बायोमेट्रिक्स और कीस्टोर

Copyfunction fromBase64(b64) { return decodeURIComponent(escape(atob(b64))); }

function readSecret() {
  var sealed = localStorage.getItem('secret');
  if (!sealed || !window.AppMintKeystore) return null;

  var r = window.AppMintKeystore.decrypt('vault', sealed);
  if (r.ok) return fromBase64(r.base64);

  switch (r.error) {
    case 'auth-required':   unlockThen(readSecretAndShow); break;   // unlock, then try again
    case 'no-such-key':
    case 'key-invalidated': alert('This secret can no longer be opened.'); break;
    default:                alert('Could not decrypt: ' + r.error);
  }
  return null;
}

Copyfunction unlock() {
  return new Promise(function (resolve) {
    var id = 'unlock_' + Date.now();
    window.__webToApkAuth = window.__webToApkAuth || {};
    window.__webToApkAuth[id] = function (json) { resolve(JSON.parse(json)); };
    window.WebToApk.authenticateBiometricEx(id, JSON.stringify({
      title: 'Unlock your settings', strong: true, allowDeviceCredential: true
    }));
  });
}

async function loadSealedSettings() {
  var sealed = localStorage.getItem('settings');
  if (!sealed || !window.AppMintKeystore || !window.AppMintKeystore.isAvailable()) return null;
  var r = window.AppMintKeystore.decrypt('vault', sealed);
  if (!r.ok && r.error === 'auth-required' && (await unlock()).ok) {
    r = window.AppMintKeystore.decrypt('vault', sealed);
  }
  return r.ok ? JSON.parse(decodeURIComponent(escape(atob(r.base64)))) : null;
}

Copyfunction loadDiary() {
  if (!window.AppMintKeystore || !window.AppMintKeystore.isAvailable()) return [];
  var entries = JSON.parse(localStorage.getItem('diary') || '[]');   // [{date, sealed}]
  return entries.map(function (e) {
    var r = window.AppMintKeystore.decrypt('diary', e.sealed);
    return {
      date: e.date,
      text: r.ok ? decodeURIComponent(escape(atob(r.base64))) : null,
      error: r.ok ? null : r.error                 // e.g. 'auth-required', 'no-such-key'
    };
  });
}

Copyfunction deleteNoteForReal() {
  if (!window.AppMintKeystore || !window.WebToApkFS) return;
  if (!confirm('Delete this note forever?')) return;

  var gone = window.AppMintKeystore.deleteKey('vault');  // secret.bin is unreadable from now on
  window.WebToApkFS.delete('secret.bin');                // tidy up the file too
  alert(gone ? 'Deleted.' : 'Nothing to delete.');
}

Copyfunction eraseEverything() {
  var K = window.AppMintKeystore;
  if (!K || !K.isAvailable()) return;
  if (!confirm('Erase all protected data on this phone? This cannot be undone.')) return;

  var aliases = K.listKeys();
  aliases.forEach(function (alias) { K.deleteKey(alias); });
  localStorage.clear();
  alert('Erased ' + aliases.length + ' key(s).');
  location.reload();
}

Copyvar MAX_TRIES = 5;

function onWrongPin() {
  var tries = Number(localStorage.getItem('pinTries') || 0) + 1;
  localStorage.setItem('pinTries', String(tries));
  if (tries < MAX_TRIES) return alert((MAX_TRIES - tries) + ' tries left.');

  if (window.AppMintKeystore) window.AppMintKeystore.deleteKey('vault');  // vault unreadable from now on
  localStorage.removeItem('vaultData');
  localStorage.removeItem('pinTries');
  alert('Too many wrong PINs. The vault was erased.');
}

Copyfunction toBase64(text) { return btoa(unescape(encodeURIComponent(text))); }

function saveSecret(text) {
  if (!window.AppMintKeystore || !window.AppMintKeystore.isAvailable()) return false;
  var r = window.AppMintKeystore.encrypt('vault', toBase64(text));
  if (r.ok) {
    localStorage.setItem('secret', r.base64);
    return true;
  }
  if (r.error === 'auth-required') {
    // the key needs a fresh unlock: ask for the fingerprint, then call saveSecret again
    unlockThen(function () { saveSecret(text); });
  } else {
    alert('Could not encrypt: ' + r.error);
  }
  return false;
}

