import {Injectable} from '@angular/core';
import {
  HttpErrorResponse,
  HttpEvent,
  HttpHandler,
  HttpHeaders,
  HttpInterceptor,
  HttpRequest,
  HttpResponse
} from '@angular/common/http';
import {Observable} from 'rxjs';
import {catchError, finalize, map} from 'rxjs/operators';
import {JsonTransformerUtil} from './json-transformer.util';
import {ActiveRequests} from '../app/services/active-requests.service';
import {UserContextHolder} from '../app/services/user-context.service';
import {PatientContextService} from '../app/services/patient-context.service';
import {ErrorService} from '../app/services/error.service';

@Injectable()
export class HttpRequestInterceptor implements HttpInterceptor {
  constructor(
    private activeRequests: ActiveRequests,
    private patientContextService: PatientContextService,
    private userContextHolder: UserContextHolder,
    private errorService: ErrorService
  ) { }

  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    let headers = this.addHeader(request.headers, 'X-NSP-GM-Platform', 'Web');
    const paths = request.url.split('/');
    if (paths[paths.length - 1] !== 'usercontext') {
      headers = this.addHeader(headers, 'X-NSP-GM-Chosen-Role', this.userContextHolder.currentRole?.educationType);
      headers = this.addHeader(headers, 'X-NSP-GM-User-Identifier', `${this.userContextHolder.uniqueIdentifier}`);
      headers = this.addHeader(headers, 'X-NSP-GM-Organization-Sor', this.userContextHolder.currentOrganization?.sorId);
      headers = this.addHeader(headers, 'X-NSP-GM-Institution-Owner-Sor',
        this.userContextHolder.currentOrganization?.institutionOwnerSorId);
      headers = this.addHeader(headers, 'X-NSP-GM-Patient-Identifier', this.patientContextService.getCurrentCpr());
    }
    headers = this.addHeader(headers, 'X-NSP-GM-Episode-Of-Care-Identifier', this.patientContextService.getCurrentEpisodeOfCare());
    if (this.patientContextService.getCurrentXBreakTheGlassReason()) {
      headers = this.addHeader(headers, 'X-NSP-GM-Break-The-Glass-Reason', this.patientContextService.getCurrentXBreakTheGlassReason());
    }

    const requestWithHeaders = request.clone({headers});

    if (this.isBlockingRequest(request)) {
      this.activeRequests._registerBlockingRequest();
    }
    return next.handle(requestWithHeaders).pipe(
      map((event: HttpEvent<any>) => {
        if (event instanceof HttpResponse) {
          const replaced = JsonTransformerUtil.transformDates(event.body);
          return event.clone({body: replaced});
        }
        return event;
      }),
      catchError((error: HttpErrorResponse) => {
        this.errorService.redirectIfRequested(error);
        return this.errorService.handleHttpErrorResponse(error);
      }),
      finalize(() => {
        if (this.isBlockingRequest(request)) {
          this.activeRequests._unregisterBlockingRequest();
        }
      })
    );
  }

  private addHeader(headers: HttpHeaders, header: string, value?: string): HttpHeaders {
    if (value) {
      return (headers || new HttpHeaders()).append(header, value);
    }
    return (headers || new HttpHeaders());
  }

  private isBlockingRequest(request: HttpRequest<any>): boolean {
    return !(request.url.includes('pdf') || request.url.includes('sorlookup'));
  }
}