/**
 * @license
 * Copyright 2020 JBoss Inc
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { Topic } from "apicurio-ts-core";
import { Document } from "apicurio-data-models";
/**
 * A service to manage a collection of APIs that should be loaded to accommodate various bits
 * of functionality, but primarily to assist with resolving external references.  This service
 * itself does not resolve external resources, but requires a helper for that.
 *
 * TODO also maintain a list of errors - populated when we fail to resolve a resource URL (and why)
 */
export declare class ApiCatalogService {
    private apiCache;
    private readonly changeTopic;
    private fetchCounter;
    private fetcher;
    /**
     * Constructor.
     */
    constructor();
    /**
     * Sets the fetcher for the service.
     * @param fetcher
     */
    setFetcher(fetcher: (externalReference: string) => Promise<any>): void;
    /**
     * Called to refresh the API cache.  This will remove any cached APIs that are not needed by
     * the given document.
     * @param document
     */
    private refresh;
    /**
     * Called to reset the API cache.  This will remove any cached APIs that are not needed by
     * the given document.
     * @param document
     */
    reset(document: Document): void;
    /**
     * Called when the document changes in any way.  When that happens, we need to detect whether any new
     * external references have been added.  If so, we need to fetch them and update the cache.
     * @param document
     */
    update(document: Document): void;
    /**
     * Return the topic that consumers can use to listen when the contents of the api cache changes.
     */
    changes(): Topic<any>;
    /**
     * Finds all the $refs anywhere in the given document.
     * @param document
     */
    private getAllRefs;
    /**
     * Fetches the given external reference (asynchronously) and caches the result if appropriate.
     * @param externalRef
     */
    private fetchAndCache;
    /**
     * Parses the given response body into a JS object.  This should support both JSON and YAML content.  If
     * parsing fails we should log an error and return null.  That will indicate to any consumers of the
     * cache that there *should* be an entry for the content but that the content failed to be fetched.
     * @param body
     */
    private parseContent;
    /**
     * Extracts the design id from the given external ref of the form: apicurio:173827
     * @param externalRef
     */
    private toDesignId;
    /**
     * Caches the given JS object content.  Also potentially fires a "changed" event.
     * @param content
     */
    private cacheContent;
    /**
     * Called to lookup a resource stored in the catalog.  Returns a JS object if one is found or null
     * if not found.
     * @param resourceUrl
     */
    lookup(resourceUrl: string): any;
}