/**
 * 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 } from "./clipboard";
import { setupAutoLock, touchAutoLock } from "./alarms";
import * as vault from "./vault";
import {
  activateLicense,
  deactivateLicense,
  getLicenseInfo,
  getLicenseKey,
  isProUser,
  markCelebrationPlayed,
  shouldPlayCelebration,
} from "./license";
import {
  cancelFirefoxPasskeyCreate,
  completeFirefoxPasskeyCreate,
  getPasskeyProviderState,
  getPendingPasskeyRequest,
  handleFirefoxPasskeyCreate,
  handleFirefoxPasskeyGet,
  handlePasskeyHasCredentials,
  initiateFirefoxPasskeyCreate,
  isPasskeyOfferDeclined,
  recordPasskeyOfferDecline,
  resolvePendingPasskeyRequest,
  setPasskeyProviderEnabled,
} from "./passkey";
import { buildAdvancedHealthReport, resolveResetUrl } from "./health";
import { storageClear, storageGet } from "../shared/storage";
import { findInvalidWords } from "../shared/recovery-words";
import {
  addPairedDevice,
  addTrustedNetwork,
  clearIncomingPairingRequest,
  getIncomingPairingRequest,
  getPairedDevices,
  getTrustedNetworks,
  removePairedDevice,
  removeTrustedNetwork,
  setIncomingPairingRequest,
  updatePairedDevice,
} from "./sync-storage";
import { getCurrentNetwork, isOnTailscale } from "./sync-network";
import {
  consumeRecentPairing,
  setActivePairingToken,
} from "./pairing-server-state";
import type {
  Message,
  MessageResponse,
  MessageType,
  ProFeature,
  VaultEntry,
} from "../shared/types";
import { isPasskeyOnly } from "../shared/types";
import type { SyncStatus, SyncableDevice } from "../shared/sync-types";
import { isNativePlatform, nativePlugin } from "../shared/native";
import { runBlobSyncSession, type SyncResult } from "./sync-coordinator";
import type { SyncDeps } from "./sync-coordinator";
import { createWebSocketSyncTransport } from "../shared/websocket-sync-transport";
import { getLocalSubnet, discoverDevice, scanForPairingPhone } from "../shared/local-network";
import { base64ToBytes, bytesToBase64 } from "../shared/sync-wire";

/**
 * 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 (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 };
}

// ---------------------------------------------------------------------------
// Local device name. Peers see this string in PAIR_REQUEST / PAIR_ACCEPT and
// next to the device in their paired-devices list. Default to a platform-aware
// fallback when the user hasn't set one explicitly.
const DEVICE_NAME_KEY = "peach_device_name";

async function getLocalDeviceName(): Promise<string> {
  try {
    const stored = await chrome.storage.local.get(DEVICE_NAME_KEY);
    const value = (stored as Record<string, string | undefined>)[DEVICE_NAME_KEY];
    if (typeof value === "string" && value.trim()) return value.trim();
  } catch {
    // fall through to default
  }
  return "Peach";
}

// ---------------------------------------------------------------------------
// 6-digit code pairing.

const PAIRING_TOKEN_TTL_MS = 5 * 60 * 1000;


function generateSixDigitToken(): string {
  // crypto.getRandomValues, not Math.random — the token is the only secret
  // protecting the pairing window from a same-LAN attacker. 6 decimal digits
  // is 1 in 1,000,000; combined with a 5-minute TTL and pairing-mode gating
  // on the responder this is the right tradeoff between UX and security.
  const buf = new Uint32Array(1);
  crypto.getRandomValues(buf);
  const value = buf[0] % 1_000_000;
  return value.toString().padStart(6, "0");
}

// ---------------------------------------------------------------------------
// Peer discovery glue (Phase 7 popup pairing flow).

