feat: nevermind, migrate push notification handling from UnifiedPush to FCM

lib/push/base64url.ts

@@ -1,14 +0,0 @@
-export function b64uEncode(buf: Buffer | Uint8Array): string {
-  const b = Buffer.isBuffer(buf) ? buf : Buffer.from(buf);
-  return b
-    .toString('base64')
-    .replace(/\+/g, '-')
-    .replace(/\//g, '_')
-    .replace(/=+$/, '');
-}
-
-export function b64uDecode(value: string): Buffer {
-  const padded = value.replace(/-/g, '+').replace(/_/g, '/');
-  const padLen = (4 - (padded.length % 4)) % 4;
-  return Buffer.from(padded + '='.repeat(padLen), 'base64');
-}

lib/push/fcm.ts

@@ -0,0 +1,158 @@
+import crypto from 'node:crypto';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import type { StateChange } from './types';
+import type { SubscriptionRecord } from './types';
+
+interface ServiceAccount {
+  type: string;
+  project_id: string;
+  private_key_id: string;
+  private_key: string;
+  client_email: string;
+  token_uri: string;
+}
+
+let cachedAccount: ServiceAccount | null = null;
+let cachedAccessToken: { token: string; expiresAt: number } | null = null;
+
+async function loadServiceAccount(): Promise<ServiceAccount> {
+  if (cachedAccount) return cachedAccount;
+
+  const inline = process.env.FCM_SERVICE_ACCOUNT_JSON;
+  if (inline && inline.trim().startsWith('{')) {
+    cachedAccount = JSON.parse(inline) as ServiceAccount;
+    return cachedAccount;
+  }
+
+  const filePath = inline && inline.trim().length > 0
+    ? inline
+    : path.join(process.env.PUSH_DATA_DIR ?? './data/push', 'fcm-service-account.json');
+  const raw = await fs.readFile(filePath, 'utf8');
+  cachedAccount = JSON.parse(raw) as ServiceAccount;
+  return cachedAccount;
+}
+
+function base64url(buf: Buffer | string): string {
+  const b = Buffer.isBuffer(buf) ? buf : Buffer.from(buf);
+  return b.toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
+}
+
+async function mintAccessToken(): Promise<string> {
+  const now = Date.now();
+  if (cachedAccessToken && cachedAccessToken.expiresAt - 60_000 > now) {
+    return cachedAccessToken.token;
+  }
+
+  const account = await loadServiceAccount();
+  const iat = Math.floor(now / 1000);
+  const exp = iat + 3600;
+  const header = { alg: 'RS256', typ: 'JWT', kid: account.private_key_id };
+  const claim = {
+    iss: account.client_email,
+    scope: 'https://www.googleapis.com/auth/firebase.messaging',
+    aud: account.token_uri ?? 'https://oauth2.googleapis.com/token',
+    iat,
+    exp,
+  };
+  const signingInput = `${base64url(JSON.stringify(header))}.${base64url(JSON.stringify(claim))}`;
+  const signature = crypto
+    .createSign('RSA-SHA256')
+    .update(signingInput)
+    .sign(account.private_key);
+  const jwt = `${signingInput}.${base64url(signature)}`;
+
+  const res = await fetch(account.token_uri ?? 'https://oauth2.googleapis.com/token', {
+    method: 'POST',
+    headers: { 'content-type': 'application/x-www-form-urlencoded' },
+    body: new URLSearchParams({
+      grant_type: 'urn:ietf:params:oauth:grant-type:jwt-bearer',
+      assertion: jwt,
+    }),
+  });
+  if (!res.ok) {
+    throw new Error(`FCM oauth2 token failed: ${res.status} ${await res.text()}`);
+  }
+  const body = (await res.json()) as { access_token: string; expires_in: number };
+  cachedAccessToken = {
+    token: body.access_token,
+    expiresAt: now + body.expires_in * 1000,
+  };
+  return body.access_token;
+}
+
+export interface FcmSendResult {
+  ok: boolean;
+  status: number;
+  unregistered: boolean;
+  body?: unknown;
+}
+
+/**
+ * Send a data message via FCM HTTP v1. Returns `unregistered: true` if the
+ * token was rejected with UNREGISTERED / NOT_FOUND — callers should delete
+ * the subscription in that case.
+ */
+export async function sendFcmPush(
+  record: SubscriptionRecord,
+  change: StateChange,
+): Promise<FcmSendResult> {
+  const account = await loadServiceAccount();
+  const accessToken = await mintAccessToken();
+  const hasEmail = Boolean(change.changed && Object.values(change.changed).some((types) => 'Email' in types));
+
+  const title = hasEmail ? 'New mail' : 'Mailbox updated';
+  const body = record.accountLabel ?? 'Tap to open Bulwark';
+
+  const message = {
+    message: {
+      token: record.fcmToken,
+      android: {
+        priority: 'HIGH',
+        notification: {
+          title,
+          body,
+          channel_id: 'bulwark_mail',
+          default_sound: true,
+        },
+      },
+      data: {
+        kind: 'jmap-state-change',
+        changed: JSON.stringify(change.changed ?? {}),
+      },
+    },
+  };
+
+  const res = await fetch(
+    `https://fcm.googleapis.com/v1/projects/${encodeURIComponent(account.project_id)}/messages:send`,
+    {
+      method: 'POST',
+      headers: {
+        authorization: `Bearer ${accessToken}`,
+        'content-type': 'application/json',
+      },
+      body: JSON.stringify(message),
+    },
+  );
+
+  const rawBody = await res.text();
+  let parsed: unknown = rawBody;
+  try {
+    parsed = rawBody.length > 0 ? JSON.parse(rawBody) : null;
+  } catch {
+    // keep raw text
+  }
+
+  const errStatus =
+    typeof parsed === 'object' && parsed && 'error' in parsed
+      ? ((parsed as { error?: { status?: string } }).error?.status ?? '')
+      : '';
+  const unregistered = res.status === 404 || errStatus === 'UNREGISTERED' || errStatus === 'NOT_FOUND';
+
+  return {
+    ok: res.ok,
+    status: res.status,
+    unregistered,
+    body: parsed,
+  };
+}

