import type { HeadConfig, PageData, SiteData } from '../../types/shared'

export type {
  Awaitable,
  DefaultTheme,
  HeadConfig,
  Header,
  LocaleConfig,
  LocaleSpecificConfig,
  MarkdownEnv,
  PageData,
  PageDataPayload,
  SSGContext,
  SiteData
} from '../../types/shared'

export const EXTERNAL_URL_RE = /^(?:[a-z]+:|\/\/)/i
export const APPEARANCE_KEY = 'vitepress-theme-appearance'

const HASH_RE = /#.*$/
const HASH_OR_QUERY_RE = /[?#].*$/
const INDEX_OR_EXT_RE = /(?:(^|\/)index)?\.(?:md|html)$/

export const inBrowser = typeof document !== 'undefined'

export const notFoundPageData: PageData = {
  relativePath: '404.md',
  filePath: '',
  title: '404',
  description: 'Not Found',
  headers: [],
  frontmatter: { sidebar: false, layout: 'page' },
  lastUpdated: 0,
  isNotFound: true
}

export function isActive(
  currentPath: string,
  matchPath?: string,
  asRegex: boolean = false
): boolean {
  if (matchPath === undefined) {
    return false
  }

  currentPath = normalize(`/${currentPath}`)

  if (asRegex) {
    return new RegExp(matchPath).test(currentPath)
  }

  if (normalize(matchPath) !== currentPath) {
    return false
  }

  const hashMatch = matchPath.match(HASH_RE)

  if (hashMatch) {
    return (inBrowser ? location.hash : '') === hashMatch[0]
  }

  return true
}

function normalize(path: string): string {
  return decodeURI(path)
    .replace(HASH_OR_QUERY_RE, '')
    .replace(INDEX_OR_EXT_RE, '$1')
}

export function isExternal(path: string): boolean {
  return EXTERNAL_URL_RE.test(path)
}

export function getLocaleForPath(
  siteData: SiteData | undefined,
  relativePath: string
): string {
  return (
    Object.keys(siteData?.locales || {}).find(
      (key) =>
        key !== 'root' &&
        !isExternal(key) &&
        isActive(relativePath, `/${key}/`, true)
    ) || 'root'
  )
}

/**
 * this merges the locales data to the main data by the route
 */
export function resolveSiteDataByRoute(
  siteData: SiteData,
  relativePath: string
): SiteData {
  const localeIndex = getLocaleForPath(siteData, relativePath)

  return Object.assign({}, siteData, {
    localeIndex,
    lang: siteData.locales[localeIndex]?.lang ?? siteData.lang,
    dir: siteData.locales[localeIndex]?.dir ?? siteData.dir,
    title: siteData.locales[localeIndex]?.title ?? siteData.title,
    titleTemplate:
      siteData.locales[localeIndex]?.titleTemplate ?? siteData.titleTemplate,
    description:
      siteData.locales[localeIndex]?.description ?? siteData.description,
    head: mergeHead(siteData.head, siteData.locales[localeIndex]?.head ?? []),
    themeConfig: {
      ...siteData.themeConfig,
      ...siteData.locales[localeIndex]?.themeConfig
    }
  })
}

/**
 * Create the page title string based on config.
 */
export function createTitle(siteData: SiteData, pageData: PageData): string {
  const title = pageData.title || siteData.title
  const template = pageData.titleTemplate ?? siteData.titleTemplate

  if (typeof template === 'string' && template.includes(':title')) {
    return template.replace(/:title/g, title)
  }

  const templateString = createTitleTemplate(siteData.title, template)

  if (title === templateString.slice(3)) {
    return title
  }

  return `${title}${templateString}`
}

function createTitleTemplate(
  siteTitle: string,
  template?: string | boolean
): string {
  if (template === false) {
    return ''
  }

  if (template === true || template === undefined) {
    return ` | ${siteTitle}`
  }

  if (siteTitle === template) {
    return ''
  }

  return ` | ${template}`
}

function hasTag(head: HeadConfig[], tag: HeadConfig) {
  const [tagType, tagAttrs] = tag
  if (tagType !== 'meta') return false
  const keyAttr = Object.entries(tagAttrs)[0] // First key
  if (keyAttr == null) return false
  return head.some(
    ([type, attrs]) => type === tagType && attrs[keyAttr[0]] === keyAttr[1]
  )
}

export function mergeHead(prev: HeadConfig[], curr: HeadConfig[]) {
  return [...prev.filter((tagAttrs) => !hasTag(curr, tagAttrs)), ...curr]
}

// https://github.com/rollup/rollup/blob/fec513270c6ac350072425cc045db367656c623b/src/utils/sanitizeFileName.ts

const INVALID_CHAR_REGEX = /[\u0000-\u001F"#$&*+,:;<=>?[\]^`{|}\u007F]/g
const DRIVE_LETTER_REGEX = /^[a-z]:/i

export function sanitizeFileName(name: string): string {
  const match = DRIVE_LETTER_REGEX.exec(name)
  const driveLetter = match ? match[0] : ''

  return (
    driveLetter +
    name
      .slice(driveLetter.length)
      .replace(INVALID_CHAR_REGEX, '_')
      .replace(/(^|\/)_+(?=[^/]*$)/, '$1')
  )
}

export function slash(p: string): string {
  return p.replace(/\\/g, '/')
}

const KNOWN_EXTENSIONS = new Set()

export function treatAsHtml(filename: string): boolean {
  if (KNOWN_EXTENSIONS.size === 0) {
    const extraExts =
      (typeof process === 'object' && process.env?.VITE_EXTRA_EXTENSIONS) ||
      (import.meta as any).env?.VITE_EXTRA_EXTENSIONS ||
      ''

    // md, html? are intentionally omitted
    ;(
      '3g2,3gp,aac,ai,apng,au,avif,bin,bmp,cer,class,conf,crl,css,csv,dll,' +
      'doc,eps,epub,exe,gif,gz,ics,ief,jar,jpe,jpeg,jpg,js,json,jsonld,m4a,' +
      'man,mid,midi,mjs,mov,mp2,mp3,mp4,mpe,mpeg,mpg,mpp,oga,ogg,ogv,ogx,' +
      'opus,otf,p10,p7c,p7m,p7s,pdf,png,ps,qt,roff,rtf,rtx,ser,svg,t,tif,' +
      'tiff,tr,ts,tsv,ttf,txt,vtt,wav,weba,webm,webp,woff,woff2,xhtml,xml,' +
      'yaml,yml,zip' +
      (extraExts && typeof extraExts === 'string' ? ',' + extraExts : '')
    )
      .split(',')
      .forEach((ext) => KNOWN_EXTENSIONS.add(ext))
  }

  const ext = filename.split('.').pop()

  return ext == null || !KNOWN_EXTENSIONS.has(ext.toLowerCase())
}

// https://github.com/sindresorhus/escape-string-regexp/blob/ba9a4473850cb367936417e97f1f2191b7cc67dd/index.js
export function escapeRegExp(str: string) {
  return str.replace(/[|\\{}()[\]^$+*?.]/g, '\\$&').replace(/-/g, '\\x2d')
}

/**
 * @internal
 */
export function escapeHtml(str: string): string {
  return str
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/&(?![\w#]+;)/g, '&amp;')
}