import { Injectable, EventEmitter } from '@angular/core';
import * as RecordRTC from 'recordrtc';
import * as Lamejs from 'lamejs';

navigator.getUserMedia =
    navigator['mediaDevices'] && navigator['mediaDevices'].getUserMedia ?
    navigator['mediaDevices'].getUserMedia : ( navigator['getUserMedia'] || navigator['webkitGetUserMedia'] || navigator['mozGetUserMedia'] || navigator['msGetUserMedia'] );

enum Time {
    Segundo = 1000,
    Minuto = 60 * Time.Segundo,
    Hora = 60 * Time.Minuto
}

@Injectable()
export class Audio2RecordService {


    private currentAudioStream: MediaStream = null;;
    private recordRTC: any = null;
	private recStoppedEvent: EventEmitter<any> = new EventEmitter<string>();
	private microphone: any = null;
	private audioContext: any = null;

    private mp3encoder;
    private mp3Data = [];
    private lameOptions = {
        channels: 1,        //1 for mono or 2 for stereo
        sampleRate: 44100,  //44.1khz (normal mp3 samplerate)
        kbps: 128           //encode 128kbps mp3
    };

    // Processor buffer size
    private readonly BUFFER_SIZE = [256, 512, 1024, 2048, 4096, 8192, 16384];
    // MP3 bit ratenumberOfAudioChannels: 1
    private readonly BIT_RATE = [64, 80, 96, 112, 128, 160, 192, 224, 256, 320];

	constructor() {

        this.mp3encoder = new Lamejs.Mp3Encoder(this.lameOptions.channels, this.lameOptions.sampleRate, this.lameOptions.kbps);

    }

    /**
     * Inicia el proceso de grabación.
     *
     * @param maxRecDuration Tiempo maximo de grabación
     */
	startRecording( maxRecDuration?: number ): Promise<void> {

        this.mp3Data = [];

		return new Promise(
            ( resolve, reject ) => {
                this.initMicrophone()
                    .then(
                        audioStream => {
                            this.currentAudioStream = audioStream;
                            let options = {
                                recorderType: RecordRTC.StereoAudioRecorder,
                                type: 'audio',
                                mimeType: 'audio/wav',
                                numberOfAudioChannels: 1,
                                bufferSize: this.BUFFER_SIZE[4],
                                bitsPerSecond: this.BIT_RATE[4],
                                sampleRate: 44100,
                                timeSlice: 1 * Time.Segundo,
                                ondataavailable: this.processAudioSlice.bind(this)
                            };

                            this.recordRTC = RecordRTC(audioStream, options);

                            // Auto stop recording after maxRecDuration seconds
                            if ( maxRecDuration )
                                this.recordRTC.setRecordingDuration(maxRecDuration).onRecordingStopped(this.emitRecStoppedEvent.bind(this));

                            this.recordRTC.startRecording();
                            resolve();
                        }, error => {
                            reject(error);
                        }
                    );
            }
        );

    }

    /**
     * Para la grabación.
     */
	stopRecording(): Promise<Blob> {



		return new Promise(
            (resolve, reject) => {

                this.recordRTC.stopRecording(
                    recURL => {
                        this.stopRecordingProcess(false);
                        let mp3Blob = this.getMP3File()
                        resolve(mp3Blob);
                    }
                );

            }
        );

    }

    /**
     * Emite una señal indicando que ha alcanzado el tiempo maximo de grabación.
     *
     * @param recURL
     */
	emitRecStoppedEvent(recURL: string){

		this.recStoppedEvent.emit(recURL);

    }

    /**
     * Cancela la grabación.
     */
	cancelRecording() {

		this.recordRTC.stopRecording(
            recURL => this.stopRecordingProcess(false)
        );

	}

    /**
     * Inicia el proceso de paro de la grabación.
     */
	stopRecordingProcess(finish) {

		this.microphone.disconnect();
        this.recordRTC.clearRecordedData();
        this.recordRTC = null;
		if (!finish && this.microphone)
            this.endMicrophone();

    }

    /**
     * Finaliza el microfono.
     */
	endMicrophone() {

        this.currentAudioStream.getAudioTracks().forEach( track => track.stop() );
		this.currentAudioStream = null;
		this.microphone = null;

		this.audioContext.close();
		this.audioContext = null;
	}

    /**
     * Codifica un archivo binario a mp3
     *
     * @param chunkBlob Pedazo de archivo binario a codificar
     */
    processAudioSlice(chunkBlob: Blob) {

        this.convBlobToBufferArray(chunkBlob)
            .then(
                arrayBuffer => this.encodeBufferChunkToMP3(arrayBuffer)
            );

    }

    /**
     * Codifica un pedazo de grabación a MP3.
     *
     * @param audioData Información a codificar
     */
    encodeBufferChunkToMP3(audioData: ArrayBuffer) {

        let samples = new Int16Array(audioData);
        let remaining = samples.length;
        let sampleBlockSize = 1152;

        for (let i = 0; i < samples.length; i += sampleBlockSize) {
            let sampleChunk = samples.subarray(i, i + sampleBlockSize);
            var mp3buf = this.mp3encoder.encodeBuffer(sampleChunk);
            if (mp3buf.length > 0) {
                this.mp3Data.push(new Int8Array(mp3buf));
            }
        }

	}

    /**
     * Obtiene un archivo MP3
     */
	getMP3File(): Blob {

        let mp3buf = this.mp3encoder.flush();   //finish writing mp3

        if (mp3buf.length > 0)
            this.mp3Data.push(new Int8Array(mp3buf));

        let mp3Blob = new Blob(this.mp3Data, {type: 'audio/mp3'});
        window.open(window.URL.createObjectURL(mp3Blob));


        return mp3Blob;

    }

    /**
     * Convierte un objeto Blob a ArrayBuffer
     *
     * @param blob Información binaria
     */
    convBlobToBufferArray(blob: Blob): Promise<ArrayBuffer> {

        return new Promise(
            ( resolve, reject ) => {
                var fileReader = new FileReader();
                fileReader.onload = ( event: any ) => {
                    let arrayBuffer = event.target.result;
                    resolve(arrayBuffer);
                };
                fileReader.readAsArrayBuffer(blob);
            }
        )

    }

    /**
     * Inicializa el microfono.
     */
	initMicrophone(): Promise<any> {

		return new Promise(
            (resolve, reject) => {
                if (this.microphone == null) {
                    var AudioContext = window['AudioContext'] || window['webkitAudioContext'];
                    this.audioContext = new AudioContext();

                    if (this.audioContext.createScriptProcessor == null)
                        this.audioContext.createScriptProcessor = this.audioContext['createJavaScriptNode'];

                    if (navigator['mediaDevices'] && navigator['mediaDevices'].getUserMedia) {
                        navigator.getUserMedia.call(navigator['mediaDevices'], { audio: true })
                            .then(
                                stream => {
                                    this.microphone = this.audioContext.createMediaStreamSource(stream);
                                    resolve(stream);
                                }
                            ).catch(
                                error => {
                                    console.error("Error: No se puede iniciar el microfono");
                                    reject(error);
                                }
                            );
                    } else {
                        navigator.getUserMedia(
                            { audio: true },
                            stream => {
                                this.microphone = this.audioContext.createMediaStreamSource(stream);
                                resolve(stream);
                            },
                            error => {
                                console.error("Error: No se puede iniciar el microfono");
                                reject(error);
                            }
                        );
                    }
                }
            }
        );

	}

}