// Ported from nanotiming 7.3.1 (MIT) — https://github.com/choojs/nanotiming
// Unified browser/Node implementation on the global `performance` object.

import { equal } from './assert.js'

const perf = typeof performance !== 'undefined' && typeof performance.mark === 'function'
  ? performance
  : null

function checkDisabled () {
  if (!perf) return true
  if (typeof process !== 'undefined' && process.env && process.env.DISABLE_NANOTIMING) return true
  if (typeof window !== 'undefined') {
    try {
      return window.localStorage.DISABLE_NANOTIMING === 'true'
    } catch (e) {
      return false
    }
  }
  return false
}

nanotiming.disabled = checkDisabled()

export default function nanotiming (name) {
  equal(typeof name, 'string', 'nanotiming: name should be type string')

  if (nanotiming.disabled) return noop

  const uuid = (perf.now() * 10000).toFixed() % Number.MAX_SAFE_INTEGER
  const startName = 'start-' + uuid + '-' + name
  perf.mark(startName)

  function end (cb) {
    const endName = 'end-' + uuid + '-' + name
    perf.mark(endName)

    let err = null
    try {
      const measureName = name + ' [' + uuid + ']'
      perf.measure(measureName, startName, endName)
      perf.clearMarks(startName)
      perf.clearMarks(endName)
    } catch (e) { err = e }
    if (cb) cb(err, name)
  }

  end.uuid = uuid
  return end
}

function noop (cb) {
  if (cb) {
    cb(new Error('nanotiming: performance API unavailable or disabled'))
  }
}