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

// Empty disables network submission while the UI continues to function as a
// no-op (the handler returns ok:true without calling fetch). When set, the
// URL is validated by `isAllowedCanaryWebhookUrl` before any request, so the
// same private-IP/HTTPS rules that gate canary webhooks apply here.
const FEEDBACK_ENDPOINT = "";

// ---------------------------------------------------------------------------
// Sync helpers
// ---------------------------------------------------------------------------

function buildSyncDeps(): SyncDeps {
  return {
    isVaultUnlocked: () => vault.isUnlocked(),
    getVaultBlobForSync: async () => {
      const base = await vault.getVaultBlobForSync();
      if (!base) return null;
      const paired = await getPairedDevices();
      return {
        ...base,
        devices: paired
          .filter(d => d.x25519PublicKey)
          .map(d => ({
            publicKeyHex: d.x25519PublicKey,
            deviceName: d.displayName,
            pairedAt: d.pairedAt,
          })),
      };
    },
    applyIncomingVault: async (blob, ts, license, devices) => {
      const applied = await vault.applyIncomingVault(blob, ts, license);
      if (devices?.length) await mergeDeviceRegistry(devices);
      if (applied) await vault.reloadEntriesAfterSync();
      return applied;
    },
  };
}

async function doVaultSync(ip: string, publicKeyHex: string): Promise<SyncResult> {
  try {
    const transport = await createWebSocketSyncTransport(`ws://${ip}:44100`, publicKeyHex);
    return await runBlobSyncSession('initiator', transport, buildSyncDeps());
  } catch (err) {
    return { status: 'errored', applied: false, error: String(err) };
  }
}

async function mergeDeviceRegistry(incoming: SyncableDevice[]): Promise<void> {
  const existing = await getPairedDevices();
  const existingKeys = new Set(existing.map(d => d.x25519PublicKey));
  for (const device of incoming) {
    if (!existingKeys.has(device.publicKeyHex)) {
      await addPairedDevice({
        deviceId: device.publicKeyHex,
        displayName: device.deviceName,
        x25519PublicKey: device.publicKeyHex,
        pairedAt: device.pairedAt,
        lastSeenAt: 0,
        lastKnownIp: '',
      }).catch(() => {});
    }
  }
}

// Background pairing scan — runs after START_PAIRING_SERVER fires on desktop.
// Scans the local subnet for a phone that has accepted the pairing token,
// stores it, runs the initial vault exchange, then notifies the popup.
async function runPairingSubnetScan(token: string): Promise<void> {
  const subnet = await getLocalSubnet();
  if (!subnet) return;

  const found = await scanForPairingPhone(subnet, token);
  if (!found) return;

  const { ip, publicKeyHex } = found;

  try {
    await addPairedDevice({
      deviceId: publicKeyHex,
      displayName: 'Peach',
      x25519PublicKey: publicKeyHex,
      pairedAt: Date.now(),
      lastSeenAt: Date.now(),
      lastKnownIp: ip,
    });
  } catch {
    // Already paired — update IP
    await updatePairedDevice(publicKeyHex, { lastKnownIp: ip, lastSeenAt: Date.now() });
  }

  // Immediate vault exchange — the free one-time transfer
  await doVaultSync(ip, publicKeyHex);

  chrome.runtime.sendMessage({
    type: 'PAIRING_COMPLETED',
    payload: { deviceName: 'Peach', publicKeyHex, deviceIp: ip },
  }).catch(() => {});
}

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;
    }
  );

  // Android: the chrome shim queues sendMessage calls until this handler is
  // registered. Without this hookup, every message hangs on Capacitor builds.
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const reg = (globalThis as any).__peachRegisterMessageHandler;
  if (typeof reg === "function") {
    reg(async (m: unknown) => {
      if (!isMessage(m)) return { ok: false, error: "invalid message" };
      try {
        return await handleMessage(m);
      } catch (err) {
        return {
          ok: false,
          error: err instanceof Error ? err.message : String(err),
        };
      }
    });
  }

  // Android: subscribe to SyncPlugin events.
  if (isNativePlatform()) {
    const syncPlug = nativePlugin<{
      addListener: (
        event: string,
        handler: (data: Record<string, string>) => void
      ) => void;
    }>("SyncPlugin");

    // Pairing probe answered — store the paired device (desktop, no IP needed
    // since the desktop never acts as a WS server).
    syncPlug?.addListener?.("peach:pair-probe-answered", (data) => {
      const deviceName = data.deviceName ?? "Peach";
      const publicKeyHex = data.publicKeyHex ?? "";
      void (async () => {
        const { addPairedDevice, setHasPaired: setPaired } = await import("./sync-storage");
        await addPairedDevice({
          deviceId: publicKeyHex || (data.connectionId ?? "unknown"),
          displayName: deviceName,
          x25519PublicKey: publicKeyHex,
          pairedAt: Date.now(),
          lastSeenAt: Date.now(),
        }).catch(() => {});
        await setPaired();
        chrome.runtime.sendMessage({
          type: "PAIRING_COMPLETED",
          payload: { deviceName },
        }).catch(() => {});
      })();
    });

