dev@132: /**
dev@132:  * Created by lucas on 17/03/2017.
dev@132:  */
dev@236: import {Injectable, Inject, NgZone} from '@angular/core';
dev@236: import {Observable} from 'rxjs/Observable';
dev@236: import {Subject} from 'rxjs/Subject';
dev@132: 
dev@132: 
dev@132: // seems the TypeScript definitions are not up to date,
dev@132: // introduce own types for now
dev@132: 
dev@293: export type AudioInputProvider = () => Promise<MediaStream>;
dev@132: 
dev@132: export interface MediaRecorderOptions {
dev@132:   mimeType?: string;
dev@132:   audioBitsPerSecond?: number;
dev@132:   videoBitsPerSecond?: number;
dev@132:   bitsPerSecond?: number;
dev@132: }
dev@132: 
dev@236: export type RecordingState = 'inactive' | 'recording' | 'paused';
dev@132: 
dev@132: export interface BlobEvent extends Event {
dev@132:   readonly data: Blob;
dev@132:   readonly timecode: number;
dev@132: }
dev@132: 
dev@132: export interface MediaRecorderErrorEvent extends Event {
dev@132:   readonly error: DOMException;
dev@132: }
dev@132: 
dev@132: export interface MediaRecorder {
dev@132:   readonly mimeType: string;
dev@132:   readonly state: RecordingState;
dev@132:   readonly stream: MediaStream;
dev@132:   ignoreMutedMedia: boolean;
dev@132:   readonly videoBitsPerSecond: number;
dev@132:   readonly audioBitsPerSecond: number;
dev@132:   // isTypeSupported(mimeType: string): boolean;
dev@132:   onstart: (evt: Event) => void;
dev@132:   onstop: (evt: Event) => void;
dev@132:   ondataavailable: (evt: BlobEvent) => void;
dev@132:   onpause: (evt: Event) => void;
dev@132:   onresume: (evt: Event) => void;
dev@132:   onerror: (evt: MediaRecorderErrorEvent) => void;
dev@236:   pause(): void;
dev@236:   requestData(): void;
dev@236:   resume(): void;
dev@236:   start(timeslice?: number): void;
dev@236:   stop(): void;
dev@132: }
dev@132: 
dev@132: export interface MediaRecorderConstructor {
dev@132:   new(stream: MediaStream,
dev@132:       options?: MediaRecorderOptions): MediaRecorder;
dev@132:   isTypeSupported(mimeType: string): boolean;
dev@132: }
dev@132: 
dev@236: export type RecorderServiceStatus = 'disabled' | 'enabled' | 'recording';
dev@132: 
dev@132: export class ThrowingMediaRecorder implements MediaRecorder {
dev@132:   mimeType: string;
dev@132:   state: RecordingState;
dev@132:   stream: MediaStream;
dev@132:   ignoreMutedMedia: boolean;
dev@132:   videoBitsPerSecond: number;
dev@132:   audioBitsPerSecond: number;
dev@132:   onstart: (evt: Event) => void;
dev@132:   onstop: (evt: Event) => void;
dev@132:   ondataavailable: (evt: BlobEvent) => void;
dev@132:   onpause: (evt: Event) => void;
dev@132:   onresume: (evt: Event) => void;
dev@132:   onerror: (evt: MediaRecorderErrorEvent) => void;
dev@132: 
dev@132:   static isTypeSupported(mimeType: string): boolean {
dev@132:     return false;
dev@132:   }
dev@132: 
dev@236:   constructor(stream: MediaStream,
dev@236:               options?: MediaRecorderOptions) {
dev@236:     throw new Error('MediaRecorder not available in this browser.');
dev@236:   }
dev@236: 
dev@236: 
dev@132:   pause(): void {
dev@132:   }
dev@132: 
dev@132:   requestData(): void {
dev@132:   }
dev@132: 
dev@132:   resume(): void {
dev@132:   }
dev@132: 
dev@132:   start(timeslice: number): void {
dev@132:   }
dev@132: 
dev@132:   stop(): void {
dev@132:   }
dev@132: }
dev@132: 
dev@132: @Injectable()
dev@132: export class AudioRecorderService {
dev@132:   private requestProvider: AudioInputProvider;
dev@132:   private recorderImpl: MediaRecorderConstructor;
dev@293:   private currentRecorder: MediaRecorder;
dev@132:   private recordingStateChange: Subject<RecorderServiceStatus>;
dev@132:   recordingStateChange$: Observable<RecorderServiceStatus>;
dev@132:   private newRecording: Subject<Blob>;
dev@132:   newRecording$: Observable<Blob>;
dev@132:   private isRecording: boolean;
dev@132:   private chunks: Blob[];
dev@132: 
dev@132:   constructor(@Inject('AudioInputProvider') requestProvider: AudioInputProvider,
dev@132:               @Inject(
dev@132:                 'MediaRecorderFactory'
dev@145:               ) recorderImpl: MediaRecorderConstructor,
dev@145:               private ngZone: NgZone) {
dev@132:     this.requestProvider = requestProvider;
dev@132:     this.recorderImpl = recorderImpl;
dev@132:     this.recordingStateChange = new Subject<RecorderServiceStatus>();
dev@132:     this.recordingStateChange$ = this.recordingStateChange.asObservable();
dev@132:     this.newRecording = new Subject<Blob>();
dev@132:     this.newRecording$ = this.newRecording.asObservable();
dev@132:     this.isRecording = false;
dev@132:     this.chunks = [];
dev@132:   }
dev@132: 
dev@293:   private getRecorderInstance(): Promise<MediaRecorder> {
dev@293:     return this.requestProvider().then(stream => {
dev@293:       const recorder = new this.recorderImpl(stream);
dev@293:       recorder.ondataavailable = e => this.chunks.push(e.data);
dev@293:       recorder.onstop = () => {
dev@293:         const blob = new Blob(this.chunks, {'type': recorder.mimeType});
dev@293:         this.chunks.length = 0;
dev@293:         this.ngZone.run(() => {
dev@293:           this.newRecording.next(
dev@293:             blob
dev@293:           );
dev@293:         });
dev@293:       };
dev@293:       return recorder;
dev@132:     });
dev@132:   }
dev@132: 
dev@132:   toggleRecording(): void {
dev@132:     if (this.isRecording) {
dev@132:       this.endRecording();
dev@132:     } else {
dev@293:       this.getRecorderInstance()
dev@293:         .then(recorder => this.startRecording(recorder))
dev@293:         .catch(e => {
dev@293:           this.recordingStateChange.next('disabled'); // don't really need to do this
dev@293:           console.warn(e); // TODO emit an error message for display?
dev@293:         });
dev@132:     }
dev@132:   }
dev@132: 
dev@293:   private startRecording(recorder: MediaRecorder): void {
dev@293:     this.currentRecorder = recorder;
dev@293:     this.isRecording = true;
dev@293:     recorder.start();
dev@293:     this.recordingStateChange.next('recording');
dev@132:   }
dev@132: 
dev@132:   private endRecording(): void {
dev@293:     if (this.currentRecorder) {
dev@132:       this.isRecording = false;
dev@293:       this.currentRecorder.stop();
dev@293:       for (const track of this.currentRecorder.stream.getAudioTracks()) {
dev@293:         track.stop();
dev@293:       }
dev@132:       this.chunks.length = 0; // empty the array
dev@236:       this.recordingStateChange.next('enabled');
dev@293:       this.currentRecorder = null;
dev@132:     }
dev@132:   }
dev@132: }