theseus/addons-host.js

// Theseus add-on framework — loader + API surface.
//
// Add-ons live in <userData>/extensions/<id>/ as ordinary folders on disk. Each
// carries an `addon.json` manifest and (per the manifest's `main` field) a
// CommonJS entry that exports `activate(api)` and optionally `deactivate()`.
// Nothing about an add-on ships in the Theseus repo or installer — drop a
// folder, restart Theseus, it's live. This is the same trust model as
// dev-mode browser extensions: the user is choosing to run local code with
// the app's full privileges.
//
// Loading is synchronous at app-ready time; there is no hot-reload. Failed
// activations are logged and skipped without breaking the app.
//
// Persistence:
//   settings.disabledAddons  — ids the user has toggled off
//   <userData>/extensions-data/<id>.json — per-add-on kv store (api.storage)

const fs = require("node:fs");
const path = require("node:path");

// Extension points the framework understands. Extending this list means also
// teaching main.js and (typically) the chrome renderer about the new point.
// Right now only sidebar panels are wired — future rev adds toolbar-chip,
// proxy, page-inject, etc.
const KNOWN_CAPABILITIES = new Set([
  "sidebar-panel", "session-proxy",
  // request-filter: api.registerRequestFilter(fn) — fn sees every subresource
  //                 request of the session ({url, resourceType, method,
  //                 frameUrl, initiator, webContentsId}) and returns true to
  //                 block it. Main never lets a filter cancel a top-level
  //                 navigation. Also unlocks api.tabs (active tab's url/host
  //                 and a change event) so a blocker can show per-site
  //                 numbers. Sees every URL the browser loads: same trust
  //                 bar as page-inject on "*://*/*".
  "request-filter",
  // vault-derive:   api.vault.derive(purposePath) — HKDF child of the password
  //                 vault's root, namespaced under the add-on id.
  // page-inject:    manifest["page-inject"] = { preload, origins } — the add-on's
  //                 preload source runs in the isolated world of every tab whose
  //                 URL matches one of the origin patterns.
  // approval-modal: api.approvalModal({...}) — user-facing consent dialog over
  //                 the active tab, resolved by main.
  // capture-tab:    api.captureTab({mode, ...}) + api.saveCapture({dataUrl, filename})
  //                 — snapshot the active tab (visible viewport / full page /
  //                 user-drawn rectangle) and save the result through the app's
  //                 downloads pipeline. The add-on sees pixels of whatever the
  //                 current tab is showing, so this is the same trust bar as a
  //                 page-inject add-on that matches "*://*/*".
  // toolbar-menu:   manifest["toolbar-menu"] = { title?, icon?, items:[{id,label,icon?}] }
  //                 — chrome renders a dropdown under the add-on's dock icon;
  //                 picking an item dispatches "menu-select" with {id} to the
  //                 add-on's onMessage("menu-select", …) handler.
  // open-tab:       api.openTab(pathOrUrl, {query?}) — for a bare http(s) URL
  //                 this stays available without the capability (legacy).
  //                 Declaring "open-tab" additionally lets the add-on open
  //                 one of its OWN HTML files as a full Theseus tab, with a
  //                 lean preload so the page can keep talking to the add-on
  //                 via window.silentmode.invoke().
  // scan-page:      api.scanActiveTabForUris({scheme, limit}) — the HOST
  //                 searches the active tab for URIs of one scheme and
  //                 returns only those. The add-on never receives page text,
  //                 markup or form values, so this sits well below
  //                 page-inject or capture-tab on the trust ladder: it can
  //                 learn that a page is offering e.g. a wiz:// pairing
  //                 code, and nothing else about the page.
  "vault-derive", "page-inject", "approval-modal", "capture-tab",
  "toolbar-menu", "open-tab", "scan-page",
  // context-menu-item: manifest["context-menu-items"] = [{id, label, when, icon?}]
  //                    — chrome merges these into every tab's right-click
  //                    menu, filtered by `when` (selectionText | linkURL |
  //                    editable | image | always). Picking one dispatches
  //                    "context-menu" with the item id + the surrounding
  //                    context (selection text, link URL, media info, host)
  //                    to the add-on's onMessage handler. Add-ons that also
  //                    declare "sidebar-panel" typically follow up with
  //                    api.revealSidebar(panelId) to surface the result.
  "context-menu-item",
]);

// Chrome-style match pattern → predicate. "<scheme>://<host>/<path>" where
// scheme may be "*", host may start with "*." (matches the bare host and any
// subdomain) or be "*", and path is a glob where "*" matches anything.
// bns:// (how Theseus fetches BCNR sites internally) is folded into https://
// so a pattern written the way the address bar shows it keeps working.
function compileOriginPattern(pattern) {
  const m = /^(\*|[a-z][a-z0-9+.-]*):\/\/(\*|\*\.[^/*]+|[^/*]+)(\/.*)?$/i.exec(String(pattern).trim());
  if (!m) throw new Error(`bad origin pattern: ${pattern}`);
  const [, scheme, host, pathGlob = "/*"] = m;
  const esc = (s) => s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
  const schemeRe = scheme === "*" ? "https?" : esc(scheme.toLowerCase());
  let hostRe;
  if (host === "*") hostRe = "[^/]+";
  else if (host.startsWith("*.")) hostRe = `(?:[^/]+\\.)?${esc(host.slice(2).toLowerCase())}`;
  else hostRe = esc(host.toLowerCase());
  const pathRe = pathGlob.split("*").map(esc).join(".*");
  const re = new RegExp(`^${schemeRe}://${hostRe}(?::\\d+)?${pathRe}$`, "i");
  return (url) => re.test(String(url).replace(/^bns:\/\//i, "https://"));
}
function urlMatchesAny(url, matchers) {
  for (const fn of matchers) { try { if (fn(url)) return true; } catch {} }
  return false;
}

