Public language selector, linked with the editor's language selection. Shared popup menu operation with edit toolbar with consistent closing logic.

AGENTS.md

@@ -29,6 +29,8 @@ Pagerite is a CMS. See `docs` for the full design and implementation details. Ke
 - `frontend/src/` — Vue editor and public-page JS entries.
   - `main.js` — Vue editor app entry.
   - `analytics-main.js` — analytics page entry (mounts `AnalyticsView` at `/_a`).
+  - `langselect-main.js` + `LangSelector.vue` — public language selector, imported on demand by pagerite.js on pages with more than one hreflang alternate (the editors' `LangSelect` flag dropdown).
+  - `store.js` — the shared Pinia store (`useStore`, id `pagerite`) for cross-bundle UI state.
   - `pagerite.js` — public page entry.
   - `editorLang.js` + `LangSelect.vue` — the editor shell's shared language selection and its selector component (page + structure tabs; drives the page preview while the panel is open, via `swapdoc.setLangOverride`).
   - `reconnect.js` — shared WebSocket pacing for all sockets (staggered connect slots, stuck-CONNECTING watchdog, exponential backoff): bursts and rapid retries trip the browser's WebSocket throttling.

docs/localization.md

@@ -53,11 +53,13 @@ Region tags normalize to their base subtag (`fi-FI` → `fi`).
   article's own language), `?lang=xx` when serving a translation — however
   the language was arrived at (query or header).
 - `<link rel="alternate" hreflang="…">` entries follow the canonical
-  directly (before the social meta tags) and are the same set on every
-  page — the site-wide configured languages (`translate_langs`, which the
-  translator works to fill in): `x-default` first, pointing at the plain
-  autodetecting URL, then every language explicitly with `?lang=`, the
-  page's own primary language included.
+  directly (before the social meta tags) and list the languages the page
+  is **actually available in**: `x-default` first, pointing at the plain
+  autodetecting URL, then every available language — the original again by
+  its plain URL, translations by `?lang=`. The public language selector
+  keys off these: pagerite.js mounts the editors' flag dropdown in the
+  top-right corner when the head advertises x-default plus more than one
+  language, loading its bundle (Vue + the flag SVG set) on demand.
 - The override sticks for the session of clicks: a page requested with
   `?lang=` replicates the query onto the navigation links it renders (nav,
   sidebar, cards, brand — in-article links are content and stay as
@@ -66,6 +68,11 @@ Region tags normalize to their base subtag (`fi-FI` → `fi`).
   `history.replaceState` (pretty, shareable URLs), remembers the language,
   and adds it to every internal fetch that lacks one (preloads,
   fetch-navigations, history traversals); history entries stay query-less.
+- The public selector's pick is the same override, pure JS state
+  (`pagerite:set-session-lang`): the session language changes and the page
+  swaps in place — no `?lang=` in the address bar, no reload. The choice is
+  linked with the editor panel's language dropdown both ways; closing the
+  panel keeps the chosen language instead of reverting.
 - A full page refresh or a shared link resets to automatic selection (header
   only). This gives a clean one-time override without cookies.
 

frontend/package.json

@@ -20,6 +20,7 @@
     "codemirror": "^6.0.2",
     "country-flag-icons": "^1.6.20",
     "overlayscrollbars": "^2.16.0",
+    "pinia": "^4.0.3",
     "transliteration": "^2.6.1",
     "vue": "^3.5.26",
     "vuedraggable": "^4.1.0"

frontend/src/EditorShell.vue

@@ -21,11 +21,11 @@ const currentPath = ref(props.pagePath)
 const activeMode = ref(props.initialMode)
 
