import { Injectable } from "@angular/core";
import {
  HttpEvent,
  HttpInterceptor,
  HttpHandler,
  HttpRequest,
} from "@angular/common/http";
import { Observable } from "rxjs/Rx";
import "rxjs/add/observable/throw";
import "rxjs/add/operator/catch";

import { Defaults } from "./default.constants";
import { ImpersonateHelper } from "./impersonate.helper";

@Injectable()
export class TokenHttpInterceptor implements HttpInterceptor {
  constructor() {}

  intercept(
    req: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {
    let headers = {};

    // Handle Impersonate
    const impersonateUser = ImpersonateHelper.getImpersonateUserId();
    if (impersonateUser)
      headers[Defaults.IMPERSONATE_ID_HEADER] = impersonateUser;

    // Set Request Headers
    req = req.clone({ setHeaders: headers });

    if (window.navigator.userAgent.search(/MSIE|Trident/i) != -1) {
      req.headers.set("Access-Control-Allow-Headers", "*");
      req.headers.set("Cache-Control", "no-store");
      req.headers.set("Cache-Control", "no-cache");
      req.headers.set("Pragma", "no-cache");
    }

    return next.handle(req).catch((error, caught) => {
      return Observable.throw(error);
    }) as any;
  }
}