// Manifest field guardrails. Reject anything shape-suspicious so a bad
// addon.json can't get past the loader gate.
function validateManifest(raw, folderName) {
  const m = raw && typeof raw === "object" ? raw : {};
  const id = String(m.id || "").trim();
  if (!/^[a-z0-9][a-z0-9._-]{0,63}$/i.test(id)) {
    throw new Error(`invalid or missing "id" (allowed: [a-z0-9._-], up to 64 chars) — folder ${folderName}`);
  }
  const name = String(m.name || id);
  const version = String(m.version || "0.0.0");
  const description = String(m.description || "");
  const author = String(m.author || "");
  const icon = String(m.icon || "🧩");
  const main = String(m.main || "index.js");
  if (main.includes("..") || path.isAbsolute(main)) {
    throw new Error(`addon "${id}": main must be a relative path inside the addon folder`);
  }
  const capabilities = Array.isArray(m.capabilities) ? m.capabilities.map(String) : [];
  for (const cap of capabilities) {
    if (!KNOWN_CAPABILITIES.has(cap)) {
      // Not fatal — log later. Unknown caps are silently dropped.
    }
  }
  let pageInject = null;
  if (capabilities.includes("page-inject")) {
    const pi = m["page-inject"];
    if (!pi || typeof pi !== "object") throw new Error(`addon "${id}": "page-inject" capability needs a "page-inject" manifest block`);
    const preload = String(pi.preload || "");
    if (!preload || preload.includes("..") || path.isAbsolute(preload)) {
      throw new Error(`addon "${id}": page-inject.preload must be a relative path inside the addon folder`);
    }
    const origins = Array.isArray(pi.origins) ? pi.origins.map(String) : [];
    if (!origins.length) throw new Error(`addon "${id}": page-inject.origins must list at least one pattern`);
    pageInject = { preload, origins, matchers: origins.map(compileOriginPattern) };
  }
  let toolbarMenu = null;
  if (capabilities.includes("toolbar-menu")) {
    const tm = m["toolbar-menu"];
    if (!tm || typeof tm !== "object") {
      throw new Error(`addon "${id}": "toolbar-menu" capability needs a "toolbar-menu" manifest block`);
    }
    const items = Array.isArray(tm.items) ? tm.items : [];
    if (!items.length) throw new Error(`addon "${id}": toolbar-menu.items must list at least one entry`);
    const seen = new Set();
    const cleanItems = items.map((it, idx) => {
      const iid = String(it && it.id || "").trim();
      if (!iid || !/^[a-z0-9][a-z0-9._-]{0,63}$/i.test(iid)) {
        throw new Error(`addon "${id}": toolbar-menu.items[${idx}].id is required and must match [a-z0-9._-]`);
      }
      if (seen.has(iid)) throw new Error(`addon "${id}": toolbar-menu.items[${idx}].id "${iid}" duplicates an earlier entry`);
      seen.add(iid);
      const label = String(it.label || iid);
      const itemIcon = it.icon == null ? "" : String(it.icon);
      return { id: iid, label, icon: itemIcon };
    });
    toolbarMenu = {
      title: tm.title == null ? name : String(tm.title),
      icon: tm.icon == null ? icon : String(tm.icon),
      items: cleanItems,
    };
  }
  const contextMenuItems = [];
  if (capabilities.includes("context-menu-item")) {
    const rawItems = m["context-menu-items"];
    if (!Array.isArray(rawItems) || !rawItems.length) {
      throw new Error(`addon "${id}": "context-menu-item" capability needs a "context-menu-items" array with at least one entry`);
    }
    const seen = new Set();
    const ALLOWED_WHEN = new Set(["selectionText", "linkURL", "editable", "image", "always"]);
    for (let idx = 0; idx < rawItems.length; idx++) {
      const it = rawItems[idx];
      const iid = String(it && it.id || "").trim();
      if (!iid || !/^[a-z0-9][a-z0-9._-]{0,63}$/i.test(iid)) {
        throw new Error(`addon "${id}": context-menu-items[${idx}].id is required and must match [a-z0-9._-]`);
      }
      if (seen.has(iid)) throw new Error(`addon "${id}": context-menu-items[${idx}].id "${iid}" duplicates an earlier entry`);
      seen.add(iid);
      const when = String(it.when || "always");
      if (!ALLOWED_WHEN.has(when)) {
        throw new Error(`addon "${id}": context-menu-items[${idx}].when must be one of ${[...ALLOWED_WHEN].join("|")}`);
      }
      contextMenuItems.push({
        id: iid,
        label: String(it.label || iid),
        when,
        icon: it.icon == null ? "" : String(it.icon),
      });
    }
  }
  // `absorbs`: legacy add-on ids whose vault-derive namespace this add-on
  // inherits. Set on a superseding add-on (e.g. aegis absorbs siawallet) so
  // funds derived under the old id's paths stay reachable through the new
  // one. Each entry is validated as an id itself and gates vault.derive by
  // (own id OR one of these) in makeApi below.
  const absorbs = Array.isArray(m.absorbs) ? m.absorbs.map(String).filter(Boolean) : [];
  for (const a of absorbs) {
    if (!/^[a-z0-9][a-z0-9._-]{0,63}$/i.test(a)) {
      throw new Error(`addon "${id}": absorbs entry "${a}" is not a valid add-on id`);
    }
    if (a === id) throw new Error(`addon "${id}": absorbs cannot list its own id`);
  }
  // Category: "plugin" for first-class Silent Mode components (Aegis and
  // future Ariadne-as-addon) that are surfaced in Settings › Plug-ins with
  // their own copy instead of the raw Extensions list. Anything else falls
  // back to plain-extension rendering.
  const category = m.category && ["plugin"].includes(String(m.category))
    ? String(m.category) : null;
  return { id, name, version, description, author, icon, main, capabilities, pageInject, toolbarMenu, contextMenuItems, absorbs, category };
}

