/* Brain of Reese — shared header module (phase 19).
 *
 * Owner report 2026-08-23: clicking "Sources" made New Chat and Sign in
 * vanish — the user expects ONE consistent bar on every page. This module
 * is the single owner of the shared header controls:
 *
 *   • the Sign in / Sign out auth pair (phase 16, exactly one visible —
 *     decided by /api/whoami at load);
 *   • the admin-only nav links — "RAG" (#nav-sources, phase 19),
 *     "Sources" (#nav-git-sources, phase 35) and "Tuning"
 *     (#nav-tuning, phase 29) — phase 19 UX revision
 *     (owner permission 2026-08-23): hidden for anonymous on EVERY
 *     page, revealed for admin. Phase 34 task 03 (owner confirmation
 *     2026-08-26): the SAME nav ships on all five pages (chat,
 *     sources, document viewer, tuning, login) — the viewer's
 *     "no nav" bar is gone. The links SHIP hidden in the HTML
 *     (anonymous-safe default — the phase-16 "absent, not hidden"
 *     spirit), so no anonymous user ever sees one for a frame; and
 *   • the sign-out click binding (POST /api/logout → reload) — moved
 *     here from app.js so there is exactly one implementation;
 *   • the mobile hamburger binding (phase 46, owner permission
 *     2026-08-27, TODO.md L9) — at ≤640px (CSS hides the button
 *     elsewhere) the #nav-toggle button opens the nav as an animated
 *     dropdown (#app-nav .is-open — the 180ms slide+fade state from
 *     task 01's CSS): a click toggles it with aria-expanded kept in
 *     sync, a nav link click shuts it (the navigation happens anyway),
 *     Esc shuts it and returns focus to the toggle, and resizing back
 *     to >640px drops the open state (matchMedia change) so
 *     aria-expanded stays honest. One binding for all six pages; a
 *     page without either element is a no-op. The binding toggles
 *     ONLY the container — the nav links keep their ship-hidden
 *     whoami contract (hidden links stay hidden inside the menu);
 *   • the steering-notes panel (phase 15, moved here from app.js in
 *     phase 34) — the #steering-panel list (newest-first,
 *     textContent-rendered, per-note delete) + the #steering-announcer
 *     live region — so every page that ships the panel markup gets
 *     exactly this behavior with zero page-script duplication. The
 *     navbar #steering-toggle was REMOVED at owner request
 *     (2026-08-28) — note management now lives on /tuning.html — so
 *     the panel ships hidden on every page and is only kept fresh,
 *     never opened from the header. refreshSteering() /
 *     announceSteering() are exported for the chat page's per-bubble
 *     Tune form (which stays in app.js); anonymous visitors get the
 *     phase-16 "absent, not hidden" treatment (panel removed from the
 *     DOM, /api/steering never fetched);
 *   • the SINGLE New chat binding (phase 34 task 02 — it was
 *     duplicated across app.js / sources.js / tuning.js / document.js;
 *     moved from the navbar to the chat page at owner request):
 *     the button now lives ONLY on the chat page (inside .chat-shell,
 *     above #messages). When clicked it dispatches window
 *     "bor:new-chat" and app.js acts (it owns the in-flight-turn
 *     guard + the list reset).
 *   • clearChatStorage() — the phase-14 conversation key, for clearing
 *     the conversation when navigating away from the chat page.
 *   • the sign-in ?next= rewrite (phase 34 task 02) — initSharedHeader
 *     points #sign-in-link at /login.html?next=<current pathname>
 *     (default "/"), so the admin lands back on the page they signed in
 *     from; the page markup keeps its own href as the no-JS fallback;
 *   • clearChatStorage() — the phase-14 conversation key, for the
 *     New chat action on the NON-CHAT pages (sources / document viewer /
 *     tuning / login): a new chat means going to the chat, fresh.
 *
 * Every page loads this module (type="module", before its page script)
 * and its page script calls initSharedHeader() once at boot. init…
 * toggles ONLY the controls that exist on the page — a missing element
 * is a no-op. Phase 34 task 03 ships the SAME full header block on all
 * five pages (the login page included), so every control resolves on
 * every page; a page that lacks one simply skips it.
 *
 * whoami is fetched at most ONCE per page load: the promise is cached in
 * the module-level `adminPromise`, so app.js's tuning gate, the sources
 * page's catalog gate, and the header toggling all share one request.
 * Anonymous-safe: any network failure resolves to false (the anonymous
 * UI), mirroring the per-page catch the pages used before phase 19.
 *
 * A10/A11 untouched: no API change, no CDN, no state beyond the cached
 * promise; the soft gate page and the A10 API split are unchanged —
 * this is UI visibility only.
 */