    // Sync frame received — route to the waiting responder session.
    syncPlug?.addListener?.("peach:sync-frame", (data) => {
      const { connectionId, frame } = data;
      if (connectionId && frame) deliverAndroidSyncFrame(connectionId, frame);
    });

    // Sync session started (SYNC_HELLO received by SyncPlugin) — dispatch as
    // a background message so SYNC_SESSION_STARTED handler runs the responder.
    syncPlug?.addListener?.("peach:sync-session-started", (data) => {
      const { connectionId } = data;
      if (!connectionId) return;
      void handleMessage({ type: "SYNC_SESSION_STARTED", payload: { connectionId } });
    });
  }
}

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

export async function handleMessage(
  msg: Message,
  sender: Partial<chrome.runtime.MessageSender> = {}
): Promise<MessageResponse> {
  try {
    // 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" };
    }

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

    switch (msg.type) {
      case "CREATE_VAULT": {
        const { password } = msg.payload as { password: string };
        await vault.createVault(password);
        await setupAutoLock();
        broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
        return { ok: true };
      }
      case "UNLOCK": {
        const { password } = msg.payload as { password: string };
        const ok = await vault.unlock(password);
        if (ok) {
          await setupAutoLock();
          broadcastToContentScripts({ type: "VAULT_UNLOCKED" });
          if (isNativePlatform()) await publishInMemoryVault(vault.getEntries());
        }
        return { ok };
      }
      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" };
        try {
          const words = await vault.getRecoveryWords();
          return { ok: true, data: words };
        } catch (e) {
          // pre-v2.12 vault that hasn't migrated
          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();
        if (isNativePlatform()) await clearInMemoryVault();
        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":
        return { ok: true, data: vault.getEntries() };
      case "ADD_ENTRY": {
        if (!vault.isUnlocked()) return { ok: false, error: "vault locked" };
        const entry = await vault.addEntry(msg.payload as any);
        return { ok: true, data: entry };
      }
      case "BATCH_ADD_ENTRIES": {
        const { entries } = msg.payload as { entries: any[] };
        const added = await vault.batchAddEntries(entries);
        return { ok: true, data: added };
      }
      case "RESTORE_ENTRIES": {
        const { entries, mode, settings } = msg.payload as {
          entries: any[];
          mode: "replace" | "merge";
          settings?: vault.VaultSettings;
        };
        const summary = await vault.restoreEntries(entries, mode);
        if (settings && typeof settings === "object") {
          await vault.updateSettings(settings);
        }
        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 { id, patch } = msg.payload as any;
        await vault.updateEntry(id, patch);
        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 "AUTOFILL_QUERY": {
        if (!vault.isUnlocked()) {
          return { ok: false, error: "VAULT_LOCKED" };
        }
        const { domain, includeAll, kind } = msg.payload as {
          domain: string;
          includeAll?: boolean;
          kind?: "login" | "card";
        };
        // 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,
            })),
          };
        }
        // 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,
                  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 } = msg.payload as { id: string };
        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" };
        // Strip the passkey credential from the response — content scripts
        // never need the private key, and there's no reason to expose the
        // public credential metadata over the boundary either.
        const { passkey: _strippedPasskey, ...safeEntry } = entry;
        return { ok: true, data: safeEntry };
      }
      case "COPY": {
        const { text, label, alreadyWritten } = msg.payload as {
          text: string;
          label: string;
          alreadyWritten?: boolean;
        };
        await copyToClipboard(text, label, Boolean(alreadyWritten));
        return { ok: true };
      }
      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 as Record<string, unknown>;
        await vault.updateSettings(patch as any);
        if (typeof patch.autoLockMinutes === "number") {
          await setupAutoLock();
          if (vault.isUnlocked()) touchAutoLock();
        }
        return { ok: true };
      }
      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) };
      }
      case "FIRE_CANARY_PING": {
        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" };
        }
        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 "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 "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 "INITIATE_PASSWORD_CHANGE": {
        const gate = await requirePro("smart_password_change");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        if (!vault.isUnlocked()) return { ok: false, error: "vault locked" };
        const { id } = msg.payload as { id: string };
        const entry = vault.getEntryById(id);
        if (!entry) return { ok: false, error: "entry not found" };
        const url = resolveResetUrl(entry);
        if (!url) return { ok: false, error: "no reset url" };
        try {
          await chrome.tabs.create({ url });
          return { ok: true, data: { url } };
        } catch (err) {
          return {
            ok: false,
            error: err instanceof Error ? err.message : "failed to open tab",
          };
        }
      }
      case "IS_DURESS_ENABLED": {
        const enabled = await vault.isDuressEnabled();
        return { ok: true, data: enabled };
      }
      case "SETUP_DURESS": {
        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 "GET_SYNC_STATE": {
        const pairedDevices = await getPairedDevices();
        const trustedNetworks = await getTrustedNetworks();
        const tailscale = await isOnTailscale();
        const pro = await isProUser();