// Loader singleton. `discoverAndActivate(opts)` returns a snapshot the rest
// of the app queries via `getActive()` / `getInstalled()`.
class AddonHost {
  constructor({ addonsDir, dataDir, isDisabled, logger, setSessionProxy, vaultDerive, vaultImports, approvalModal, emitToPanel, hostRequire, hostImport, openTab, openAddonTab, openSettings, captureTab, saveCapture, scanTabForUris, checkAndStageUpdates, restartApp, revealSidebar, requestFilter, tabs }) {
    this.addonsDir = addonsDir;
    this.dataDir = dataDir;
    this.isDisabled = isDisabled || (() => false);
    this.log = logger || ((...a) => console.log("[addons]", ...a));
    this._installed = []; // [{ manifest, folder, error? }]
    this._active = new Map(); // id -> { manifest, folder, exports, sidebarPanels: [...], handlers: Map, inject }
    // Capability hooks injected by main. Each is (args..., addonId) so main
    // can log/gate per add-on. Missing hook = capability unavailable.
    this._vaultDerive = typeof vaultDerive === "function" ? vaultDerive : null;
    // vaultImports: main-process shim {list, add, remove, signer} that owns
    // wallet-imports.enc. Same trust tier as vaultDerive — an add-on that
    // holds vault-derive can also see imports (design §3.2 co-tenancy).
    this._vaultImports = vaultImports && typeof vaultImports.list === "function" ? vaultImports : null;
    // vaultLifecycle: main-process shim {status, setup, unlock, lock} so the
    // wallet add-on can drive vault setup/unlock without redirecting users
    // to Settings > Passwords. Same "vault-derive" capability gate.
    this._vaultLifecycle = arguments[0].vaultLifecycle && typeof arguments[0].vaultLifecycle.unlock === "function"
      ? arguments[0].vaultLifecycle : null;
    this._approvalModal = typeof approvalModal === "function" ? approvalModal : null;
    this._emitToPanel = typeof emitToPanel === "function" ? emitToPanel : null;
    this._scanTabForUris = typeof scanTabForUris === "function" ? scanTabForUris : null;
    // Add-ons live outside the app's node_modules tree, so a bare require()
    // from their folder can't see Theseus's deps (ws, @noble/*, …). Main
    // hands us its own require so add-ons can share the bundled tree.
    this._hostRequire = typeof hostRequire === "function" ? hostRequire : null;
    this._requestFilter = requestFilter && typeof requestFilter.set === "function" ? requestFilter : null;
    this._tabs = tabs && typeof tabs.active === "function" ? tabs : null;
    // ESM-only deps (@noble/*, @scure/*) can't be require()d by Electron's
    // Node; hostImport resolves them from the app tree and import()s them.
    this._hostImport = typeof hostImport === "function" ? hostImport : null;
    this._openTab = typeof openTab === "function" ? openTab : null;
    // open-tab: opens one of the add-on's own HTML files as a full Theseus tab.
    // Signature: (addonId, relPath, queryString) => Promise<void>.
    this._openAddonTab = typeof openAddonTab === "function" ? openAddonTab : null;
    // openSettings: opens Theseus's Settings tab, optionally scrolled to a
    // named section (e.g. "passwords"). Uses the same IPC route the picker
    // uses for "Search settings…". Signature: (section?: string) => void.
    this._openSettings = typeof openSettings === "function" ? openSettings : null;
    // Panel-driven self-update: an add-on may ask the host to run the
    // OTA check + verify + stage flow for itself and, if a newer signed
    // build lands, restart Theseus so promoteStagedUpdates picks it up.
    // Owns the entire trust chain (sig, hash, manifest match) so no
    // add-on ever gets to hand-write into its own installed folder.
    this._checkAndStageUpdates = typeof checkAndStageUpdates === "function" ? checkAndStageUpdates : null;
    this._restartApp = typeof restartApp === "function" ? restartApp : null;
    // revealSidebar: opens the sidebar and switches to the given panel id.
    // Signature: (addonId, panelId) => void. Add-ons use this from their
    // context-menu handler to surface a result in their sidebar UI.
    this._revealSidebar = typeof revealSidebar === "function" ? revealSidebar : null;
    // Session-proxy hook — injected by main so add-ons can swap the default
    // session's proxy rules (e.g. a "route everything through my VPS" add-on).
    // Signature: (rules: string | { proxyRules, proxyBypassRules }) => Promise<void>
    // A `null` rule clears the proxy. Kept as a callback rather than requiring
    // the loader itself import electron.
    this._setSessionProxy = typeof setSessionProxy === "function" ? setSessionProxy : null;
    // capture-tab hooks — main captures/saves; the loader only enforces the
    // manifest gate.
    this._captureTab = typeof captureTab === "function" ? captureTab : null;
    this._saveCapture = typeof saveCapture === "function" ? saveCapture : null;
    // api.whenUiReady() plumbing — see signalUiReady().
    this._uiReady = false;
    this._uiReadyWaiters = [];
  }

