class MeanCalc {
  constructor(count) {
    this.metrics = []
    this.count = count
  }

  inspect() {
    return this.val()
  }

  add(value) {
    if (this.metrics.length >= this.count) {
      this.metrics.shift()
    }
    this.metrics.push(value)
  }

  val() {
    if (this.metrics.length == 0) return 0
    let sum = this.metrics.reduce((prev, curr) => curr += prev)
    return Math.floor((sum / this.metrics.length) * 1000) / 1000
  }
}

module.exports = MeanCalc