 // The shared language selection (./editorLang, v-modeled by the tabs'
-// LangSelects) also drives the page preview: while the shell is open it
-// overrides the normal language preferences (?lang= / Accept-Language),
-// so the page renders in the language being edited; closing restores.
-// The primary selection pins by the CURRENT PAGE's own primary language
-// (pages may differ — Node.language is inherited down the tree).
+// LangSelects) is linked to the whole-page language: while the shell is
+// open it drives the page preview (overrides ?lang= / Accept-Language),
+// and closing keeps the pick as the session language. The primary
+// selection pins by the CURRENT PAGE's own primary language (pages may
+// differ — Node.language is inherited down the tree).
 let pinned = false
 function pinPreviewLang() {
   pinned = true
@@ -34,6 +34,15 @@ function pinPreviewLang() {
   setLangOverride(editorLang.value || pagePrimary.value || 'en')
   loadPlain(currentPath.value)
 }
+// Opening the panel must not switch the page's language: adopt the
+// session's chosen language (public selector / earlier pick) once, then
+// pin. Runs only on (re)open — after that the selection is the user's.
+function openShell() {
+  const session = window.__pageriteLang
+  if (!editorLang.value && session && session !== (pagePrimary.value || 'en'))
+    editorLang.value = session
+  pinPreviewLang()
+}
 function unpinPreviewLang() {
   if (!pinned) return
   pinned = false
@@ -89,13 +98,13 @@ function onSwitchEvent(ev) {
 onMounted(() => {
   document.body.dataset.editorMode = activeMode.value
   addEventListener('pagerite:switch-editor', onSwitchEvent)
-  addEventListener('pagerite:editor-shown', pinPreviewLang)
+  addEventListener('pagerite:editor-shown', openShell)
   addEventListener('pagerite:editor-hidden', unpinPreviewLang)
-  // The shell mounts visible (openEditor), so pin immediately. The site
+  // The shell mounts visible (openEditor), so open immediately. The site
   // default primary language comes from the settings — it only fills the
   // unknown; the page/structure tabs refine pagePrimary per page as they
   // learn it (their knowledge is strictly better).
-  pinPreviewLang()
+  openShell()
   fetch('/_api/settings').then((r) => r.json()).then((s) => {
     if (!pagePrimary.value) pagePrimary.value = s.primary_lang || 'en'
   }).catch(() => { /* keep the fallback */ })
@@ -103,7 +112,7 @@ onMounted(() => {
 
 onUnmounted(() => {
   removeEventListener('pagerite:switch-editor', onSwitchEvent)
-  removeEventListener('pagerite:editor-shown', pinPreviewLang)
+  removeEventListener('pagerite:editor-shown', openShell)
   removeEventListener('pagerite:editor-hidden', unpinPreviewLang)
 })
 </script>

frontend/src/LangSelect.vue

@@ -3,7 +3,8 @@
 // flag button opening a clean dropdown, v-modeled on the shared editorLang
 // ('' = the primary language). The lang tab's flag grid is a different
 // control (toggles, not a select) and stays as it is.
-import { computed, ref } from 'vue'
+import { computed, nextTick, ref } from 'vue'
+import { usePopup } from './dropdown'
 
 const props = defineProps({
   modelValue: { type: String, default: '' },
@@ -13,8 +14,12 @@ const props = defineProps({
 const emit = defineEmits(['update:modelValue'])
 
 const open = ref(false)
+const root = ref(null)
 const toggleBtn = ref(null)
+const pop = ref(null)
 const popStyle = ref({})
+// Closes on outside click / Escape (./dropdown), not on mouseleave.
+usePopup(open, root)
 const current = computed(
   () => props.options.find((o) => o.tag === props.modelValue) ?? props.options[0],
 )
@@ -26,6 +31,17 @@ function toggle() {
     // onto the page area instead of being clipped by it.
     const r = toggleBtn.value.getBoundingClientRect()
     popStyle.value = { top: `${r.bottom + 2}px`, left: `${r.left}px` }
+    // A toggle mounted near the right window edge (the public page
+    // selector sits top-right) opens the popup flush against that edge.
+    nextTick(() => {
+      const p = pop.value?.getBoundingClientRect()
+      if (p && p.right > innerWidth - 4) {
+        popStyle.value = {
+          ...popStyle.value,
+          left: `${Math.max(4, innerWidth - 4 - p.width)}px`,
+        }
+      }
+    })
   }
 }
 
@@ -36,7 +52,7 @@ function select(tag) {
 </script>
 
 <template>
-  <span v-if="options.length > 1" class="lang-select">
+  <span v-if="options.length > 1" ref="root" class="lang-select">
     <button
       ref="toggleBtn"
       type="button"
@@ -47,7 +63,7 @@ function select(tag) {
         : '')"
       @click="toggle"
     ><span v-if="current?.flag" class="flag" v-html="current.flag" /></button>
-    <span v-if="open" class="lang-pop" :style="popStyle" @mouseleave="open = false">
+    <span v-if="open" ref="pop" class="lang-pop" :style="popStyle">
       <button
         v-for="o in options"
         :key="o.code"
@@ -66,20 +82,23 @@ function select(tag) {
   display: flex;
 }
 
