WebDevicePerformance

// https://browser.primatelabs.com/ios-benchmarks
// https://mydevice.io/devices/
// http://vizdevices.yesviz.com/devices.php
const IPHONE5_SIZE = 568
const IPAD_SIZE = 1024

const MIN_OPS = 165 /* Upper limit cpu for iPad4 */
const CACHE_KEY = 'anim'



function getCache(params) {
  const ca = document.cookie.split(';')
  let cacheVal = null

  for (let i = 0; i < ca.length; i++) {
    const c = ca[i].trim()
    if (c.indexOf(CACHE_KEY) === 0) {
      cacheVal = c.substring(CACHE_KEY.length + 1, c.length)
      break
    }
  }

  if (!cacheVal) {
    return null
  }
  const cache = JSON.parse(decodeURIComponent(cacheVal))

  const vals = cache.split('&').map(el => +el.slice(2))
  if (vals[1] !== params.width || vals[2] !== params.height) {
    return null
  }

  return cache
}

function setCache(isAnimate, data) {
  const d = new Date()
  d.setTime(d.getTime() + (1 * 24 * 60 * 60 * 1000))
  const expires = `expires=${d.toGMTString()}`
  const str = `a=${isAnimate}&w=${data.width}&h=${data.height}`
  document.cookie = CACHE_KEY + '=' + encodeURIComponent(JSON.stringify(str)) + ';path = /;' + expires
}

function isDevicePossiblySlow(params) {
  const { width, height, device } = params
  if (device.type === 'desktop') return false

  if (getCache(params)) return false

  if (device.os === 'iOS') {
    const size = width > height ? width : height
    if (device.model === 'iPhone' && size > IPHONE5_SIZE) {
      return false
    } else if (device.model === 'iPad' && size > IPAD_SIZE) {
      return false
    }
  }

  return true
}

async function getOps() {
  const startTime = new Date()
  let runs = 0
  let totalTime

  do {
    runs++
    totalTime = new Date() - startTime
    Math.sqrt(runs * Math.random())
  } while (totalTime < 500)
  const result = runs / totalTime
  return result
}

export async function isAnimationEnable(params) {

  if (isDevicePossiblySlow(params)) {
    const ops = await getOps()
    const disableAnimate = ops < MIN_OPS ? 1 : 0
    makeGDocRequest(params, ops)
    setCache(disableAnimate, params)

    if (disableAnimate) {
      return false
    }
  }

  return true
}