Copyfunction sealJson(alias, obj) {
  if (!window.AppMintKeystore || !window.AppMintKeystore.isAvailable()) return null;
  var b64 = btoa(unescape(encodeURIComponent(JSON.stringify(obj))));
  var r = window.AppMintKeystore.encrypt(alias, b64);
  if (!r.ok) { console.warn('encrypt failed:', r.error, r.detail); return null; }
  return r.base64;
}

var sealed = sealJson('notes', { title: 'Shopping', items: ['milk', 'eggs'] });
if (sealed) localStorage.setItem('note-1', sealed);

Copyfunction encryptWithKeyReady(alias, b64) {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return { ok: false, error: 'unsupported' };
  var r = ks.encrypt(alias, b64);
  if (!r.ok && r.error === 'no-such-key') {
    var g = ks.generateKey(alias);          // plain key, no unlock needed
    if (!g.ok) return g;
    r = ks.encrypt(alias, b64);
  }
  return r;                                 // {ok:true, base64} or {ok:false, error, detail}
}

Copyfunction createVault() {
  if (!window.AppMintKeystore || !window.AppMintKeystore.isAvailable()) {
    alert('Secure keys are not available in this app.');
    return;
  }
  var r = window.AppMintKeystore.generateKey('vault', {
    requireAuth: true,         // usable only after a fingerprint / PIN unlock...
    authValiditySeconds: 30    // ...for 30 seconds after it
  });
  if (!r.ok) { alert('Could not create the key: ' + r.error); return; }
  console.log('Hardware key:', r.hardwareBacked);
}

Copyvar r = window.AppMintKeystore.generateKey('notes');   // options default to {}

Copyvar r = window.AppMintKeystore.generateKey('wallet', { strongBox: true });
if (!r.ok && r.error === 'strongbox-unavailable') {
  alert('This phone has no secure chip.');
}

Copyfunction startVault() {
  if (!window.AppMintKeystore || !window.AppMintKeystore.isAvailable()) return;
  if (window.AppMintKeystore.hasKey('vault')) {
    showUnlockScreen();
  } else {
    showCreateVaultScreen();
  }
}
window.addEventListener('load', startVault);

Copyfunction ensureKey(alias) {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return false;
  if (ks.hasKey(alias)) return true;
  var r = ks.generateKey(alias);   // generateKey REPLACES an existing key, so only call it when hasKey says no
  if (!r.ok) console.warn('Could not create key:', r.error);
  return r.ok;
}

if (ensureKey('notes')) enableSaveButton();

Copyfunction checkVault() {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return;
  var sealed = localStorage.getItem('secret');
  if (sealed && !ks.hasKey('vault')) {
    localStorage.removeItem('secret');   // without the key it can never be opened
    showMessage('Your saved secret could not be recovered and was removed.');
  }
}
window.addEventListener('load', checkVault);

Copyfunction secureKeysReady() {
  return !!window.AppMintKeystore && window.AppMintKeystore.isAvailable();
}

// Check when the user acts (the helper is added when the page finishes loading):
document.getElementById('vault-button').addEventListener('click', function () {
  if (!secureKeysReady()) {
    alert('The secure vault is not available in this app.');
    return;
  }
  openVault();
});

Copywindow.addEventListener('load', function () {
  var ok = !!window.AppMintKeystore && window.AppMintKeystore.isAvailable();
  document.querySelectorAll('.needs-secure-keys').forEach(function (el) {
    el.hidden = !ok;
  });
});

Copyfunction vaultState() {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return 'off';   // a browser, or Secure Keys not on in this build
  return ks.hasKey('vault') ? 'ready' : 'new';
}

document.getElementById('vault-button').addEventListener('click', function () {
  var state = vaultState();
  if (state === 'off') alert('The secure vault is not available in this app.');
  else if (state === 'new') showCreateVaultScreen();
  else showUnlockScreen();
});

Copyfunction showKeyStrength() {
  if (!window.AppMintKeystore || !window.AppMintKeystore.hasKey('vault')) return;
  var hw = window.AppMintKeystore.isHardwareBacked('vault');
  document.getElementById('strength').textContent = hw
    ? 'Protected by secure hardware'
    : 'Protected by software (this phone has no secure hardware for keys)';
}

