// ==UserScript==
// @name         Manga Bookmark Sync
// @namespace    mangabm
// @version      1.5.0
// @description  Track read progress on Asura & Demonic and sync to a self-hosted backend. Bromite-compatible (no GM_* APIs).
// @author       you
// @downloadURL  https://manga-api.violetcrown.my.id/u/40d79969b5442f90df4fe306a092c7c50e7b4a7a98099f98cc398f4fb374b1df/manga-bookmark.user.js
// @updateURL    https://manga-api.violetcrown.my.id/u/40d79969b5442f90df4fe306a092c7c50e7b4a7a98099f98cc398f4fb374b1df/manga-bookmark.user.js
// @match        https://asuracomic.net/*
// @match        https://asurascans.com/*
// @match        https://demonicscans.org/*
// @run-at       document-idle
// @noframes
// ==/UserScript==

(function () {
  "use strict";

  // ============================================================
  // CONFIG — fill these in before installing.
  // ============================================================
  const API_BASE = "https://manga-api.violetcrown.my.id"; // your backend origin, no trailing slash
  const API_TOKEN = "40d79969b5442f90df4fe306a092c7c50e7b4a7a98099f98cc398f4fb374b1df"; // must equal backend API_TOKEN
  const WEB_BASE = "https://manga.violetcrown.my.id"; // the browser UI, for the panel's nav chips

  // Safe in Bromite's isolated world: the page's own JS cannot read these.
  const CACHE_KEY = "mangabm:cache";

  // Per-device record of when each series was last checked for new chapters.
  // Deliberately not synced: each device does its own checking.
  const LASTCHECKED_KEY = "mangabm:lastchecked";
  const LATEST_CHECK_THROTTLE_MS = 4 * 60 * 60 * 1000;
  const LATEST_CHECK_BATCH = 1; // series fetched per navigation

  // ============================================================
  // Site adapters
  //
  // Page type + IDs come from URL regex (most stable); title/cover come from
  // og: meta tags. Verified live 2026-07-24 against asurascans.com and
  // demonicscans.org — see README "Adapter reference".
  // ============================================================

  function meta(prop) {
    const el = document.querySelector('meta[property="' + prop + '"]');
    return el ? el.getAttribute("content") : null;
  }

  // Chapter lists are read from two places: the page we are standing on, and
  // series pages fetched in the background. Both are reduced to {href, text}
  // pairs so each adapter needs only one rule for picking the latest chapter.

  function anchorsFromDocument(doc) {
    return Array.from(doc.querySelectorAll("a[href]")).map((a) => ({
      href: a.getAttribute("href") || "",
      text: a.textContent || "",
    }));
  }

  // A fetched page is raw text; DOMParser would run against markup we do not
  // control, so anchors are pulled out directly instead.
  function anchorsFromHTML(html) {
    const re = /<a\b[^>]*\shref\s*=\s*["']([^"']*)["'][^>]*>([\s\S]*?)<\/a>/gi;
    const out = [];
    let m;
    while ((m = re.exec(html))) {
      out.push({ href: m[1], text: m[2].replace(/<[^>]*>/g, " ") });
    }
    return out;
  }

  // Asura appends a site-wide build hash to every slug
  // ("...-059befe1"); it rotates on each redeploy, so it must not be part
  // of the series identity — old keys can never match pages after a
  // redeploy. Only the ID strips it; seriesUrl keeps the full slug because
  // navigation needs the current hash (stale ones 302). Must stay in sync
  // with asuraBuildHash in backend/store.go.
  // ponytail: a real title ending in exactly 8 hex chars would lose its
  // last segment; none known.
  function stripBuildHash(slug) {
    return slug.replace(/-[0-9a-f]{8}$/, "");
  }

  const asura = {
    site: "asura",
    // asuracomic.net deep links 301 to the asurascans.com *root*, dropping the
    // path, and that happens at the edge before this script gets a document —
    // so those URLs cannot be handled here at all (checked 2026-07-25). It stays
    // matched in case the redirect starts preserving paths again; until then,
    // reach series through asurascans.com.
    matches: (loc) => /(^|\.)asurascans\.com$|(^|\.)asuracomic\.net$/.test(loc.hostname),
    detect(loc) {
      const path = loc.pathname;
      // /comics/<slug-hash>/chapter/<n>
      let m = path.match(/^\/comics\/([^/]+)\/chapter\/([^/?#]+)/);
      if (m) {
        const num = parseFloat(m[2]);
        return {
          type: "chapter",
          site: this.site,
          seriesId: stripBuildHash(m[1]),
          title: cleanTitle(meta("og:title")),
          cover: meta("og:image") || "",
          seriesUrl: loc.origin + "/comics/" + m[1],
          chapterLabel: "Chapter " + m[2],
          chapterNum: isNaN(num) ? null : num,
          chapterUrl: loc.href,
        };
      }
      // /comics/<slug-hash>
      m = path.match(/^\/comics\/([^/?#]+)\/?$/);
      if (m) {
        return {
          type: "series",
          site: this.site,
          seriesId: stripBuildHash(m[1]),
          title: cleanTitle(meta("og:title")),
          cover: meta("og:image") || "",
          seriesUrl: loc.origin + "/comics/" + m[1],
          chapterLabel: null,
          chapterNum: null,
          chapterUrl: null,
        };
      }
      return { type: "other" };

      // Strips "Chapter N - Read Online" and the " | Asura Scans" suffix.
      function cleanTitle(t) {
        if (!t) return "";
        return t
          .replace(/\s*Chapter\s+[\d.]+\s*-\s*Read Online\s*/i, " ")
          .replace(/\s*\|\s*Asura Scans\s*$/i, "")
          .trim();
      }
    },
    // Series pages link every chapter. The link text check skips the
    // "First Chapter" shortcut, which points at a chapter but is not one
    // of the list entries.
    latestChapterFromAnchors(anchors) {
      let best = null;
      for (const a of anchors) {
        const m = a.href.match(/\/chapter\/([\d.]+)$/);
        if (!m || !/Chapter\s+[\d.]+/i.test(a.text)) continue;
        const num = parseFloat(m[1]);
        if (isNaN(num)) continue;
        if (!best || num > best.num) best = { num, label: "Chapter " + m[1] };
      }
      return best;
    },
  };