-/* The closed state is just the small flag — no button chrome until hovered. */
+/* The closed state is just the small flag — no button chrome at all, on
+   hover either (it sits among borderless emoji-icon buttons); like them it
+   rests dimmed and brightens on hover. */
 .lang-current {
   display: flex;
   align-items: center;
   padding: 2px;
   background: none;
-  border: 1px solid transparent;
+  border: none;
   border-radius: 4px;
   cursor: pointer;
+  opacity: 0.7;
 }
 
 .lang-current:hover,
 .lang-current.open {
-  border-color: var(--line);
+  opacity: 1;
 }
 
 /* The dropdown matches the page's existing popups (.picker-pop look).
@@ -127,11 +146,13 @@ function select(tag) {
   color: var(--muted);
 }
 
-/* Flags render like in the analytics visitor cells. */
+/* em-sized so the chip matches the surrounding text/icon size in each
+   context; the hairline border delineates white-flagged countries (not
+   button chrome). */
 .flag {
   display: inline-flex;
-  width: 18px;
-  height: 12px;
+  width: 1.5em;
+  height: 1em;
   flex: 0 0 auto;
   border-radius: 2px;
   overflow: hidden;

frontend/src/LangSelector.vue

@@ -0,0 +1,41 @@
+<script setup>
+// The public page's language selector: the editors' flag dropdown
+// (LangSelect) as the first item of the banner's corner container, fed
+// from the shared store (pagerite.js sets the page's hreflang alternates
+// and served language per navigation). It binds the same store.lang the
+// editor's dropdown binds, so both always show the same selection. A pick
+// also dispatches pagerite:set-session-lang — pagerite.js swaps the page
+// in place when the editor is closed (open, the editor reacts to the
+// store and re-renders it).
+import { computed } from 'vue'
+import LangSelect from './LangSelect.vue'
+import { flagFor, langName } from './langs'
+import { useStore } from './store'
+
+const store = useStore()
+
+// The "(primary)" marker is admin-panel information; the public selector
+// lists plain languages.
+const options = computed(() =>
+  store.langAlternates.map((a) => ({
+    tag: a.tag,
+    code: a.tag,
+    name: langName(a.tag),
+    flag: flagFor(a.tag),
+    primary: false,
+  })),
+)
+const primaryTag = computed(() => store.langAlternates.find((a) => a.primary)?.tag ?? '')
+// The explicit pick, else the served language (header-autodetected pages
+// may have neither), else the primary.
+const model = computed(() => store.lang || store.servedLang || primaryTag.value)
+
+function go(tag) {
+  store.lang = tag === primaryTag.value ? '' : tag
+  dispatchEvent(new CustomEvent('pagerite:set-session-lang', { detail: { lang: tag } }))
+}
+</script>
+
+<template>
+  <LangSelect :model-value="model" :options="options" @update:model-value="go" />
+</template>

frontend/src/PageEditor.vue

@@ -26,6 +26,7 @@
 // renders the version being edited, whichever language the page itself
 // was loaded in.
 import { computed, onActivated, onMounted, onUnmounted, ref, watch } from 'vue'
+import { usePopup } from './dropdown'
 import { EditorView, basicSetup } from 'codemirror'
 import { Compartment, EditorState } from '@codemirror/state'
 import { keymap } from '@codemirror/view'
@@ -621,8 +622,15 @@ const TABLE_MAX_ROWS = 6
 // Class pickers: popup listing the block class toggles (placement ↔︎,
 // text size AA), closed after applying. The block's current class of the
 // group is marked; choosing "normal" (or the current class) removes it.
+// All popups share the close behavior of ./dropdown (outside click /
+// Escape; never mouseleave).
 const classPicker = ref(null) // 'place' | 'size' | null
 const activeClasses = ref(new Set())
+const placeRoot = ref(null)
+const sizeRoot = ref(null)
+const tableRoot = ref(null)
+usePopup(classPicker, computed(() => (classPicker.value === 'place' ? placeRoot : sizeRoot).value))
+usePopup(tablePicker, tableRoot)
 