let adminPromise = null;

/* The SINGLE /api/whoami call site for the whole frontend. First call
   stores the promise in `adminPromise`; every later call — on this page
   — returns the same promise, i.e. exactly one request per page load.
   Anonymous-safe: non-2xx or a network failure resolves to false. */
export function fetchIsAdmin() {
  if (!adminPromise) {
    adminPromise = fetch("/api/whoami")
      .then(async (r) => (r.ok ? (await r.json()).authenticated === true : false))
      .catch(() => false);
  }
  return adminPromise;
}

/* Toggle the shared header controls, only the ones present on this page
   (querySelector, null-safe — missing → no-op). Returns the admin flag
   so callers can reuse it instead of awaiting fetchIsAdmin() again (the
   cached promise makes both awaits the same single request). */
export async function initSharedHeader() {
  const admin = await fetchIsAdmin();
  // The Sign in link: hidden for the admin, visible otherwise — and its
  // href is rewritten to return the admin to THIS page after login
  // (phase 34 task 02: "return to where you were"). The markup keeps its
  // own static ?next= as the no-JS fallback. location.pathname is always
  // a query-safe "/…" string (never "//"; ? # and spaces stay
  // percent-encoded in it), so it rides in next= as-is — the same shape
  // the static fallbacks use (login.js safeNext re-validates it).
  //
  // Phase 51 (owner-locked 2026-08-29, TODO.md L6): the ONE exception —
  // on the NESTED /shared/<token> page "where you were" is a public
  // link, not a place in the app: the rewrite stays at the APP ROOT
  // ("/"), so a guest signing in from a shared page lands in the chat
  // (the static ?next=/ fallback in shared.html matches — the rewrite
  // only ever KEEPS it there). A signed-in admin on the shared page
  // never sees the link (hidden = admin), so this only shapes the
  // guest experience.
  const nextPath = window.location.pathname || "/";
  const signInNext = nextPath.startsWith("/shared/") ? "/" : nextPath;
  document.querySelectorAll(".sign-in-link").forEach(link => {
    link.hidden = admin;
    link.href = "/login.html?next=" + signInNext;
  });
  document.querySelectorAll(".sign-out-btn").forEach(btn => { btn.hidden = !admin; });
  const navSources = document.querySelector("#nav-sources");
  if (navSources) navSources.hidden = !admin;
  // Phase 35 (owner permission 2026-08-26): the Sources nav link —
  // admin-only, the same ship-hidden / reveal-for-admin contract as
  // the RAG link above.
  const navGitSources = document.querySelector("#nav-git-sources");
  if (navGitSources) navGitSources.hidden = !admin;
  // Phase 29: the Global Tuning nav link (every page from phase 34
  // task 03) — admin-only, the same ship-hidden / reveal-for-admin
  // contract as the Sources link.
  const navTuning = document.querySelector("#nav-tuning");
  if (navTuning) navTuning.hidden = !admin;
  // Phase 50 (owner permission 2026-08-29, `TODO.md` L5): the History
  // nav link (the phase-34 one-bar contract — it ships on every page)
  // — admin-only, the same ship-hidden / reveal-for-admin contract as
  // the Tuning link above.
  const navHistory = document.querySelector("#nav-history");
  if (navHistory) navHistory.hidden = !admin;
  // Phase 34: the steering panel (phase 15) is module-owned. The
  // navbar #steering-toggle was removed at owner request (2026-08-28)
  // — the panel ships hidden and is only kept fresh. Admin: refresh
  // the list (fire-and-forget). Anonymous: the panel is REMOVED from
  // the DOM entirely — the phase-16 contract says "absent", not just
  // hidden — and /api/steering is never fetched.
  if (admin) {
    if (steeringPanel) refreshSteering();
  } else {
    steeringPanel?.remove();
  }
  return admin;
}

