osuAutoDownloadAllBeatsmaps.js

const version = 'v0.0.1-alpha'
const links = [...new Set(Array.from(document.querySelectorAll('.play-detail__title')).map(ele => ele.href))]
const maxOpenWindowsSameTime = 20
const totalRuntime = Math.ceil(links.length / maxOpenWindowsSameTime)
const offsetTime = 5000 // millionseconds
const oneRuntimeMaxTimeSpend = ((offsetTime * 2) * maxOpenWindowsSameTime) * 2 + offsetTime * 2

let holds = []
let ready = []
let relay = 0

const runtime = () => {
  console.log(`
  - ${links.length} beatsmaps found.
  - ${totalRuntime} parts of download task.
  - ${oneRuntimeMaxTimeSpend * totalRuntime / 1000} seconds taken (approximate).

  OSU! Beatsmaps auto downloader by @Aries0d0f (aries0d0f.me)
  Script version ${version}
  `)
  console.log(`Please keeps your browser window and console both open, and do not do any operation until all runtime finished.`)
  Array(totalRuntime).fill(0).forEach((_, index) => {
    setTimeout(() => {
      console.log(`Now task runing ${relay + 1}/${totalRuntime}...`)
      openBeatsmaps(relay * maxOpenWindowsSameTime, (relay + 1) * maxOpenWindowsSameTime)
      relay += 1
    }, oneRuntimeMaxTimeSpend * index)
  })
}

const openBeatsmaps = (start, end) => {
  console.log(`[${relay + 1}/${totalRuntime}] Fetching...`)
  links
    .slice(start, end)
    .forEach((url, index) => {
      setTimeout(() => { holds.push(window.open(url)) }, offsetTime * index + Math.random() * offsetTime)
    })

  setInterval(() => {
    if (holds.length === maxOpenWindowsSameTime) {
      preDownloadProcess()
    }
  }, offsetTime)
}

const preDownloadProcess = () => {
  console.log(`[${relay + 1}/${totalRuntime}] Fetching down.`)
  ready = [...new Set(holds.map(_window => `${_window.document.location.origin}${_window.document.location.pathname}`))]
  if (maxOpenWindowsSameTime > ready.length) {
    console.log(`[${relay + 1}/${totalRuntime}] Found ${maxOpenWindowsSameTime - ready.length} duplicate beatsmaps, shake it off.`)
  }
  console.log(`[${relay + 1}/${totalRuntime}] Clear workplace...`)
  closeHolding()
  setTimeout(() => {
    downloadBeatsmaps()
  }, offsetTime * 2)
}

const closeHolding = () => {
  holds.forEach(_window => _window.close())
  holds = []
  console.log(`[${relay + 1}/${totalRuntime}] Workplace cleared`)
}

const downloadBeatsmaps = () => {
  console.log(`[${relay + 1}/${totalRuntime}] Downloading...`)
  ready.forEach((url, index) => {
    setTimeout(() => { window.open(`${url}/download`) }, offsetTime * index + Math.random() * offsetTime)
  })
}

runtime()