 function openClassPicker(which) {
   classPicker.value = classPicker.value === which ? null : which
@@ -1136,15 +1144,31 @@ onUnmounted(() => {
     <div class="format-bar">
       <button type="button" class="code-btn" title="code — inline wrap, or a fenced block for line-spanning selections; click again to unwrap" @click="insertCode"><code>&lt;/&gt;</code></button>
       <button type="button" title="link (toggle: click inside a link to unwrap it)" @click="insertLink">🔗︎</button>
+      <span class="picker" ref="tableRoot">
         <button
           type="button"
           title="table"
           :class="{ active: tablePicker }"
           @click="tablePicker = !tablePicker"
         >⊞</button>
+        <div v-if="tablePicker" class="table-picker" @mouseleave="tableSize = { cols: 0, rows: 0 }">
+          <div class="tp-grid" :style="{ gridTemplateColumns: `repeat(${TABLE_MAX_COLS}, 1fr)` }">
+            <button
+              v-for="n in TABLE_MAX_COLS * TABLE_MAX_ROWS"
+              :key="n"
+              type="button"
+              class="tp-cell"
+              :class="{ on: tableSize.cols >= (n - 1) % TABLE_MAX_COLS + 1 && tableSize.rows >= Math.floor((n - 1) / TABLE_MAX_COLS) + 1 }"
+              @mouseenter="tableSize = { cols: (n - 1) % TABLE_MAX_COLS + 1, rows: Math.floor((n - 1) / TABLE_MAX_COLS) + 1 }"
+              @click="insertTable(tableSize.cols, tableSize.rows)"
+            />
+          </div>
+          <div class="tp-size">{{ tableSize.cols || '–' }} × {{ tableSize.rows || '–' }}</div>
+        </div>
+      </span>
       <button type="button" title="insert image (upload) — pasting works too" @click="fileInput.click()">🖼︎</button>
       <button type="button" title="aside box (::: aside) — wraps the selection or the cursor's line; clicked inside one, removes it" @click="insertAside">◧</button>
-      <span class="picker">
+      <span class="picker" ref="placeRoot">
         <button
           type="button"
           title="block placement class"
@@ -1166,7 +1190,7 @@ onUnmounted(() => {
       </span>
       <button type="button" title="bold" @click="wrapInline('**')"><b>B</b></button>
       <button type="button" title="italic" @click="wrapInline('*')"><i>i</i></button>
-      <span class="picker">
+      <span class="picker" ref="sizeRoot">
         <button
           type="button"
           title="text size class"
@@ -1368,7 +1392,7 @@ onUnmounted(() => {
 .table-picker {
   position: absolute;
   top: 100%;
-  left: 6.5rem;
+  left: 0;
   z-index: 20;
   padding: 0.5rem;
   background: var(--bg);

frontend/src/dropdown.js

@@ -0,0 +1,24 @@
+// Shared popup open-state behavior: while `open` (a ref, truthy = open)
+// is set, a pointerdown outside `root` (a template ref covering both the
+// toggle button and the popup) or Escape resets it to null. One logic for
+// every dropdown (LangSelect, the page editor's class/table pickers), so
+// they can't drift apart.
+import { onBeforeUnmount, watch } from 'vue'
+
+export function usePopup(open, root) {
+  let off = null
+  const stop = watch(open, (v) => {
+    off?.()
+    off = null
+    if (!v) return
+    const down = (ev) => { if (!root.value?.contains(ev.target)) open.value = null }
+    const key = (ev) => { if (ev.key === 'Escape') open.value = null }
+    addEventListener('pointerdown', down, true)
+    addEventListener('keydown', key)
+    off = () => {
+      removeEventListener('pointerdown', down, true)
+      removeEventListener('keydown', key)
+    }
+  })
+  onBeforeUnmount(() => { off?.(); stop() })
+}

frontend/src/editorLang.js

@@ -1,10 +1,15 @@
 // The editor shell's shared language selection ('' = the primary language):
-// one state, v-modeled by the LangSelect of every tab that has one (page,
-// structure). While the panel is open it also drives the page preview —
-// EditorShell applies it as the fetch-time language override (swapdoc).
-import { ref } from 'vue'
+// backed by the app-wide store (./store), so the editor tabs' LangSelects
+// and the public corner selector bind the same value. Linked to the
+// whole-page language: while the panel is open it drives the page preview
+// (EditorShell applies it as the fetch-time language override, swapdoc).
+import { computed, ref } from 'vue'
+import { pinia, useStore } from './store'
 
