/**
 * messages.ts — the only background message handler.
 *
 * All `chrome.runtime.onMessage` handling for the service worker lives here.
 * Do not handle messages inline in entry.ts, alarms.ts, or any other
 * background file. Every background-bound MessageType in shared/types.ts
 * must have a case below. Content-script-bound message types (PING,
 * SUMMON_AUTOFILL, VAULT_LOCKED) are documented in shared/types.ts and
 * intentionally have no case here — they are sent *to* content scripts.
 */

import { copyToClipboard, getEffectiveClearSeconds } from "./clipboard";
import { getPendingSyncAlerts, clearPendingSyncAlerts } from "./sync-alerts";
import { extractDomain } from "../shared/domain";
import {
  getPendingVouchedDevice,
  listPendingVouchedDevices,
  removePendingVouchedDevice,
} from "./pending-vouched-devices";
import { isRecoveryConfirmPending } from "./recovery-pending";
import { setupAutoLock, touchAutoLock } from "./alarms";
import { runSelfTest } from "./self-test";
import * as vault from "./vault";
import {
  handleEstimateCodexPages,
  handleGetCodexVaultData,
  handleRestoreFromCodex,
} from "./codex-handlers";
import type { CodexRestorePayload } from "../shared/codex-types";
import {
  activateLicense,
  deactivateLicense,
  getLicenseInfo,
  getLicenseKey,
  isProUser,
  markCelebrationPlayed,
  shouldPlayCelebration,
} from "./license";
import {
  completeFirefoxPasskeyCreate,
  getPasskeyProviderState,
  getPendingPasskeyRequest,
  handleFirefoxPasskeyCreate,
  handleFirefoxPasskeyGet,
  handlePasskeyHasCredentials,
  initiateFirefoxPasskeyCreate,
  isPasskeyOfferDeclined,
  onVaultUnlocked,
  recordPasskeyOfferDecline,
  resolvePendingPasskeyRequest,
  setPasskeyProviderEnabled,
} from "./passkey";
import { buildAdvancedHealthReport } from "./health";
import { storageClear } from "../shared/storage";
import { findInvalidWords } from "../shared/recovery-words";
import type {
  Message,
  MessageResponse,
  MessageType,
  ProFeature,
  VaultEntry,
} from "../shared/types";
import { isPasskeyOnly } from "../shared/types";
import { generateTOTP } from "../crypto/totp";
import { isValidRpId } from "../shared/passkey-utils";
import { predictBatch as mlPredictBatch } from "./ml";
import type { MLFieldFeatures } from "../shared/ml";
import {
  buildLocalIdentity,
  getOrCreateDeviceId,
  setDeviceName as setDeviceNameV3,
} from "./device-identity";
import {
  isDeviceRevoked,
  listPairedDevices as listPairedDevicesV3,
  renamePairedDevice as renamePairedDeviceV3,
  revokeDeviceById as revokeDeviceByIdV3,
  upsertPairedDevice as upsertPairedDeviceV3,
} from "./paired-devices";
// Sync and pairing are imported statically, never with `await import()`.
// `import()` throws `TypeError: import() is disallowed on
// ServiceWorkerGlobalScope` at runtime in MV3, and Vite's preload helper
// reports the failure through `window.dispatchEvent`, which does not exist in
// a worker either — so the real reason was replaced by "window is not defined"
// and the pairing UI just stopped. scripts/check-sw-static-imports.mjs fails
// the build if a runtime import() reappears anywhere in the worker's graph.
import {
  cancelRelayAdoptionSource,
  isRelayAdoptionSourceInFlight,
  resolveSourceSasConfirmation,
  startRelayAdoptionReceiver,
  startRelayAdoptionSource,
} from "./relay-adoption-bg";
import {
  getSyncSettings,
  setRelayUrl,
  setSyncMode,
  type SyncMode,
} from "./sync-settings";
import {
  getSyncState,
  triggerSyncIfReachable,
} from "./sync-trigger";

// Compile-time E2E flag, folded to a literal by Vite's `define` (false in
// every production build — verified in the bundled output). Mirrors the
// create-path bypass in passkey.ts so the Playwright passkey smoke can enable
// the provider without a real Pro licence; the gate is fully intact for users.
declare const __PEACH_E2E_PASSKEYS__: boolean;
const PASSKEY_E2E_PRO_BYPASS = __PEACH_E2E_PASSKEYS__ === true;

function unhexBytes(hex: string): Uint8Array {
  if (hex.length % 2 !== 0) throw new Error("invalid hex");
  const out = new Uint8Array(hex.length / 2);
  for (let i = 0; i < out.length; i++) {
    out[i] = parseInt(hex.slice(i * 2, i * 2 + 2), 16);
  }
  return out;
}

/**
 * The single Pro gate. Every gated handler calls this first; the broadcast
 * lets the popup react (navigate to the License section, highlight the
 * relevant feature). Background never touches the popup view directly —
 * the popup owns navigation. See Projects.md "Pro gate rule".
 */
async function requirePro(
  feature: ProFeature,
  trigger: "user" | "background" = "user"
): Promise<{ allowed: boolean }> {
  if (PASSKEY_E2E_PRO_BYPASS && feature === "passkeys") return { allowed: true };
  if (await isProUser()) return { allowed: true };

  if (trigger === "user") {
    // User deliberately triggered this feature — redirect the popup immediately.
    chrome.runtime
      .sendMessage({ type: "PRO_GATE_TRIGGERED", payload: { feature } })
      .catch(() => {
        // Popup may be closed — the gate signal is best-effort.
      });
  } else {
    // Background trigger (e.g. passive sync initiation) — no popup is open.
    // Queue a notice so the next popup open shows a soft banner instead of
    // silently failing.
    if (chrome.storage.session) {
      chrome.storage.session
        .set({ pendingProNotice: { feature, triggeredAt: Date.now() } })
        .catch(() => {});
    }
  }

  return { allowed: false };
}

// ---------------------------------------------------------------------------
// PCH-01-018: operations that irreversibly destroy or replace vault contents,
// handlers that store passkey material, and handlers that return sensitive
// credential material (e.g. the Pro license key). These are gated to trusted
// extension-page senders in handleMessage; the confirmation UX otherwise
// lives only in the popup. Keep this in sync when adding new destructive or
// sensitive handlers. (Codex Security 2026-08-04: GET_ADOPTION_MATERIAL and
// COMPLETE_PAIRING were gated here, then deleted outright — they had no
// legitimate senders; adoption runs in-background via relay-adoption-bg.ts.
// Audit 2026-08-20 #4: GET_LOCAL_IDENTITY gated here — it returns the Pro
// license key, which a compromised content script could exfiltrate.
// PB-26-001: GET_CODEX_VAULT_DATA gated here — it returns the encrypted vault
// slots and (with a fresh password proof) the recovery words, i.e. everything
// needed to reconstruct the root key. ESTIMATE_CODEX_PAGES is gated for
// symmetry (it is popup-only and reveals vault size).
const PRIVILEGED_MESSAGE_TYPES: ReadonlySet<string> = new Set([
  "DESTROY_VAULT",
  "CLEAR_VAULT_ENTRIES",
  "RESTORE_VAULT_SNAPSHOT",
  "RESTORE_FROM_CODEX",
  "COMPLETE_FIREFOX_PASSKEY_CREATE",
  "UNLOCK_WITH_PIN",
  "SETUP_PIN",
  "DISABLE_PIN",
  "GET_LOCAL_IDENTITY",
  "GET_CODEX_VAULT_DATA",
  "ESTIMATE_CODEX_PAGES",
]);

// LV-3: minimum interval between non-test canary pings per webhook+entry.
const CANARY_MIN_INTERVAL_MS = 60 * 60 * 1000; // 1 hour

const PRIVATE_IPV4_RANGES = [
  { prefix: "10." },
  { prefix: "127." },
  { prefix: "169.254." },
  { prefix: "192.168." },
];

export function setupMessageHandler(): void {
  chrome.runtime.onMessage.addListener(
    (msg: unknown, sender, sendResponse) => {
      if (!isMessage(msg)) {
        sendResponse({ ok: false, error: "invalid_message" });
        return true;
      }
      handleMessage(msg, sender)
        .then(sendResponse)
        .catch((err) =>
          sendResponse({
            ok: false,
            error: err instanceof Error ? err.message : String(err),
          })
        );
      return true;
    }
  );
}

function isMessage(m: unknown): m is Message {
  return typeof m === "object" && m !== null && "type" in m;
}