/* Remove the phase-14 conversation key — same key + fail-silence
   contract as app.js's clearStoredConversation: private mode or a
   storage error is swallowed, the navigation still happens. */
export function clearChatStorage() {
  try {
    localStorage.removeItem("bor.chat.v1");
  } catch {
    /* nothing was stored */
  }
}

/* Sign-out binding (phase 16 behavior, now module-owned): runs at module
   import, so every page that loads header.js gets it exactly once.
   Binds to all .sign-out-btn elements (bar copy for desktop + mobile
   dropdown copy for ≤640px). Disable during the call, POST /api/logout
   (the result is ignored — the reload resets the UI either way), then
   reload so the header re-resolves to the anonymous state (Sign in
   back, Sources gone). */
document.querySelectorAll(".sign-out-btn").forEach(btn => {
  btn.addEventListener("click", async () => {
    btn.disabled = true;
    try {
      await fetch("/api/logout", { method: "POST" });
    } catch {
      /* the reload resets the UI either way */
    }
    window.location.reload();
  });
});

/* ---------- mobile hamburger (phase 46; module-owned) ----------
 * ≤640px only (CSS hides the button elsewhere): #nav-toggle opens the
 * nav as a dropdown (#app-nav .is-open — the animated state, task 01
 * CSS). One binding for all six pages; a page without either element
 * is a no-op, like the rest of this module. The nav LINKS keep their
 * ship-hidden whoami contract (hidden links stay hidden inside the
 * menu) — this binding only toggles the container. */
const navToggle = document.querySelector("#nav-toggle");
const appNav = document.querySelector("#app-nav");

function setNavMenu(open) {
  if (!appNav || !navToggle) return;
  appNav.classList.toggle("is-open", open);
  navToggle.setAttribute("aria-expanded", open ? "true" : "false");
}

if (navToggle && appNav) {
  navToggle.addEventListener("click", () =>
    setNavMenu(!appNav.classList.contains("is-open")));
  // A link click navigates (or closes same-page) — shut the menu.
  appNav.addEventListener("click", (e) => {
    if (e.target.closest("a")) setNavMenu(false);
  });
  // Esc closes while open (document-level — no other modal to fight
  // for a key).
  document.addEventListener("keydown", (e) => {
    if (e.key === "Escape" && appNav.classList.contains("is-open")) {
      setNavMenu(false);
      navToggle.focus(); // focus returns to the opener
    }
  });
  // Resize back to desktop: the inline nav reappears — no stale open
  // state (the .is-open class is scoped by the ≤640px CSS anyway, but
  // dropping it keeps aria-expanded honest).
  const mq = window.matchMedia("(max-width: 640px)");
  const onMqChange = () => { if (!mq.matches) setNavMenu(false); };
  if (mq.addEventListener) mq.addEventListener("change", onMqChange);
  else mq.addListener(onMqChange); // older engines, defensive
}

/* ---------- steering notes (phase 15; module-owned from phase 34) ----------
 *
 * The owner's tuning notes steer every future answer: they live in
 * Postgres (stateless API, A10) and the chat turn reads them into the
 * system prompt. The header panel — list, per-note delete, announcer —
 * is owned by THIS module: every page that ships the panel markup gets
 * exactly this behavior, with zero page-script duplication. The navbar
 * #steering-toggle was removed at owner request (2026-08-28) — note
 * management now lives on /tuning.html — so the panel ships hidden and
 * is only kept fresh. The chat page keeps only its per-bubble Tune form
 * (app.js), which refreshes the panel through refreshSteering() and
 * announces through announceSteering().
 *
 * All elements are looked up null-safe (querySelector + guard): a page
 * that lacks the panel markup is a no-op — the same contract as
 * initSharedHeader().
 */
const steeringPanel = document.querySelector("#steering-panel");
const steeringList = document.querySelector("#steering-list");
const steeringEmpty = document.querySelector("#steering-empty");
const steeringAnnouncer = document.querySelector("#steering-announcer");