-export const editorLang = ref('')
+export const editorLang = computed({
+  get: () => useStore(pinia).lang,
+  set: (v) => { useStore(pinia).lang = v },
+})
 
 // The CURRENT PAGE's primary language ('' = not yet learned): the shell's
 // settings fetch fills it with the site default; the page/structure tabs

frontend/src/langselect-main.js

@@ -0,0 +1,50 @@
+// Public language-selector entry: imported on demand by pagerite.js on
+// pages advertising more than one language in their hreflang alternates.
+// Vue, Pinia and the flag SVG set live in this chunk only — untranslated
+// pages never pay for them. The selector's state lives in the shared
+// store (./store), not the DOM: the corner container is rebuilt freely
+// and ensureMounted re-mounts from the store.
+import { createApp } from 'vue'
+import LangSelector from './LangSelector.vue'
+import { pinia, useStore } from './store'
+
+let app = null
+
+function store() {
+  return useStore(pinia)
+}
+
+// The current page's languages (called on every navigation).
+export function setLanguages(alternates, current) {
+  Object.assign(store(), {
+    langAlternates: alternates,
+    servedLang: current,
+    langSelectorActive: true,
+  })
+}
+
+// The current page is single-language: the selector goes away.
+export function hide() {
+  store().langSelectorActive = false
+  app?.unmount()
+  app = null
+}
+
+// Mount the selector as the container's first item; re-mount when its
+// element went away with a container rebuild (a live app updates from the
+// store reactively).
+export function ensureMounted(host) {
+  if (!store().langSelectorActive || !host) {
+    app?.unmount()
+    app = null
+    return
+  }
+  if (app && host.contains(app._container)) return
+  app?.unmount()
+  const el = document.createElement('div')
+  el.id = 'lang-selector'
+  host.prepend(el)
+  app = createApp(LangSelector)
+  app.use(pinia)
+  app.mount(el)
+}

frontend/src/pagerite.js

@@ -51,13 +51,18 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
     url.searchParams.delete("lang");
     history.replaceState(history.state, "", url);
   }
-  // The session language. While the editor panel is open, its language
-  // selection overrides the normal preference (swapdoc.setLangOverride):
-  // internal fetches and prefetches follow it until the panel closes and
-  // the override clears (null restores the initial ?lang=, if any).
+  // The session language: the user's explicit pick (initial ?lang=, public
+  // selector, editor dropdown) is kept in chosenLang; while the editor is
+  // open its selection overrides it (swapdoc.setLangOverride), and closing
+  // falls back to chosenLang. JS state only — pretty URLs, no reloads.
+  // window.__pageriteLang is the pin for swapdoc.loadPlain's fetches.
+  let chosenLang = langParam;
   let sessionLang = langParam;
+  window.__pageriteLang = sessionLang;
   addEventListener("pagerite:session-lang", (ev) => {
-    sessionLang = ev.detail?.lang || langParam;
+    if (ev.detail?.lang) chosenLang = ev.detail.lang;
+    sessionLang = ev.detail?.lang || chosenLang;
+    window.__pageriteLang = sessionLang;
   });
   // An internal URL as fetched: carries the session's ?lang= unless the
   // link already pins a language of its own. With no ?lang= on the initial
@@ -167,6 +172,22 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
     return a;
   }
 
