import {Injectable} from '@angular/core';

import { Http, Response, Headers } from '@angular/http';
import { environment } from '../../../../environments/environment';

import { Adal4Service, Adal4HTTPService } from 'adal-angular4';
import { NgProgressService } from 'ngx-progressbar';

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';

import { GlobalService } from '../global/global.service';

@Injectable()
export class RestService {

    private headers: Headers;
    private activeCalls: number;

    constructor(private http: Http, private service: Adal4Service, private httpAdal: Adal4HTTPService, private globalService: GlobalService, private progressService: NgProgressService){
      this.activeCalls = 0;
    }

    public get(url: string, loadingBar: boolean = false): any{
      this.appendHeaders();
      return loadingBar ? this.getRequestWithLoadingBar(url) : this.getRequest(url);
    }

    private getRequest(url: string): any {
        return this.http.get(environment.webApiUrl + url, {
            headers: this.headers
        }).map(this.extractData)
        .catch(err => {
          return Observable.throw(err)
        });
    }

    private getRequestWithLoadingBar(url: string): any {
      this.httpCallRequested();
      return this.getRequest(url)
      .finally(
        () => {
          this.httpCallReady();
        }
      );
    }

    private appendHeaders(){
        this.headers = new Headers();
        this.headers.append('Authorization', `Bearer ${this.service.userInfo.token}`);
        if(this.globalService.getDomain())this.headers.append('DomainId', this.globalService.getDomain().domainId);
        if(this.globalService.getModule())this.headers.append('ModuleId', this.globalService.getModule().moduleId);
    }

    public getText(url: string) : Observable<string> {
        return this.http.get(environment.webApiUrl + url, {
            headers: this.headers
        }).map((response: Response) => response.text());
    }

    private extractData(res: Response) {
        return res.json() || [];
    }

    private httpCallReady(): void {
        this.activeCalls--;
        if (this.activeCalls === 0) {
          this.progressService.done();
        }
    }

    private httpCallRequested(): void {
        if (this.activeCalls === 0) {
          this.progressService.start();
        }
        this.activeCalls++;
    }
 }