class Analyser {

constructor () {

this.startingScale = 0

this.pulseRatio = 1

this.maxValueHistory = 100

this.hzHistory = []

}

initialise = (analyser) => {

this.analyser = analyser

this.analyser.fftSize = 2048

}

reset = () => {

this.hzHistory = []

this.frequences = new Uint8Array(this.analyser.frequencyBinCount)

}

analyse = () => {

this.analyser.getByteFrequencyData(this.frequences)

for(let i=0; i < this.frequences.length; i++){

if(!this.hzHistory[i]){

this.hzHistory[i] = []

}

if(this.hzHistory[i].length > this.maxValueHistory){

this.hzHistory[i].shift()

}

this.hzHistory[i].push(this.frequences[i])

}

}

getRangeAverageRatio = (startingValue, nbValue) => {

let total = 0

for(let i=startingValue; i<nbValue+startingValue; i++){

total += this.getFrequenceRatio(i)

}

return total/nbValue

}

getFrequenceRatio = (index) => {

let min = 255

let max = 0

this.hzHistory[index].forEach(value => {

if(value < min){

min = value

}

if(value > max){

max = value

}

})

const scale = max - min

const actualValue = this.frequences[index] -min

const percentage = (actualValue/scale)

return this.startingScale + (this.pulseRatio * percentage)

}

}

export default new Analyser