import { Context, internal, LDLogger } from '@launchdarkly/js-sdk-common';
import FlagStore from './FlagStore';
import { ItemDescriptor } from './ItemDescriptor';
export type FlagChangeType = 'init' | 'patch' | 'override';
/**
 * This callback indicates that the details associated with one or more flags
 * have changed.
 *
 * This could be the value of the flag, but it could also include changes
 * to the evaluation reason, such as being included in an experiment.
 *
 * It can include new or deleted flags as well, so an evaluation may result
 * in a FLAG_NOT_FOUND reason.
 *
 * This event does not include the value of the flag. It is expected that you
 * will call a variation method for flag values which you require.
 */
export type FlagsChangeCallback = (context: Context, flagKeys: Array<string>, type: FlagChangeType) => void;
/**
 * The flag updater handles logic required during the flag update process.
 * It handles versions checking to handle out of order flag updates and
 * also handles flag comparisons for change notification.
 */
export interface FlagUpdater {
    /**
     * Handles the flag changes by calling the change callbacks.
     *
     * @param keys keys of the flags that changed
     * @param type type of change that occurred see {@link FlagChangeType}
     */
    handleFlagChanges(keys: string[], type: FlagChangeType): void;
    /**
     * Initializes the flag updater with the given context and flags.
     * This will be called every time a new context is identified.
     *
     * @param context the context to initialize the flag updater with
     * @param newFlags the flags to initialize the flag updater with
     */
    init(context: Context, newFlags: {
        [key: string]: ItemDescriptor;
    }): void;
    initCached(context: Context, newFlags: {
        [key: string]: ItemDescriptor;
    }): void;
    /**
     * Upserts the flag with the given key and item.
     *
     * @param context the context to upsert the flag with
     * @param key the key of the flag to upsert
     * @param item the item to upsert the flag with
     * @returns true if the flag was upserted, false otherwise
     */
    upsert(context: Context, key: string, item: ItemDescriptor): boolean;
    /**
     * Applies a changeset directly to the flag store, bypassing version checks
     * and inactive-context guards. Used by the FDv2 data path where ordering
     * is handled at the protocol layer.
     *
     * - `'full'`: replaces all flags and emits change events for differences.
     * - `'partial'`: merges updates and emits change events for each key.
     * - `'none'`: no flag changes (caller handles freshness separately).
     */
    applyChanges(context: Context, updates: {
        [key: string]: ItemDescriptor;
    }, type: internal.PayloadType): void;
    /**
     * Registers a callback to be called when the flags change.
     *
     * @param callback the callback to register
     */
    on(callback: FlagsChangeCallback): void;
    /**
     * Unregisters a callback to be called when the flags change.
     *
     * @param callback the callback to unregister
     */
    off(callback: FlagsChangeCallback): void;
}
export default function createFlagUpdater(_flagStore: FlagStore, _logger: LDLogger): FlagUpdater;
//# sourceMappingURL=FlagUpdater.d.ts.map