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";

  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);
          });
  }
}