Copyfunction walletKeyIsHardware() {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return false;
  if (!ks.hasKey('wallet')) {
    var r = ks.generateKey('wallet', { requireAuth: true });
    if (!r.ok) return false;
  }
  return ks.isHardwareBacked('wallet');
}

if (!walletKeyIsHardware()) {
  alert('This phone cannot keep the wallet key in secure hardware.');
}

Copyfunction keyReport() {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return { secureKeys: false };
  return {
    secureKeys: true,
    keys: ks.listKeys().map(function (alias) {
      return { alias: alias, hardware: ks.isHardwareBacked(alias) };
    })
  };
}
console.log(JSON.stringify(keyReport()));

Copyfunction renderKeyList() {
  var list = document.getElementById('key-list');
  list.innerHTML = '';
  if (!window.AppMintKeystore) return;
  window.AppMintKeystore.listKeys().forEach(function (alias) {
    var li = document.createElement('li');
    li.textContent = alias + (window.AppMintKeystore.isHardwareBacked(alias) ? ' (hardware)' : '');
    list.appendChild(li);
  });
}

Copyfunction eraseAllKeys() {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return 0;
  var removed = 0;
  ks.listKeys().forEach(function (alias) {
    if (ks.deleteKey(alias)) removed++;
  });
  localStorage.clear();   // the sealed copies can no longer be opened anyway
  return removed;
}

Copyfunction pruneUserKeys(currentUserId) {
  var ks = window.AppMintKeystore;
  if (!ks || !ks.isAvailable()) return;
  var keep = 'user-' + currentUserId;   // aliases: letters, digits, _ - . only
  ks.listKeys().forEach(function (alias) {
    if (alias.indexOf('user-') === 0 && alias !== keep) ks.deleteKey(alias);
  });
}

Copyfunction unlockWithFingerprint() {
  return new Promise(function (resolve) {
    if (!window.WebToApk || typeof window.WebToApk.authenticateBiometric !== 'function') {
      resolve({ ok: false, error: 'not_in_app' });
      return;
    }
    var id = 'bio_' + Date.now();
    window.__webToApkAuth = window.__webToApkAuth || {};
    window.__webToApkAuth[id] = function (json) { resolve(JSON.parse(json)); };
    window.WebToApk.authenticateBiometric(id, 'Unlock', 'Touch the fingerprint sensor');
  });
}

document.getElementById('unlock').addEventListener('click', async function () {
  var r = await unlockWithFingerprint();
  if (r.ok) showMyApp();
  else if (r.error === 'user_cancel') { /* the user closed it — do nothing */ }
  else if (r.error === 'none_enrolled') alert('Please add a fingerprint in phone settings.');
  else if (r.error === 'lockout') alert('Too many tries. Wait a little and try again.');
  else alert('Could not unlock: ' + r.error);
});

Copyfunction confirmItsYou(subtitle) {
  return new Promise(function (resolve) {
    if (!window.WebToApk || typeof window.WebToApk.authenticateBiometric !== 'function') {
      resolve({ ok: false, error: 'not_in_app' });
      return;
    }
    var id = 'confirm_' + Date.now();
    window.__webToApkAuth = window.__webToApkAuth || {};
    window.__webToApkAuth[id] = function (json) { resolve(JSON.parse(json)); };
    window.WebToApk.authenticateBiometric(id, '', subtitle);
  });
}

document.getElementById('delete-account').addEventListener('click', async function () {
  var r = await confirmItsYou('Confirm to delete your account');
  if (r.ok) deleteMyAccount();
  else if (r.error !== 'user_cancel') alert('Not confirmed: ' + r.error);
});

Copyvar hiddenAt = 0;

document.addEventListener('visibilitychange', async function () {
  if (document.visibilityState === 'hidden') {
    hiddenAt = Date.now();
    return;
  }
  if (!hiddenAt || Date.now() - hiddenAt < 60000) return;
  hiddenAt = 0;
  hideMyApp();
  var r = await unlockWithFingerprint();     // from the first example
  if (r.ok) showMyApp();
  else showLockedScreen();                   // with its own "Unlock" button
});

Copyfunction verifyUser(options) {
  return new Promise(function (resolve) {
    if (!window.WebToApk || typeof window.WebToApk.authenticateBiometricEx !== 'function') {
      resolve({ ok: false, error: 'not_in_app' });
      return;
    }
    var id = 'bio_' + Date.now() + '_' + Math.random().toString(36).slice(2);
    window.__webToApkAuth = window.__webToApkAuth || {};
    window.__webToApkAuth[id] = function (json) { resolve(JSON.parse(json)); };
    window.WebToApk.authenticateBiometricEx(id, JSON.stringify(options));
  });
}