/**
 * The browser-attested origin of the page that originated this message. A web
 * page cannot call chrome.runtime.sendMessage directly (no externally_connectable),
 * so every page-driven message arrives via the content-script relay and the
 * browser stamps `sender.origin`/`sender.url` with the real frame origin — a
 * value the page cannot forge. This is the ONLY trustworthy origin for passkey
 * rpId<->origin enforcement; payload-supplied origins are attacker-controlled.
 */
function attestedSenderOrigin(sender: Partial<chrome.runtime.MessageSender>): string | undefined {
  if (sender.origin) return sender.origin;
  if (sender.url) {
    try { return new URL(sender.url).origin; } catch { return undefined; }
  }
  return undefined;
}

// Resolves once restoreFromSession() has run, so handlers see the correct
// post-restore unlock state. entry.ts registers this BEFORE the message
// handler so the onMessage listener is added synchronously at SW startup
// (MV3 requirement) while unlock-dependent handlers still wait for restore.
let restoreReady: Promise<void> = Promise.resolve();

/** Called by entry.ts at startup with the in-flight restoreFromSession promise. */
export function setRestoreReady(p: Promise<unknown>): void {
  restoreReady = p.then(() => undefined, () => undefined);
}

export async function handleMessage(
  msg: Message,
  sender: Partial<chrome.runtime.MessageSender> = {}
): Promise<MessageResponse> {
  try {
    // Wait for session-restore to finish before reading any unlock/vault state.
    // On a cold SW start the popup's first message arrives while restore is
    // still in flight; without this gate IS_UNLOCKED would report locked (a
    // spurious lock screen) and the storage reads could race. The onMessage
    // listener itself is registered synchronously (entry.ts) so this gate, not
    // listener registration, is what absorbs the cold-start window.
    await restoreReady;
    // Validate sender — only allow messages from our extension pages/scripts.
    // `sender.id` is undefined for messages originating from extension UI
    // (popup/options), which is legitimate; reject only when it is defined
    // and does not match our extension id.
    if (
      sender.id !== undefined &&
      sender.id !== chrome.runtime.id
    ) {
      return { ok: false, error: "invalid_sender" };
    }

    // PCH-01-018: destructive and sensitive operations must originate from a
    // trusted extension page (popup/options), never from a content script. The
    // sender.id check above only proves the message came from *our* extension —
    // a content script injected into an attacker page passes it. A single
    // XSS-class bug in the injected UI would otherwise escalate to vault
    // destruction, root-key exfiltration, or attacker device registration.
    // Extension pages carry an extension-origin sender.url; content scripts
    // carry a page URL.
    if (PRIVILEGED_MESSAGE_TYPES.has(msg.type)) {
      const extensionOrigin = chrome.runtime.getURL("");
      if (!sender.url?.startsWith(extensionOrigin)) {
        return { ok: false, error: "invalid_sender" };
      }
    }

    if (shouldRefreshAutoLock(msg.type) && vault.isUnlocked()) {
      touchAutoLock();
    }

    switch (msg.type) {
      case "CREATE_VAULT": {
        const { password } = msg.payload as { password: string };
        // Refuse to create a vault under an empty master password — the derived
        // key would be publicly known and the at-rest AES-GCM protection void
        // (audit HIGH; the CSV-import path previously passed ""). Length/strength
        // policy lives in the onboarding UI; this is the non-negotiable floor.
        if (typeof password !== "string" || password.length === 0) {
          return { ok: false, error: "invalid_payload" };
        }
        await vault.createVault(password);
        await setupAutoLock();
        broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
        onVaultUnlocked();
        return { ok: true };
      }
      case "CREATE_VAULT_FROM_ROOT_KEY": {
        const { password, rootKeyHex } = (msg.payload ?? {}) as {
          password?: unknown;
          rootKeyHex?: unknown;
        };
        if (typeof password !== "string" || password.length === 0 || typeof rootKeyHex !== "string") {
          return { ok: false, error: "invalid_payload" };
        }