/* Announce a steering change through the polite live region
   (role="status", aria-live="polite") — exported so the chat page's
   per-bubble Tune form (app.js) announces on the exact same channel. */
export function announceSteering(message) {
  if (steeringAnnouncer) steeringAnnouncer.textContent = message;
}

/* Fetch + render the note list (exported — the chat page's per-bubble
   Tune form calls it on save, so the panel updates without owning the
   fetch itself). Non-2xx (the anonymous 403) or an unreachable API
   render the empty state: the "no notes yet" text visible — the safe
   fallback in either case. */
export async function refreshSteering() {
  let notes = [];
  try {
    const r = await fetch("/api/steering");
    if (r.ok) notes = (await r.json()).notes || [];
  } catch {
    /* API unreachable: the empty list state is the safe fallback */
  }
  renderSteeringPanel(notes);
  return notes;
}

/* Newest-first list — the note is ALWAYS rendered with textContent
   (XSS-safe, never innerHTML), a per-note Remove button with a labeled
   aria-label, and the empty text toggled on notes.length. */
function renderSteeringPanel(notes) {
  if (!steeringList) return;
  steeringList.textContent = "";
  for (const n of notes) {
    const li = document.createElement("li");
    li.className = "steering-note";
    const text = document.createElement("span");
    text.className = "steering-note-text";
    text.textContent = n.note; // rendered as text, never as HTML
    li.appendChild(text);
    const del = document.createElement("button");
    del.type = "button";
    del.className = "steering-delete";
    del.setAttribute("aria-label", `Delete tuning note: ${n.note}`);
    del.innerHTML =
      '<svg aria-hidden="true" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round"><path d="M5 7h14M10 7V5h4v2M8.5 7l.7 12h5.6l.7-12"/></svg>';
    del.addEventListener("click", () => deleteSteeringNote(n.id, del));
    li.appendChild(del);
    steeringList.appendChild(li);
  }
  if (steeringEmpty) steeringEmpty.hidden = notes.length > 0;
}

/* Per-note delete: disable the row button (no double-fire), DELETE
   /api/steering/{id}, re-load the list, announce through
   #steering-announcer. A 404 means the note was already gone — say so
   and still refresh; any other failure re-enables the button so the
   user can retry. */
async function deleteSteeringNote(id, btn) {
  btn.disabled = true;
  try {
    const r = await fetch(`/api/steering/${encodeURIComponent(id)}`, { method: "DELETE" });
    if (r.status === 404) {
      announceSteering("That note was already removed.");
      await refreshSteering();
      return;
    }
    if (!r.ok) {
      announceSteering("Could not delete the note — try again.");
      btn.disabled = false;
      return;
    }
    await refreshSteering();
    announceSteering("Tuning note deleted.");
  } catch {
    announceSteering("Could not delete the note — is the app reachable?");
    btn.disabled = false;
  }
}

/* ---------- New chat (the SINGLE binding — module-owned from phase 34
 * task 02; moved from navbar to chat page at owner request) ----------
 *
 * The binding used to be duplicated across app.js / sources.js /
 * tuning.js / document.js. It lives here exactly once (module import,
 * like the sign-out binding). The button now lives ONLY on the chat
 * page (inside .chat-shell, above #messages), so the click always
 * dispatches "bor:new-chat" — app.js acts (it owns the in-flight-turn
 * guard and the rendered-list reset).
 */
const newChatBtn = document.querySelector("#new-chat-btn");
if (newChatBtn) {
  newChatBtn.addEventListener("click", () => {
    window.dispatchEvent(new CustomEvent("bor:new-chat"));
  });
}