  const demonic = {
    site: "demonic",
    matches: (loc) => /(^|\.)demonicscans\.org$/.test(loc.hostname),
    detect(loc) {
      const path = loc.pathname;
      // Canonical reader: /title/<slug>/chapter/<n>/<page>
      // (chaptered.php?manga=<id>&chapter=<n> 301s to this before we run.)
      let m = path.match(/^\/title\/([^/]+)\/chapter\/([^/?#]+)/);
      if (m) {
        const num = parseFloat(m[2]);
        return {
          type: "chapter",
          site: this.site,
          seriesId: decodeURIComponent(m[1]),
          title: cleanTitle(meta("og:title")),
          cover: meta("og:image") || "",
          seriesUrl: loc.origin + "/manga/" + m[1],
          chapterLabel: "Chapter " + m[2],
          chapterNum: isNaN(num) ? null : num,
          chapterUrl: loc.href,
        };
      }
      // Series: /manga/<slug>
      m = path.match(/^\/manga\/([^/?#]+)/);
      if (m) {
        return {
          type: "series",
          site: this.site,
          seriesId: decodeURIComponent(m[1]),
          title: cleanTitle(meta("og:title")),
          cover: meta("og:image") || "",
          seriesUrl: loc.origin + "/manga/" + m[1],
          chapterLabel: null,
          chapterNum: null,
          chapterUrl: null,
        };
      }
      return { type: "other" };

      // Demonic chapter og:title is "<Title> Chapter N"; series is clean.
      function cleanTitle(t) {
        if (!t) return "";
        return t.replace(/\s*Chapter\s+[\d.]+\s*$/i, "").trim();
      }
    },
    // Series pages still link chapters through the pre-redirect chaptered.php
    // form. Their order is not dependable, so take the highest number.
    latestChapterFromAnchors(anchors) {
      let best = null;
      for (const a of anchors) {
        const m = a.href.match(/chaptered\.php\?manga=\d+&(?:amp;)?chapter=([\d.]+)/);
        if (!m) continue;
        const num = parseFloat(m[1]);
        if (isNaN(num)) continue;
        if (!best || num > best.num) best = { num, label: "Chapter " + m[1] };
      }
      return best;
    },
  };

  const ADAPTERS = [asura, demonic];

  function detect() {
    const loc = window.location;
    for (const a of ADAPTERS) {
      if (a.matches(loc)) return a.detect(loc);
    }
    return { type: "other" };
  }

  function keyOf(page) {
    return page.site + ":" + page.seriesId;
  }

  function adapterFor(site) {
    return ADAPTERS.find((a) => a.site === site) || null;
  }

  // Highest chapter the site lists, or null when the markup yields nothing.
  function computeLatestChapter(site, anchors) {
    const a = adapterFor(site);
    return a ? a.latestChapterFromAnchors(anchors) : null;
  }

  function currentSite() {
    for (const a of ADAPTERS) if (a.matches(window.location)) return a.site;
    return null;
  }

  // ============================================================
  // API client + local cache
  // ============================================================

  function loadCache() {
    try {
      const raw = localStorage.getItem(CACHE_KEY);
      return raw ? JSON.parse(raw) : [];
    } catch (e) {
      return [];
    }
  }

  function saveCache(list) {
    try {
      localStorage.setItem(CACHE_KEY, JSON.stringify(list));
    } catch (e) {
      /* quota / private mode — ignore */
    }
  }

  function loadLastChecked() {
    try {
      const raw = localStorage.getItem(LASTCHECKED_KEY);
      return raw ? JSON.parse(raw) : {};
    } catch (e) {
      return {};
    }
  }

  function saveLastChecked(map) {
    try {
      localStorage.setItem(LASTCHECKED_KEY, JSON.stringify(map));
    } catch (e) {
      /* quota / private mode — ignore */
    }
  }

  function authHeaders(extra) {
    return Object.assign({ Authorization: "Bearer " + API_TOKEN }, extra || {});
  }

  // The retry queue treats a 400 differently from a dropped connection, so the
  // status has to survive the throw. A network failure leaves it undefined.
  function httpError(what, status) {
    const e = new Error(what + " " + status);
    e.status = status;
    return e;
  }

  async function apiGet() {
    const res = await fetch(API_BASE + "/bookmarks", { headers: authHeaders() });
    if (!res.ok) throw new Error("GET /bookmarks " + res.status);
    return res.json();
  }

  // Only an explicit archive/restore has an opinion about the bucket. Every
  // other write omits `status`, so the server keeps the stored one — otherwise
  // a cached value would resend "finished" (which the API rejects with 400) or
  // silently un-archive a series archived on another device.
  async function apiPut(key, obj, { sendStatus = false } = {}) {
    const body = Object.assign({}, obj);
    if (!sendStatus) delete body.status;
    const res = await fetch(API_BASE + "/bookmarks/" + encodeURIComponent(key), {
      method: "PUT",
      headers: authHeaders({ "Content-Type": "application/json" }),
      body: JSON.stringify(body),
    });
    if (!res.ok) throw httpError("PUT /bookmarks", res.status);
    return res.json();
  }

  async function apiDelete(key) {
    const res = await fetch(API_BASE + "/bookmarks/" + encodeURIComponent(key), {
      method: "DELETE",
      headers: authHeaders(),
    });
    // 404 means the row is already gone, which is what the caller wanted.
    if (!res.ok && res.status !== 404) throw httpError("DELETE /bookmarks", res.status);
  }

  // ============================================================
  // State
  // ============================================================

  const state = {
    list: loadCache(), // last-known bookmarks (array)
    byKey: {},
    page: { type: "other" },
  };
  reindex();

  function reindex() {
    state.byKey = {};
    for (const b of state.list) state.byKey[b.key] = b;
    state.list.sort((a, b) => (b.updated_at || 0) - (a.updated_at || 0));
  }

  function setList(list) {
    state.list = Array.isArray(list) ? list : [];
    reindex();
    saveCache(state.list);
  }

  function upsertLocal(bm) {
    const i = state.list.findIndex((b) => b.key === bm.key);
    if (i >= 0) state.list[i] = bm;
    else state.list.push(bm);
    reindex();
    saveCache(state.list);
  }

  function removeLocal(key) {
    state.list = state.list.filter((b) => b.key !== key);
    reindex();
    saveCache(state.list);
  }

  // A list cached by an older version has no status field, and a row the
  // server defaulted has "reading" — both mean the same thing here.
  function statusOf(b) {
    return b.status || "reading";
  }

