D-Net

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

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

import {Observable, throwError, of, BehaviorSubject, from, Subscriber} from 'rxjs';

import {AutoCompleteValue} from '../../searchPages/searchUtils/searchHelperClasses.class';

import 'rxjs/add/observable/zip';

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

import {catchError, map} from "rxjs/operators";

@Injectable({  providedIn: 'root' })

export class ISVocabulariesService {

  private vocabularies: Map<string, BehaviorSubject<AutoCompleteValue[]>> = new Map<string, BehaviorSubject<AutoCompleteValue[]>>();

  private provenanceActionVocabulary: BehaviorSubject<{}> = new BehaviorSubject(null);

  private subscriptions = [];

  constructor(private http: HttpClient) {}

  ngOnDestroy() {

    this.clearSubscriptions();

  }

  clearSubscriptions() {

    this.subscriptions.forEach(subscription => {

      if (subscription instanceof Subscriber) {

        subscription.unsubscribe();

      }

    });

  }

  getVocabularyByType(field: string, entity: string, properties: EnvProperties): Observable<any> {

    //console.log("getVocabulary field: "+ field + " for entity: "+ entity);

    var file = "";

    var vocabulary = "";

    if (field == "lang") {

      // file="languages.json";

      // return this.getVocabularyFromFile(file);

      vocabulary = "dnet:languages.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    } else if (field == "type" && (entity == "publication")) {

      // file = "publicationTypes.json";

      // return this.getVocabularyFromFile(file);

      vocabulary = "dnet:publication_resource.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    } else if (field == "type" && (entity == "dataset")) {

      // file = "dnet:dataCite_resource.json";

      // return this.getVocabularyFromFile(file);

      vocabulary = "dnet:dataCite_resource.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    } else if (field == "type" && (entity == "software" || entity == "other")) {

      return of([]);

    } else if (field == "type" && entity == "result" ) {

      //return Observable.zip(this.getVocabularyFromService("dnet:publication_resource.json", properties),this.getVocabularyFromService("dnet:dataCite_resource.json", properties));

      return Observable.zip(from(this.getVocabularyFromServiceAsync("dnet:publication_resource.json", properties)),from(this.getVocabularyFromServiceAsync("dnet:dataCite_resource.json", properties)));

    } else if (field == "access" && (entity == "publication" || entity == "dataset" || entity == "software" || entity == "other" || entity == "result")) {

      // file= "accessMode.json";

      // return this.getVocabularyFromFile(file);

      vocabulary = "dnet:access_modes.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    } else if ((field == "type") && (entity == "dataprovider")) {

      // file = "dataProviderType.json";

      //   return this.getVocabularyFromFile(file);

      vocabulary = "dnet:datasource_typologies.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    } else if (field == "compatibility" && (entity == "dataprovider")) {

      // file = "dataProviderCompatibility.json";

      //   return this.getVocabularyFromFile(file);

      vocabulary = "dnet:datasourceCompatibilityLevel.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    } else if (field == "country") {

      // file = "countries.json";

      //   return this.getVocabularyFromFile(file);

      vocabulary = "dnet:countries.json";

      //return this.getVocabularyFromService(vocabulary, properties);

      return from(this.getVocabularyFromServiceAsync(vocabulary, properties));

    }

    return null;

  }

  async getVocabularyFromServiceAsync(vocabularyName: string, properties: EnvProperties): Promise<AutoCompleteValue[]> {

    if(!this.vocabularies.has(vocabularyName)) {

      await  new Promise<any>(resolve => {

        this.vocabularies.set(vocabularyName, new BehaviorSubject<any>(null));

        this.subscriptions.push(this.getVocabularyFromService(vocabularyName, properties).subscribe(

          vocabularyRes => {

            this.vocabularies.get(vocabularyName).next(vocabularyRes);

            resolve();

          }, error => {

            this.vocabularies.get(vocabularyName).next(null);

            resolve();

          }

        ));

      });

      this.clearSubscriptions();

    }

    return this.vocabularies.get(vocabularyName).getValue();

  }

  getVocabularyFromService(vocabularyName: string, properties: EnvProperties): Observable<AutoCompleteValue[]> {

    let url = properties.vocabulariesAPI + vocabularyName;

    return this.http.get((properties.useLongCache) ? (properties.cacheUrl + encodeURIComponent(url)) : url)

      //.map(res => <any> res.json())

      .pipe(map(res => res['terms']))

      .pipe(map(res => this.parse(res, vocabularyName)))

      .pipe(catchError(this.handleError));

  }

  parse(data: any, vocabularyName: string): AutoCompleteValue[] {

    var array: AutoCompleteValue[] = []

    for (var i = 0; i < data.length; i++) {

      var value: AutoCompleteValue = new AutoCompleteValue();

      value.id = data[i].englishName;//data[i].code;

      if (vocabularyName == 'dnet:countries.json') { //use Country code instead of country name

        value.id = data[i].code;

      }

      value.label = data[i].englishName;

      array.push(value);

    }

    return array;

  }

  getProvenanceActionVocabulary(properties: EnvProperties): Observable<any> {

      let vocabulary = "dnet:provenanceActions.json";

      return from(this.getProvenanceActionVocabularyFromServiceAsync(vocabulary, properties));

    }

  async getProvenanceActionVocabularyFromServiceAsync (vocabularyName: string, properties: EnvProperties): Promise<{}> {

    if(!this.provenanceActionVocabulary || !this.provenanceActionVocabulary.getValue()) {

      await  new Promise<any>(resolve => {

        this.subscriptions.push(this.getProvenanceActionVocabularyFromService(vocabularyName, properties).subscribe(

          vocabularyRes => {

            this.provenanceActionVocabulary.next(vocabularyRes);

            resolve();

          },

          error => {

            this.provenanceActionVocabulary.next(null);

            resolve();

          }

        ));

      });

      this.clearSubscriptions();

    }

    return this.provenanceActionVocabulary.getValue();

  }

  getProvenanceActionVocabularyFromService (vocabularyName: string, properties: EnvProperties): any {

    let url = properties.vocabulariesAPI+vocabularyName;

    return this.http.get((properties.useLongCache) ? (properties.cacheUrl + encodeURIComponent(url)) : url)

      .pipe(map(res => res['terms']))

      .pipe(map(res => this.parseProvenanceActionVocabulary(res)));

  }

  parseProvenanceActionVocabulary(terms: any) {

    var provenanceActionVocabulary: {} = {};

    for(let term of terms) {

      provenanceActionVocabulary[term.code] = term.englishName;

    }

    return provenanceActionVocabulary;

  }

  private handleError(error: HttpErrorResponse) {

    // in a real world app, we may send the error to some remote logging infrastructure

    // instead of just logging it to the console

    console.log(error);

    return throwError(error || 'Server error');

  }

}