Copyasync function unlockApp() {
  var r = await verifyUser({
    title: 'Unlock',
    subtitle: 'Use your fingerprint or PIN',
    allowDeviceCredential: true       // Android 11+: the system adds "Use PIN"
  });
  if (r.ok) showMyApp();
  else if (r.error === 'lockout') alert('Too many tries. Wait a little and try again.');
}

Copyasync function confirmPayment() {
  var r = await verifyUser({
    title: 'Confirm payment',
    description: 'Pay 12.00 to Coffee House',
    negativeButtonText: 'Not now',
    strong: true                      // BIOMETRIC_STRONG (Android 11+)
  });
  if (r.ok) sendPayment();
  else if (r.error !== 'user_cancel') alert('Could not confirm: ' + r.error);
}

Copyasync function openVault() {
  var r = await verifyUser({ title: 'Open vault', allowDeviceCredential: true });
  if (r.ok) readSecret();    // AppMintKeystore.decrypt works for authValiditySeconds now
}

Copyfunction fromBase64(b64) { return decodeURIComponent(escape(atob(b64))); }

function openNote() {
  if (!window.WebToApk || typeof window.WebToApk.decryptWithKey !== 'function') return null;
  var sealed = localStorage.getItem('note');
  if (!sealed) return null;
  var r = JSON.parse(window.WebToApk.decryptWithKey('vault', sealed));
  if (r.ok) return fromBase64(r.base64);

  if (r.error === 'auth-required') {
    askUserToUnlockThenRetry();          // unlock with authenticateBiometricEx, then call again
  } else if (r.error === 'no-such-key' || r.error === 'key-invalidated') {
    alert('This note can no longer be opened.');   // the key was deleted or the screen lock changed
  } else {
    alert('Could not open the note: ' + r.error);
  }
  return null;
}

Copyfunction unlock() {
  return new Promise(function (resolve) {
    var id = 'unlock_' + Date.now();
    window.__webToApkAuth = window.__webToApkAuth || {};
    window.__webToApkAuth[id] = function (json) { resolve(JSON.parse(json)); };
    window.WebToApk.authenticateBiometricEx(id, JSON.stringify({
      title: 'Unlock your notes', strong: true, allowDeviceCredential: true
    }));
  });
}

async function openNoteWithUnlock() {
  if (!window.WebToApk || typeof window.WebToApk.decryptWithKey !== 'function') return null;
  var sealed = localStorage.getItem('note');
  if (!sealed) return null;
  var r = JSON.parse(window.WebToApk.decryptWithKey('vault', sealed));
  if (!r.ok && r.error === 'auth-required') {
    var auth = await unlock();
    if (!auth.ok) return null;                      // cancelled or failed
    r = JSON.parse(window.WebToApk.decryptWithKey('vault', sealed));
  }
  return r.ok ? decodeURIComponent(escape(atob(r.base64))) : null;
}

Copyfunction showSealedPhoto(sealedB64, img) {
  if (!window.WebToApk || typeof window.WebToApk.decryptWithKey !== 'function') return;
  var r = JSON.parse(window.WebToApk.decryptWithKey('vault', sealedB64));
  if (!r.ok) {
    alert('Could not open the photo: ' + r.error);
    return;
  }
  var bin = atob(r.base64);
  var bytes = new Uint8Array(bin.length);
  for (var i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
  var url = URL.createObjectURL(new Blob([bytes], { type: 'image/jpeg' }));
  img.onload = function () { URL.revokeObjectURL(url); };
  img.src = url;
}

Copyfunction destroyVault() {
  if (!window.WebToApk || typeof window.WebToApk.deleteKey !== 'function') return;
  if (!confirm('Delete the vault? This cannot be undone.')) return;

  var gone = window.WebToApk.deleteKey('vault') === 'true';
  localStorage.removeItem('note');              // the sealed data is now useless anyway
  alert(gone ? 'Vault deleted.' : 'There was no vault to delete.');
}