  // ============================================================
  // Retry queue
  //
  // A failed write is not rolled back and not lost: the key is parked here and
  // replayed when the backend is next reachable. Entries carry no payload — the
  // body is read from state.byKey at send time, because state.list *is* the
  // desired state and is already persisted in mangabm:cache. One entry per key,
  // so two writes to the same series cannot replay out of order, an
  // archive-then-unarchive collapses to whatever the cache now says, and a
  // queued DELETE replaces a queued PUT rather than racing it.
  // ============================================================

  const QUEUE_KEY = "mangabm:queue";
  const QUEUE_MAX = 200; // ~12 KB; realistically bounded by the bookmark count
  const QUEUE_MAX_ATTEMPTS = 10;

  let authFailed = false; // a 401 was seen; retrying cannot help until the token changes

  function loadQueue() {
    try {
      const raw = localStorage.getItem(QUEUE_KEY);
      return raw ? JSON.parse(raw) : [];
    } catch (e) {
      return [];
    }
  }

  function saveQueue(q) {
    try {
      localStorage.setItem(QUEUE_KEY, JSON.stringify(q));
    } catch (e) {
      /* quota / private mode — ignore */
    }
  }

  const queue = loadQueue();

  // Keys cached (or parked in the retry queue) by versions before the
  // Asura build-hash strip still carry the hash. Align them with the
  // server-side migration so a queued PUT cannot resurrect an orphaned
  // row and the cache matches what the server now returns. Duplicate
  // cache entries collapsing onto one key are left as-is — the next
  // refresh() replaces the whole list from the already-merged server.
  (function migrateLocalKeys() {
    let dirty = false;
    for (let i = 0; i < state.list.length; i++) {
      const b = state.list[i];
      if (b.site !== "asura" || !b.series_id) continue;
      const id = stripBuildHash(b.series_id);
      if (id === b.series_id) continue;
      state.list[i] = Object.assign({}, b, { series_id: id, key: "asura:" + id });
      dirty = true;
    }
    if (dirty) {
      reindex();
      saveCache(state.list);
    }
    dirty = false;
    for (const e of queue) {
      if (!e.key.startsWith("asura:")) continue;
      const k = "asura:" + stripBuildHash(e.key.slice("asura:".length));
      if (k !== e.key) {
        e.key = k;
        dirty = true;
      }
    }
    if (dirty) saveQueue(queue);
  })();

  function queueCount() {
    return queue.length;
  }

  function queueGet(key) {
    return queue.find((e) => e.key === key) || null;
  }

  function titleFor(key) {
    const b = state.byKey[key];
    return (b && (b.title || b.series_id)) || key;
  }

  // Oldest goes first when the cap is hit: the newest entry is the action the
  // user just took, and dropping that is the bug this queue exists to fix.
  function queuePush(entry) {
    if (queue.length >= QUEUE_MAX) {
      const evicted = queue.shift();
      toast("Sync queue full — dropped " + titleFor(evicted.key), true);
    }
    queue.push(entry);
    return entry;
  }

  function queueDrop(key) {
    const i = queue.findIndex((e) => e.key === key);
    if (i >= 0) {
      queue.splice(i, 1);
      saveQueue(queue);
    }
  }

  // Parks a write without counting it as a failure. Used when the key is already
  // on the wire: the write is owed, but nothing went wrong, so it must not spend
  // one of the ten attempts.
  function queueDefer(key, op, sendStatus) {
    const e = queueGet(key) || queuePush({ key: key, op: op, sendStatus: false, attempts: 0 });
    e.op = op; // a delete replaces a put, and a put replaces a delete
    e.sendStatus = e.sendStatus || sendStatus; // sticky: an archive intent is never dropped
    saveQueue(queue);
    return e;
  }

  // Records a failed write and classifies why it failed. A 400 is a payload the
  // server will never accept, so it is dropped now instead of being retried ten
  // times; a 401 is the wrong token, so the entry is kept untouched and the
  // drain gives up until the token changes.
  function queueEnqueue(key, op, sendStatus, err) {
    const status = err && err.status;
    if (status === 400) {
      queueDrop(key);
      toast("Couldn't sync " + titleFor(key) + " — change lost", true);
      return;
    }
    const e = queueDefer(key, op, sendStatus);
    if (status === 401) {
      authFailed = true;
    } else if (++e.attempts >= QUEUE_MAX_ATTEMPTS) {
      queueDrop(key);
      toast("Gave up syncing " + titleFor(key), true);
      return;
    }
    saveQueue(queue);
  }

  // Keys with a request on the wire right now, mapped to "another write arrived
  // while this one was flying". A second write to the same key is never sent
  // concurrently — the two responses would race to own the row — it is parked in
  // the queue instead and a later drain replays it. The flight already in the
  // air must then leave that entry alone and not adopt its own now-stale
  // response, or it would undo the write the user just made.
  const inFlight = new Map();

  let draining = null; // the pass in progress, so a second caller awaits it

  // Replays everything owed. Cheap in the normal case — it returns on the first
  // line when the queue is empty, which is why it can hang off navigation. A
  // 401 stops the whole pass: the token is wrong, so the next entry would fail
  // the same way, and the queue is left intact so fixing the token fixes it.
  //
  // Returns the in-flight pass when one is already running, so refresh()'s
  // `await drain()` really does wait for what we owe instead of racing a drain
  // that onNavigate or the online listener started unawaited.
  function drain() {
    if (queue.length === 0) return Promise.resolve();
    if (draining) return draining;
    const pass = (async () => {
      authFailed = false;
      try {
        for (const e of queue.slice()) {
          if (e.op === "delete") await pushDelete(e.key);
          else await pushBookmark(e.key, e.sendStatus);
          if (authFailed) {
            toast("Sync auth failed — check the token", true);
            break;
          }
        }
      } finally {
        render();
      }
    })();
    // Swallowed, not surfaced: drain is called unawaited from onNavigate and the
    // online listener, and an uncaught rejection on a page we do not control is
    // a console error nobody can act on. Every real sync failure is already
    // toasted and queued by pushBookmark/pushDelete.
    draining = pass
      .catch(() => {})
      .finally(() => {
        draining = null;
      });
    return draining;
  }

  // Keys the server has not heard about yet must survive a fetched list, or the
  // card the user just changed silently flaps back — the exact bug this queue
  // exists to fix. Reads state.byKey, so it must run *before* setList replaces
  // it.
  function overlayPending(list) {
    if (queue.length === 0) return list;
    const out = list.filter((b) => {
      const e = queueGet(b.key);
      return !(e && e.op === "delete");
    });
    for (const e of queue) {
      if (e.op !== "put") continue;
      const local = state.byKey[e.key];
      if (!local) continue;
      const i = out.findIndex((b) => b.key === e.key);
      if (i >= 0) out[i] = local;
      else out.push(local);
    }
    return out;
  }

  // ============================================================
  // Mutations (optimistic: update UI/cache first, then sync)
  // ============================================================