  // main calls this once the browser chrome has painted. Add-ons that pull
  // in heavy dependencies (Aegis: noble curve precompute, bitcoinjs, libauth,
  // WizardConnect) gate that work on api.whenUiReady() so module evaluation
  // doesn't land on the main thread while chrome.html is still trying to
  // paint. Sticky: a later discoverAndActivate() resolves immediately.
  signalUiReady() {
    this._uiReady = true;
    for (const resolve of this._uiReadyWaiters.splice(0)) { try { resolve(); } catch {} }
  }

  ensureDirs() {
    for (const d of [this.addonsDir, this.dataDir]) {
      try { fs.mkdirSync(d, { recursive: true }); } catch (e) { this.log("mkdir failed", d, e?.message); }
    }
  }

  // api.vault.lifecycle namespace: unlock/setup/status/lock the vault. Same
  // "vault-derive" cap. Purpose: let the wallet add-on drive vault setup from
  // its own gate instead of redirecting users to Settings > Passwords.
  _makeLifecycleApi(manifest) {
    const requireCap = () => {
      if (!manifest.capabilities.includes("vault-derive")) {
        throw new Error(`add-on "${manifest.id}" must declare the "vault-derive" capability in addon.json`);
      }
      if (!this._vaultLifecycle) throw new Error("vault.lifecycle unavailable (host not wired)");
    };
    return {
      status: async () => { requireCap(); return this._vaultLifecycle.status(); },
      unlock: async (pw) => { requireCap(); return this._vaultLifecycle.unlock(String(pw || ""), manifest.id); },
      setup: async (pw, seedSource) => { requireCap(); return this._vaultLifecycle.setup(String(pw || ""), seedSource, manifest.id); },
      lock: async () => { requireCap(); return this._vaultLifecycle.lock(manifest.id); },
    };
  }

  // api.vault.imports namespace factory. Gated by the "vault-derive" cap
  // because the two surfaces sit at the same trust tier (design §3.2). If
  // main didn't wire the vaultImports shim, calls throw a clear error.
  _makeImportsApi(manifest) {
    const requireCap = () => {
      if (!manifest.capabilities.includes("vault-derive")) {
        throw new Error(`add-on "${manifest.id}" must declare the "vault-derive" capability in addon.json`);
      }
      if (!this._vaultImports) throw new Error("vault.imports unavailable (host not wired)");
    };
    return {
      list: async () => { requireCap(); return this._vaultImports.list(); },
      add: async (spec) => { requireCap(); return this._vaultImports.add(spec, manifest.id); },
      remove: async (id) => { requireCap(); return this._vaultImports.remove(String(id || ""), manifest.id); },
      signer: async (id) => { requireCap(); return this._vaultImports.signer(String(id || ""), manifest.id); },
    };
  }

  discoverAndActivate() {
    this.ensureDirs();
    this._deactivateAll();
    this._installed = [];
    let entries = [];
    try { entries = fs.readdirSync(this.addonsDir, { withFileTypes: true }); } catch { entries = []; }
    for (const dirent of entries) {
      if (!dirent.isDirectory()) continue;
      const folder = path.join(this.addonsDir, dirent.name);
      try {
        const manifest = this._readManifest(folder, dirent.name);
        this._installed.push({ manifest, folder });
        if (this.isDisabled(manifest.id)) {
          this.log(`skipping disabled add-on ${manifest.id}`);
          continue;
        }
        this._activateOne(manifest, folder);
      } catch (e) {
        this.log(`failed to load ${dirent.name}: ${e?.message || e}`);
        // A manifest that parsed but whose activate() threw was already
        // pushed above — replace it rather than listing the add-on twice.
        const i = this._installed.findIndex((x) => x.folder === folder);
        const entry = { manifest: null, folder, error: String(e?.message || e) };
        if (i >= 0) this._installed[i] = entry; else this._installed.push(entry);
      }
    }
    return this.snapshot();
  }

  _readManifest(folder, folderName) {
    const p = path.join(folder, "addon.json");
    const raw = JSON.parse(fs.readFileSync(p, "utf8"));
    return validateManifest(raw, folderName);
  }

  _activateOne(manifest, folder) {
    const mainPath = path.join(folder, manifest.main);
    // require() from a folder outside asar is fine — Electron just uses Node's
    // resolver. This is where the trust decision lives: we're loading arbitrary
    // JS into the main process with full API access.
    let mod;
    try {
      // Bust the require cache so a manual reload (future feature) picks up
      // edits — cheap since add-ons are small.
      delete require.cache[require.resolve(mainPath)];
      mod = require(mainPath);
    } catch (e) {
      throw new Error(`require() failed: ${e?.message || e}`);
    }
    if (!mod || typeof mod.activate !== "function") {
      throw new Error(`main file must export an activate(api) function`);
    }
    const active = { manifest, folder, exports: mod, sidebarPanels: [], handlers: new Map(), inject: null, tabListeners: [] };
    if (manifest.pageInject) {
      // Read the inject source once at activation. It's shipped to every
      // matching tab's preload verbatim, so a syntax error surfaces in the
      // tab's console, not here — but a missing file is fatal for the add-on.
      const abs = path.join(folder, manifest.pageInject.preload);
      let source;
      try { source = fs.readFileSync(abs, "utf8"); }
      catch (e) { throw new Error(`page-inject preload not readable: ${abs} (${e?.message || e})`); }
      active.inject = { source, matchers: manifest.pageInject.matchers, origins: manifest.pageInject.origins };
    }
    const api = this._makeApi(active);
    try { mod.activate(api); }
    catch (e) { throw new Error(`activate() threw: ${e?.message || e}`); }
    this._active.set(manifest.id, active);
    this.log(`activated ${manifest.id} v${manifest.version}`);
  }

