import { environment } from './../../../../environments/environment';
import { Observable } from 'rxjs';
import { HttpClient } from '@angular/common/http';
import { LinksModel } from './../../models/links/links.model';
import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class LinksService {

  links: LinksModel[];

  constructor(
    private http: HttpClient,
  ) {}


  /**
   * method to be use when calling api for HATEOAS
   * @param type (i.e. authentication, user, usergroup etc.)
   * @param rel relative
   * @param payload
   */
  action<T>(type: string, rel: string, payload?: any): Observable<T> {
    this.links = JSON.parse(localStorage.getItem('links'))[type];
    const link = this.links.find(l => String(l.rel).toLowerCase() === rel.toLowerCase());
    const url = link.href;
    const method = link.method;

    switch (method) {
      case 'GET': {
        return this.http.get<T>(`${environment.link}` + url);
      }
      case 'PUT': {
        return this.http.put<T>(`${environment.link}` + url, payload);
      }
      case 'POST': {
        return this.http.post<T>(`${environment.link}` + url, payload);
      }
      case 'DELETE': {
        return this.http.delete<T>(`${environment.link}` + url);
      }
    }
  }

  /**
   * responsible for adding links to localstorage
   * @param type (i.e. authentication, user, usergroup etc.)
   * @param links list of links
   * @return void
   */
  addLinks(type: string, links: LinksModel[]) {
    // check if links not exist
    if (localStorage.getItem('links') === null) {
      const data = { [type]: links };
      localStorage.setItem('links', JSON.stringify(data));
    } else {
      // insert type into the links
      const link = JSON.parse(localStorage.getItem('links'));
      link[type] = links;
      localStorage.setItem('links', JSON.stringify(link));
    }
  }


}