        let status: SyncStatus = "offline";
        if (tailscale || trustedNetworks.some((n: { isTailscale?: boolean }) => !n.isTailscale)) {
          if (pairedDevices.length === 0) {
            status = "no_peers";
          } else {
            status = "synced";
          }
        } else {
          status = "not_trusted";
        }

        const lastSyncRaw = await storageGet("peach_last_sync_at");
        const lastSyncParsed = lastSyncRaw ? Number.parseInt(lastSyncRaw, 10) : NaN;
        const lastSyncAt = Number.isFinite(lastSyncParsed) ? lastSyncParsed : undefined;

        return { ok: true, data: { pairedDevices, trustedNetworks, status, lastSyncAt, isPro: pro } };
      }
      case "GET_PAIRED_DEVICES": {
        const devices = await getPairedDevices();
        return { ok: true, data: { devices } };
      }
      case "GET_SYNC_STATUS": {
        const lastSyncRaw = await storageGet("peach_last_sync_at");
        const lastSyncParsed = lastSyncRaw ? parseInt(lastSyncRaw, 10) : NaN;
        const lastSyncAt = Number.isFinite(lastSyncParsed) ? lastSyncParsed : null;
        const status: 'up_to_date' | 'never' = lastSyncAt ? 'up_to_date' : 'never';
        return { ok: true, data: { status, lastSyncAt } };
      }
      case "ACCEPT_PAIRING": {
        // One-time mobile→desktop transfer is free; only continuous sync gates on Pro.
        return { ok: true };
      }
      case "REMOVE_PAIRED_DEVICE": {
        const { deviceId } = msg.payload as { deviceId: string };
        await removePairedDevice(deviceId);
        return { ok: true };
      }
      case "REMOVE_TRUSTED_NETWORK": {
        const { ssid, bssid, isTailscale } = msg.payload as any;
        const networks = await getTrustedNetworks();
        const network = networks.find((n: { ssid?: string; bssid?: string; isTailscale?: boolean }) => 
          (isTailscale ? n.isTailscale : n.ssid === ssid) && 
          (!bssid || n.bssid === bssid)
        );
        if (network) {
          await removeTrustedNetwork(network.addedAt);
        }
        return { ok: true };
      }
      case "MARK_NETWORK_TRUSTED": {
        const network = await getCurrentNetwork();
        await addTrustedNetwork({
          ssid: network.ssid,
          bssid: network.bssid,
          isTailscale: network.isTailscale,
          addedAt: Date.now(),
        });
        return { ok: true };
      }
      case "GET_INCOMING_PAIRING_REQUEST": {
        const request = await getIncomingPairingRequest();
        return { ok: true, data: request };
      }
      case "RESPOND_INCOMING_PAIRING": {
        const { accept } = msg.payload as { accept: boolean };
        const request = await getIncomingPairingRequest();
        if (!request) return { ok: false, error: "no_pending_request" };
        if (Date.now() > request.expiresAt) {
          await clearIncomingPairingRequest();
          return { ok: false, error: "expired" };
        }
        await clearIncomingPairingRequest();
        if (accept) {
          await addPairedDevice({
            deviceId: request.publicKeyHex,
            displayName: request.deviceName,
            x25519PublicKey: request.publicKeyHex,
            pairedAt: Date.now(),
            lastSeenAt: Date.now(),
          });
        }
        return { ok: true, data: { accepted: accept, deviceName: request.deviceName } };
      }
      case "START_PAIRING_SERVER": {
        // One-time mobile→desktop transfer is free; only continuous sync gates on Pro.
        const token = generateSixDigitToken();
        const expiresAt = Date.now() + PAIRING_TOKEN_TTL_MS;
        await setActivePairingToken({ token, expiresAt });
        // Fire-and-forget subnet scan — finds the phone after it scans the QR
        // and calls SCAN_PAIRING_QR to register the token with SyncPlugin.
        if (!isNativePlatform()) {
          void runPairingSubnetScan(token);
        }
        return { ok: true, data: { token, expiresAt } };
      }
      case "STOP_PAIRING_SERVER": {
        try {
          await setActivePairingToken(null);
        } catch { /* best-effort */ }
        return { ok: true };
      }
      case "GET_RECENT_PAIRING": {
        const recent = await consumeRecentPairing();
        return { ok: true, data: recent };
      }
      case "DEBUG_INJECT_INCOMING_PAIRING": {
        // Manual E2E rehearsal hook. Inserts a synthetic incoming pairing
        // request into session storage so Phase 7 banner UX can be exercised
        // without a live native host. No Pro gate — this is a no-op in
        // production unless explicitly invoked from a Settings debug action.
        const { deviceName, publicKeyHex } = (msg.payload ?? {}) as {
          deviceName?: string;
          publicKeyHex?: string;
        };
        if (!deviceName || !publicKeyHex) {
          return { ok: false, error: "missing_payload" };
        }
        const now = Date.now();
        await setIncomingPairingRequest({
          deviceName,
          publicKeyHex,
          receivedAt: now,
          expiresAt: now + 60_000,
        });
        return { ok: true };
      }
      case "RESET_SYNC_IDENTITY": {
        const gate = await requirePro("sync");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        const devices = await getPairedDevices();
        for (const device of devices) {
          await removePairedDevice(device.deviceId);
        }
        return { ok: true, data: { removedDevices: devices.length, nativePublicKey: 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,
        });
      }