  // Tear down every active add-on before a re-discover so long-lived state
  // (sockets, timers) from a previous activation doesn't pile up.
  _deactivateAll() {
    for (const [id, active] of this._active) {
      try { if (this._requestFilter) this._requestFilter.clear(active.manifest.id); } catch {}
      for (const off of active.tabListeners || []) { try { off(); } catch {} }
      try { if (typeof active.exports.deactivate === "function") active.exports.deactivate(); }
      catch (e) { this.log(`[${id}] deactivate() threw: ${e?.message || e}`); }
    }
    this._active.clear();
  }

  _makeApi(active) {
    const { manifest, folder } = active;
    const storageFile = path.join(this.dataDir, `${manifest.id}.json`);
    return {
      // Metadata the add-on may want to reflect on
      id: manifest.id,
      folder,
      // Per-extension data folder (<userData>/extensions-data): where the kv
      // store lives and where an add-on should keep scratch files rather
      // than guessing the path from its own folder.
      dataDir: this.dataDir,
      log: (...a) => this.log(`[${manifest.id}]`, ...a),
      // Persistent per-add-on storage. Small kv JSON on disk.
      storage: {
        get: (key, fallback = null) => {
          try {
            const raw = JSON.parse(fs.readFileSync(storageFile, "utf8"));
            return key in raw ? raw[key] : fallback;
          } catch { return fallback; }
        },
        set: (key, value) => {
          let store = {};
          try { store = JSON.parse(fs.readFileSync(storageFile, "utf8")); } catch {}
          store[key] = value;
          try { fs.writeFileSync(storageFile, JSON.stringify(store)); } catch (e) { this.log(`[${manifest.id}] storage.set failed:`, e?.message); }
        },
        all: () => { try { return JSON.parse(fs.readFileSync(storageFile, "utf8")); } catch { return {}; } },
      },
      // Register a sidebar panel — a right-side WebContentsView that hosts
      // one of the add-on's HTML pages. `page` is a path RELATIVE to the
      // add-on folder. `title` shows in the sidebar tab strip. `icon` is
      // a short emoji/glyph.
      registerSidebarPanel: ({ id, title, icon = manifest.icon, page }) => {
        if (!id || !title || !page) throw new Error(`registerSidebarPanel needs {id, title, page}`);
        const abs = path.join(folder, String(page).replace(/^[\\/]/, ""));
        if (!fs.existsSync(abs)) throw new Error(`sidebar panel page not found: ${abs}`);
        // Namespaced id so two add-ons can't collide.
        const panelId = `${manifest.id}:${id}`;
        active.sidebarPanels.push({ panelId, title, icon, pageFile: abs, addonId: manifest.id });
        this.log(`[${manifest.id}] registered sidebar panel: ${panelId}`);
      },
      // Programmatically open the sidebar and switch to one of THIS add-on's
      // panels. `panelId` is the un-namespaced id passed to registerSidebarPanel
      // (e.g. "main"); host prefixes with the add-on id under the hood. Used
      // by context-menu handlers to surface a result in the sidebar. No-op if
      // the add-on doesn't own that panel or the host isn't wired.
      revealSidebar: (panelId) => {
        if (!this._revealSidebar) { this.log(`[${manifest.id}] revealSidebar unavailable (host not wired)`); return; }
        const pid = String(panelId || "").trim();
        const full = pid.includes(":") ? pid : `${manifest.id}:${pid || (active.sidebarPanels[0] && active.sidebarPanels[0].panelId.split(":")[1])}`;
        const owned = active.sidebarPanels.some((p) => p.panelId === full);
        if (!owned) { this.log(`[${manifest.id}] revealSidebar: no such panel ${full}`); return; }
        this._revealSidebar(manifest.id, full);
      },
      // Swap the default session's proxy. Rules follow Chromium's proxy
      // format ("socks5://1.2.3.4:1080" for a single SOCKS server,
      // "http=1.2.3.4:8080;https=5.6.7.8:8080" for scheme-split HTTP, etc.).
      // Pass null to clear. Add-ons that opt into this capability are
      // fully replacing the browser's outgoing network path — they're
      // the trust boundary while active. Same-signature as the built-in
      // Tor toggle uses under the hood.
      // Request filter: one function per add-on, consulted by main for every
      // subresource request. Returns an unregister function.
      registerRequestFilter: (fn) => {
        if (typeof fn !== "function") throw new Error(`registerRequestFilter needs a function`);
        if (!manifest.capabilities.includes("request-filter")) throw new Error(`add-on "${manifest.id}" must declare the "request-filter" capability in addon.json`);
        if (!this._requestFilter) { this.log(`[${manifest.id}] request filter unavailable (host not wired)`); return () => {}; }
        this._requestFilter.set(manifest.id, fn);
        return () => { try { this._requestFilter.clear(manifest.id); } catch {} };
      },
      // The active tab (id, url, host) and a change event — enough for a
      // per-site view, nothing about page content.
      tabs: {
        active: () => {
          if (!manifest.capabilities.includes("request-filter")) throw new Error(`add-on "${manifest.id}" must declare the "request-filter" capability to read tabs`);
          return this._tabs ? this._tabs.active() : null;
        },
        onChange: (cb) => {
          if (!manifest.capabilities.includes("request-filter")) throw new Error(`add-on "${manifest.id}" must declare the "request-filter" capability to read tabs`);
          if (!this._tabs || typeof cb !== "function") return () => {};
          const off = this._tabs.onChange(cb);
          active.tabListeners.push(off);
          return off;
        },
      },
      setSessionProxy: async (rules) => {
        if (!this._setSessionProxy) {
