export declare const CURRENT_REDIRECT_START_TIME_SESSION_STORAGE_KEY: string;
export declare const CORRELATION_ID_SESSION_STORAGE_KEY: string;
/**
 * This class is used to manage session storage states needed for redirects when using MSAL.js.
 *
 * Each MSAL.js client, v1 or v2, should create an instance of MsalRedirectManager and:
 *  - Check the result of isAllowedToRedirect() to see if you are allowed to redirect.
 *  - Call prepareForRedirect() before redirecting.
 *  - Call cancelRedirect() if the redirect will be cancelled and prepareRedirect() has already been called.
 * Note that a maximum of 2 redirect attempts may be tried in 1 minute.
 *
 * The session storage information written by this class is expected by spfxsinglesignon.aspx.
 * Any changes to keys or behaviour here should be accompanied with changes to spfxsinglesignon.aspx.
 *
 * @internal
 */
export declare class MsalRedirectManager {
    static _ALLOWED_REDIRECT_ATTEMPTS: number;
    private static _MAX_REDIRECT_TIME_IN_MIN;
    private static _isRedirectInProgress;
    private readonly _STORAGE_KEYS;
    private readonly _authority;
    private readonly _clientId;
    private readonly _shouldUseMsalBrowser;
    /**
     * Creates an MsalRedirectManager to manage the necessary state for redirects.
     *
     * @param authority - The authority string to be used on spfxsinglesignon.aspx when instantiating msal.
     * @param clientId -  The client id string to be used on spfxsignlesignon.aspx when instantiating msal.
     * @param shouldUseMsalBrowser - Whether or not spfxsinglesignon.aspx should use msal-browser.
     */
    constructor(authority: string, clientId: string, shouldUseMsalBrowser: boolean);
    /**
     * Determines if the caller may attempt a redirect and invoke prepareForRedirect(). Redirects can
     * be attempted if:
     *  - There have not been more than ALLOWED_REDIRECT_ATTEMPTS in the last 60 seconds.
     *  - There is no redirect currently in progress.
     *
     * @returns True if the caller can call prepareForRedirect().
     */
    isAllowedToRedirect(): boolean;
    /**
     * This method determines whether or not there are any redirect attempts left.
     * There can be a maximum of ALLOWED_REDIRECT_ATTEMPTS in 60 seconds.
     *
     * @returns True if thre are any redirect attempts left.
     */
    hasRedirectAttemptsLeft(): boolean;
    /**
     * Determines whether or not a redirect is already in progress. The caller should not attempt
     * to redirect if there is a redirect in progress.
     *
     * @returns True if there is currently a redirect in progress.
     */
    isRedirectInProgress(): boolean;
    /**
     * Should be called before attempting to redirect. This method prepares the browser for a redirect by
     * saving necessary state data in session storage.
     *
     * The items saved are:
     *  - authority: Used to configure MSAL on spfxsinglesignon.aspx
     *  - clientId: Used to configure MSAL on spfxsinglesignon.aspx
     *  - redirectUri: Used to determine where to redirect back to on spfxsinglesignon.aspx
     *  - shouldUseMsalBrowser: Used to determine whether to instantiate MSAL.js v1 or v2 on
     *                          spfxsinglesignon.aspx
     *  - isRedirectInProgress: Indicates whether or not a redirect is in progress for either MSAL.js v1 or v2.
     *                          We will not proceed with a redirect if one is in progress.
     *  - isSsoSilent: Used to determine whether or not to instantiate MSAL.js on spfxsinglesignon.aspx.
     *                 This is different than shouldUseMsalBrowser as no instances of MSAL.js v1 or v2 are
     *                 created.
     *
     * These items are deleted from session storage on spfxsinglesignon.aspx before returning to the current
     * page.
     *
     * This method also updates the first redirect time and current redirect attempt count in session storage.
     */
    prepareForRedirect(correlationId?: string): void;
    /**
     * Should be called to cancel a redirect after prepareForRedirect() has already been called.
     * This method clears all the states saved by prepareForRedirect().
     */
    cancelRedirect(): void;
    /**
     * Determines the number of redirect attempts in the last 2 minutes using storage states.
     *
     * @returns The number of redirects in the 2 minutes.
     */
    getCurrentNumberOfRedirectAttempts(): number;
    /**
     * Increments the number of redirect attempts in session storage. If this is the first redirect attempt,
     * this method will also write to the first redirect key.
     */
    private _incrementRedirectAttempts;
    /**
     * This method gets the current number of previous redirect attempts saved in session storage.
     * This does not account for how old the previous redirect attempts are.
     *
     * @returns The current number of previous redirect attempts saved in session storage.
     */
    private _getRedirectAttemptNumberFromSessionStorage;
    /**
     * Given an attempt number, this method will update the current redirect attempt number in session storage.
     * The number is saved as a string.
     *
     * @param attempt - Current attempt number to write to session storage.
     */
    private _setRedirectAttemptNumberInSessionStorage;
    /**
     * Returns the first time a redirect was attempted as a date string. This string can be used in the
     * constructor of a Date object, but only if it is not null.
     *
     * @returns The first attempted redirect time or null if the key is not found.
     */
    private _getFirstRedirectTimeFromSessionStorage;
    /**
     * Creates a date object capturing the current time and saves it to session storage as the first redirect
     * time.
     */
    private _setFirstRedirectTimeInSessionStorage;
    /**
     * Creates a date object capturing the current time while on the current redirect attempt and saves it to session storage as the start time
     * of the current redirect attempt.
     */
    private _setCurrentRedirectTimeInSessionStorage;
}
//# sourceMappingURL=MsalRedirectManager.d.ts.map