Copyfunction rotateVault() {
  var W = window.WebToApk;
  if (!W || typeof W.deleteKey !== 'function') return false;
  var sealed = localStorage.getItem('note');
  if (!sealed) return false;

  var clear = JSON.parse(W.decryptWithKey('vault', sealed));
  if (!clear.ok) return false;
  var made = JSON.parse(W.generateKey('vault2', '{}'));
  if (!made.ok) return false;
  var fresh = JSON.parse(W.encryptWithKey('vault2', clear.base64));
  if (!fresh.ok) return false;

  localStorage.setItem('note', fresh.base64);
  localStorage.setItem('noteKey', 'vault2');
  return W.deleteKey('vault') === 'true';          // the old copies are dead from here on
}

Copyfunction signOutAndForget(userId) {
  var alias = 'user_' + userId;
  if (window.WebToApk && typeof window.WebToApk.deleteKey === 'function') {
    var gone = window.WebToApk.deleteKey(alias) === 'true';
    console.log(gone ? 'Account key destroyed' : 'No key for this account');
  }
  localStorage.removeItem('messages_' + userId);   // sealed with that key, unreadable now
  signOut();
}

Copyfunction toBase64(text) { return btoa(unescape(encodeURIComponent(text))); }

function sealNote(text) {
  if (!window.WebToApk || typeof window.WebToApk.encryptWithKey !== 'function') return null;
  var r = JSON.parse(window.WebToApk.encryptWithKey('vault', toBase64(text)));
  if (r.ok) {
    localStorage.setItem('note', r.base64);   // safe to store anywhere: useless without the key
    return r.base64;
  }
  if (r.error === 'auth-required') {
    // key was made with requireAuth — unlock first (authenticateBiometricEx), then call again
    askUserToUnlockThenRetry();
  } else {
    alert('Could not encrypt: ' + r.error);
  }
  return null;
}

Copyfunction sealJson(alias, obj) {
  if (!window.WebToApk || typeof window.WebToApk.encryptWithKey !== 'function') return null;
  var b64 = btoa(unescape(encodeURIComponent(JSON.stringify(obj))));
  var r = JSON.parse(window.WebToApk.encryptWithKey(alias, b64));
  if (!r.ok) console.warn('encrypt failed: ' + r.error);
  return r.ok ? r.base64 : null;
}

var sealed = sealJson('vault', { token: accessToken, savedAt: Date.now() });
if (sealed) localStorage.setItem('session', sealed);

Copydocument.getElementById('id-photo').addEventListener('change', async function (e) {
  var file = e.target.files[0];
  if (!file || !window.WebToApk || typeof window.WebToApk.encryptWithKey !== 'function') return;
  var bytes = new Uint8Array(await file.arrayBuffer());
  var bin = '';
  for (var i = 0; i < bytes.length; i += 0x8000) {
    bin += String.fromCharCode.apply(null, bytes.subarray(i, i + 0x8000));
  }
  var r = JSON.parse(window.WebToApk.encryptWithKey('vault', btoa(bin)));
  if (r.ok) {
    saveSealedPhoto(file.name, r.base64);          // your own storage
  } else if (r.error.indexOf('chunk too large') === 0) {
    alert('That photo is too big. Pick one under 4 MB.');
  } else {
    alert('Could not encrypt the photo: ' + r.error);
  }
});

Copyfunction createVaultKey() {
  if (!window.WebToApk || typeof window.WebToApk.generateKey !== 'function') {
    alert('Secure keys work only in the app.');
    return false;
  }
  var options = {
    requireAuth: true,          // key works only after the user unlocks (fingerprint / PIN)
    authValiditySeconds: 30,    // ...and for 30 seconds after that unlock
    strongBox: false            // true = demand the separate secure chip (fails if missing)
  };
  var r = JSON.parse(window.WebToApk.generateKey('vault', JSON.stringify(options)));
  if (!r.ok) {
    alert('Could not create the key: ' + r.error);
    return false;
  }
  if (!r.hardwareBacked) console.log('Key is kept in software on this phone');
  return true;
}

Copyvar r = JSON.parse(window.WebToApk.generateKey('notes', '{}'));

Copyfunction ensureKey(alias) {
  if (!window.WebToApk || typeof window.WebToApk.generateKey !== 'function') return false;
  if (window.WebToApk.hasKey(alias) === 'true') return true;    // keep the existing key
  var r = JSON.parse(window.WebToApk.generateKey(alias, '{}'));
  if (!r.ok && r.error === 'disabled') {
    console.warn('Secure Keys was not turned on for this build');
  }
  return r.ok;
}

if (ensureKey('notes')) enableEncryptedNotes();