          this.log(`[${manifest.id}] setSessionProxy unavailable (host not wired)`);
          return;
        }
        if (!manifest.capabilities.includes("session-proxy")) {
          throw new Error(`add-on "${manifest.id}" must declare the "session-proxy" capability in addon.json`);
        }
        await this._setSessionProxy(rules, manifest.id);
      },
      // Resolve a module from Theseus's own dependency tree. Add-ons run with
      // the app's full privileges anyway; this only saves them from shipping
      // a second copy of ws / @noble / etc.
      require: (name) => {
        if (!this._hostRequire) throw new Error(`api.require unavailable (host not wired)`);
        return this._hostRequire(name);
      },
      // Same, for ES-module-only packages: resolves to a Promise of the
      // module namespace.
      import: async (name) => {
        if (!this._hostImport) throw new Error(`api.import unavailable (host not wired)`);
        return this._hostImport(name);
      },
      // Open a new Theseus tab. Two shapes:
      //   - api.openTab("https://…")                    — no capability needed
      //   - api.openTab("editor.html", { query: {...} }) — opens one of the
      //     add-on's OWN files as a full tab; requires the "open-tab" cap.
      //     Path is resolved inside the add-on folder and rejected if it
      //     escapes it (path traversal). Query is URL-encoded. The page
      //     loads under addon-tab-preload.js so window.silentmode.invoke()
      //     reaches the same handlers as a sidebar panel — main gates by
      //     sender URL so a page hosted anywhere else gets nothing back.
      openTab: (pathOrUrl, opts) => {
        const s = String(pathOrUrl || "");
        // Bare http(s) URL with no opts — legacy behaviour, unchanged.
        if (/^https?:\/\//i.test(s) && !opts) {
          if (!this._openTab) throw new Error("openTab unavailable (host not wired)");
          this._openTab(s, manifest.id);
          return;
        }
        if (!manifest.capabilities.includes("open-tab")) {
          throw new Error(`add-on "${manifest.id}" must declare the "open-tab" capability in addon.json to open its own files in a tab`);
        }
        if (!this._openAddonTab) throw new Error("openAddonTab unavailable (host not wired)");
        if (!s || path.isAbsolute(s) || s.includes("..")) {
          throw new Error(`openTab: path must be a relative file inside the add-on folder (got "${s}")`);
        }
        let qs = "";
        if (opts && opts.query && typeof opts.query === "object") {
          const usp = new URLSearchParams();
          for (const [k, v] of Object.entries(opts.query)) usp.append(String(k), String(v));
          qs = usp.toString();
        }
        return this._openAddonTab(manifest.id, s, qs);
      },
      // Open Theseus's Settings tab, optionally scrolled to a named section
      // (validated against a known list in main). No capability needed —
      // it's the same thing the user could do from the ⋮ menu, just a
      // one-click shortcut so add-ons can point users at the right place
      // (e.g. Aegis's "Set up vault" gate → Passwords).
      openSettings: (section) => {
        if (!this._openSettings) throw new Error("openSettings unavailable (host not wired)");
        this._openSettings(typeof section === "string" ? section : "");
      },
      // Check the OTA channel for a newer signed build of THIS add-on and
      // stage it if one is found. Returns { status, staged, current, next }
      // — status matches the shared addon-updater report vocabulary
      // ("up-to-date" | "staged" | "already-staged" | "fetch-failed" | …).
      // The staged copy activates on the next Theseus launch, so pair with
      // restartApp() when the caller wants an immediate apply. Scoped to
      // the calling add-on so a plug-in can't stage updates for its
      // neighbours.
      checkAndStageSelfUpdate: async () => {
        if (!this._checkAndStageUpdates) throw new Error("checkAndStageSelfUpdate unavailable (host not wired)");
        const full = await this._checkAndStageUpdates();
        const own = (full?.report || []).find((r) => r.id === manifest.id) || { status: "no-update-url" };
        return {
          status: own.status || "unknown",
          detail: own.detail || null,
          current: own.currentVer || manifest.version,
          next: own.newVer || null,
          staged: (full?.staged || []).find((s) => s.id === manifest.id) || null,
        };
      },
      // Ask Theseus to relaunch (the plug-in card's "apply update" chip).
      // The host asks the user first and resolves { restarted, deferred }
      // — an add-on cannot restart the browser on its own.
      restartApp: () => {
        if (!this._restartApp) throw new Error("restartApp unavailable (host not wired)");
        return Promise.resolve(this._restartApp(manifest.name || manifest.id));
      },
      // Resolves once the browser chrome has painted (immediately if it
      // already has). Put expensive dependency loading behind this so it
      // never competes with the first frame at launch.
      whenUiReady: () => (this._uiReady ? Promise.resolve() : new Promise((resolve) => this._uiReadyWaiters.push(resolve))),
      // Panel ↔ activate() messaging. Panels (and, for page-inject add-ons,
      // injected page bridges) call into the add-on with a message name +
      // one JSON payload; the handler's return value goes back as the
      // response. `ctx.from` is "panel" or "page"; pages also carry
      // `ctx.origin` ("https://host") so the add-on can scope permissions.
      onMessage: (msg, handler) => {
        if (typeof msg !== "string" || !msg || typeof handler !== "function") throw new Error(`onMessage needs (name, fn)`);