      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 ?? [],
        });
      }

      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);
      }

      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);
      }

      case "GET_PASSKEY_FOR_DOMAIN": {
        const { domain } = (msg.payload ?? {}) as { domain?: string };
        if (!domain) return { ok: false, error: "domain required" };
        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.
        vault.lock();
        await storageClear();
        await vault.clearVaultHistory();
        if (chrome.storage.session) {
          await chrome.storage.session.clear();
        }
        return { ok: true };
      }

      case "SUBMIT_FEEDBACK": {
        const { category, message, version, browser } = msg.payload as {
          category: string;
          message: string;
          version: string;
          browser: string;
        };
        if (!message.trim()) return { ok: false, error: "message is empty" };
        if (!FEEDBACK_ENDPOINT) return { ok: true };
        if (!isAllowedCanaryWebhookUrl(FEEDBACK_ENDPOINT)) {
          return { ok: false, error: "invalid feedback endpoint" };
        }
        try {
          const res = await fetch(FEEDBACK_ENDPOINT, {
            method: "POST",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify({ category, message, version, browser, source: "peach-extension" }),
          });
          return { ok: res.ok, error: res.ok ? undefined : `HTTP ${res.status}` };
        } catch (err) {
          return { ok: false, error: err instanceof Error ? err.message : "network error" };
        }
      }
      case "TRIGGER_SYNC": {
        const gate = await requirePro("sync");
        if (!gate.allowed) return { ok: false, error: "pro_required" };
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };

        if (isNativePlatform()) {
          // Phone is the server — ensure it's listening for desktop connections.
          syncBridge()?.ensureServerRunning?.();
          return { ok: true, data: { syncedCount: 0, mode: "server" as const } };
        }

        // Desktop: iterate all paired devices and sync with each.
        const paired = await getPairedDevices();
        if (!paired.length) return { ok: true, data: { syncedCount: 0, reason: "no_paired_devices" } };

        const subnet = await getLocalSubnet();
        const results: Array<{ device: string } & SyncResult> = [];

        for (const device of paired) {
          if (!device.x25519PublicKey) continue;

          let result: SyncResult;