        try {
          const { vaultId } = await vault.createVaultFromRootKey(password, rootKeyHex);
          await setupAutoLock();
          broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
          onVaultUnlocked();
          return { ok: true, vaultId };
        } catch (err) {
          return { ok: false, error: err instanceof Error ? err.message : String(err) };
        }
      }
      case "UNLOCK": {
        const { password } = msg.payload as { password: string };
        const ok = await vault.unlock(password);
        if (ok) {
          // KAT: verify the WebCrypto stack is healthy before the user relies on it.
          // Runs after unlock so latency is hidden behind the vault-load time.
          const kat = await runSelfTest();
          if (!kat.ok) {
            console.error("[Peach] Crypto self-test FAILED:", kat.error);
            await vault.lock();
            return { ok: false, error: "self_test_failed" };
          }
          await vault.updateSettings({ pinPreferred: false });
          await setupAutoLock();
          broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
          onVaultUnlocked();
          return { ok: true };
        }
        // Distinguish corruption from wrong password so the popup can offer
        // a history-restore path instead of falsely accusing the user of
        // mistyping (M7/COR-007).
        const failure = vault.consumeLastUnlockFailureReason();
        if (failure) {
          return {
            ok: false,
            error: "vault_corrupted",
            canRestoreFromHistory: true,
          } as MessageResponse;
        }
        return { ok: false };
      }
      case "UNLOCK_WITH_PIN": {
        const { pin } = (msg.payload ?? {}) as { pin?: unknown };
        if (typeof pin !== "string") return { ok: false, error: "invalid_payload" };
        const ok = await vault.unlockWithPin(pin);
        if (!ok) return { ok: false };
        const kat = await runSelfTest();
        if (!kat.ok) {
          await vault.lock();
          return { ok: false, error: "self_test_failed" };
        }
        await vault.updateSettings({ pinPreferred: true });
        await setupAutoLock();
        broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
        onVaultUnlocked();
        return { ok: true };
      }
      case "VALIDATE_RECOVERY_WORDS": {
        const { words } = msg.payload as { words: string[] };
        const invalid = findInvalidWords(words);
        return { ok: true, data: { valid: invalid.length === 0, invalid } };
      }
      case "GET_RECOVERY_WORDS": {
        // Must be unlocked and have recovery set up (vault must be v2.12+).
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        // LV-4: the recovery words re-derive the ROOT KEY — the highest-
        // value secret in the vault. A session unlock (which may be hours
        // old on a shared machine) is not enough; require a fresh password
        // proof, matching the 1Password/Bitwarden pattern for revealing
        // escrow material. EXEMPTION: the create-vault / rotation confirmation
        // window (peach_recovery_pending) shows the words immediately after
        // the user authenticated, and that confirmation UI has no password to
        // resend — skip the re-auth there only.
        if (!(await isRecoveryConfirmPending())) {
          const { password } = (msg.payload ?? {}) as { password?: string };
          if (typeof password !== "string" || !password) {
            return { ok: false, error: "password_required" };
          }
          if (!(await vault.verifyMainPassword(password))) {
            return { ok: false, error: "wrong_password" };
          }
        }
        try {
          const words = await vault.getRecoveryWords();
          return { ok: true, data: words };
        } catch {
          return { ok: false, error: "recovery_not_setup" };
        }
      }
      case "RECOVER_WITH_WORDS": {
        // User has lost their password but has their 12 recovery words.
        // We: (1) validate the words, (2) re-encrypt vault with new password.
        const { words, newPassword } = msg.payload as {
          words: string[];
          newPassword: string;
        };
        const stored = await vault.loadSlotA();
        if (!stored) return { ok: false, error: "no_vault" };
        if (!stored.recovery_salt || !stored.recovery_wrapped_root_key) {
          return { ok: false, error: "recovery_not_setup" };
        }
        // Unwrap the root key from the recovery escrow.
        try {
          await vault.unwrapRootKeyForRecovery(
            stored.recovery_wrapped_root_key,
            stored.recovery_nonce ?? "",
            stored.recovery_tag ?? "",
            stored.recovery_salt,
            words
          );
        } catch {
          return { ok: false, error: "invalid_recovery_words" };
        }
        // Re-key: derive fresh salt + key from new password.
        const newSalt = vault.generateSalt();
        const newKey = await vault.deriveKey(newPassword, newSalt);
        // Re-wrap root key under the new password's derived key so the same
        // recovery words continue to work after the password change.
        await vault.rewrapRootKeyForPassword(newKey, newSalt);
        // Re-encrypt vault entries with the new key.
        await vault.changePasswordWithNewKey(newSalt, newKey);
        await setupAutoLock();
        broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
        return { ok: true };
      }
      case "LOCK":
        vault.lock();
        return { ok: true };
      case "IS_UNLOCKED":
        return { ok: true, data: vault.isUnlocked() };
      case "GET_VAULT_STATUS":
        return { ok: true, unlocked: vault.isUnlocked() };
      case "HAS_VAULT":
        return { ok: true, data: await vault.hasVault() };
      case "GET_ENTRIES":
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        return { ok: true, data: vault.getEntries() };
      case "ADD_ENTRY": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const payload = msg.payload;
        if (!payload || typeof payload !== "object" || Array.isArray(payload)) {
          return { ok: false, error: "invalid_payload" };
        }
        const entry = await vault.addEntry(payload as Parameters<typeof vault.addEntry>[0]);
        return { ok: true, data: entry };
      }
      case "BATCH_ADD_ENTRIES": {
        const payload = msg.payload as { entries?: unknown } | null | undefined;
        if (!payload || typeof payload !== "object" || Array.isArray(payload)) {
          return { ok: false, error: "invalid_payload" };
        }
        if (!Array.isArray(payload.entries)) {
          return { ok: false, error: "invalid_payload" };
        }
        const added = await vault.batchAddEntries(payload.entries as Parameters<typeof vault.batchAddEntries>[0]);
        return { ok: true, data: added };
      }
      case "RESTORE_ENTRIES": {
        const payload = msg.payload as
          | { entries?: unknown; mode?: unknown; settings?: unknown }
          | null
          | undefined;
        if (!payload || typeof payload !== "object" || Array.isArray(payload)) {
          return { ok: false, error: "invalid_payload" };
        }
        if (!Array.isArray(payload.entries)) {
          return { ok: false, error: "invalid_payload" };
        }
        if (payload.mode !== "replace" && payload.mode !== "merge") {
          return { ok: false, error: "invalid_payload" };
        }
        const summary = await vault.restoreEntries(
          payload.entries as Parameters<typeof vault.restoreEntries>[0],
          payload.mode
        );
        if (payload.settings && typeof payload.settings === "object" && !Array.isArray(payload.settings)) {
          await vault.updateSettings(payload.settings as vault.VaultSettings);
        }
        return { ok: true, data: summary };
      }
      case "CLEAR_VAULT_ENTRIES": {
        await vault.clearVaultEntries("REPLACE_ALL");
        return { ok: true };
      }
      case "GET_VAULT_HISTORY": {
        const snapshots = await vault.getVaultHistory();
        return { ok: true, data: snapshots };
      }
      case "RESTORE_VAULT_SNAPSHOT": {
        const { snapshotId } = msg.payload as { snapshotId: string };
        const result = await vault.restoreVaultSnapshot(snapshotId);
        if (!result.ok) return { ok: false, error: result.error };
        broadcastToContentScripts({ type: "VAULT_LOCKED" });
        return { ok: true };
      }
      case "COUNT_DUPLICATES": {
        return { ok: true, data: vault.countDuplicates() };
      }
      case "DEDUPLICATE_ENTRIES": {
        const removed = await vault.deduplicateEntries();
        return { ok: true, data: removed };
      }
      case "UPDATE_ENTRY": {
        const payload = msg.payload as { id?: unknown; patch?: unknown } | null | undefined;
        if (!payload || typeof payload !== "object" || Array.isArray(payload)) {
          return { ok: false, error: "invalid_payload" };
        }
        const { id, patch } = payload;
        if (typeof id !== "string" || !id || !patch || typeof patch !== "object" || Array.isArray(patch)) {
          return { ok: false, error: "invalid_payload" };
        }
        // Single enforcement point for the Canary Entries Pro gate. Only
        // gates the transition into a canary entry — clearing/disabling a
        // canary (`canary: undefined`) is always allowed, so existing
        // canary entries remain manageable.
        const incomingCanary = (patch as { canary?: unknown }).canary;
        if (incomingCanary && typeof incomingCanary === "object") {
          const existing = vault.getEntryById(id);
          if (!existing?.canary) {
            const gate = await requirePro("canary_entry");
            if (!gate.allowed) return { ok: false, error: "pro_required" };
          }
        }
        await vault.updateEntry(id, patch as Parameters<typeof vault.updateEntry>[1]);
        return { ok: true };
      }
      case "ADD_ADDITIONAL_URL": {
        const { id, url } = msg.payload as { id: string; url: string };
        const trimmed = typeof url === "string" ? url.trim() : "";
        if (!trimmed) return { ok: false, error: "url_required" };
        const existing = vault.getEntryById(id);
        if (!existing) return { ok: false, error: "entry_not_found" };
        if (existing.type !== "login") return { ok: false, error: "login_entries_only" };
        const merged = [...(existing.additionalUrls ?? []), trimmed];
        await vault.updateEntry(id, { additionalUrls: merged });
        return { ok: true };
      }
      case "DELETE_ENTRY": {
        const { id } = msg.payload as { id: string };
        await vault.deleteEntry(id);
        return { ok: true };
      }
      case "GET_DELETED_ENTRIES":
        return { ok: true, data: vault.getDeletedEntries() };
      case "RESTORE_ENTRY": {
        const { id } = msg.payload as { id: string };
        await vault.restoreEntry(id);
        return { ok: true };
      }
      case "PURGE_ENTRY": {
        const { id } = msg.payload as { id: string };
        await vault.purgeEntry(id);
        return { ok: true };
      }
      case "PURGE_EXPIRED_TRASH": {
        const { retentionMs } = msg.payload as { retentionMs: number };
        const purged = await vault.purgeExpiredTrash(retentionMs);
        return { ok: true, data: purged };
      }
      case "SAVE_NOTE": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const { id, title, body } = msg.payload as { id?: string; title: string; body: string };
        const now = Date.now();
        if (id) {
          const existing = vault.getEntryById(id);
          if (!existing) return { ok: false, error: "not_found" };
          await vault.updateEntry(id, { title: title || "Untitled", notes: body, modifiedAt: now });
          return { ok: true, data: vault.getEntryById(id) };
        } else {
          // PCH-01-026 #10: addEntry stamps its own createdAt/modifiedAt
          // (EntryDraft omits both), so passing them was the only reason the
          // `as any` cast existed. Dropping them makes the call type-check.
          const entry = await vault.addEntry({
            type: "note",
            title: title || "Untitled",
            notes: body,
          });
          return { ok: true, data: entry };
        }
      }
      case "DELETE_NOTE": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const { id } = msg.payload as { id: string };
        await vault.deleteEntry(id);
        return { ok: true };
      }
      case "GET_NOTES": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const notes = vault.getEntries().filter(
          (e) => e.type === "note" && !e.deletedAt
        );
        return { ok: true, data: notes } as MessageResponse;
      }
      case "SEARCH_VAULT": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        // AUD-002: shape-validate the payload before calling string methods.
        // A raw cast lets a malformed message crash the handler with TypeError.
        const { query } = (msg.payload ?? {}) as { query?: unknown };
        if (typeof query !== "string") {
          return { ok: false, error: "invalid_payload" };
        }
        const q = query.toLowerCase();
        const searchResults = vault.getEntries().filter(
          (e) =>
            !e.deletedAt &&
            (e.title.toLowerCase().includes(q) ||
              e.notes?.toLowerCase().includes(q) ||
              e.username?.toLowerCase().includes(q))
        );
        return { ok: true, data: searchResults } as MessageResponse;
      }
      case "AUTOFILL_QUERY": {
        if (!vault.isUnlocked()) {
          return { ok: false, error: "vault_locked" };
        }
        let { includeAll } = msg.payload as { includeAll?: boolean };
        const { domain, kind, userGesture } = msg.payload as {
          domain: string;
          kind?: "login" | "card" | "totp";
          userGesture?: boolean;
        };
        // MV-2: the vault-wide inventory (every title/username/email/url)
        // may only leave the background on an explicit user gesture — the
        // user opening the search affordance — never on passive form focus.
        // userGesture is self-declared by our own content script; the value
        // of this gate is that PASSIVE code paths (which never set it)
        // cannot ship the inventory, shrinking what a compromised page that
        // merely triggers focus events can observe.
        if (includeAll && userGesture !== true) {
          includeAll = false;
        }
        // kind="card": return saved cards as compact summaries for the
        // inline card silver platter. Cards are not domain-scoped — every
        // saved card is a candidate on every checkout page — so domain is
        // ignored when kind === "card".
        if (kind === "card") {
          const cards = vault.getEntries().filter((e) => e.type === "card");
          return {
            ok: true,
            data: cards.map((e) => ({
              id: e.id,
              title: e.cardNickname || e.title,
              cardholderName: e.cardholderName,
              last4: e.last4,
              expMonth: e.expMonth,
              expYear: e.expYear,
              network: e.network,
            })),
          };
        }
        if (kind === "totp") {
          const matches = (
            includeAll
              ? vault.getEntries().filter((entry) => entry.type !== "note" && entry.type !== "card")
              : vault.queryDomain(domain)
          ).filter((entry) => !isPasskeyOnly(entry) && Boolean(entry.totp));
          return {
            ok: true,
            data: matches.map((e) => ({
              id: e.id,
              title: e.title,
              username: e.username,
              email: e.email,
              url: e.url,
              hasTotp: true,
            })),
          };
        }
        // The inline selector fills username+password into a form. Passkey-
        // only entries have no password to fill; sign-in for those goes
        // through the WebAuthn path instead. Filter them out everywhere so
        // the user doesn't see four "GitHub" rows that mostly do nothing.
        // Notes and cards never belonged here either.
        const matches = (
          includeAll
            ? vault
                .getEntries()
                .filter((entry) => entry.type !== "note" && entry.type !== "card")
            : vault.queryDomain(domain)
        ).filter((entry) => !isPasskeyOnly(entry));
        return {
          ok: true,
          data: matches.map((e) =>
            includeAll
              ? {
                  id: e.id,
                  title: e.title,
                  // username/email/url shipped so the inline popup's search
                  // affordance can match on them, not just titles. No secrets
                  // cross the boundary — same shape as the domain-matched
                  // response below minus hasTotp (which the search list
                  // doesn't surface).
                  username: e.username,
                  email: e.email,
                  url: e.url,
                  hasPasskey: e.passkey !== undefined,
                }
              : {
                  id: e.id,
                  title: e.title,
                  username: e.username,
                  email: e.email,
                  url: e.url,
                  hasTotp: Boolean(e.totp),
                  hasPasskey: e.passkey !== undefined,
                }
          ),
        };
      }
      case "GET_ENTRY_FOR_FILL": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const { id, explicitSummon } = msg.payload as {
          id: string;
          explicitSummon?: boolean;
        };
        const entry = vault.getEntryById(id);
        if (!entry) return { ok: false, error: "entry_not_found" };
        // Passkey-only entries (passkey credential, no password) cannot be
        // filled into a form — sign-in goes through the WebAuthn path. A
        // login that ALSO has a passkey is still fillable for its password.
        if (isPasskeyOnly(entry)) return { ok: false, error: "passkey_not_fillable" };