        active.handlers.set(msg, handler);
      },
      // Push an event to the add-on's own sidebar panel if it's currently
      // loaded. Fire-and-forget; silently dropped when the panel is closed.
      emit: (msg, payload) => {
        if (this._emitToPanel) this._emitToPanel(manifest.id, String(msg), payload);
      },
      // vault-derive: a 32-byte HKDF child of the password vault's root,
      // keyed by a path that MUST start with this add-on's id — or one of
      // the ids it declared under `absorbs` in addon.json, so a superseding
      // add-on can keep deriving the same keys as the add-on it replaced
      // (funds stay reachable across the transition). Resolves only once
      // the user has unlocked the vault (main polls; the await can be long).
      vault: {
        derive: async (purposePath) => {
          if (!manifest.capabilities.includes("vault-derive")) {
            throw new Error(`add-on "${manifest.id}" must declare the "vault-derive" capability in addon.json`);
          }
          if (!this._vaultDerive) throw new Error(`vault.derive unavailable (host not wired)`);
          const p = String(purposePath || "");
          if (/[^a-z0-9/._-]/i.test(p) || p.includes("..")) {
            throw new Error(`vault.derive: purposePath must look like "${manifest.id}/<name>"`);
          }
          const allowed = [manifest.id, ...(manifest.absorbs || [])];
          if (!allowed.some((prefix) => p.startsWith(prefix + "/"))) {
            const list = allowed.length > 1
              ? `one of "${allowed.join('", "')}"`
              : `"${manifest.id}"`;
            throw new Error(`vault.derive: purposePath must start with ${list} + "/"`);
          }
          return this._vaultDerive(p, manifest.id);
        },
        imports: this._makeImportsApi(manifest),
        lifecycle: this._makeLifecycleApi(manifest),
      },
      // approval-modal: ask the user. Resolves to the chosen action id, or
      // "cancel" (Escape / mask click / window closed). With `checkbox` set
      // and ticked, the id comes back suffixed "+<checkbox.id>"; with
      // `select` {id, label, options:[{value,label}]} and a non-empty value
      // chosen, "+<select.id>=<value>".
      approvalModal: async (opts) => {
        if (!manifest.capabilities.includes("approval-modal")) {
          throw new Error(`add-on "${manifest.id}" must declare the "approval-modal" capability in addon.json`);
        }
        if (!this._approvalModal) throw new Error(`approvalModal unavailable (host not wired)`);
        return this._approvalModal(opts || {}, manifest.id);
      },
      // capture-tab: snapshot the currently-active tab.
      //   opts.mode      "visible" | "full" | "region"    (required)
      //   opts.format    "png" | "jpeg"                   (default "png")
      //   opts.quality   1-100                            (jpeg only, default 90)
      //   opts.overlaySource  string                       (region only — DOM
      //                       code the add-on wants injected while the user
      //                       drags a selection. Must resolve to `{x,y,w,h}`
      //                       in CSS pixels; return null/undefined to cancel.)
      // Resolves to `{ dataUrl, width, height, host, format }`.
      captureTab: async (opts) => {
        if (!manifest.capabilities.includes("capture-tab")) {
          throw new Error(`add-on "${manifest.id}" must declare the "capture-tab" capability in addon.json`);
        }
        if (!this._captureTab) throw new Error(`captureTab unavailable (host not wired)`);
        return this._captureTab(opts || {}, manifest.id);
      },
      // capture-tab: route an in-memory image into the app's downloads pipeline
      // so it lands in the user's Downloads folder AND shows up in the
      // download-chip list the same way any HTTP download would.
      //   opts.dataUrl   "data:image/png;base64,…"        (required)
      //   opts.filename  filename shown in the chip       (required)
      // Resolves to `{ savePath }`.
      saveCapture: async (opts) => {
        if (!manifest.capabilities.includes("capture-tab")) {
          throw new Error(`add-on "${manifest.id}" must declare the "capture-tab" capability in addon.json`);
        }
        if (!this._saveCapture) throw new Error(`saveCapture unavailable (host not wired)`);
        return this._saveCapture(opts || {}, manifest.id);
      },
      // scan-page: pull URIs of ONE scheme out of the active tab.
      //
      // Deliberately not a "read the page" API. The host does the matching
      // and hands back only the URIs that matched, so an add-on with this
      // capability still cannot see page text, form values or anything else
      // it did not ask for. The scheme is fixed by the caller and validated
      // here, and every call is expected to be user-initiated — nothing in
      // the host polls a page on an add-on's behalf.
      //
      //   opts.scheme   e.g. "wiz"   (required, [a-z][a-z0-9+.-]{0,19})
      //   opts.limit    max URIs to return (default 20, hard cap 50)
      // Resolves to `{ origin, uris: [string] }`.
      scanActiveTabForUris: async (opts) => {
        if (!manifest.capabilities.includes("scan-page")) {
          throw new Error(`add-on "${manifest.id}" must declare the "scan-page" capability in addon.json`);
        }
        if (!this._scanTabForUris) throw new Error(`scanActiveTabForUris unavailable (host not wired)`);
        const scheme = String(opts?.scheme || "").toLowerCase();
        if (!/^[a-z][a-z0-9+.-]{0,19}$/.test(scheme)) throw new Error("invalid scheme");
        const limit = Math.min(Math.max(Number(opts?.limit) || 20, 1), 50);
        return this._scanTabForUris({ scheme, limit }, manifest.id);
      },
    };
  }