Copyfunction createWalletKey() {
  if (!window.WebToApk || typeof window.WebToApk.generateKey !== 'function') return false;
  var r = JSON.parse(window.WebToApk.generateKey('wallet', JSON.stringify({
    requireAuth: true,
    authValiditySeconds: 10,
    strongBox: true
  })));
  if (r.ok) return true;
  if (r.error === 'strongbox-unavailable') {
    alert('The wallet needs a phone with a dedicated security chip.');
  } else if (r.error === 'bad alias') {
    alert('Key names may use letters, digits, _ - . only.');
  } else {
    alert('Could not create the wallet key: ' + r.error);
  }
  return false;
}

Copyfunction vaultExists() {
  if (!window.WebToApk || typeof window.WebToApk.hasKey !== 'function') return false;
  return window.WebToApk.hasKey('vault') === 'true';   // compare the string
}

if (!vaultExists()) {
  showCreateVaultScreen();
}

Copyfunction chooseStartScreen() {
  if (!window.WebToApk || typeof window.WebToApk.hasKey !== 'function') return showMyApp();
  var hasVault = window.WebToApk.hasKey('vault') === 'true';
  var hasData = localStorage.getItem('note') !== null;

  if (hasVault) {
    showUnlockScreen();
  } else if (hasData) {
    localStorage.removeItem('note');          // sealed with a key that no longer exists
    showCreateVaultScreen('Your old vault could not be opened, so it was cleared.');
  } else {
    showCreateVaultScreen();
  }
}

Copyfunction keyAliasFor(userId) {
  // aliases allow letters, digits, _ - . and at most 64 characters
  return 'user_' + String(userId).replace(/[^A-Za-z0-9_.-]/g, '_').slice(0, 59);
}

function onSignedIn(user) {
  if (!window.WebToApk || typeof window.WebToApk.hasKey !== 'function') return openAccount(user, null);
  var alias = keyAliasFor(user.id);
  if (window.WebToApk.hasKey(alias) !== 'true') {
    var r = JSON.parse(window.WebToApk.generateKey(alias, '{}'));
    if (!r.ok) return alert('Could not set up secure storage: ' + r.error);
  }
  openAccount(user, alias);
}

Copyfunction setupFingerprintButton() {
  var btn = document.getElementById('fingerprint-button');
  if (!window.WebToApk || typeof window.WebToApk.isBiometricAvailable !== 'function') {
    btn.hidden = true;                      // browser: no fingerprint bridge
    return;
  }
  var state = window.WebToApk.isBiometricAvailable();
  if (state === 'available') {
    btn.hidden = false;
  } else if (state === 'not_enrolled') {
    btn.hidden = true;
    showHint('Add a fingerprint in your phone settings to unlock with it.');
  } else {
    btn.hidden = true;                      // no_hardware / unavailable
  }
}

Copyvar BIO_REASONS = {
  no_hardware: 'This phone has no fingerprint or face sensor.',
  not_enrolled: 'Set up a fingerprint or face unlock in your phone settings first.',
  unavailable: 'The sensor cannot be used right now.'
};

function renderBioSwitch() {
  var sw = document.getElementById('bio-switch');
  var note = document.getElementById('bio-note');
  var inApp = window.WebToApk && typeof window.WebToApk.isBiometricAvailable === 'function';
  var state = inApp ? window.WebToApk.isBiometricAvailable() : 'not_in_app';
  sw.disabled = state !== 'available';
  if (sw.disabled) sw.checked = false;
  note.textContent = state === 'not_in_app' ? 'Available in the app.' : (BIO_REASONS[state] || '');
}

Copydocument.addEventListener('visibilitychange', function () {
  if (document.visibilityState !== 'visible') return;
  if (!window.WebToApk || typeof window.WebToApk.isBiometricAvailable !== 'function') return;
  if (window.WebToApk.isBiometricAvailable() === 'available') {
    renderBioSwitch();
    showHint('Fingerprint unlock is ready. Turn it on in Settings.');
  }
});