        // MV-1: re-validate the entry against the requesting frame's origin.
        // sender.url / sender.tab.url are browser-attested — a page cannot
        // forge them. PB-26-005: the FRAME url (sender.url) is authoritative
        // for an all_frames content script; the top-frame tab.url would
        // misattribute a cross-origin iframe's request to the top page. When
        // the request does not come from a tab at all (popup surfaces use
        // GET_ENTRY_FOR_EDIT, not this), refuse.
        if (sender.tab !== undefined || sender.url !== undefined) {
          let senderDomain: string | null = null;
          try {
            const rawUrl = sender.url ?? sender.tab?.url ?? "";
            senderDomain = rawUrl ? extractDomain(new URL(rawUrl).hostname) : null;
          } catch {
            senderDomain = null;
          }
          if (!senderDomain) return { ok: false, error: "origin_unverified" };

          const entryDomains = new Set<string>();
          const primary = extractDomain(entry.url ?? "");
          if (primary) entryDomains.add(primary);
          for (const extra of entry.additionalUrls ?? []) {
            const d = extractDomain(extra);
            if (d) entryDomains.add(d);
          }

          // explicitSummon=true means the user actively picked this entry
          // from the cross-domain search affordance — an intentional
          // off-domain fill. Passive fill paths must stay domain-bound.
          if (explicitSummon !== true && !entryDomains.has(senderDomain)) {
            // Domain mismatch — refuse silently (no oracle about which ids exist).
            return { ok: false, error: "entry_not_found" };
          }
        }
        // Strip the passkey credential AND the raw base32 TOTP seed from the
        // response. Content scripts never need either: the private key is the
        // authenticator's, and handing over the TOTP seed would let a
        // compromised content script mint valid codes indefinitely (SEV-3-C).
        // Generate the *current* 6-digit code here in the background and send
        // only that, plus the seconds left so the UI can render a countdown.
        // Also drop passwordHistory: filling needs only the *current* password.
        // Handing every past password to a content script during passive
        // autofill on an arbitrary page would widen the blast radius of a
        // compromised page far beyond the one credential being filled.
        const {
          passkey: _strippedPasskey,
          totp: seed,
          totpAlgorithm,
          totpDigits,
          totpPeriod,
          passwordHistory: _ph,
          ...safeEntry
        } = entry;
        let totpCode: string | undefined;
        let totpRemaining: number | undefined;
        if (seed) {
          try {
            // PCH-01-019: honour stored algorithm/digits/period (defaults apply
            // when these are undefined, i.e. RFC-default bare-seed entries).
            const generated = generateTOTP(seed, totpAlgorithm, totpDigits, totpPeriod);
            totpCode = generated.code;
            totpRemaining = generated.remaining;
          } catch {
            totpCode = undefined;
          }
        }
        return { ok: true, data: { ...safeEntry, totpCode, totpRemaining } };
      }
      // Trusted full-entry fetch for Peach's own inline-popup surfaces that
      // genuinely need the raw TOTP seed: the edit form (which re-saves the
      // seed and would otherwise wipe it) and nothing else. Unlike
      // GET_ENTRY_FOR_FILL this fires only on an explicit user action inside
      // the inline popup, never during passive autofill on an arbitrary page.
      // The passkey credential is still stripped — the edit form never touches it.
      case "GET_ENTRY_FOR_EDIT": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const { id, explicitSummon } = msg.payload as {
          id: string;
          explicitSummon?: boolean;
        };
        const entry = vault.getEntryById(id);
        if (!entry) return { ok: false, error: "entry_not_found" };

        // PCH-01-006: re-validate the browser-attested sender origin, mirroring
        // GET_ENTRY_FOR_FILL (MV-1). The edit channel ships the raw TOTP seed and
        // full password history — at least as sensitive as the fill response — so
        // the boundary must be enforced here, not only by UI reachability. Today
        // the sole caller is the popup (no sender.tab, so this is a structural
        // no-op), but a future tab-context caller or an id leak would otherwise
        // inherit a full-credential oracle. Unlike the fill path we SKIP (not
        // refuse) when no sender domain resolves, to keep the popup caller working.
        // PB-26-005: the frame url (sender.url) is authoritative over the
        // top-frame sender.tab.url — mirrors the fill path.
        if (sender.tab !== undefined || sender.url !== undefined) {
          let senderDomain: string | null = null;
          try {
            const rawUrl = sender.url ?? sender.tab?.url ?? "";
            senderDomain = rawUrl ? extractDomain(new URL(rawUrl).hostname) : null;
          } catch {
            senderDomain = null;
          }
          if (senderDomain) {
            const entryDomains = new Set<string>();
            const primary = extractDomain(entry.url ?? "");
            if (primary) entryDomains.add(primary);
            for (const extra of entry.additionalUrls ?? []) {
              const d = extractDomain(extra);
              if (d) entryDomains.add(d);
            }
            if (explicitSummon !== true && !entryDomains.has(senderDomain)) {
              return { ok: false, error: "entry_not_found" }; // no id oracle
            }
          }
        }