  // Route a message to an add-on's registered handler. Callers (main) have
  // already established WHO is asking; `ctx` carries that provenance.
  async dispatch(id, msg, payload, ctx) {
    const active = this._active.get(id);
    if (!active) throw new Error(`add-on "${id}" is not active`);
    const handler = active.handlers.get(String(msg));
    if (!handler) throw new Error(`add-on "${id}" has no handler for "${msg}"`);
    return handler(payload, ctx || {});
  }
  hasHandler(id, msg) {
    const active = this._active.get(id);
    return !!(active && active.handlers.has(String(msg)));
  }
  // Inject scripts that apply to a tab URL — [{ id, source }].
  injectionsFor(url) {
    const out = [];
    for (const active of this._active.values()) {
      if (active.inject && urlMatchesAny(url, active.inject.matchers)) {
        out.push({ id: active.manifest.id, source: active.inject.source });
      }
    }
    return out;
  }
  // Does this add-on's page-inject declaration cover the URL? Used to gate
  // page → add-on IPC so a non-matching page can't spoof a matching one.
  pageAllowed(id, url) {
    const active = this._active.get(id);
    return !!(active && active.inject && urlMatchesAny(url, active.inject.matchers));
  }

  // Read-only views for the rest of the app.
  snapshot() {
    return {
      installed: this._installed.map(({ manifest, folder, error }) => ({
        id: manifest?.id ?? null,
        name: manifest?.name ?? null,
        version: manifest?.version ?? null,
        description: manifest?.description ?? "",
        author: manifest?.author ?? "",
        icon: manifest?.icon ?? "🧩",
        capabilities: manifest?.capabilities ?? [],
        // "plugin" — first-class Silent Mode component (Aegis, future
        // Ariadne-as-addon) surfaced in Settings › Plug-ins instead of
        // the raw Extensions list. Absent → plain extension.
        category: manifest?.category || null,
        folder,
        enabled: manifest?.id ? this._active.has(manifest.id) : false,
        error: error || null,
      })),
      sidebarPanels: this.getSidebarPanels(),
      toolbarMenus: this.getToolbarMenus(),
    };
  }
  // `plugin` marks surfaces of a first-class Silent Mode component (manifest
  // category "plugin", e.g. Aegis): the chrome pins those to their own dock
  // instead of the extensions row.
  getSidebarPanels() {
    const out = [];
    for (const active of this._active.values()) {
      const plugin = active.manifest.category === "plugin";
      for (const p of active.sidebarPanels) out.push({ ...p, plugin, addonName: active.manifest.name });
    }
    return out;
  }
  // Menu declarations from every active add-on that carries a toolbar-menu
  // manifest block. Chrome renders one dock button per entry, opens the
  // dropdown, then dispatches "menu-select" with the picked item id.
  getToolbarMenus() {
    const out = [];
    for (const active of this._active.values()) {
      const tm = active.manifest.toolbarMenu;
      if (!tm) continue;
      out.push({
        addonId: active.manifest.id,
        title: tm.title,
        icon: tm.icon,
        plugin: active.manifest.category === "plugin",
        items: tm.items.map((it) => ({ id: it.id, label: it.label, icon: it.icon })),
      });
    }
    return out;
  }
  // Right-click menu items declared by add-ons, filtered by the current
  // context. `ctx` is what Electron's context-menu event carries:
  //   { selectionText, linkURL, mediaType, srcURL, isEditable, pageURL }
  // Returns [{ addonId, id, label, icon, when }]. `when` filters:
  //   selectionText — non-empty text is selected
  //   linkURL       — right-clicked on a link
  //   editable      — right-clicked inside a form control / contenteditable
  //   image         — mediaType === "image" and srcURL is present
  //   always        — every menu
  getContextMenuItems(ctx = {}) {
    const has = {
      selectionText: !!(ctx.selectionText && String(ctx.selectionText).trim()),
      linkURL: !!ctx.linkURL,
      editable: !!ctx.isEditable,
      image: ctx.mediaType === "image" && !!ctx.srcURL,
    };
    const out = [];
    for (const active of this._active.values()) {
      const items = active.manifest.contextMenuItems || [];
      for (const it of items) {
        if (it.when !== "always" && !has[it.when]) continue;
        out.push({ addonId: active.manifest.id, id: it.id, label: it.label, icon: it.icon, when: it.when });
      }
    }
    return out;
  }
  getInstalled() { return this._installed.slice(); }
  isActive(id) { return this._active.has(id); }
  // Absolute folder of an active add-on, or null. Public so main can resolve
  // add-on-relative paths (openAddonTab) without reaching into internals.
  folderOf(id) { const a = this._active.get(id); return a ? a.folder : null; }
}

module.exports = { AddonHost, KNOWN_CAPABILITIES, validateManifest, compileOriginPattern };