  // Every write goes through here, queued or not, so there is one place that
  // talks to the API and one place that decides `sendStatus`. That flag is
  // sticky: while an archive is pending for a key, a later progress write to the
  // same key still carries the bucket — otherwise the server would answer with
  // the old status and the adopted row would silently un-archive the series.
  async function pushBookmark(key, sendStatus) {
    const pending = queueGet(key);
    const withStatus = sendStatus || (pending ? pending.sendStatus : false);
    const bm = state.byKey[key];
    if (!bm) {
      queueDrop(key); // removed locally in the meantime — nothing left to send
      return true;
    }
    if (inFlight.has(key)) {
      queueDefer(key, "put", withStatus); // see inFlight — parked, not sent
      inFlight.set(key, true); // supersedes the flight already in the air
      return false;
    }
    inFlight.set(key, false);
    let ok = false;
    try {
      // ponytail: last-write-wins, so a replay can overwrite a newer server
      // value (a poller-written latest_chapter, or progress from another
      // device). Single user, self-healing on the next poll — revisit only if
      // this ever runs multi-user.
      const saved = await apiPut(key, bm, { sendStatus: withStatus });
      if (!inFlight.get(key)) {
        upsertLocal(saved);
        queueDrop(key);
      }
      ok = true;
    } catch (e) {
      // Same guard as the success path: a newer write is parked for this key, so
      // classifying *this* failure would clobber its op or, on a 400, drop it
      // outright. Its own drain reports its own outcome. The one thing that must
      // still carry across is sendStatus — this flight may have been the archive
      // replay, and losing its flag here would narrow the parked write into a
      // silent un-archive.
      const parked = inFlight.get(key) ? queueGet(key) : null;
      if (parked) queueDefer(key, parked.op, withStatus);
      else queueEnqueue(key, "put", withStatus, e);
    } finally {
      inFlight.delete(key);
    }
    // Outside the try: a throw in render() is a UI bug, not a write failure, and
    // must not re-queue a write that already landed.
    if (ok) render();
    return ok;
  }

  async function pushDelete(key) {
    if (inFlight.has(key)) {
      queueDefer(key, "delete", false); // see inFlight — parked, not sent
      inFlight.set(key, true); // supersedes the flight already in the air
      return false;
    }
    inFlight.set(key, false);
    try {
      await apiDelete(key);
      if (!inFlight.get(key)) queueDrop(key);
      return true;
    } catch (e) {
      if (!inFlight.get(key)) queueEnqueue(key, "delete", false, e); // see pushBookmark
      return false;
    } finally {
      inFlight.delete(key);
    }
  }

  async function bookmarkCurrent() {
    const p = state.page;
    if (p.type !== "series" && p.type !== "chapter") return;
    const key = keyOf(p);
    const existing = state.byKey[key];
    const bm = {
      key: key,
      site: p.site,
      series_id: p.seriesId,
      title: p.title || (existing && existing.title) || p.seriesId,
      series_url: p.seriesUrl || (existing && existing.series_url) || "",
      cover: p.cover || (existing && existing.cover) || "",
      last_chapter: p.chapterLabel || (existing && existing.last_chapter) || "",
      last_chapter_num:
        p.chapterNum != null ? p.chapterNum : existing ? existing.last_chapter_num : null,
      last_chapter_url: p.chapterUrl || (existing && existing.last_chapter_url) || "",
      updated_at: Date.now(),
    };
    await syncUpsert(bm, "Bookmarked");
  }

  async function updateToCurrentChapter() {
    cancelDwell(); // manual button + timer-fire both clear any pending dwell
    const p = state.page;
    if (p.type !== "chapter") return;
    const key = keyOf(p);
    const existing = state.byKey[key] || {};
    const bm = Object.assign({}, existing, {
      key: key,
      site: p.site,
      series_id: p.seriesId,
      title: existing.title || p.title || p.seriesId,
      series_url: existing.series_url || p.seriesUrl || "",
      cover: existing.cover || p.cover || "",
      last_chapter: p.chapterLabel || "",
      last_chapter_num: p.chapterNum,
      last_chapter_url: p.chapterUrl || "",
      updated_at: Date.now(),
    });
    await syncUpsert(bm, "Progress updated");
  }

  async function syncUpsert(bm, okMsg) {
    upsertLocal(bm); // optimistic
    render();
    if (await pushBookmark(bm.key, false)) toast(okMsg);
    else toast("Saved — will sync when online", true);
  }

  async function toggleFavorite(key) {
    const existing = state.byKey[key];
    if (!existing) return;
    const bm = Object.assign({}, existing, {
      favorite: !existing.favorite,
      updated_at: Date.now(), // candidate only; the server keeps the stored one
    });
    upsertLocal(bm); // optimistic
    render();
    if (!(await pushBookmark(bm.key, false))) toast("Saved — will sync when online", true);
  }

  // Archive parks a series: it leaves All and Favourites but the server keeps
  // polling it for new chapters. "finished" is deliberately not reachable from
  // here — the API rejects that value, it is a web-UI decision.
  async function toggleArchive(key) {
    const existing = state.byKey[key];
    if (!existing) return;
    const next = statusOf(existing) === "archived" ? "reading" : "archived";
    upsertLocal(Object.assign({}, existing, { status: next }));
    render();
    // The only write with an opinion about the bucket, so the only one that
    // sends `status` at all.
    if (await pushBookmark(key, true)) {
      toast(next === "archived" ? "Archived" : "Back in your list");
    } else {
      toast((next === "archived" ? "Archived" : "Restored") + " — will sync when online", true);
    }
  }

  // Records the newest chapter a site has published. Silent: this fires from
  // page visits and background checks the user did not ask for, and it never
  // reorders the list — updated_at is a candidate the server discards unless
  // reading progress moved.
  async function applyLatestChapterIfChanged(existing, latest) {
    if (!existing || !latest) return;
    if (existing.latest_chapter_num === latest.num) return;
    const bm = Object.assign({}, existing, {
      latest_chapter: latest.label,
      latest_chapter_num: latest.num,
      updated_at: Date.now(),
    });
    upsertLocal(bm);
    render();
    // A queued write owns this row; the drain sends latest_chapter
    // with it, carrying the correct bucket.
    if (queueGet(bm.key)) return;
    try {
      const saved = await apiPut(bm.key, bm);
      upsertLocal(saved);
      render();
    } catch (e) {
      /* offline — the local cache still shows it, retried on a later visit */
    }
  }

