import { HttpEvent, HttpRequest, HttpResponse } from '@angular/common/http';
import { Timespan } from '@helgoland/core';
import { Observable } from 'rxjs';

import { CachedIntersection, CachedObject } from './get-data-cache/local-http-cache-interval';

export abstract class HttpCache {
    /**
     * Returns a cached response, if any, or null, if not present.
     */
    public abstract get(req: HttpRequest<any>, expirationAtMs?: number): HttpResponse<any> | null;

    /**
     * Adds or updates the response in the cache.
     */
    public abstract put(req: HttpRequest<any>, resp: HttpResponse<any>, expirationAtMs?: number): void;
}

export abstract class OnGoingHttpCache {
    public abstract has(req: HttpRequest<any>): boolean;
    public abstract set(req: HttpRequest<any>, request: Observable<HttpEvent<any>>): void;
    public abstract observe(req: HttpRequest<any>): Observable<HttpEvent<any>>;
    public abstract clear(req: HttpRequest<any>): void;

}

export abstract class HttpCacheInterval {
    /**
     * Returns a cached response, if any, or null, if not present.
     */
    public abstract get(url: string, generalized: boolean): CachedObject[] | null;
    /**
     * Returns a cached response with intersecting timespans, if any, or null, if not present.
     * Further returns an array of timespans that need to be requested (not covered by cached timespans),
     * if any, or null, if only one cached object covers the requested timespan.
     */
    public abstract getIntersection(url: string, timespan: Timespan, generalized: boolean): CachedIntersection | null;
    /**
     * Saves new object into cache.
     * 'originReq' indicates, if the request is the original request (e.g. forceUpdate), so the cache can be filtered
     */
    public abstract put(url: string, obj: CachedObject, generalized: boolean, originReq?: boolean): void;
}