D-Net

import {Injectable, OnInit, PLATFORM_ID, Inject, InjectionToken, Optional, Injector, inject} from '@angular/core';

import { isPlatformBrowser} from '@angular/common';

import { Http, Response, Headers, RequestOptions } from '@angular/http';

import {HttpClient} from "@angular/common/http";

import { Observable, Subscription, BehaviorSubject ,  of } from 'rxjs';

import {Request} from 'express';

import {REQUEST} from '@nguniversal/express-engine/tokens';

import { EnvProperties } from './env-properties';

import { DOCUMENT } from '@angular/common';

import {map} from "rxjs/operators";

import {Type} from "@angular/compiler";

//export const REQUEST_TOKEN = new InjectionToken<Request>('request');

@Injectable()

export class EnvironmentSpecificService {

  public envSpecific: EnvProperties;

  public domain: string;

  public envSpecificNull: EnvProperties = null;

  testBrowser: boolean;

  private envSpecificSubject: BehaviorSubject<EnvProperties> = new BehaviorSubject<EnvProperties>(null);

  private propertiesUrl = "/assets/env-properties.json?v=1";

  constructor(private http: HttpClient,  @Inject(PLATFORM_ID) private platformId: string, /*private injector: Injector,*/

              @Optional() @Inject(REQUEST) private request: Request) {

      this.testBrowser = isPlatformBrowser(platformId);

      if (this.testBrowser) {

          //this is only executed on the browser

      }

  }

  public loadEnvironment() {

      // Only want to do this once - if root page is revisited, it calls this again.

      if (this.envSpecific === null || this.envSpecific === undefined) {

        var domain  = this.getDomain();

        var location = this.getFullUrl();

        // console.log('loadEnvironment: Loading  '+ location);

        return this.http.get<EnvProperties>(location)

            .pipe(map((data) => {

                                    var properties:EnvProperties=data;//.json();

                                    properties.domain = domain;

                                    this.envSpecific = properties;

                                    return properties;

                      }))

            .toPromise<EnvProperties>();

      }

      // console.log('loadEnvironment: already loaded ');

      return Promise.resolve(this.envSpecific);

  }

  public subscribeEnvironment() {

      // Only want to do this once - if root page is revisited, it calls this again.

      if (this.envSpecific === null || this.envSpecific === undefined) {

        var domain  = this.getDomain();

        var location = this.getFullUrl();

        // console.log('subscribeEnvironment: Loading  '+ location);

        return this.http.get<EnvProperties>(location)

        .pipe(map((data) => {

                                var properties:EnvProperties=data;//.json();

                                properties.domain = domain;

                                this.envSpecific = properties;

                                return properties;

                  }))

      }

      // console.log('subscribeEnvironment: already loaded  ');

      return of(this.envSpecific);

  }

  getFullUrl(){

    var location ="";

      var domain  = "";

    if (typeof document == 'undefined') {

      //let req = this.injector.get('request');

      //let req: Request = this.injector.get(REQUEST_TOKEN);

      domain = this.request.get('host').split(":")[0];

      location = (domain.indexOf(".openaire.eu")!=-1?"https://":"http://")+ this.request.get('host') + this.propertiesUrl;

     }else{

      location = document.location.protocol +"//" + document.location.host+this.propertiesUrl;

      domain = document.location.hostname;

   }

   return location;

  }

  getDomain(){

    var domain  = "";

    if (typeof document == 'undefined') {

      //let req = this.injector.get('request');

      //let req: Request = this.injector.get(REQUEST_TOKEN);

      domain = this.request.get('host').split(":")[0];

    }else{

      domain = document.location.hostname;

   }

   return domain;

  }

  public setEnvProperties(es: EnvProperties) {

    // This has already been set so bail out.

    if (es === null || es === undefined) {

        return;

    }

    this.envSpecific = es;

    //console.log(this.envSpecific);

    if (this.envSpecificSubject) {

        this.envSpecificSubject.next(this.envSpecific);

    }

  }

  /*

    Call this if you want to know when EnvProperties is set.

  */

  public subscribe(caller: any, callback: (caller: any, es: EnvProperties) => void) {

      this.envSpecificSubject

          .subscribe((es) => {

              if (es === null) {

                  return;

              }

              callback(caller, es);

          });

  }

}