+  // The banner top-right corner container: the language selector (first
+  // item) plus the admin pens and auth links. renderAuthUi rebuilds it from
+  // scratch; the selector's state lives in the shared store, not the DOM,
+  // so the langselect bundle re-mounts it into the fresh container.
+  function pensContainer() {
+    let pens = document.querySelector(".editor-pens");
+    if (!pens) {
+      const banner = document.getElementById("page-banner");
+      if (!banner) return null;
+      pens = document.createElement("div");
+      pens.className = "editor-pens";
+      banner.after(pens);
+    }
+    return pens;
+  }
+
   function removePens() {
     document.querySelectorAll(".editor-pens, #main article button.edit-link")
       .forEach((el) => el.remove());
@@ -178,18 +199,15 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
     // pens that may have been injected while the browser cache made us look
     // authenticated.
     removePens();
-    if (!authReady) return;
-
+    if (authReady) {
       // Editing is open for admins and, as a dev/no-proxy fallback, when no
       // Paskia SSO is detected at all.
       const canEdit = isAdmin || !ssoAvailable;
       // The analytics page is a read-only dashboard: editing pens and the side
       // panel do not apply there. Login/logout links are still useful.
       const onAnalytics = currentPath === "/_a";
-    const banner = document.getElementById("page-banner");
-    if (banner) {
-      const pens = document.createElement("div");
-      pens.className = "editor-pens";
+      if (document.getElementById("page-banner")) {
+        const pens = pensContainer();
         if (canEdit && !onAnalytics) {
           // Analytics viewer is now a normal page at /_a.
           const a = document.createElement("a");
@@ -201,10 +219,14 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
           pens.append(makePen("site"));
         }
         if (ssoAvailable) pens.append(makeAuthLink(isAdmin));
-      banner.after(pens);
+        if (!pens.firstElementChild) pens.remove();
       }
       if (canEdit && !onAnalytics) injectPagePen();
     }
+    // Re-mount the selector into the fresh container (no-op until the
+    // bundle has been loaded once).
+    langselectMod?.ensureMounted(document.querySelector(".editor-pens"));
+  }
 
   async function setupAuth() {
     authReady = false;
@@ -407,6 +429,9 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
     // copy pinned to a language (?lang=) caches under its own key, where
     // navigation with the same session language finds it.
     pageCache.set(rawKey(ev.detail.url), ev.detail.html);
+    // Editor-driven swaps don't go through load(): re-evaluate the
+    // language selector from the fresh copy too.
+    mountLangselect(new DOMParser().parseFromString(ev.detail.html, "text/html"));
   });
 
   // Editors mutate site-wide state (theme, structure, headings, banners),
@@ -742,6 +767,56 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
     }
   }
 
+  // --- Public language selector ------------------------------------------
+  // Pages translated into more than one language advertise it via hreflang
+  // alternates (x-default + one link per language). Those pages get the
+  // editors' flag dropdown as the first item of the corner container; its
+  // bundle (Vue + the flag SVG set) loads on demand. Re-evaluated from the
+  // fresh document on every swap (the head's own alternates stay stale).
+  let langselectMod = null;
+  async function mountLangselect(doc) {
+    const links = [...doc.head.querySelectorAll('link[rel="alternate"][hreflang]')];
+    const dflt = links.find((l) => l.hreflang === "x-default");
+    const langs = links.filter((l) => l.hreflang && l.hreflang !== "x-default");
+    if (!dflt || langs.length <= 1) return langselectMod?.hide();
+    try {
+      langselectMod ??= await import(/* @vite-ignore */ assets["pagerite:langselect-src"]);
+      for (const css of (assets["pagerite:langselect-css"] || "").split(",")) {
+        if (css && !document.querySelector(`link[href="${css}"]`)) {
+          const link = document.createElement("link");
+          link.rel = "stylesheet";
+          link.href = css;
+          link.dataset.pagerite = "langselect-css";
+          document.head.append(link);
+        }
+      }
+      langselectMod.setLanguages(
+        // The original's alternate is the plain URL — x-default's href —
+        // which also marks it as the primary option.
+        langs.map((l) => ({ tag: l.hreflang, href: l.href, primary: l.href === dflt.href })),
+        doc.documentElement.lang,
+      );
+      langselectMod.ensureMounted(pensContainer());
+    } catch (e) {
+      console.error("language selector mount failed:", e);
+    }
+  }
+
+  // The selector's pick (LangSelector dispatches this): make it the
+  // session language and swap the page in place. With the editor open the
+  // pick already landed in the shared store — the editor's watch re-renders
+  // the page itself, so there is nothing to do here.
+  addEventListener("pagerite:set-session-lang", async (ev) => {
+    const tag = ev.detail?.lang;
+    if (!tag || tag === sessionLang) return;
+    if (document.body.classList.contains("editing")) return;
+    chosenLang = sessionLang = tag;
+    window.__pageriteLang = tag;
+    const y = scrollY; // a language switch is not a navigation: keep scroll
+    await load(currentPath, false);
+    scrollTo(0, y);
+  });
+
   // --- Fetch navigation ------------------------------------------------
   async function load(url, push = true, back = false) {
     // Navigating with the editor open closes it; unsaved edits are lost
@@ -843,6 +918,7 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
       runScripts(document.getElementById("main"));
       applyEffects();
       mountAnalytics(doc);
+      mountLangselect(doc);
     };
     // Rotating cube page transition (styles injected as #pagerite-transition
     // from the selected design's transition.css, e.g. themes/cube/);
@@ -1076,4 +1152,5 @@ import { reconnectPolicy, socketSlot, watchConnecting } from "./reconnect";
   setupAuth();
   applyEffects();
   mountAnalytics(document);
+  mountLangselect(document);
 })();

