import { internal } from '@launchdarkly/js-sdk-common';
import DataSourceStatusErrorInfo from '../DataSourceStatusErrorInfo';
/**
 * Possible states for a status result from an FDv2 data source.
 *
 * - `interrupted`: Transient error; synchronizer will retry automatically.
 * - `shutdown`: Graceful shutdown; no further results will be produced.
 * - `terminal_error`: Unrecoverable error; no further results will be produced.
 * - `goodbye`: Server-initiated disconnect; no further results will be produced.
 */
export type SourceState = 'interrupted' | 'shutdown' | 'terminal_error' | 'goodbye';
/**
 * A change set result containing a processed FDv2 payload.
 */
export interface ChangeSetResult {
    type: 'changeSet';
    payload: internal.Payload;
    fdv1Fallback: boolean;
    environmentId?: string;
    /** Freshness timestamp from cache, if this result originated from cached data. */
    freshness?: number;
}
/**
 * A status result indicating a state transition (error, shutdown, goodbye).
 */
export interface StatusResult {
    type: 'status';
    state: SourceState;
    errorInfo?: DataSourceStatusErrorInfo;
    reason?: string;
    fdv1Fallback: boolean;
}
/**
 * The result type for FDv2 initializers and synchronizers.
 *
 * An initializer produces a single result, while a synchronizer produces a
 * stream of results. Each result is either a change set (containing a payload
 * of flag data) or a status (indicating a state transition like an error or
 * shutdown).
 */
export type FDv2SourceResult = ChangeSetResult | StatusResult;
/**
 * Creates a change set result containing processed flag data.
 */
export declare function changeSet(payload: internal.Payload, fdv1Fallback: boolean, environmentId?: string, freshness?: number): FDv2SourceResult;
/**
 * Creates an interrupted status result. Indicates a transient error; the
 * synchronizer will attempt to recover automatically.
 *
 * When used with an initializer, this is still a terminal state.
 */
export declare function interrupted(errorInfo: DataSourceStatusErrorInfo, fdv1Fallback: boolean): FDv2SourceResult;
/**
 * Creates a shutdown status result. Indicates the data source was closed
 * gracefully and will not produce any further results.
 */
export declare function shutdown(): FDv2SourceResult;
/**
 * Creates a terminal error status result. Indicates an unrecoverable error;
 * the data source will not produce any further results.
 */
export declare function terminalError(errorInfo: DataSourceStatusErrorInfo, fdv1Fallback: boolean): FDv2SourceResult;
/**
 * Creates a goodbye status result. Indicates the server has instructed the
 * client to disconnect.
 */
export declare function goodbye(reason: string, fdv1Fallback: boolean): FDv2SourceResult;
/**
 * Helper to create a {@link DataSourceStatusErrorInfo} from an HTTP status code.
 */
export declare function errorInfoFromHttpError(statusCode: number): DataSourceStatusErrorInfo;
/**
 * Helper to create a {@link DataSourceStatusErrorInfo} from a network error.
 */
export declare function errorInfoFromNetworkError(message: string): DataSourceStatusErrorInfo;
/**
 * Helper to create a {@link DataSourceStatusErrorInfo} from invalid data.
 */
export declare function errorInfoFromInvalidData(message: string): DataSourceStatusErrorInfo;
/**
 * Helper to create a {@link DataSourceStatusErrorInfo} for unknown errors.
 */
export declare function errorInfoFromUnknown(message: string): DataSourceStatusErrorInfo;
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