        const { passkey: _passkey, ...safeEntry } = entry;
        return { ok: true, data: safeEntry };
      }
      case "COPY": {
        // AUD-002: shape-validate the payload before passing to the clipboard
        // helper. A raw cast lets a malformed message reach the clipboard API
        // with a non-string and throw.
        const { text, label, alreadyWritten } = (msg.payload ?? {}) as {
          text?: unknown;
          label?: unknown;
          alreadyWritten?: unknown;
        };
        if (typeof text !== "string" || typeof label !== "string") {
          return { ok: false, error: "invalid_payload" };
        }
        await copyToClipboard(text, label, Boolean(alreadyWritten));
        return { ok: true, clearSeconds: getEffectiveClearSeconds() };
      }
      case "CHECK_ALL_BREACHES": {
        const allEntries = vault.getEntries();
        const results: Record<string, number> = {};
        for (const entry of allEntries) {
          if (entry.type === "note") continue;
          if (!entry.password) continue;
          results[entry.id] = await vault.checkBreach(entry.password);
          // Small delay — be a good citizen to the HIBP API
          await new Promise((r) => setTimeout(r, 200));
        }
        // Persist any non-zero counts back to entries
        for (const [id, count] of Object.entries(results)) {
          const entry = vault.getEntryById(id);
          if (entry && (entry.breach ?? 0) !== count) {
            await vault.updateEntry(id, { breach: count > 0 ? count : undefined });
          }
        }
        return { ok: true, data: results };
      }
      case "GET_SETTINGS":
        return { ok: true, data: await vault.ensureSettingsLoaded() };
      case "UPDATE_SETTINGS": {
        const patch = msg.payload;
        if (!patch || typeof patch !== "object" || Array.isArray(patch)) {
          return { ok: false, error: "invalid_payload" };
        }
        await vault.updateSettings(patch as vault.VaultSettings);
        if (typeof (patch as Record<string, unknown>).autoLockMinutes === "number") {
          await setupAutoLock();
          if (vault.isUnlocked()) touchAutoLock();
        }
        return { ok: true };
      }
      case "SETUP_PIN": {
        const { currentPassword, pin } = (msg.payload ?? {}) as {
          currentPassword?: unknown;
          pin?: unknown;
        };
        if (typeof currentPassword !== "string" || typeof pin !== "string") {
          return { ok: false, error: "invalid_payload" };
        }
        return (await vault.setupPinUnlock(currentPassword, pin))
          ? { ok: true }
          : { ok: false, error: "incorrect_current_password" };
      }
      case "DISABLE_PIN": {
        const { currentPassword } = (msg.payload ?? {}) as { currentPassword?: unknown };
        if (typeof currentPassword !== "string") return { ok: false, error: "invalid_payload" };
        return (await vault.disablePinUnlock(currentPassword))
          ? { ok: true }
          : { ok: false, error: "incorrect_current_password" };
      }
      case "GET_PENDING_PASSKEY":
        return { ok: true, data: await getPendingPasskeyRequest() };
      case "APPROVE_PASSKEY": {
        const { requestId } = msg.payload as { requestId: number };
        await resolvePendingPasskeyRequest(requestId, true);
        return { ok: true };
      }
      case "DENY_PASSKEY": {
        const { requestId } = msg.payload as { requestId: number };
        await resolvePendingPasskeyRequest(requestId, false);
        return { ok: true };
      }
      case "GET_PASSKEY_PROVIDER_STATE":
        return { ok: true, data: await getPasskeyProviderState() };
      case "SET_PASSKEY_PROVIDER_ENABLED": {
        const { enabled } = msg.payload as { enabled: boolean };
        // Disabling is always free; gating fires only when a free user is
        // trying to turn passkey interception on.
        if (enabled) {
          const gate = await requirePro("passkeys");
          if (!gate.allowed) return { ok: false, error: "pro_required" };
        }
        return { ok: true, data: await setPasskeyProviderEnabled(enabled) };
      }
      // AUD-003: this handler POSTs `entryTitle` to a user-configured HTTPS
      // endpoint. Intentional product behavior — users configure their own
      // dead-man's-switch. isAllowedCanaryWebhookUrl blocks localhost, private
      // IPs, and non-HTTPS schemes, but cannot defend against every DNS-
      // rebinding case. The UI under CanarySection (Entry.tsx) discloses to
      // users that the entry title leaves the device when the canary fires.
      case "FIRE_CANARY_PING": {
        // Canary alert fires unconditionally for any entry with canary: true.
        // The Pro gate only governs creation/flagging of canary entries; once
        // an entry is flagged, the alert path is a security property and must
        // never be license-gated.
        const { webhookUrl, entryTitle, trigger } = msg.payload as {
          webhookUrl: string;
          entryTitle: string;
          trigger: "password_copied" | "username_copied" | "autofilled" | "submitted" | "test";
        };
        if (!isAllowedCanaryWebhookUrl(webhookUrl)) {
          return { ok: false, error: "invalid_webhook_url" };
        }
        // LV-3: debounce non-test pings per (webhook, entry) so a page that
        // strobes focus/fill events can't turn the canary into a request
        // firehose at the user's endpoint. Test pings are exempt — they are
        // explicit user clicks in the settings UI and are awaited for
        // feedback. The FIRST ping in a window always goes out, so the
        // dead-man's-switch property (canary fires on access) is preserved;
        // only repeats within the window are coalesced.
        if (trigger !== "test") {
          const rlKey = `canary-last-fetch:${webhookUrl}:${entryTitle}`;
          const stored = await chrome.storage.local.get(rlKey);
          const last = (stored as Record<string, unknown>)[rlKey];
          if (typeof last === "number" && Date.now() - last < CANARY_MIN_INTERVAL_MS) {
            return { ok: true, data: { rateLimited: true } };
          }
          await chrome.storage.local.set({ [rlKey]: Date.now() });
        }
        const body = JSON.stringify({
          event: trigger === "test" ? "peach_canary_test" : "peach_canary_accessed",
          entry: entryTitle,
          trigger,
          timestamp: new Date().toISOString(),
          source: "peach-extension",
        });
        if (trigger === "test") {
          // Permitted outbound fetch: user-configured canary alert endpoint
          // (validated by isAllowedCanaryWebhookUrl above). This is the
          // only non-HIBP outbound call in the extension — see
          // Projects.md §3.7. Test pings are awaited so the UI can show
          // success/failure.
          try {
            const res = await fetch(webhookUrl, {
              method: "POST",
              headers: { "Content-Type": "application/json" },
              body,
            });
            return { ok: res.ok, error: res.ok ? undefined : `HTTP ${res.status}` };
          } catch (err) {
            return { ok: false, error: err instanceof Error ? err.message : "network_error" };
          }
        }
        // Non-test triggers are fire-and-forget
        fetch(webhookUrl, {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body,
        }).catch(() => {});
        return { ok: true };
      }
      case "ACTIVATE_LICENSE": {
        const { key } = msg.payload as { key: string };
        const licenseInfo = await activateLicense(key);
        return { ok: true, data: licenseInfo };
      }
      case "GET_LICENSE": {
        const licenseInfo = await getLicenseInfo();
        return { ok: true, data: licenseInfo };
      }
      case "GET_LICENSE_KEY": {
        const key = await getLicenseKey();
        return { ok: true, data: key };
      }
      case "DEACTIVATE_LICENSE": {
        await deactivateLicense();
        return { ok: true };
      }
      case "SHOULD_PLAY_CELEBRATION": {
        const should = await shouldPlayCelebration();
        return { ok: true, data: should };
      }
      case "MARK_CELEBRATION_PLAYED": {
        await markCelebrationPlayed();
        return { ok: true };
      }
      case "GET_CODEX_VAULT_DATA": {
        // Pro-gated. requirePro broadcasts PRO_GATE_TRIGGERED on miss so the
        // popup navigates to the License section without further coordination.
        // Also privileged-page-gated (PB-26-001), and recoveryWords inside the
        // snapshot additionally require a fresh master-password proof.
        const gate = await requirePro("codex");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        const { password } = (msg.payload ?? {}) as { password?: string };
        return await handleGetCodexVaultData(password);
      }
      case "ESTIMATE_CODEX_PAGES": {
        const gate = await requirePro("codex");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        return await handleEstimateCodexPages();
      }
      case "RESTORE_FROM_CODEX": {
        // !! IMPORTANT: intentionally NOT Pro-gated. A free device must still
        // be able to restore a vault that was printed by a Pro user.
        // DO NOT add a Pro gate here.
        const payload = msg.payload as CodexRestorePayload;
        return await handleRestoreFromCodex(payload);
      }
      case "OPEN_PRO_GATE": {
        // Content script requests: open popup and navigate to License section.
        const { feature } = (msg.payload ?? {}) as { feature?: string };
        if (chrome.storage.session) {
          await chrome.storage.session.set({ pendingProGate: { feature: feature ?? "passkeys" } });
        }
        try { await chrome.action.openPopup(); } catch { /* badge fallback */ }
        return { ok: true };
      }
      case "OPEN_POPUP": {
        // Content script asks to open the trusted extension popup — used by the
        // inline locked bubble so the master password is entered in the popup,
        // never in page-hosted DOM (audit HIGH). Best-effort: openPopup needs a
        // user gesture + Chrome 127+/Firefox; on failure the user clicks the
        // toolbar icon. The badge already signals Peach needs attention.
        //
        // Set a session flag so the popup knows it was opened for inline unlock
        // and should close itself once the vault is unlocked (returning the user
        // to the inline autofill selector on the page).
        if (chrome.storage.session) {
          await chrome.storage.session.set({ peach_inline_unlock: true });
        }
        try { await chrome.action.openPopup(); } catch { /* user opens via toolbar */ }
        return { ok: true };
      }
      case "OPEN_DETACHED_POPUP": {
        // A window created by the action popup and then orphaned with
        // window.close() is cascaded shut by Chrome, so the file-picker
        // flows (OS dialogs that dismiss the popup on focus loss) ask the SW
        // to open the standalone window instead — the SW has no window to be
        // associated with. The query string is allowlisted so this can never
        // open an arbitrary URL.
        const { route } = (msg.payload ?? {}) as { route?: string };
        const search = route === "peachscript"
          ? "?restore=peachscript"
          : route === "csv"
            ? "?restore=csv"
            : route === "codex-pdf"
              ? "?codex=pdf"
              : null;
        if (!search) return { ok: false, error: "bad_route" };
        try {
          const popupHtml =
            chrome.runtime.getManifest().action?.default_popup ?? "src/popup/index.html";
          await chrome.windows.create({
            url: chrome.runtime.getURL(`${popupHtml}${search}`),
            type: "popup",
            width: 320,
            height: 550,
          });
          return { ok: true, data: { detached: true } };
        } catch {
          return { ok: false };
        }
      }
      case "GET_IDENTITIES": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        return { ok: true, data: vault.getIdentities() };
      }
      case "TOUCH_AUTO_LOCK": {
        // touchAutoLock() is already called by shouldRefreshAutoLock above;
        // this case just gives the popup a typed message to keep the session alive.
        return { ok: true };
      }
      case "GET_ADVANCED_HEALTH_REPORT": {
        const gate = await requirePro("advanced_health");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const report = await buildAdvancedHealthReport(vault.getEntries());
        return { ok: true, data: report };
      }
      case "IS_DURESS_ENABLED": {
        const enabled = await vault.isDuressEnabled();
        return { ok: true, data: enabled };
      }
      case "SETUP_DURESS": {
        // Single enforcement point for the Duress Vault Pro gate. Free users
        // who somehow reach this handler are rejected here; the popup also
        // pre-checks isPro() to avoid showing the setup form to free users,
        // but server-side is the actual security boundary.
        const gate = await requirePro("duress_vault");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        // MV3 service workers restart after inactivity, losing the in-memory
        // derived key. Detect this before calling setupDuress so the popup
        // can show a meaningful prompt to re-lock and re-unlock.
        if (!vault.isUnlocked()) return { ok: false, error: "session_expired" };
        const { duressPassword } = msg.payload as { duressPassword: string };
        await vault.setupDuress(duressPassword);
        return { ok: true };
      }
      case "DISABLE_DURESS": {
        await vault.disableDuress();
        return { ok: true };
      }
      case "VERIFY_MAIN_PASSWORD": {
        const { password } = msg.payload as { password: string };
        const ok = await vault.verifyMainPassword(password);
        return { ok: true, data: ok };
      }
      case "CHANGE_PASSWORD": {
        const { currentPassword, newPassword } = msg.payload as {
          currentPassword: string;
          newPassword: string;
        };
        const changed = await vault.changePassword(currentPassword, newPassword);
        return changed
          ? { ok: true }
          : { ok: false, error: "incorrect_current_password" };
      }
      case "GET_SITE_PASSWORD_POLICY": {
        const [tab] = await chrome.tabs.query({ active: true, currentWindow: true });
        if (!tab?.id) return { ok: true, data: null };
        try {
          const response = await chrome.tabs.sendMessage(tab.id, {
            type: "GET_SITE_PASSWORD_POLICY",
          });
          return (response as MessageResponse) ?? { ok: true, data: null };
        } catch {
          return { ok: true, data: null };
        }
      }
      case "RECORD_MANUAL_SUMMON": {
        const { domain } = msg.payload as { domain: string };
        const settings = vault.getSettings();
        const existing = settings.manualSummonDomains?.[domain];
        const now = Date.now();
        await vault.updateSettings({
          manualSummonDomains: {
            ...settings.manualSummonDomains,
            [domain]: {
              firstSummonedAt: existing?.firstSummonedAt ?? now,
              summonCount: (existing?.summonCount ?? 0) + 1,
              lastSummonedAt: now,
            },
          },
        });
        return { ok: true };
      }
      case "DECLINE_CARD_SAVE": {
        const { last4, expMonth, expYear } = msg.payload as { last4: string; expMonth: string; expYear: string };
        await vault.declineCardSaveOffer(last4, expMonth, expYear);
        return { ok: true };
      }
      case "IS_CARD_DECLINED": {
        const { last4, expMonth, expYear } = msg.payload as { last4: string; expMonth: string; expYear: string };
        const declined = await vault.isCardDeclined(last4, expMonth, expYear);
        return { ok: true, data: declined };
      }
      case "INITIATE_FIREFOX_PASSKEY_CREATE": {
        const { rpId, rpName, userName, userDisplayName } = (msg.payload ?? {}) as {
          rpId?: string;
          rpName?: string;
          userName?: string;
          userDisplayName?: string;
        };
        if (!rpId || !userName) return { ok: false, error: "rpid_and_username_required" };
        return await initiateFirefoxPasskeyCreate({
          rpId,
          rpName: rpName ?? rpId,
          userName,
          userDisplayName,
        }, attestedSenderOrigin(sender));
      }

