/* The window's own habits.

   These are the two things the wiki does differently once it is a desktop app
   rather than a page of the web — see utils/desktop.ts for the asking, and
   src-tauri/ for the shell. The web build takes the first line and returns:
   nothing here changes how a browser sees the wiki.

   Runs after the auth plugin (plugins come in name order), which matters: by
   now a signed-in person's account has already had its say about the interface
   language, and an account outranks this device. */

import { isDesktop, leadsOutward, openExternal, storeGet, storeSet } from '~/utils/desktop'

/** Where a window keeps the interface language it was last shown. Also the
 *  name of the cookie the web build writes it to — the same choice, remembered
 *  the way this kind of host can be sure of remembering it. */
const LOCALE_KEY = 'mathew-locale'

export default defineNuxtPlugin(() => {
  if (!import.meta.client || !isDesktop()) return

  /* Links. The wiki's own addresses are relative and the router turns them as
     it always does; an absolute one is about something outside this window —
     and a window has one page, no tab strip, no back button a reader would
     trust after the wiki had been replaced by some other site's document. So
     those go out to the system's browser instead, and the window keeps
     showing the wiki it was asked to show.

     Captured on the way in, so it also catches the links drawn from article
     Markdown — the rendered text belongs to the article, which has no reason
     to know it is not in a browser. */
  document.addEventListener(
    'click',
    (event) => {
      if (event.defaultPrevented || event.button !== 0) return
      // a modified click is the reader asking for the browser's own gesture
      if (event.metaKey || event.ctrlKey || event.shiftKey || event.altKey) return
      const target = event.target as Element | null
      const href = target?.closest?.('a')?.getAttribute('href')
      if (!href || !leadsOutward(href)) return
      event.preventDefault()
      void openExternal(href)
    },
    true,
  )

  /* The interface language, kept where a window can be certain of keeping it.
     On the web the choice rides on the `mathew-locale` cookie, which the server
     reads so the first draw already speaks it. A window draws nothing on a
     server, and its own address — `tauri://localhost` — is one a webview is
     not everywhere obliged to keep cookies for, so the choice is mirrored into
     localStorage: a lost cookie costs a language switch at the next start, and
     that is all.

     An account's own choice outranks the mirror, as it outranks the cookie —
     hence the guard, the auth plugin having run first. Whatever the UI ends up
     speaking is then written back, so the mirror always says what this window
     last showed. */
  const { locale, choose } = useAppLocale()
  const { user } = useAuth()
  const remembered = storeGet(LOCALE_KEY)
  if (remembered && !user.value?.locale) void choose(remembered)

  watch(locale, (code) => storeSet(LOCALE_KEY, code))
})