  // Standing on a bookmarked series page: its chapter list is already here.
  function maybeCaptureLatestOnSeriesPage() {
    const p = state.page;
    if (p.type !== "series") return;
    const existing = state.byKey[keyOf(p)];
    if (!existing) return;
    applyLatestChapterIfChanged(
      existing,
      computeLatestChapter(p.site, anchorsFromDocument(document))
    );
  }

  // Everything else is only learned by fetching a series page. Same-origin
  // only: these requests carry the session that gets us past the site's bot
  // checks, which a request to the other site (or from a server) would not.
  // One series per navigation keeps it indistinguishable from browsing.
  async function backgroundRefreshLatest() {
    const site = currentSite();
    if (!site) return;

    const checked = loadLastChecked();
    const now = Date.now();
    const due = state.list
      .filter((b) => b.site === site && b.series_url)
      .filter((b) => statusOf(b) !== "finished")
      .filter((b) => now - (checked[b.key] || 0) >= LATEST_CHECK_THROTTLE_MS)
      .sort((a, b) => (checked[a.key] || 0) - (checked[b.key] || 0))
      .slice(0, LATEST_CHECK_BATCH);
    if (due.length === 0) return;

    for (const bm of due) {
      // Recorded even when the fetch fails, so a broken series is retried on
      // the next throttle window rather than on every single page load.
      checked[bm.key] = Date.now();
      try {
        const res = await fetch(bm.series_url, { credentials: "same-origin" });
        if (!res.ok) continue;
        const html = await res.text();
        const latest = computeLatestChapter(bm.site, anchorsFromHTML(html));
        await applyLatestChapterIfChanged(state.byKey[bm.key] || bm, latest);
      } catch (e) {
        /* offline or blocked — try again after the throttle window */
      }
    }
    saveLastChecked(checked);
  }

  async function removeBookmark(key) {
    removeLocal(key); // optimistic
    render();
    if (await pushDelete(key)) toast("Removed");
    else toast("Removed — will sync when online", true);
  }

  // Dwell timer: don't advance progress the instant a newer chapter opens (guards
  // against a misclick on "latest chapter"). Arm a 25s timer instead; the tab fills
  // bottom-up to show it counting down. The manual "Update to X" button still fires
  // immediately. Timer is keyed to the chapter, not the URL, so turning pages within
  // the same chapter (Demonic /chapter/N/<page>) keeps it counting rather than resetting.
  const DWELL_MS = 25000;
  let dwell = null; // { id, timerId }

  function chapterIdentity(p) {
    return p && p.type === "chapter" ? p.site + ":" + p.seriesId + "@" + p.chapterNum : null;
  }

  function armDwell(id) {
    dwell = {
      id,
      timerId: setTimeout(() => {
        dwell = null;
        stopRing();
        updateToCurrentChapter();
      }, DWELL_MS),
    };
    startRing(DWELL_MS);
  }

  function cancelDwell() {
    if (dwell) clearTimeout(dwell.timerId);
    dwell = null;
    stopRing();
  }

  // Auto-record on opening a chapter of a bookmarked series (after the dwell delay).
  function maybeAutoUpdate() {
    const p = state.page;
    const id = chapterIdentity(p);
    if (dwell && id === dwell.id) return; // same chapter, page turn — keep timer running
    cancelDwell(); // navigated elsewhere — drop any stale dwell
    if (p.type !== "chapter") return;
    const existing = state.byKey[keyOf(p)];
    if (!existing) return; // only track series the user bookmarked

    const cur = p.chapterNum;
    const prev = existing.last_chapter_num;
    // Advance when current >= stored, or when either is unparseable (set current).
    const advance = cur == null || prev == null || cur >= prev;
    if (!advance) return;
    if (existing.last_chapter_url === p.chapterUrl && existing.last_chapter === p.chapterLabel) {
      return; // already recorded
    }
    armDwell(id);
  }

  // ============================================================
  // UI — Shadow DOM (isolated from site CSS)
  // ============================================================

  let root, panelOpen = false;
  let activeTab = "all"; // "all" | "favorites" | "archived"; resets each page, by design

  function buildUI() {
    const host = document.createElement("div");
    host.id = "mangabm-host";
    host.style.cssText = "all: initial;";
    (document.body || document.documentElement).appendChild(host);
    root = host.attachShadow({ mode: "open" });

    const style = document.createElement("style");
    style.textContent = CSS;
    root.appendChild(style);

    const wrap = document.createElement("div");
    wrap.id = "wrap";
    wrap.innerHTML = TEMPLATE;
    root.appendChild(wrap);

    const fab = root.getElementById("fab");
    fab.addEventListener("click", () => {
      if (fab.dataset.dragged) {
        delete fab.dataset.dragged; // this click is the tail of a drag — swallow it
        return;
      }
      togglePanel();
    });
    root.getElementById("backdrop").addEventListener("click", togglePanel);
    root.getElementById("closeBtn").addEventListener("click", togglePanel);
    root.getElementById("pending").addEventListener("click", () => drain());

    for (const [id, tab] of [["tabAll", "all"], ["tabFav", "favorites"], ["tabArc", "archived"]]) {
      root.getElementById(id).addEventListener("click", () => {
        activeTab = tab;
        render();
      });
    }

    placeFab(fab);
    makeDraggable(fab);
    window.addEventListener("resize", () => placeFab(fab)); // re-clamp on rotation
  }

  // ============================================================
  // FAB placement + dragging (snaps to nearest left/right edge)
  // ============================================================

  const FAB_KEY = "mangabm:fabpos";
  const FAB_MARGIN = 12; // vertical breathing room at the top and bottom
  const FAB_EDGE = 0;    // horizontal: an edge tab sits flush against the side

  function clamp(v, lo, hi) {
    return Math.max(lo, Math.min(hi, v));
  }

  function applyFabPos(fab, side, y) {
    fab.style.top = y + "px";
    fab.style.bottom = "auto";
    fab.classList.toggle("left", side === "left");
    if (side === "left") {
      fab.style.left = FAB_EDGE + "px";
      fab.style.right = "auto";
    } else {
      fab.style.right = FAB_EDGE + "px";
      fab.style.left = "auto";
    }
  }

  function loadFabPos() {
    try {
      return JSON.parse(localStorage.getItem(FAB_KEY));
    } catch (e) {
      return null;
    }
  }

  function saveFabPos(side, yRatio) {
    try {
      localStorage.setItem(FAB_KEY, JSON.stringify({ side, yRatio }));
    } catch (e) {
      /* quota / private mode — ignore */
    }
  }

