// The surface where to tap
const ttt = document.querySelector("#ttt")

// The input to store a sequence
const s = document.querySelector("#s")


let series = []
let initial = null

// The function of a tap
const tap = () => {
    if (initial == null) {
        initial = new Date()
        series.push(0)
    } else {
        series.push((new Date() - initial))
    }

   ttt.innerHTML = series 
}


const stap = () => {
    if (initial == null) return
    
    // insert the final value
    series.push((new Date() - initial))

    // copy the series
    let sequence = series
    
    // reset series and initial date 
    series = []
    initial = null

    return sequence
}

const audioContext = new AudioContext()
const gain = new GainNode(audioContext, {
    value: 0.05
})


const playNoise = (bandHz=1000, time=0) => {
    
    let noiseDuration = 0.05
    
    const bufferSize = audioContext.sampleRate * noiseDuration
    const noiseBuffer = new AudioBuffer({
        length: bufferSize,
        sampleRate: audioContext.sampleRate
    })

    const data = noiseBuffer.getChannelData(0)
    for (let i=0; i<bufferSize; i++){
        data[i] = Math.random() * 2 - 1;
    }


    const noise = new AudioBufferSourceNode(audioContext, {
        buffer: noiseBuffer
    })


    const bandpass = new BiquadFilterNode(audioContext, {
        type: "bandpass",
        frequency: bandHz
    })

    noise.connect(bandpass).connect(gain).connect(audioContext.destination);
    noise.start(time)
}

const playOsc = (freq=440) => {
    const osc = new OscillatorNode(audioContext, {
        type: "sine",
        frequency: freq
    })
    osc.connect(gain).connect(audioContext.destination);
    osc.start()
    osc.stop(audioContext.currentTime + 0.1)
}

const seq = (sequence, fn) => {
    if (!sequence.length) return
    setTimeout(fn, sequence[0])
    let copy = [...sequence]
    copy.shift()
    seq(copy,fn)
    }


ttt.addEventListener("click", () => tap())


s.addEventListener("click", () => { 
    let sequence = stap();  
    let period = sequence.pop()
    let freq = Math.random() * 1000
    seq(sequence, ()=> playOsc(freq))
    setInterval(seq, period, sequence, ()=>playOsc(freq))
    
})