          // Fast path — use last known IP
          if (device.lastKnownIp) {
            result = await doVaultSync(device.lastKnownIp, device.x25519PublicKey);
          } else {
            result = { status: 'errored', applied: false, error: 'no_ip' };
          }

          // Discovery path — scan if fast path failed
          if (result.status === 'errored' && subnet) {
            const newIp = await discoverDevice(subnet, device.x25519PublicKey);
            if (newIp) {
              await updatePairedDevice(device.x25519PublicKey, { lastKnownIp: newIp });
              result = await doVaultSync(newIp, device.x25519PublicKey);
            }
          }

          if (result.status === 'completed') {
            await updatePairedDevice(device.x25519PublicKey, {
              lastSeenAt: Date.now(),
              lastSyncAt: Date.now(),
            });
          }

          results.push({ device: device.displayName, ...result });
        }

        const syncedCount = results.filter(r => r.status === 'completed').length;
        if (syncedCount > 0) {
          await chrome.storage.local.set({ peach_last_sync_at: String(Date.now()) });
        }
        return { ok: true, data: { syncedCount, results } };
      }
      // Android-only: biometric unlock with pre-derived key.
      case "UNLOCK_WITH_KEY": {
        const { masterKeyHex } = msg.payload as { masterKeyHex: string };
        if (!isNativePlatform()) {
          return { ok: false, error: "desktop_only_uses_password" };
        }
        try {
          const result = await vault.unlockWithKey(masterKeyHex);
          if (result.ok) await publishInMemoryVault(result.entries);
          return { ok: result.ok, data: result.ok ? { entries: result.entries } : undefined, error: result.ok ? undefined : result.error };
        } catch {
          return { ok: false, error: "invalid_key" };
        }
      }
      // Android: returns current in-memory derived key as hex. Used by biometric enable flow.
      case "GET_DERIVED_KEY": {
        if (!isNativePlatform()) {
          return { ok: false, error: "android_only" };
        }
        if (!vault.isUnlocked()) {
          return { ok: false, error: "vault_locked" };
        }
        return { ok: true, data: { masterKeyHex: vault.getDerivedKeyHex() } };
      }
      // Android: scanned a QR containing a desktop pairing token.
      case "SCAN_PAIRING_QR": {
        if (!isNativePlatform()) {
          return { ok: false, error: "android_only" };
        }
        const { token } = msg.payload as { token: string };
        syncBridge()?.startPairingSession?.({ token });
        return { ok: true };
      }
      // Android: desktop opened a sync connection to the phone's WS server.
      // Run the responder side of the vault exchange.
      case "SYNC_SESSION_STARTED": {
        if (!isNativePlatform()) return { ok: false };
        if (!vault.isUnlocked()) {
          return { ok: false, error: "vault_locked" };
        }
        const { connectionId } = (msg.payload ?? {}) as { connectionId?: string };
        if (!connectionId) return { ok: false, error: "missing_connection_id" };

        const transport = createAndroidResponderTransport(connectionId);
        const result = await runBlobSyncSession('responder', transport, buildSyncDeps());
        if (result.applied) {
          await publishInMemoryVault(vault.getEntries());
        }
        return { ok: true, data: result };
      }
      // Android: returns the phone's WiFi IP address.
      case "GET_LOCAL_IP": {
        if (!isNativePlatform()) {
          return { ok: false, error: "android_only" };
        }
        const { ip } = (await syncBridge()?.getLocalIp?.()) ?? { ip: "" };
        return { ok: true, data: { ip } };
      }
      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 "POPULATE_INLINE_VAULT": {
        if (!isNativePlatform()) return { ok: false };
        if (!vault.isUnlocked()) return { ok: false, error: "vault_locked" };
        const entries = vault.getEntries();
        await publishInMemoryVault(entries);
        return { ok: true };
      }
      // --- PNA compatibility test handlers — REMOVE BEFORE RELEASE ---
      case "TEST_LOCAL_WEBSOCKET": {
        const { ip } = (msg.payload ?? {}) as { ip?: string };
        if (!ip) return { ok: false, error: "ip required" };
        return new Promise((resolve) => {
          try {
            const ws = new WebSocket(`ws://${ip}:44100`);
            ws.onopen = () => { ws.close(); resolve({ ok: true, data: { connected: true } }); };
            ws.onerror = () => resolve({ ok: false, error: "connection_failed" });
            setTimeout(() => { ws.close(); resolve({ ok: false, error: "timeout" }); }, 3000);
          } catch (err) {
            resolve({ ok: false, error: String(err) });
          }
        });
      }
      case "TEST_SUBNET_DETECTION": {
        const subnet = await getLocalSubnet();
        return { ok: true, data: { subnet } };
      }
      case "TEST_SUBNET_SCAN": {
        const subnet = await getLocalSubnet();
        if (!subnet) return { ok: false, error: "no_subnet" };
        const start = Date.now();
        const result = await discoverDevice(subnet, "000000000000000000000000000000000000000000000000000000000000000000");
        return { ok: true, data: { elapsed: Date.now() - start, found: !!result } };
      }
      // --- end test handlers ---
      default:
        return { ok: false, error: "unknown message type" };
    }
  } catch (err) {
    return {
      ok: false,
      error: err instanceof Error ? err.message : "operation failed",
    };
  }
}