  function placeFab(fab) {
    const h = fab.offsetHeight || 44;
    const p = loadFabPos();
    const maxY = window.innerHeight - h - FAB_MARGIN;
    const side = p && p.side === "left" ? "left" : "right";
    const y = p ? clamp(p.yRatio * window.innerHeight, FAB_MARGIN, maxY) : maxY - 8;
    applyFabPos(fab, side, y);
  }

  function makeDraggable(fab) {
    let down = false, moved = false, sx = 0, sy = 0, offX = 0, offY = 0;
    fab.addEventListener("pointerdown", (e) => {
      down = true;
      moved = false;
      sx = e.clientX;
      sy = e.clientY;
      const r = fab.getBoundingClientRect();
      offX = e.clientX - r.left;
      offY = e.clientY - r.top;
      fab.setPointerCapture(e.pointerId);
      fab.style.transition = "none";
    });
    fab.addEventListener("pointermove", (e) => {
      if (!down) return;
      if (!moved && (Math.abs(e.clientX - sx) > 6 || Math.abs(e.clientY - sy) > 6)) moved = true;
      if (!moved) return;
      e.preventDefault();
      const w = fab.offsetWidth, h = fab.offsetHeight;
      fab.style.left = clamp(e.clientX - offX, 0, window.innerWidth - w) + "px";
      fab.style.right = "auto";
      fab.style.top = clamp(e.clientY - offY, 0, window.innerHeight - h) + "px";
      fab.style.bottom = "auto";
    });
    fab.addEventListener("pointerup", (e) => {
      if (!down) return;
      down = false;
      fab.style.transition = "";
      if (!moved) return; // tap — let the click handler toggle the panel
      fab.dataset.dragged = "1"; // suppress the click that trails this drag
      const w = fab.offsetWidth, h = fab.offsetHeight;
      const r = fab.getBoundingClientRect();
      const side = r.left + w / 2 < window.innerWidth / 2 ? "left" : "right";
      const y = clamp(r.top, FAB_MARGIN, window.innerHeight - h - FAB_MARGIN);
      fab.style.transition = "left .2s ease, right .2s ease, top .2s ease";
      applyFabPos(fab, side, y);
      saveFabPos(side, y / window.innerHeight);
    });
  }

  // ============================================================
  // Dwell-timer progress: the tab fills bottom-up. A 7px sliver has no room
  // for the ring this replaced.
  // ============================================================

  function startRing(ms) {
    if (!root) return;
    const fill = root.getElementById("fill");
    fill.style.transition = "none";
    fill.style.height = "0";
    fill.getBoundingClientRect(); // reflow so the next assignment animates
    fill.style.transition = "height " + ms + "ms linear";
    fill.style.height = "100%";
  }

  function stopRing() {
    if (!root) return;
    const fill = root.getElementById("fill");
    if (!fill) return;
    fill.style.transition = "none";
    fill.style.height = "0";
  }

  function togglePanel() {
    panelOpen = !panelOpen;
    render();
    if (panelOpen) refresh(); // pull latest from server on open
  }

  function el(tag, props, children) {
    const e = document.createElement(tag);
    if (props) for (const k in props) {
      if (k === "text") e.textContent = props[k];
      else if (k === "html") e.innerHTML = props[k];
      else if (k.slice(0, 2) === "on") e.addEventListener(k.slice(2).toLowerCase(), props[k]);
      else e.setAttribute(k, props[k]);
    }
    if (children) for (const c of children) if (c) e.appendChild(c);
    return e;
  }

  function render() {
    if (!root) return;
    root.getElementById("panel").classList.toggle("open", panelOpen);
    root.getElementById("backdrop").classList.toggle("open", panelOpen);

    // Silent while everything is synced; honest the moment something is stuck.
    const pending = root.getElementById("pending");
    pending.hidden = queueCount() === 0;
    pending.textContent = "⟳ " + queueCount() + " pending";

    // Context header for the current page.
    const ctx = root.getElementById("context");
    ctx.innerHTML = "";
    const p = state.page;
    if (p.type === "series" || p.type === "chapter") {
      const key = keyOf(p);
      const existing = state.byKey[key];
      ctx.appendChild(el("div", { class: "ctx-title", text: p.title || p.seriesId }));
      if (!existing) {
        ctx.appendChild(el("button", { class: "btn primary", text: "+ Bookmark this", onclick: () => bookmarkCurrent() }));
      } else {
        const cur = existing.last_chapter || "—";
        ctx.appendChild(el("div", { class: "ctx-sub", text: "Tracked · last read: " + cur }));
        if (p.type === "chapter" && p.chapterLabel && p.chapterLabel !== existing.last_chapter) {
          ctx.appendChild(el("button", { class: "btn primary", text: "Update to " + p.chapterLabel, onclick: () => updateToCurrentChapter() }));
        }
      }
    } else {
      ctx.appendChild(el("div", { class: "ctx-sub", text: "Open a series or chapter to bookmark it." }));
    }

    // Tabs narrow what is drawn; state.list always holds every bookmark.
    // Archived rows are hidden from All and Favourites, and finished ones —
    // which only the web UI can set — are hidden from every tab.
    for (const [id, tab] of [["tabAll", "all"], ["tabFav", "favorites"], ["tabArc", "archived"]]) {
      root.getElementById(id).classList.toggle("active", activeTab === tab);
    }

    const listEl = root.getElementById("list");
    listEl.innerHTML = "";
    const items = state.list.filter((b) => {
      const s = statusOf(b);
      if (activeTab === "archived") return s === "archived";
      if (s !== "reading") return false;
      return activeTab !== "favorites" || b.favorite;
    });
    if (items.length === 0) {
      const empty = {
        favorites: "No favourites yet.",
        archived: "Nothing archived.",
        all: "No bookmarks yet.",
      }[activeTab];
      listEl.appendChild(el("div", { class: "empty", text: empty }));
    }
    for (const b of items) {
      listEl.appendChild(renderItem(b));
    }
  }

