dev@47: import {Injectable} from '@angular/core';
dev@47: import {
dev@51:   ListResponse, ListRequest
dev@47: } from "piper";
dev@64: import {
dev@64:   SimpleRequest, SimpleResponse
dev@64: } from "piper/HigherLevelUtilities";
dev@51: import {Subject} from "rxjs/Subject";
dev@51: import {Observable} from "rxjs";
dev@44: 
dev@47: interface RequestMessage<RequestType> {
dev@47:   method: string;
dev@47:   params: RequestType;
dev@47: }
dev@47: 
dev@47: interface ResponseMessage<ResponseType> {
dev@47:   method: string;
dev@47:   result: ResponseType;
dev@47: }
dev@40: 
dev@40: @Injectable()
dev@40: export class FeatureExtractionService {
dev@40: 
dev@40:   private worker: Worker;
dev@64:   private featuresExtracted: Subject<SimpleResponse>;
dev@64:   featuresExtracted$: Observable<SimpleResponse>;
dev@44: 
dev@40:   constructor() {
dev@40:     this.worker = new Worker('bootstrap-feature-extraction-worker.js');
dev@64:     this.featuresExtracted = new Subject<SimpleResponse>();
dev@51:     this.featuresExtracted$ = this.featuresExtracted.asObservable();
dev@40:   }
dev@40: 
dev@47:   list(): Promise<ListResponse> {
dev@47:     return this.request<ListRequest, ListResponse>(
dev@47:       {method: 'list', params: {}},
dev@47:       (ev: MessageEvent) => ev.data.result.available !== undefined
dev@47:     ).then(msg => msg.result);
dev@40:   }
dev@40: 
dev@64:   process(request: SimpleRequest): Promise<SimpleResponse> {
dev@64:     return this.request<SimpleRequest, SimpleResponse>(
dev@47:       {method: 'process', params: request},
dev@47:       (ev: MessageEvent) => ev.data.method === 'process'
dev@51:     ).then(msg => {
dev@51:       this.featuresExtracted.next(msg.result);
dev@51:       return msg.result;
dev@51:     });
dev@44:   }
dev@44: 
dev@64:   collect(request: SimpleRequest): Promise<SimpleResponse> {
dev@64:     return this.request<SimpleRequest, SimpleResponse>(
dev@62:       {method: 'collect', params: request},
dev@62:       (ev: MessageEvent) => ev.data.method === 'collect'
dev@62:     ).then(msg => {
dev@62:       this.featuresExtracted.next(msg.result);
dev@62:       return msg.result;
dev@62:     });
dev@62:   }
dev@62: 
dev@47:   private request<Req, Res>(request: RequestMessage<Req>,
dev@47:                             predicate: (ev: MessageEvent) => boolean)
dev@47:   : Promise<ResponseMessage<Res>> {
dev@44:     return new Promise(res => {
dev@47:       const listener = (ev: MessageEvent) => {
dev@44:         this.worker.removeEventListener('message', listener);
dev@44:         if (predicate(ev))
dev@44:           res(ev.data);
dev@44:       };
dev@44:       this.worker.addEventListener('message', listener);
dev@44:       this.worker.postMessage(request);
dev@47:     }).catch(err => console.error(err));
dev@44:   }
dev@40: }