/// <reference types="ember" />
import Ember from 'ember';
import EmberObject from '@ember/object';
/**
 * Keeps track of the order of the steps in the step manager, as well as
 * the current step.
 *
 * @class StateMachine
 * @private
 * @hide
 */
export default abstract class StateMachine extends EmberObject {
    /**
     * @property {A} stepTransitions
     * @private
     */
    stepTransitions: Ember.MutableArray<string>;
    /**
     * @property {string} firstStep
     * @private
     */
    firstStep: string;
    /**
     * @property {string} lastStep
     * @private
     */
    lastStep: string;
    /**
     * @property {string} currentStep
     * @public
     */
    currentStep: string;
    stepsToRemove: Ember.NativeArray<string>;
    stepsToAdd: Ember.NativeArray<string>;
    constructor(initialStep: string);
    addStep(this: StateMachine, name: string): void;
    removeStep(this: StateMachine, name: string): void;
    updateFirstCurrentAndLastSteps(this: StateMachine): void;
    abstract pickNext(currentStep?: string): string;
    abstract pickPrevious(currentStep?: string): string;
    activate(name: string): void;
    /**
     * @property {number} length
     * @public
     */
    length: number;
}