  function renderItem(b) {
    const cont = b.last_chapter_url || b.series_url || "#";
    // Only worth naming the latest chapter while it is ahead of the read one.
    const behind =
      b.latest_chapter &&
      b.latest_chapter_num != null &&
      (b.last_chapter_num == null || b.latest_chapter_num > b.last_chapter_num);
    const sub = behind
      ? "Read: " + (b.last_chapter || "—") + " · Latest: " + b.latest_chapter
      : (b.last_chapter || "—") + " · " + b.site;
    // Cover and text are one link: the card body *is* the continue button, so
    // there is no separate one. The action row is a sibling of that link, never
    // a child — a thumb that misses ★ must not land on a navigation target, and
    // Remove must never be one.
    return el("div", { class: "item" }, [
      el("a", { class: "go", href: cont }, [
        b.cover
          ? el("img", { class: "cover", src: b.cover, loading: "lazy", alt: "" })
          : el("div", { class: "cover ph" }),
        el("div", { class: "meta" }, [
          el("div", { class: "t", text: b.title || b.series_id }),
          el("div", { class: "c" + (behind ? " behind" : ""), text: sub }),
        ]),
      ]),
      el("div", { class: "actions" }, [
        el("button", {
          class: "btn small star" + (b.favorite ? " on" : ""),
          text: b.favorite ? "★" : "☆",
          title: b.favorite ? "Remove from favourites" : "Add to favourites",
          onclick: () => toggleFavorite(b.key),
        }),
        el("button", {
          class: "btn small",
          text: statusOf(b) === "archived" ? "Unarchive" : "Archive",
          onclick: () => toggleArchive(b.key),
        }),
        el("button", {
          class: "btn small danger",
          text: "Remove",
          onclick: () => confirmRemove(b),
        }),
      ]),
    ]);
  }

  // Removal syncs to every device, so it asks first. confirm() is the page's
  // own dialog, not a shadow-root one — modal, and the site cannot style it.
  function confirmRemove(b) {
    if (confirm('Remove "' + (b.title || b.series_id) + '" from your bookmarks?')) {
      removeBookmark(b.key);
    }
  }

  // Toast inside the shadow root.
  function toast(msg, isErr) {
    if (!root) return;
    const t = el("div", { class: "toast" + (isErr ? " err" : ""), text: msg });
    root.getElementById("toasts").appendChild(t);
    setTimeout(() => t.classList.add("show"), 10);
    setTimeout(() => {
      t.classList.remove("show");
      setTimeout(() => t.remove(), 300);
    }, 2600);
  }

  // ============================================================
  // Refresh + navigation
  // ============================================================

  async function refresh() {
    await drain(); // push what we owe before adopting the server's view of it
    try {
      const list = await apiGet();
      setList(overlayPending(list));
      render();
    } catch (e) {
      render(); // fall back to cache
    }
  }

  let lastUrl = location.href;
  function onNavigate() {
    state.page = detect();
    render();
    maybeAutoUpdate();
    maybeCaptureLatestOnSeriesPage();
    // Asura is client-routed, so full loads are rare — checking here too is
    // what keeps its bookmarks current. The throttle still caps the rate.
    backgroundRefreshLatest();
    // Drain only, not a full refresh: Asura may go a long time without a
    // reload, and an extra GET per client-side route change is not wanted.
    drain();
  }

  // Framework-agnostic URL-change watcher: patch history + poll as a fallback,
  // so it works whether the site is client-routed (Asura) or reloads (Demonic).
  function installNavWatcher() {
    const fire = () => {
      if (location.href !== lastUrl) {
        lastUrl = location.href;
        // Meta tags update slightly after the URL on client routes.
        setTimeout(onNavigate, 300);
      }
    };
    const wrap = (name) => {
      const orig = history[name];
      history[name] = function () {
        const r = orig.apply(this, arguments);
        fire();
        return r;
      };
    };
    wrap("pushState");
    wrap("replaceState");
    window.addEventListener("popstate", fire);
    setInterval(fire, 1500); // catch routes that bypass history
  }

  // ============================================================
  // Two-finger long-press — a way in that does not depend on finding a 7px tab
  //
  // Deliberately two fingers, not one: Chromium claims the one-finger long
  // press for image context menus, text selection, and link previews, and on a
  // manga reader the whole viewport is images. It assigns no two-finger long
  // press, so these listeners stay passive and never preventDefault.
  // ============================================================

  const LONGPRESS_MS = 500;
  const LONGPRESS_SLOP = 15; // px either finger may drift before it counts as a drag

  function installLongPress() {
    let timer = null;
    let start = null; // [{x, y}, {x, y}] — where each finger landed

    const cancel = () => {
      if (timer) clearTimeout(timer);
      timer = null;
      start = null;
    };

    const opts = { passive: true, capture: true };

    // Fires once per finger, so the first touch cancels and the second arms.
    // A third finger cancels again.
    document.addEventListener(
      "touchstart",
      (e) => {
        cancel();
        if (e.touches.length !== 2) return;
        start = [
          { x: e.touches[0].clientX, y: e.touches[0].clientY },
          { x: e.touches[1].clientX, y: e.touches[1].clientY },
        ];
        timer = setTimeout(() => {
          cancel();
          togglePanel();
        }, LONGPRESS_MS);
      },
      opts
    );

    // A pinch-zoom is two fingers held down, so the slop check is what keeps a
    // normal-speed one from opening the panel mid-gesture. Verified 2026-07-28:
    // a pinch that reaches 240px in ~240ms cancels well before the timer. A
    // deliberately slow pinch that stays inside the slop for the full 500ms
    // does open the panel — accepted, since an absolute per-finger drift
    // threshold cannot tell that apart from two fingers resting, which is the
    // gesture this is for.
    document.addEventListener(
      "touchmove",
      (e) => {
        if (!start || e.touches.length !== 2) return cancel();
        for (let i = 0; i < 2; i++) {
          if (
            Math.abs(e.touches[i].clientX - start[i].x) > LONGPRESS_SLOP ||
            Math.abs(e.touches[i].clientY - start[i].y) > LONGPRESS_SLOP
          ) {
            return cancel();
          }
        }
      },
      opts
    );

    document.addEventListener("touchend", cancel, opts);
    document.addEventListener("touchcancel", cancel, opts);
  }

  // ============================================================
  // Boot
  // ============================================================

  function init() {
    buildUI();
    state.page = detect();
    render();
    installNavWatcher();
    installLongPress();
    window.addEventListener("online", drain); // signal returned while the page stayed open
    // Sync first: both auto-record and the latest-chapter checks below need to
    // know which series are bookmarked and how fresh they are.
    refresh().then(() => {
      maybeAutoUpdate();
      maybeCaptureLatestOnSeriesPage();
      backgroundRefreshLatest();
    });
  }

