#!/usr/bin/env node
const spinner = require('char-spinner')
const {gray, green, yellow, red, bold} = require('colorette')
const {SiteChecker} = require('broken-link-checker')

const yargs = require('yargs')
  .option('excluded-schemes', {type: String, alias: 's', default: ['dash-feed', 'mailto']})
  .option('filter-level', {type: Number, alias: 'L', default: 3})
  .option('max-sockets-per-host', {type: Number, alias: 'm', default: 1})
  .option('verbose', {type: Boolean, alias: 'v', default: false})

const options = yargs.argv

const args = options._
const VERBOSE = options.verbose

const pages = []
const seen = new Set()
const excepted = new Map()

const OK = ' ✓ '
const NOT_OK = ' ✘ '
const TAG_LENGTH = 3

const URL = args[0]
if (URL) {
  log(green('go!'), bold(URL))
} else {
  log('err', 'you must provide a URL')
  process.exit(1)
}

let page = {url: URL, links: []}

const exceptions = {
  'GitHub private repo': url =>
    [
      // this is a list of known GitHub private repos
      'https://github.com/github/accessibility',
      'https://github.com/github/design',
      'https://github.com/github/design-systems',
      'https://github.com/github/github',
      'https://github.com/github/sentinel'
    ].some(repo => url.startsWith(repo))
}

const checker = new SiteChecker(options, {
  page(error, url) {
    if (error) {
      log(red('ERR'), `${url} (${error.code})`)
    } else if (page) {
      const {url, response, links = []} = page
      const num = String(links.length).padEnd(TAG_LENGTH)
      let message = `${bold(num)}${pages.length ? ' unique' : ''} links`
      if (!VERBOSE) message = `${message} on ${yellow(url)}`
      log(OK, message)
      if (links.length) {
        pages.push(page)
      }
    }
  },

  html(tree, robots, response, url) {
    if (VERBOSE) log(yellow('get'), url)
    page = {url, links: []}
  },

  junk(result) {
    const url = result.url.resolved || result.url.original
    if (!url || seen.has(url)) {
      return
    } else if (VERBOSE) {
      log(' '.repeat(TAG_LENGTH), gray(`skip ${shorten(url)}`))
    } else if (result.excluded && url.indexOf(URL) !== 0) {
      log(yellow('---'), gray(`excluded: ${url}`))
    }
    seen.add(url)
  },

  link(result) {
    const url = result.url.resolved || result.url.original
    if (VERBOSE && !seen.has(url)) log(' + ', gray('link'), shorten(url))

    for (const [reason, test] of Object.entries(exceptions)) {
      if (test(url)) {
        log(yellow('---'), gray(`skip ${url}`), yellow(reason))
        excepted.set(url, reason)
        seen.add(url)
        return
      }
    }

    if (!seen.has(url)) page.links.push(result)
    seen.add(url)
  },

  end() {
    const allBroken = []
    for (const page of pages) {
      const broken = page.links.filter(link => link.broken)
      allBroken.push(...broken)

      if (!broken.length && !VERBOSE) {
        continue
      } else {
        const num = broken.length ? red(` ${broken.length}`.padEnd(TAG_LENGTH)) : green(' 0').padEnd(TAG_LENGTH)
        log(bold(num), `broken links on ${bold(page.url)}`)
      }

      for (const link of page.links) {
        if (!link.broken && !VERBOSE) continue
        const tag = link.broken ? red(NOT_OK) : green(OK)
        const reason = link.broken ? link.brokenReason.replace(/HTTP_/, '') : ''
        const url = link.url.resolved || link.url.original
        log(tag, shorten(url), yellow(reason))
        link.source = url
        link.reason = reason
      }
      log('')
    }

    if (excepted.size) {
      log(yellow(OK), `Excepted ${excepted.size} links:`)
      const exceptedURLs = Array.from(excepted.keys()).sort()
      for (const url of exceptedURLs) {
        log(yellow(OK), `${yellow(excepted.get(url))} ${gray(url)}`)
      }
      log('')
    }

    if (allBroken.length) {
      log(red(NOT_OK), `${red(allBroken.length)} broken links:`)
      for (const link of allBroken) {
        log(red(NOT_OK), red(link.reason), link.url.original, gray('from'), shorten(link.source))
      }
      log('')
      process.exitCode = 1
    } else {
      log(green(OK), bold('0'), 'broken links')
    }

    log('')
  }
})

spinner()
checker.enqueue(URL)
checker.resume()

function log(tag, ...args) {
  spinner.clear()
  console.log(tag ? gray(`[${tag}]`) : '', ...args)
}

function shorten(url) {
  return String(url).indexOf(URL) === 0 ? gray(URL) + (url.substr(URL.length) || '/') : url
}