import DataSourceStatusErrorInfo from './DataSourceStatusErrorInfo';
/**
 * The initial state of the data source when the SDK is being
 * initialized.
 *
 * If it encounters an error that requires it to retry initialization,
 * the state will remain at Initializing until it either succeeds and
 * becomes {@link DataSourceValidState}, or permanently fails and becomes
 * {@link DataSourceClosedState}.
 */
export type DataSourceInitializingState = 'INITIALIZING';
/**
 * Indicates that the data source is currently operational and has not
 * had any problems since the last time it recieved data.
 *
 * In streaming mode, this means that there is currently an open stream
 * connection and that at least one initial message has been recieved on
 * the stream. In polling mode, this means that the last poll request
 * succeeded.
 */
export type DataSourceValidState = 'VALID';
/**
 * Indicates that the data source encountered an error that it will
 * attempt to recover from.
 *
 * In streaming mode, this means that the stream connection failed, or
 * had to be dropped due to some other error, and will be retried after
 * a backoff delay. In polling mode, it means that the last poll request
 * failed, and a new poll request will be made after the configured
 * polling interval.
 *
 * @remarks
 * Currently, support for this state is unreliable in the client-side SDKs
 * due to limitations with default EventSource implementations. We do not
 * recommend solely relying on this state for your application logic.
 */
export type DataSourceInterruptedState = 'INTERRUPTED';
/**
 * Indicates that the application has told the SDK to stay offline.
 */
export type DataSourceSetOfflineState = 'SET_OFFLINE';
/**
 * Indicates that the data source has been permanently closed.
 *
 * This could be because it encountered an unrecoverable error (for
 * instance, the LaunchDarkly service rejected the client key; an invalid
 * client key will never become valid), or because the SDK client was
 * explicitly shut down.
 */
export type DataSourceClosedState = 'CLOSED';
export type DataSourceState = DataSourceInitializingState | DataSourceValidState | DataSourceInterruptedState | DataSourceSetOfflineState | DataSourceClosedState;
export default interface DataSourceStatus {
    /**
     * An enumerated value representing the overall current state of the data source.
     */
    readonly state: DataSourceState;
    /**
     * The UNIX epoch timestamp in milliseconds that the value of State most recently changed.
     *
     * The meaning of this depends on the current state:
     * For 'INITIALIZING', it is the time that the datasource started
     * attempting to retrieve data.
     *
     * For 'VALID', it is the time that the data source most
     * recently entered a valid state, after previously having been
     * 'INITIALIZING' or an invalid state such as
     * 'INTERRUPTED'.
     *
     * - For 'INTERRUPTED', it is the time that the data source
     * most recently entered an error state, after previously having been
     * 'VALID'.
     *
     * For 'CLOSED', it is the time that the data source
     * encountered an unrecoverable error or that the datasource was explicitly closed.
     */
    readonly stateSince: number;
    /**
     * The last error encountered. May be absent after application restart.
     */
    readonly lastError?: DataSourceStatusErrorInfo;
}
export declare const DataSourceState: {
    readonly Initializing: 'INITIALIZING';
    readonly Valid: 'VALID';
    readonly Interrupted: 'INTERRUPTED';
    readonly SetOffline: 'SET_OFFLINE';
    readonly Closed: 'CLOSED';
};
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