// --- Mobile platform helpers ---

// Android: populates the in-memory vault used by PeachAutofillService.
async function publishInMemoryVault(entries: VaultEntry[]): Promise<void> {
  const plugin = nativePlugin<{
    setEntries?: (args: {
      entries: Array<{
        id: string;
        title: string;
        username: string;
        email: string;
        password: string;
        url: string;
        totp: string;
        additionalUrls: string[];
      }>;
    }) => Promise<void>;
  }>("InMemoryVaultPlugin");
  if (!plugin?.setEntries) return;
  await plugin.setEntries({
    entries: entries.map((e) => ({
      id: e.id,
      title: e.title ?? "",
      username: e.username ?? "",
      email: (e as VaultEntry & { email?: string }).email ?? "",
      password: e.password ?? "",
      url: e.url ?? "",
      totp: (e as VaultEntry & { totp?: string }).totp ?? "",
      additionalUrls: (e as VaultEntry & { additionalUrls?: string[] }).additionalUrls ?? [],
    })),
  });
}

// Android: clear the autofill in-memory store on lock.
async function clearInMemoryVault(): Promise<void> {
  const plugin = nativePlugin<{ clearEntries?: () => Promise<void> }>("InMemoryVaultPlugin");
  if (!plugin?.clearEntries) return;
  await plugin.clearEntries();
}

interface SyncBridge {
  ensureServerRunning?: () => void;
  startPairingSession?: (args: { token: string }) => void;
  getLocalIp?: () => Promise<{ ip: string }>;
  sendToConnection?: (args: { connectionId: string; data: string }) => Promise<void>;
  addListener?: (event: string, handler: (data: Record<string, string>) => void) => void;
}

// Resolve the Capacitor SyncPlugin at call time — module-load resolution
// races with Capacitor's plugin registration on the Android WebView.
function syncBridge(): SyncBridge | null {
  return nativePlugin<SyncBridge>("SyncPlugin");
}

// Build a SyncTransport for the Android responder path — the phone's WS server
// already has an open connection from the desktop. We send back via
// SyncPlugin.sendToConnection and receive via the peach:sync-frame queue.
const androidSyncFrameQueues = new Map<string, Array<(frame: string) => void>>();

export function deliverAndroidSyncFrame(connectionId: string, frame: string): void {
  const queue = androidSyncFrameQueues.get(connectionId);
  if (queue?.length) queue.shift()!(frame);
}

function createAndroidResponderTransport(connectionId: string) {
  const pendingReceivers: Array<(frame: string) => void> = [];
  androidSyncFrameQueues.set(connectionId, pendingReceivers);

  return {
    send: async (data: Uint8Array) => {
      await syncBridge()?.sendToConnection?.({ connectionId, data: bytesToBase64(data) });
    },
    receive: (): Promise<Uint8Array> => new Promise((res) => {
      pendingReceivers.push((frame) => {
        res(frame ? base64ToBytes(frame) : new Uint8Array(0));
      });
    }),
    close: async () => {
      androidSyncFrameQueues.delete(connectionId);
    },
  };
}

// 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" &&
    type !== "SUBMIT_FEEDBACK"
  );
}

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();
  return (
    normalized === "::1" ||
    normalized.startsWith("fc") ||
    normalized.startsWith("fd") ||
    normalized.startsWith("fe80:")
  );
}