      case "COMPLETE_FIREFOX_PASSKEY_CREATE": {
        const payload = msg.payload as Parameters<typeof completeFirefoxPasskeyCreate>[0] | undefined;
        if (!payload) return { ok: false, error: "missing_payload" };
        return await completeFirefoxPasskeyCreate(payload);
      }

      case "PASSKEY_OFFER_DECLINE": {
        const { domain } = (msg.payload ?? {}) as { domain?: string };
        if (!domain) return { ok: false, error: "domain_required" };
        await recordPasskeyOfferDecline(domain);
        return { ok: true };
      }

      case "GET_PASSKEY_OFFER_DECLINED": {
        const { domain } = (msg.payload ?? {}) as { domain?: string };
        if (!domain) return { ok: false, error: "domain_required" };
        return { ok: true, data: await isPasskeyOfferDeclined(domain) };
      }

      case "PASSKEY_HAS_CREDENTIALS": {
        const payload = msg.payload as {
          rpId?: string;
          allowCredentials?: Array<{ id: string; type?: string }>;
        } | undefined;
        if (!payload?.rpId) return { ok: false, error: "rpid_required" };
        return await handlePasskeyHasCredentials({
          rpId: payload.rpId,
          allowCredentials: payload.allowCredentials ?? [],
        }, attestedSenderOrigin(sender));
      }

      case "PASSKEY_CREATE": {
        const payload = msg.payload as Parameters<typeof handleFirefoxPasskeyCreate>[0] | undefined;
        if (!payload?.rpId || !payload?.userName) {
          return { ok: false, error: "rpid_and_username_required" };
        }
        return await handleFirefoxPasskeyCreate(payload, attestedSenderOrigin(sender));
      }

      case "PASSKEY_GET": {
        const payload = msg.payload as Parameters<typeof handleFirefoxPasskeyGet>[0] | undefined;
        if (!payload?.rpId) return { ok: false, error: "rpid_required" };
        return await handleFirefoxPasskeyGet(payload, attestedSenderOrigin(sender));
      }

      case "PASSKEY_AUTH_RESPONSE": {
        const { requestId, approved } = (msg.payload ?? {}) as {
          requestId?: string | number;
          approved?: boolean;
        };
        if (requestId === undefined || requestId === null || typeof approved !== 'boolean') {
          return { ok: false, error: 'requestId and approved required' };
        }
        await resolvePendingPasskeyRequest(Number(requestId), approved);
        return { ok: true };
      }