frontend/src/store.js

@@ -0,0 +1,26 @@
+// The app's shared Pinia store — cross-bundle UI state lives here. Every
+// entry chunk imports its own copy of this module, so the Pinia instance
+// is parked on window (Vue itself is a shared chunk, so reactivity works
+// across the copies). Pass `pinia` explicitly when calling useStore
+// outside a component (module code, no active instance).
+import { createPinia, defineStore } from 'pinia'
+
+export const pinia = (window.__pageritePinia ??= createPinia())
+
+export const useStore = defineStore('pagerite', {
+  state: () => ({
+    // The ONE language selection, v-modeled by both dropdowns (editor
+    // tabs, public corner selector): '' = no explicit pick (the page's
+    // primary / autodetect), else a concrete tag. A pick from either
+    // dropdown is visible to everyone immediately.
+    lang: '',
+    // The language the current page was actually served in (set by
+    // pagerite.js per navigation) — the selector's highlight fallback
+    // when there is no explicit pick.
+    servedLang: '',
+    // The public selector's page data: hreflang alternates
+    // ([{tag, href, primary}]) and whether to show at all.
+    langAlternates: [],
+    langSelectorActive: false,
+  }),
+})

frontend/src/swapdoc.js

@@ -12,12 +12,13 @@ export function dropPageCache() {
 }
 
 // The editor's language override (set by EditorShell): while the panel is
-// open, its language selection wins over the normal preferences (?lang= /
-// Accept-Language) — every in-place re-render asks for that language
-// explicitly, and pagerite.js applies it to its own fetches and prefetches
-// (pagerite:session-lang). The primary selection pins by its code:
-// ?lang=<primary> selects the original explicitly (i18n.select_language).
-let overrideLang = null // the ?lang= value in force, null = normal prefs
+// open, its language selection wins over the normal preferences — every
+// in-place re-render asks for that language explicitly, and pagerite.js
+// applies it to its own fetches and prefetches (pagerite:session-lang).
+// The primary selection pins by its code: ?lang=<primary> selects the
+// original explicitly (i18n.select_language). Panel closed, the session's
+// chosen language (window.__pageriteLang) takes over — the pick stays.
+let overrideLang = null // the ?lang= value in force, null = the session's
 
 export function setLangOverride(queryLang) {
   overrideLang = queryLang || null
@@ -129,14 +130,16 @@ function swapRegions(doc) {
 // Fetch /p, swap its regions into the live page and replaceState to it.
 // Returns the final URL (after redirects), or null when the fetch did not
 // yield a page. Category and missing URLs render a placeholder 404 page —
-// fine to swap in (new pages are created by editing them). While the
-// editor's language override is set the fetch pins that language.
+// fine to swap in (new pages are created by editing them). The fetch pins
+// the editor's language override, or — panel closed — the session's chosen
+// language (window.__pageriteLang).
 export async function loadPlain(p) {
   let doc
   let finalUrl = `/${p}`
   let html
   try {
-    const res = await fetch(overrideLang ? `${finalUrl}?lang=${overrideLang}` : finalUrl)
+    const pin = overrideLang || window.__pageriteLang
+    const res = await fetch(pin ? `${finalUrl}?lang=${pin}` : finalUrl)
     const type = res.headers.get('content-type') || ''
     if (!type.includes('text/html')) return null
     if (res.redirected) finalUrl = res.url