  // ============================================================
  // Markup + styles (kept at bottom for readability)
  // ============================================================

  const TEMPLATE = `
    <button id="fab" aria-label="Manga bookmarks"><span id="fill"></span></button>
    <div id="backdrop"></div>
    <aside id="panel" role="dialog" aria-label="Manga bookmarks">
      <header>
        <span>Manga Bookmarks</span>
        <button id="closeBtn" aria-label="Close">✕</button>
      </header>
      <div id="nav">
        <a class="chip" href="${WEB_BASE}" target="_blank" rel="noopener">🌐 Web</a>
        <a class="chip" href="https://asurascans.com" target="_blank" rel="noopener">Asura</a>
        <a class="chip" href="https://demonicscans.org" target="_blank" rel="noopener">Demonic</a>
        <button id="pending" class="chip pending" hidden>⟳ 0 pending</button>
      </div>
      <section id="context"></section>
      <div id="tabs" role="tablist">
        <button id="tabAll" class="tab active" role="tab">All</button>
        <button id="tabFav" class="tab" role="tab">★ Favourites</button>
        <button id="tabArc" class="tab" role="tab">Archived</button>
      </div>
      <div id="list"></div>
    </aside>
    <div id="toasts"></div>
  `;

  const CSS = `
    :host { all: initial; }
    * { box-sizing: border-box; font-family: system-ui, -apple-system, sans-serif; }
    #fab {
      position: fixed;
      width: 7px; height: 44px; border: none; padding: 0;
      border-radius: 4px 0 0 4px;
      background: #6d28d9; opacity: .45;
      box-shadow: 0 2px 8px rgba(0,0,0,.4); z-index: 2147483646; cursor: pointer;
      touch-action: none; user-select: none; overflow: hidden;
    }
    #fab.left { border-radius: 0 4px 4px 0; }
    #fab:active { opacity: 1; }
    #fill {
      position: absolute; left: 0; right: 0; bottom: 0; height: 0;
      background: #c4b5fd; pointer-events: none;
    }
    #backdrop {
      position: fixed; inset: 0; background: rgba(0,0,0,.5);
      opacity: 0; pointer-events: none; transition: opacity .2s; z-index: 2147483646;
    }
    #backdrop.open { opacity: 1; pointer-events: auto; }
    #panel {
      position: fixed; top: 0; right: 0; height: 100%;
      width: min(400px, 92vw); background: #1b1b22; color: #eee;
      transform: translateX(105%); transition: transform .25s ease;
      z-index: 2147483647; display: flex; flex-direction: column;
      padding-bottom: env(safe-area-inset-bottom, 0px);
      box-shadow: -4px 0 20px rgba(0,0,0,.5);
    }
    #panel.open { transform: translateX(0); }
    header {
      display: flex; align-items: center; justify-content: space-between;
      padding: 14px 16px; border-bottom: 1px solid #33333d; font-weight: 600; font-size: 16px;
    }
    #closeBtn { background: none; border: none; color: #aaa; font-size: 18px; cursor: pointer; }
    #nav { display: flex; gap: 8px; padding: 10px 16px; border-bottom: 1px solid #33333d; }
    .chip {
      background: #2a2a33; color: #c4b5fd; text-decoration: none;
      padding: 6px 11px; border-radius: 999px; font-size: 12px; font-weight: 600;
      white-space: nowrap;
    }
    .chip:active { opacity: .8; }
    .chip.pending { background: #4c1d95; border: none; cursor: pointer; }
    .chip.pending[hidden] { display: none; }
    #context {
      padding: 12px 16px; border-bottom: 1px solid #33333d;
      display: flex; flex-direction: column; gap: 8px;
    }
    .ctx-title { font-weight: 600; font-size: 15px; }
    .ctx-sub { color: #9a9aa5; font-size: 13px; }
    #tabs { display: flex; gap: 14px; padding: 10px 16px 0; border-bottom: 1px solid #33333d; }
    .tab {
      background: none; border: none; color: #9a9aa5; cursor: pointer;
      font-size: 13px; font-weight: 600; padding: 4px 0 9px;
      border-bottom: 2px solid transparent; margin-bottom: -1px;
    }
    .tab.active { color: #eee; border-bottom-color: #6d28d9; }
    #list { overflow-y: auto; flex: 1; padding: 8px 0; }
    .empty { color: #9a9aa5; text-align: center; padding: 30px 16px; font-size: 14px; }
    .item {
      display: flex; flex-direction: column; gap: 8px;
      padding: 10px 16px; border-bottom: 1px solid #2a2a33;
    }
    .go { display: flex; gap: 10px; text-decoration: none; color: inherit; }
    .go:active { opacity: .7; }
    .cover { width: 46px; height: 62px; object-fit: cover; border-radius: 4px; flex: none; background: #333; }
    .cover.ph { display: block; }
    .meta { min-width: 0; flex: 1; }
    .t { font-weight: 600; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
    .c { color: #9a9aa5; font-size: 12px; margin: 2px 0 0; }
    .c.behind { color: #c4b5fd; }
    .actions { display: flex; gap: 6px; flex-wrap: wrap; }
    .btn {
      background: #33333d; color: #eee; border: none; border-radius: 6px;
      padding: 8px 12px; font-size: 13px; cursor: pointer; text-decoration: none; display: inline-block;
    }
    .btn:active { opacity: .8; }
    .btn.primary { background: #6d28d9; color: #fff; }
    .btn.small { padding: 6px 10px; font-size: 12px; }
    .btn.danger { background: #7f1d1d; }
    .btn.star { line-height: 1; }
    .btn.star.on { background: #6d28d9; color: #fff; }
    #toasts {
      position: fixed; left: 50%; transform: translateX(-50%);
      bottom: calc(80px + env(safe-area-inset-bottom, 0px));
      z-index: 2147483647; display: flex; flex-direction: column; gap: 8px; align-items: center;
    }
    .toast {
      background: #2f2f3a; color: #fff; padding: 10px 16px; border-radius: 8px;
      font-size: 13px; opacity: 0; transform: translateY(10px); transition: all .3s;
      box-shadow: 0 4px 14px rgba(0,0,0,.4); max-width: 80vw;
    }
    .toast.show { opacity: 1; transform: translateY(0); }
    .toast.err { background: #7f1d1d; }
  `;

  // ============================================================
  // Test hook
  //
  // Fires only in Node, where window is undefined. The typeof window check keeps it
  // inert on pages whose own scripts define a UMD module shim — under @grant none
  // the userscript shares page globals, so we must not clobber the page's exports.
  // Exposes pure logic only — see userscript/test/logic.test.js.
  // ============================================================
  if (typeof window === "undefined" && typeof module === "object" && module.exports) {
    module.exports = { stripBuildHash, asura, demonic, anchorsFromHTML, statusOf };
  }

  // ============================================================
  // Boot — MUST run last: init() -> buildUI() reads TEMPLATE/CSS,
  // which are const (TDZ) and only initialized above. At
  // @run-at document-idle document.body already exists, so init()
  // fires synchronously here, after the consts are set.
  // ============================================================
  if (document.body) init();
  else document.addEventListener("DOMContentLoaded", init);
})();