      case "GET_PASSKEY_FOR_DOMAIN": {
        const { domain } = (msg.payload ?? {}) as { domain?: string };
        if (!domain) return { ok: false, error: "domain_required" };
        // Scope to the caller's own origin: a page may only ask about passkeys
        // for a domain it actually owns, so an arbitrary page cannot enumerate
        // which sites the user holds passkeys for or read the username (audit MEDIUM).
        const origin = attestedSenderOrigin(sender);
        if (!origin || !isValidRpId(domain, origin)) return { ok: true, data: null };
        if (!vault.isUnlocked()) return { ok: true, data: null };
        const match = vault
          .getEntries()
          .find((entry) => entry.passkey?.rpId === domain);
        if (!match || !match.passkey) return { ok: true, data: null };
        // Slim shape — only the fields State 11 needs. Never expose private
        // key material, even though this is locked behind isUnlocked.
        return {
          ok: true,
          data: {
            rpId: match.passkey.rpId,
            userName: match.passkey.userName,
            browser: match.passkey.browser,
          },
        };
      }

      case "DESTROY_VAULT": {
        // Irreversible by design. Lock zeroes the derived key + in-memory entries;
        // storage.local.clear() wipes every Peach key (slots, settings, license,
        // onboarded flag, history, sync state, declined cards, recall, etc.);
        // session.clear() wipes pending passkey requests + pro-notice queues.
        // Caller (Panic.tsx) handles UI navigation back to onboarding.
        //
        // The Pro license is the one thing that must survive: the user paid for
        // it, and destroying a vault (panic wipe, fresh start) is not a refund.
        // Capture it before the clear and restore it after. peach_pro_celebrated
        // rides along so the Pro celebration doesn't replay on the next unlock.
        const preserved = await chrome.storage.local.get([
          "peach_license",
          "peach_pro_celebrated",
        ]);
        vault.lock();
        await storageClear();
        await vault.clearVaultHistory();
        const toRestore: Record<string, unknown> = {};
        if (preserved.peach_license !== undefined) toRestore.peach_license = preserved.peach_license;
        if (preserved.peach_pro_celebrated !== undefined) toRestore.peach_pro_celebrated = preserved.peach_pro_celebrated;
        if (Object.keys(toRestore).length > 0) {
          await chrome.storage.local.set(toRestore);
        }
        if (chrome.storage.session) {
          await chrome.storage.session.clear();
        }
        return { ok: true };
      }

      case "GET_IDENTITY_SUGGESTIONS": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const entries = vault.getEntries();
        const suggestions = buildIdentitySuggestions(entries);
        return { ok: true, data: { suggestions } };
      }
      case "ML_INIT":
        return { ok: true };

      case "ML_PREDICT_BATCH": {
        // AUD-002: shape-validate before forwarding to the ML helper.
        const { featuresArray } = (msg.payload ?? {}) as { featuresArray?: unknown };
        if (!Array.isArray(featuresArray)) {
          return { ok: false, error: "invalid_payload" };
        }
        return { ok: true, data: mlPredictBatch(featuresArray as MLFieldFeatures[]) };
      }

      // ── Vault sync (v3) ───────────────────────────────────────────────
      // Returns the public-facing local identity needed by the popup to
      // drive Phase-1 audio pairing. The private long-term key never
      // leaves the background.
      case "GET_LOCAL_IDENTITY": {
        // Not Pro-gated: a free device may attempt to pair so it can RECEIVE a
        // Pro license from an already-Pro peer (at least one device must be Pro).
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        // Identity derives from the stable root key, not the password-derived
        // key, so pairing survives a master-password change (SEV-2-B).
        const masterKeyHex = vault.getRootKeyHex();
        if (!masterKeyHex) return { ok: false, error: "vault_locked" };
        const masterKey = unhexBytes(masterKeyHex);
        try {
          const identity = await buildLocalIdentity(masterKey);
          // If this device is Pro, advertise the signed license so the peer can
          // activate it after SAS confirmation — pairing carries Pro across.
          if (await isProUser()) {
            const license = await getLicenseKey();
            if (license) (identity as { license?: string }).license = license;
          }
          return { ok: true, data: identity };
        } finally {
          masterKey.fill(0);
        }
      }

      case "LIST_PAIRED_DEVICES": {
        const devices = await listPairedDevicesV3();
        return { ok: true, data: { devices } };
      }

      case "RENAME_PAIRED_DEVICE": {
        const { deviceId, name } = (msg.payload ?? {}) as { deviceId?: string; name?: string };
        if (typeof deviceId !== "string" || !deviceId || typeof name !== "string") {
          return { ok: false, error: "invalid_payload" };
        }
        await renamePairedDeviceV3(deviceId, name);
        return { ok: true };
      }

      case "UNPAIR_DEVICE": {
        const { deviceId } = (msg.payload ?? {}) as { deviceId?: string };
        if (typeof deviceId !== "string" || !deviceId) {
          return { ok: false, error: "invalid_payload" };
        }
        // Removing a device REVOKES it rather than just dropping the local
        // row: a plain removal is undone the moment any other peer vouches it
        // back through a manifest, which is exactly what the relay makes easy.
        await revokeDeviceByIdV3(deviceId, await getOrCreateDeviceId());
        // Sync against the remaining hosts — the unpaired device no longer
        // matters but the next alarm tick is up to ten minutes away.
        void triggerSyncIfReachable({ reason: "device_list_changed" }).catch(() => undefined);
        return { ok: true };
      }

      case "RENAME_LOCAL_DEVICE": {
        const { name } = (msg.payload ?? {}) as { name?: string };
        if (typeof name !== "string") return { ok: false, error: "invalid_payload" };
        await setDeviceNameV3(name);
        return { ok: true };
      }

      // ── Relay pairing ─────────────────────────────────────────────────────
      // Not Pro-gated (a free device may pair to receive Pro/sync). The whole NK
      // session runs in the background; the SAS and the terminal result reach
      // the popup as ADOPTION_SOURCE_SAS / ADOPTION_SOURCE_RESULT pushes.
      case "START_ADOPTION_SOURCE": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        if (isRelayAdoptionSourceInFlight()) {
          return { ok: false, error: "adoption_source_in_progress" };
        }
        try {
          return { ok: true, data: await startRelayAdoptionSource() };
        } catch (error) {
          return {
            ok: false,
            error: error instanceof Error ? error.message : "adoption_source_failed",
          };
        }
      }

      // Onboarding receiver — empty extension shows a QR, phone scans and
      // sends the vault. The popup supplies the local-only password here so
      // the background can wrap the adopted root key at rest without ever
      // asking the user to retype it.
      case "START_ADOPTION_RECEIVER": {
        if (isRelayAdoptionSourceInFlight()) {
          return { ok: false, error: "adoption_receiver_in_progress" };
        }
        const password = (msg.payload as { password?: unknown } | undefined)?.password;
        if (typeof password !== "string" || password.length === 0) {
          return { ok: false, error: "invalid_payload" };
        }
        try {
          return { ok: true, data: await startRelayAdoptionReceiver(password) };
        } catch (error) {
          return {
            ok: false,
            error: error instanceof Error ? error.message : "adoption_receiver_failed",
          };
        }
      }

      // Popup→bg counterpart to ADOPTION_SOURCE_SAS (receiver flow).
      // The receiver now auto-accepts the SAS (both sides derive it from the
      // same Noise handshake hash, so the codes match by construction) so
      // the popup never has a SAS screen to tap on. The id round-trips the
      // same way so a stale late response can't approve the wrong session.
      // Popup→bg counterpart for the source flow: Confirm/Cancel on the
      // source's SAS screen.