frontend/vite.config.js

@@ -38,7 +38,7 @@ export default defineConfig({
     chunkSizeWarningLimit: 1200,
     // Mirror the URL space in the build output: hashed files land under
     // frontend-build/_assets/ and the Frontend serves the build directory
-    // at the site root (frontend/public/favicon.ico -> /favicon.ico).
+    // at the site root.
     manifest: true,
     assetsDir: '_assets',
     rollupOptions: {
@@ -50,6 +50,7 @@ export default defineConfig({
         main: fileURLToPath(new URL('./src/main.js', import.meta.url)),
         pagerite: fileURLToPath(new URL('./src/pagerite.js', import.meta.url)),
         analytics: fileURLToPath(new URL('./src/analytics-main.js', import.meta.url)),
+        langselect: fileURLToPath(new URL('./src/langselect-main.js', import.meta.url)),
         // Only the base CSS is built; theme/banner-design stylesheets live
         // in pagerite/themes/{name}/ and are served by the backend as-is.
         pagerite_base: fileURLToPath(new URL('./src/assets/pagerite.css', import.meta.url)),

pagerite/views.py

@@ -385,10 +385,14 @@ def _layout(
     # carries the on-demand URLs in one JSON script instead.
     vite_url = os.environ.get("PAGERITE_VITE_URL")
     editor_scripts, editor_css = _editor_assets()
+    langselect_scripts, langselect_css = _langselect_assets()
     config = {
         "pagerite:editor-src": editor_scripts[-1],
         "pagerite:analytics-src": _analytics_assets()[0][0],
+        "pagerite:langselect-src": langselect_scripts[-1],
     }
+    if langselect_css:
+        config["pagerite:langselect-css"] = ",".join(langselect_css)
     if editor_css:
         config["pagerite:editor-css"] = editor_css
     if vite_url:
@@ -1050,10 +1054,10 @@ def render_page(
     # the actually served language — the plain URL for the original (for
     # SEO the non-query URL means the article's language), ?lang= for a
     # translation — regardless of how the language was arrived at (query
-    # or header). The alternates are site-wide, the same set on every
-    # page: the configured translate_langs (the translator works to fill
-    # them all in), x-default first (the plain, autodetecting URL), then
-    # every language explicitly, the page's own primary included.
+    # or header). The alternates list the languages the page is actually
+    # available in: x-default first (the plain, autodetecting URL), then
+    # every available language — the original again by its plain URL,
+    # translations by ?lang=. The public language selector keys off these.
     canonical = ""
     alternates = []
     if base_url:
@@ -1061,8 +1065,8 @@ def render_page(
         canonical = url if lang == original else f"{url}?lang={lang}"
         if data.translate_langs:
             alternates = [("x-default", url)] + [
-                (tag, f"{url}?lang={tag}")
-                for tag in sorted({original, *data.translate_langs})
+                (tag, url if tag == original else f"{url}?lang={tag}")
+                for tag in sorted({original, *node.langs})
             ]
     return str(
         _layout(
@@ -1228,6 +1232,31 @@ def _analytics_assets() -> tuple[list[str], list[str]]:
     return _asset_cache["analytics"]
 
 
+def _langselect_assets() -> tuple[list[str], list[str]]:
+    """Script and stylesheet URLs for the on-demand public language selector."""
+    vite_url = os.environ.get("PAGERITE_VITE_URL")
+    if vite_url:
+        return [f"{vite_url}/src/langselect-main.js"], []
+    if "langselect" not in _asset_cache:
+        manifest = _manifest()
+        # import() loads no CSS automatically: collect the stylesheets of
+        # the entry and its imported chunks (LangSelect's ride on the
+        # shared langs chunk).
+        scripts, stylesheets, seen = [], [], set()
+        queue = ["src/langselect-main.js"]
+        for key in queue:  # grows with imported chunks
+            if key in seen:
+                continue
+            seen.add(key)
+            entry = manifest[key]
+            if entry.get("isEntry"):
+                scripts.append(f"/{entry['file']}")
+            stylesheets += [f"/{css}" for css in entry.get("css", [])]
+            queue += entry.get("imports", [])
+        _asset_cache["langselect"] = scripts, stylesheets
+    return _asset_cache["langselect"]
+
+
 def render_analytics(
     menu: dict[str, Node],
     brand: str = SITE_NAME,