import { HttpClient, HttpRequest } from '@angular/common/http';
import { InjectionToken, NgZone } from '@angular/core';
import { MatSnackBar } from '@angular/material/snack-bar';
import { Observable } from 'rxjs';
import { RequestMetadataInternal } from '../models/request-metadata-internal.model';
/**
 * The Generic Base EntityType.
 */
export type BaseEntityType<T> = {
    [K in keyof T]: unknown;
};
export declare const NGX_PWA_OFFLINE_SERVICE: InjectionToken<void>;
/**
 * The type of a cached offline request.
 * Contains the http request as well as some metadata.
 */
export interface CachedRequest<T> {
    /**
     * The actual http request.
     */
    request: HttpRequest<T>;
    /**
     * The metadata for that request.
     */
    metadata: RequestMetadataInternal;
}
/**
 * The base class for an offline service.
 */
export declare class NgxPwaOfflineService {
    private readonly http;
    private readonly snackBar;
    private readonly zone;
    private readonly platformId;
    /**
     * The key under which any requests are saved in local storage.
     */
    readonly CACHED_REQUESTS_KEY: string;
    /**
     * The prefix of offline generated ids.
     * Is used to check if a request still has unresolved dependencies.
     */
    readonly OFFLINE_ID_PREFIX: string;
    /**
     * A snackbar message to display when the synchronization of all cached requests has been finished.
     */
    protected readonly ALL_SYNC_FINISHED_SNACK_BAR_MESSAGE: string;
    /**
     * A snackbar message to display when the synchronization of all cached requests fails.
     */
    protected readonly ALL_SYNC_FAILED_SNACK_BAR_MESSAGE: string;
    /**
     * A snackbar message to display when the synchronization of a single cached requests has been finished.
     */
    protected readonly SINGLE_SYNC_FINISHED_SNACK_BAR_MESSAGE: string;
    /**
     * A snackbar message to display when the synchronization of a single cached requests fails.
     */
    protected readonly SINGLE_SYNC_FAILED_SNACK_BAR_MESSAGE: string;
    /**
     * Whether or not the user has no internet connection.
     */
    isOffline: boolean;
    /**
     * A subject of all the requests that have been done while offline.
     * Needs to be used for applying offline data or syncing the requests to the api.
     */
    private readonly cachedRequestsSubject;
    /**
     * The currently stored cached requests (if there are any).
     */
    get cachedRequests(): CachedRequest<unknown>[];
    set cachedRequests(cachedRequests: CachedRequest<unknown>[]);
    constructor(http: HttpClient, snackBar: MatSnackBar, zone: NgZone, platformId: Object);
    /**
     * Applies any offline data that has been cached to the given values.
     * @param type - The type of the provided entities. Is needed to check if any cached requests of the same type exist.
     * @param entities - The already existing data.
     * @returns The already existing entities extended/modified by the offline cached requests.
     */
    applyOfflineData<EntityType extends BaseEntityType<EntityType>>(type: string, entities: EntityType[]): EntityType[];
    /**
     * Applies an UPDATE to an entity without sending a request to the server.
     * @param changes - The changes that should be made to the entity.
     * @param entity - The entity that should be updated.
     * @returns The updated entity.
     */
    protected updateOffline<EntityType extends BaseEntityType<EntityType>>(changes: Partial<EntityType>, entity: EntityType): EntityType;
    /**
     * Sends a specific cached request to the server.
     * @param request - The request that should be synced.
     */
    sync<T>(request: CachedRequest<T>): Promise<void>;
    /**
     * Sends all cached requests to the server. Tries to handle dependencies of requests on each other.
     */
    syncAll(): Promise<void>;
    /**
     * The recursive method used to syn all requests to the api.
     */
    protected syncAllRecursive(): Promise<void>;
    /**
     * Sends a single cached request to the server.
     * @param request - The request that should be synced.
     * @returns A promise of the request result.
     */
    protected syncSingleRequest<T>(request: CachedRequest<T>): Promise<T>;
    private updateOfflineIdsInRequests;
    /**
     * Calls http.post/patch/delete etc. On the provided request.
     * @param request - The request that should be sent.
     * @returns The observable of the request or undefined if something went wrong.
     */
    protected request<EntityType extends BaseEntityType<EntityType>>(request: CachedRequest<EntityType>): Observable<EntityType> | undefined;
    /**
     * Checks if the given request has an unresolved dependency by looking for the keyword 'offline' inside of it.
     * @param request - The request that should be checked.
     * @returns Whether or no the given request has an unresolved dependency.
     */
    hasUnresolvedDependency(request: CachedRequest<unknown>): boolean;
    /**
     * Removes a single request from the cache.
     * @param request - The request that should be removed.
     */
    removeSingleRequest(request: CachedRequest<unknown>): void;
}