    readonly seed: number;
    readonly events: Event[];
    readonly worlds: World[];
    readonly initial: World;
    private current;
    constructor(spec: Spec, seed?: number, 
    /** Where to start; by default the spec's start, where the singletons exist, in their initial state. */
    initial?: World);
    get world(): World;
    apply(step: Step): Event;
    spawn(actor: string, label: string): Event;
    act(instance: string, key: string, inputs?: Record<string, unknown>): Event;
    /** What the system does next left alone: a fair guarded transition that holds, else the next message, else the next timer. A step with `fair: false`, such as a fault, waits to be asked for. */
    next(): Event | null;
    /** Leave the system alone until nothing is pending, or for SETTLE_LIMIT events. */
    settle(): void;
    /** Leave the system alone until `until` holds; an error if it settles, or runs SETTLE_LIMIT events, first. */
    settleUntil(until: (world: World) => boolean): void;
    /** Fire an instance's timer now, ahead of anything in flight. */
    fireTimer(instance: string, timer: string): Event;
    /** A message in flight to `instance`: the oldest named `message`, or the oldest carrying `payload`. */
    inFlight(instance: string, message: string, payload?: unknown): number;
    deliver(instance: string, message: string, payload?: unknown): Event;
    /** One of an instance's steps, by name: on a message, it takes the oldest it is on in flight; else a guard. */
    step(instance: string, name: string, payload?: unknown): Event;
    guard(instance: string, transition: string): Event;
    run(): Run;
}
/** Run a scenario, from the world its setup sets, or from the spec's start. */
export declare function runScenario(spec: Spec, scenario: ScenarioInfo, seed?: number): Run & {
    error?: string;
};
/** The world a scenario starts in: the spec's start, with the scenario's setup applied. */
export declare function scenarioStart(spec: Spec, scenario: ScenarioInfo, seed?: number): World;