index.ts

/**
 * @module @xmcl/forge-site-parser
 */
import { parse as parseHtml, HTMLElement, Node } from 'node-html-parser'

/**
 * One forge version download info
 */
interface Download {
  md5: string
  sha1: string
  path: string
}

function notnull<T>(v: T | undefined): v is T { return !!v }

function parseLink(elem: Node) {
  const e = (elem as HTMLElement).removeWhitespace()
  /*
     * <div class="info-tooltip">
     *   <strong>MD5:</strong> 31742b6c996f53af96f606b7a0c46e2a<br>
     *   <strong>SHA1:</strong> 8d6a23554839d6f6014fbdb7991e3cd8af7eca80
     * </div>
     */
  const tooltipInfo = e.querySelector('.info-tooltip')
  const url = tooltipInfo?.querySelector('a')?.attributes?.href ||
        e.querySelector('.info-link')?.attributes?.href ||
        e.querySelector('a')?.attributes?.href

  if (!url) {
    return undefined
  }
  // href is like /maven/net/minecraftforge/forge/1.14.4-28.1.70/forge-1.14.4-28.1.70-changelog.txt
  const href = url.trim()
  const matched = /forge-.+-.+-(\w+)\.\w+/.exec(href)
  let name = ''; let sha1 = ''; let md5 = ''
  if (matched) { name = matched[1] }
  if (!name) {
    throw new SyntaxError(`Cannot determine name for forge url "${href}". Maybe the forge webisite changed?`)
  }
  try {
    md5 = tooltipInfo?.childNodes[1].text.trim() ?? ''
    sha1 = tooltipInfo?.childNodes[4].text.trim() ?? ''
  } catch {
    console.warn(`Error during fetching the sha1 and md5 for the forge "${href}". The result might be wrong.`)
  }
  const isSha1 = /\b([a-f0-9]{40})\b/i
  const isMd5 = /\b[a-f0-9]{32}\b/i
  if (!isMd5.test(md5.trim())) {
    console.warn(`Illegal Md5 for "${href}": ${md5}`)
    md5 = ''
  }
  if (!isSha1.test(sha1.trim())) {
    console.warn(`Illegal Sha1 for "${href}": ${sha1}`)
    sha1 = ''
  }
  return {
    name,
    md5,
    sha1,
    path: href,
  }
}
/**
 * Parse the html string of forge webpage
 */
export function parse(content: string): ForgeWebPage {
  const dom = parseHtml(content)
  if (!(dom instanceof HTMLElement)) {
    throw new SyntaxError('The content is not the HTML format.')
  }
  const selected = dom.querySelector('.elem-active')
  if (!selected) {
    throw new SyntaxError('Corrupted Forge Web Page')
  }
  const mcversion = selected.text

  function parseVersion(e: HTMLElement): Version {
    const links = e.querySelector('.download-links')?.childNodes
      .filter((elem) => elem instanceof HTMLElement && elem.rawTagName === 'li')
      .map(parseLink)
      .filter(notnull)
    const downloadVersionElem = e.querySelector('.download-version')
    let version: string
    let type: Version['type'] = 'common'
    const icon = downloadVersionElem?.querySelector('i')
    if (icon) {
      if (icon.classNames.indexOf('promo-recommended') !== -1) {
        type = 'recommended'
      } else if (icon.classNames.indexOf('promo-latest') !== -1) {
        type = 'latest'
      } else if (icon.classNames.indexOf('fa-bug') !== -1) {
        type = 'buggy'
      }
      version = downloadVersionElem?.firstChild?.text.trim() ?? ''
    } else {
      version = downloadVersionElem?.text.trim() ?? ''
    }
    const installer = links?.find((l) => l.name === 'installer')
    const universal = links?.find((l) => l.name === 'universal')
    const changelog = links?.find((l) => l.name === 'changelog')
    const installerWin = links?.find((l) => l.name === 'installer-win')
    const source = links?.find((l) => l.name === 'source')
    const launcher = links?.find((l) => l.name === 'launcher')
    const mdk = links?.find((l) => l.name === 'mdk')

    if (installer === undefined && universal === undefined) {
      throw new SyntaxError('Cannot parse forge web since it missing installer and universal jar info.')
    }
    const result: Version = {
      version,
      date: e.querySelector('.download-time')?.text.trim() ?? '',
      changelog,
      installer,
      mdk,
      universal,
      source,
      launcher,
      'installer-win': installerWin,
      mcversion,
      type,
    }

    return result
  }
  const versions = dom.querySelector('.download-list')!.querySelector('tbody')!.querySelectorAll('tr')!
    .map(parseVersion)
  return {
    mcversion,
    versions,
  }
}
/**
 * A richer version info than forge installer required
 */
interface Version {
  /**
     * The minecraft version
     */
  mcversion: string
  /**
     * The version of forge
     */
  version: string
  date: string
  /**
     * The changelog info
     */
  changelog?: Download
  installer?: Download
  mdk?: Download
  universal?: Download
  source?: Download
  launcher?: Download
  ['installer-win']: Download | undefined

  /**
     * The type of the forge release. The `common` means the normal release.
     */
  type: 'buggy' | 'recommended' | 'common' | 'latest'
}

/**
 * Forge webpack contains the forge versions for a Minecraft version.
 */
export interface ForgeWebPage {
  versions: Version[]
  mcversion: string
}