const slash = require('slash')
const path = require('path')
const patterns = require('./patterns')
const { deprecated } = require('./enterprise-server-releases')
const allProducts = require('./all-products')
const allVersions = require('./all-versions')
const { getNewVersionedPath } = require('./old-versions-utils')

// construct appropriate versioned path for any given HREF
function getVersionedPathWithoutLanguage (href, version) {
  // start clean without language code or trailing slash
  href = getPathWithoutLanguage(href.replace(patterns.trailingSlash, '$1'))

  // if this is an old versioned path that includes a deprecated version, do not change!
  // example: /enterprise/11.10.340/admin/articles/upgrading-to-the-latest-release
  const oldEnterpriseVersionNumber = href.match(patterns.getEnterpriseVersionNumber)
  if (oldEnterpriseVersionNumber && deprecated.includes(oldEnterpriseVersionNumber[1])) {
    return href
  }

  // try to derive the current version from the path
  // example: enterprise-server@2.22 or free-pro-team@latest
  let versionFromPath = getVersionStringFromPath(href)

  // if this is an old versioned path, convert to new versioned path
  // OLD: /enterprise/2.22/admin/installation or /enterprise/admin/installation
  // NEW: /enterprise-server@2.22/admin/installation
  // OLD: /desktop/installing-and-configuring-github-desktop
  // NEW: /free-pro-team@latest/desktop/installing-and-configuring-github-desktop
  if (!Object.keys(allVersions).includes(versionFromPath)) {
    href = getNewVersionedPath(href)
    versionFromPath = getVersionStringFromPath(href)
  }

  // derive the product from the path (e.g., github or admin) and get corresponding object
  const productObjectFromPath = getProductObjectFromPath(href)

  // if the product's versions don't include the specified version, nothing to change!
  if (productObjectFromPath && !productObjectFromPath.versions.includes(version)) {
    return slash(href)
  }

  // update the version
  return slash(href.replace(versionFromPath, version))
}

// add language code
function getVersionedPathWithLanguage (href, version, languageCode) {
  return getPathWithLanguage(getVersionedPathWithoutLanguage(href, version), languageCode)
}

// add the language to the given HREF
// /en/articles/foo -> /articles/foo
function getPathWithLanguage (href, languageCode) {
  return slash(path.posix.join('/', languageCode, getPathWithoutLanguage(href)))
    .replace(patterns.trailingSlash, '$1')
}

// remove the language from the given HREF
// /articles/foo -> /en/articles/foo
function getPathWithoutLanguage (href) {
  const newHref = href.match(patterns.hasLanguageCode)
    ? '/' + href.split('/').slice(2).join('/')
    : href

  return slash(newHref)
}

function getPathWithoutVersion (href) {
  return href.replace(`/${getVersionStringFromPath(href)}`, '')
}

function getVersionStringFromPath (href) {
  href = getPathWithoutLanguage(href)
  const versionString = href.split('/')[1]

  return versionString || 'homepage'
}

function getVersionObjectFromPath (href) {
  const versionId = getVersionStringFromPath(href)
  const version = allVersions[versionId]

  if (!version) throw new Error(`No version found for ${href}`)

  return version
}

function getProductStringFromPath (href) {
  href = getPathWithoutLanguage(href)
  const productString = href.split('/')[2]

  return productString || 'homepage'
}

function getProductObjectFromPath (href) {
  const productId = getProductStringFromPath(href)
  // Return undefined if product id derived from path can't be found in allProducts
  return allProducts[productId]
}

module.exports = {
  getVersionedPathWithLanguage,
  getVersionedPathWithoutLanguage,
  getPathWithLanguage,
  getPathWithoutLanguage,
  getPathWithoutVersion,
  getVersionStringFromPath,
  getVersionObjectFromPath,
  getProductStringFromPath,
  getProductObjectFromPath
}