///
/// Copyright © 2016-2022 The Thingsboard Authors
///
/// 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 { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { PageLink } from '@shared/models/page/page-link';
import { defaultHttpOptionsFromConfig, RequestConfig } from '@core/http/http-utils';
import { forkJoin, Observable, of } from 'rxjs';
import { PageData } from '@shared/models/page/page-data';
import { Resource, ResourceInfo } from '@shared/models/resource.models';
import { catchError, map, mergeMap } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class ResourceService {
  constructor(
    private http: HttpClient
  ) {

  }

  public getResources(pageLink: PageLink, config?: RequestConfig): Observable<PageData<ResourceInfo>> {
    return this.http.get<PageData<ResourceInfo>>(`/api/resource${pageLink.toQuery()}`,
      defaultHttpOptionsFromConfig(config));
  }

  public getResource(resourceId: string, config?: RequestConfig): Observable<Resource> {
    return this.http.get<Resource>(`/api/resource/${resourceId}`, defaultHttpOptionsFromConfig(config));
  }

  public downloadResource(resourceId: string): Observable<any> {
    return this.http.get(`/api/resource/${resourceId}/download`, {
      responseType: 'arraybuffer',
      observe: 'response'
    }).pipe(
      map((response) => {
        const headers = response.headers;
        const filename = headers.get('x-filename');
        const contentType = headers.get('content-type');
        const linkElement = document.createElement('a');
        try {
          const blob = new Blob([response.body], {type: contentType});
          const url = URL.createObjectURL(blob);
          linkElement.setAttribute('href', url);
          linkElement.setAttribute('download', filename);
          const clickEvent = new MouseEvent('click',
            {
              view: window,
              bubbles: true,
              cancelable: false
            }
          );
          linkElement.dispatchEvent(clickEvent);
          return null;
        } catch (e) {
          throw e;
        }
      })
    );
  }

  public saveResources(resources: Resource[], config?: RequestConfig): Observable<Resource[]> {
    let partSize = 100;
    partSize = resources.length > partSize ? partSize : resources.length;
    const resourceObservables: Observable<Resource>[] = [];
    for (let i = 0; i < partSize; i++) {
      resourceObservables.push(this.saveResource(resources[i], config).pipe(catchError(() => of({} as Resource))));
    }
    return forkJoin(resourceObservables).pipe(
      mergeMap((resource) => {
        resources.splice(0, partSize);
        if (resources.length) {
          return this.saveResources(resources, config);
        } else {
          return of(resource);
        }
      })
    );
  }

  public saveResource(resource: Resource, config?: RequestConfig): Observable<Resource> {
    return this.http.post<Resource>('/api/resource', resource, defaultHttpOptionsFromConfig(config));
  }

  public deleteResource(resourceId: string, config?: RequestConfig) {
    return this.http.delete(`/api/resource/${resourceId}`, defaultHttpOptionsFromConfig(config));
  }

}