Copyfunction describeVault() {
  if (!window.WebToApk || typeof window.WebToApk.isKeyHardwareBacked !== 'function') return;
  var hw = window.WebToApk.isKeyHardwareBacked('vault') === 'true';
  document.getElementById('vault-info').textContent = hw
    ? 'Your key is locked in this phone\'s secure hardware.'
    : 'Your key is protected by software on this phone.';
}

Copyfunction setUpWalletKey() {
  var W = window.WebToApk;
  if (!W || typeof W.isKeyHardwareBacked !== 'function') return false;
  var r = JSON.parse(W.generateKey('wallet', JSON.stringify({ requireAuth: true })));
  if (!r.ok) return false;
  if (W.isKeyHardwareBacked('wallet') !== 'true') {
    W.deleteKey('wallet');
    alert('This phone cannot keep the wallet key in secure hardware, so the wallet is off here.');
    return false;
  }
  return true;
}

Copyfunction deviceSecurity() {
  var W = window.WebToApk;
  var inApp = !!W && typeof W.isKeyHardwareBacked === 'function';
  return {
    secureKeys: inApp && W.isKeystoreEnabled() === 'true',
    hardwareKey: inApp && W.isKeyHardwareBacked('vault') === 'true'
  };
}

fetch('/api/sign-in', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ email: email, password: password, device: deviceSecurity() })
});

Copyfunction keystoreReady() {
  return !!window.WebToApk &&
    typeof window.WebToApk.isKeystoreEnabled === 'function' &&
    window.WebToApk.isKeystoreEnabled() === 'true';
}

document.getElementById('vault-button').hidden = !keystoreReady();

Copyvar canSeal = !!window.WebToApk &&
  typeof window.WebToApk.isKeystoreEnabled === 'function' &&
  window.WebToApk.isKeystoreEnabled() === 'true';

var remember = document.getElementById('remember-me');
remember.parentElement.hidden = !canSeal;

function afterSignIn(token) {
  if (!canSeal || !remember.checked) return;      // nothing stored in plain text
  if (window.WebToApk.hasKey('session') !== 'true') window.WebToApk.generateKey('session', '{}');
  var r = JSON.parse(window.WebToApk.encryptWithKey('session', btoa(token)));
  if (r.ok) localStorage.setItem('token', r.base64);
}

Copyfunction keystoreStatus() {
  if (!window.WebToApk) return 'browser: no app bridge';
  if (typeof window.WebToApk.isKeystoreEnabled !== 'function') return 'app without the keystore bridge';
  return window.WebToApk.isKeystoreEnabled() === 'true'
    ? 'Secure Keys on'
    : 'Secure Keys off in this build';
}

console.log('Keystore:', keystoreStatus());

Copyfunction showKeys() {
  if (!window.WebToApk || typeof window.WebToApk.listKeys !== 'function') return;
  var aliases = JSON.parse(window.WebToApk.listKeys());
  document.getElementById('keys').textContent =
    aliases.length ? aliases.join(', ') : 'No keys yet';
}

Copyfunction renderKeyManager() {
  if (!window.WebToApk || typeof window.WebToApk.listKeys !== 'function') return;
  var list = document.getElementById('key-list');
  list.innerHTML = '';
  JSON.parse(window.WebToApk.listKeys()).forEach(function (alias) {
    var hw = window.WebToApk.isKeyHardwareBacked(alias) === 'true';
    var li = document.createElement('li');
    li.textContent = alias + (hw ? ' (secure hardware) ' : ' (software) ');
    var del = document.createElement('button');
    del.textContent = 'Delete';
    del.onclick = function () {
      if (!confirm('Delete "' + alias + '"? Data sealed with it is lost for good.')) return;
      window.WebToApk.deleteKey(alias);
      renderKeyManager();
    };
    li.appendChild(del);
    list.appendChild(li);
  });
}

Copyfunction forgetAllAccounts() {
  if (!window.WebToApk || typeof window.WebToApk.listKeys !== 'function') return 0;
  var removed = 0;
  JSON.parse(window.WebToApk.listKeys()).forEach(function (alias) {
    if (alias.indexOf('user_') === 0 && window.WebToApk.deleteKey(alias) === 'true') removed++;
  });
  return removed;
}

document.getElementById('sign-out').addEventListener('click', function () {
  var n = forgetAllAccounts();
  console.log('Destroyed ' + n + ' account key(s)');
  signOut();
});