      // Source-side mirror of RECEIVER_SAS_DECISION: the popup's confirm/cancel
      // on the source's SAS screen. The id round-trips the same way so a stale
      // late response can't approve the wrong session.
      case "SOURCE_SAS_DECISION": {
        const payload = msg.payload as { id?: unknown; ok?: unknown } | undefined;
        if (typeof payload?.id !== "string" || typeof payload?.ok !== "boolean") {
          return { ok: false, error: "invalid_payload" };
        }
        return { ok: resolveSourceSasConfirmation(payload.id, payload.ok) };
      }

      case "CANCEL_ADOPTION_SOURCE": {
        cancelRelayAdoptionSource();
        return { ok: true };
      }

      case "TRIGGER_SYNC": {
        const payload = (msg.payload ?? {}) as {
          reason?: "vault_change" | "foreground" | "manual";
          force?: boolean;
        };
        const reason = payload.reason ?? "foreground";

        void triggerSyncIfReachable({ reason, force: payload.force === true });
        return { ok: true };
      }

      case "GET_SYNC_STATE": {
        return { ok: true, data: getSyncState() };
      }

      case "GET_SYNC_SETTINGS": {
        return { ok: true, data: await getSyncSettings() };
      }

      case "SET_SYNC_SETTINGS": {
        const payload = (msg.payload ?? {}) as {
          mode?: unknown;
          relayUrl?: unknown;
        };
        try {
          // A custom relay URL implies private mode; Peach's own relay stays
          // public. See setRelayUrl.
          if (payload.relayUrl !== undefined) {
            if (typeof payload.relayUrl !== "string") {
              return { ok: false, error: "invalid_relay_url" };
            }
            return { ok: true, data: await setRelayUrl(payload.relayUrl) };
          }
          if (payload.mode !== undefined) {
            if (payload.mode !== "public" && payload.mode !== "private" && payload.mode !== "off") {
              return { ok: false, error: "invalid_sync_mode" };
            }
            return { ok: true, data: await setSyncMode(payload.mode as SyncMode) };
          }
          return { ok: true, data: await getSyncSettings() };
        } catch (error) {
          return {
            ok: false,
            error: error instanceof Error ? error.message : "invalid_relay_url",
          };
        }
      }

      case "GET_SYNC_ALERTS": {
        const { consume } = (msg.payload ?? {}) as { consume?: boolean };
        const alerts = await getPendingSyncAlerts();
        // The popup reads on open and acknowledges with consume:true after
        // rendering, so a popup crash between read and render doesn't lose
        // the alerts.
        if (consume) await clearPendingSyncAlerts();
        return { ok: true, data: alerts };
      }

      case "GET_PENDING_VOUCHED_DEVICES": {
        return { ok: true, data: await listPendingVouchedDevices() };
      }
      case "CONFIRM_VOUCHED_DEVICE": {
        const { deviceId } = msg.payload as { deviceId: string };
        const pending = await getPendingVouchedDevice(deviceId);
        if (!pending) return { ok: false, error: "not_pending" };
        // Last gate before a vouched device becomes a sync peer. A queue entry
        // can predate the revocation that names it, so revocation is re-checked
        // here rather than trusted to have swept the queue.
        if (await isDeviceRevoked(pending.deviceId, pending.longTermPublicKeyHex)) {
          await removePendingVouchedDevice(deviceId);
          return { ok: false, error: "device_revoked" };
        }
        await upsertPairedDeviceV3({
          deviceId: pending.deviceId,
          deviceName: pending.deviceName,
          deviceType:
            pending.deviceType as import("../shared/sync-types").PairedDevice["deviceType"],
          longTermPublicKeyHex: pending.longTermPublicKeyHex,
          signingPublicKeyHex: pending.signingPublicKeyHex,
          wsPort: pending.wsPort,
          pairedAt: pending.pairedAt,
          trustSource: "vouched",
        });
        await removePendingVouchedDevice(deviceId);
        // Newly confirmed vouched device is now a sync target — kick a round
        // so the mesh introduction pays off without a 10-minute wait.
        void triggerSyncIfReachable({ reason: "device_list_changed" }).catch(() => undefined);
        return { ok: true };
      }
      case "REJECT_VOUCHED_DEVICE": {
        const { deviceId } = msg.payload as { deviceId: string };
        await removePendingVouchedDevice(deviceId);
        return { ok: true };
      }
      case "ROTATE_SYNC_IDENTITY": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const result = await vault.rotateSyncIdentity();
        return result.ok ? { ok: true } : { ok: false, error: result.error };
      }

      default:
        return { ok: false, error: "unknown_message_type" };
    }
  } catch (err) {
    return {
      ok: false,
      error: err instanceof Error ? err.message : "operation_failed",
    };
  }
}

// Returns username use-counts from the vault, sorted by frequency. Each row
// also carries the entry's email so the popup can suggest the email/username
// pair the user has actually used together.
function buildIdentitySuggestions(
  entries: VaultEntry[],
): Array<{ email: string; username: string; count: number }> {
  const usernameCounts = new Map<string, number>();
  const usernameEmail = new Map<string, string>();
  for (const entry of entries) {
    const username = entry.username ?? "";
    const email = (entry as VaultEntry & { email?: string }).email ?? "";
    if (!username && !email) continue;
    const key = username || email;
    usernameCounts.set(key, (usernameCounts.get(key) ?? 0) + 1);
    if (!usernameEmail.has(key)) usernameEmail.set(key, email);
  }
  return Array.from(usernameCounts.entries())
    .sort((a, b) => b[1] - a[1])
    .map(([username, count]) => ({
      email: usernameEmail.get(username) ?? "",
      username,
      count,
    }));
}

/** Notify all content scripts that the vault just became available. */
function broadcastToContentScripts(message: { type: string }): void {
  if (!chrome.tabs?.query) return;
  chrome.tabs.query({}, (tabs) => {
    for (const tab of tabs) {
      if (tab.id !== undefined) {
        chrome.tabs.sendMessage(tab.id, message).catch(() => {
          // Tab may not have a content script — silently ignore
        });
      }
    }
  });
}

function shouldRefreshAutoLock(type: MessageType): boolean {
  return (
    type !== "HAS_VAULT" &&
    type !== "IS_UNLOCKED" &&
    type !== "GET_VAULT_STATUS" &&
    type !== "LOCK" &&
    type !== "UPDATE_SETTINGS" &&
    type !== "GET_PENDING_PASSKEY" &&
    type !== "GET_PASSKEY_PROVIDER_STATE" &&
    type !== "DECLINE_CARD_SAVE" &&
    type !== "IS_CARD_DECLINED"
  );
}

function isAllowedCanaryWebhookUrl(value: string): boolean {
  try {
    const url = new URL(value);
    if (url.protocol !== "https:") return false;

    const hostname = url.hostname.toLowerCase();
    if (
      hostname === "localhost" ||
      hostname.endsWith(".localhost") ||
      isPrivateIpv4(hostname) ||
      isPrivateIpv6(hostname)
    ) {
      return false;
    }

    return true;
  } catch {
    return false;
  }
}

function isPrivateIpv4(hostname: string): boolean {
  if (PRIVATE_IPV4_RANGES.some((range) => hostname.startsWith(range.prefix))) {
    return true;
  }

  const octets = hostname.split(".").map((part) => Number(part));
  if (octets.length !== 4 || octets.some((octet) => !Number.isInteger(octet) || octet < 0 || octet > 255)) {
    return false;
  }

  return octets[0] === 172 && octets[1] >= 16 && octets[1] <= 31;
}

function isPrivateIpv6(hostname: string): boolean {
  const normalized = hostname.replace(/^\[|\]$/g, "").toLowerCase();
  // IPv4-mapped IPv6 literals embed a plain IPv4 address that the prefix
  // list below can never match (WHATWG URL serializes [::ffff:192.168.0.1]
  // as ::ffff:c0a8:1). Unwrap and test the embedded IPv4; unparseable mapped
  // tails fail closed. (Codex Security 2026-08-04 LOW,
  // ssrf.webhook-url-private-ip-filter.) DNS rebinding is out of scope for a
  // one-shot host check.
  const mapped = /^::ffff:(.+)$/.exec(normalized);
  if (mapped) {
    const tail = mapped[1] ?? "";
    if (tail.includes(".")) return isPrivateIpv4(tail);
    const parts = tail.split(":");
    const [hi, lo] = parts;
    if (
      parts.length !== 2 ||
      !hi ||
      !lo ||
      !/^[0-9a-f]{1,4}$/.test(hi) ||
      !/^[0-9a-f]{1,4}$/.test(lo)
    ) {
      return true;
    }
    const octets = [
      (Number.parseInt(hi, 16) >>> 8) & 0xff,
      Number.parseInt(hi, 16) & 0xff,
      (Number.parseInt(lo, 16) >>> 8) & 0xff,
      Number.parseInt(lo, 16) & 0xff,
    ];
    return isPrivateIpv4(octets.join("."));
  }
  return (
    normalized === "::1" ||
    normalized.startsWith("fc") ||
    normalized.startsWith("fd") ||
    normalized.startsWith("fe80:")
  );
}