lib/push/types.ts

@@ -2,13 +2,7 @@
 // so both server code and admin UIs can import without pulling `node:fs`.
 
 export interface SubscriptionRecord {
-  // UnifiedPush / Web Push endpoint the distributor gave the app. The relay
-  // POSTs RFC 8291 aes128gcm-encrypted bodies here.
-  endpoint: string;
-  // P-256 public key (UA), uncompressed 65-byte point, base64url without padding.
-  p256dh: string;
-  // Auth secret, 16 bytes, base64url without padding.
-  auth: string;
+  fcmToken: string;
   verificationCode: string | null;
   createdAt: number;
   lastPushAt: number | null;

lib/push/unified-push.ts

@@ -1,57 +0,0 @@
-import { logger } from '@/lib/logger';
-import type { StateChange, SubscriptionRecord } from './types';
-import { sendWebPush } from './web-push';
-import { getVapidKeys } from './vapid';
-
-interface UnifiedPushPayload {
-  kind: 'jmap-state-change';
-  title: string;
-  body: string;
-  changed: Record<string, Record<string, string>>;
-}
-
-function buildPayload(record: SubscriptionRecord, change: StateChange): UnifiedPushPayload {
-  const types = new Set<string>();
-  for (const perAccount of Object.values(change.changed)) {
-    for (const type of Object.keys(perAccount)) types.add(type);
-  }
-  const hasEmail = types.has('Email') || types.has('EmailDelivery');
-  return {
-    kind: 'jmap-state-change',
-    title: hasEmail ? 'New mail' : 'Mailbox updated',
-    body: record.accountLabel ?? '',
-    changed: change.changed,
-  };
-}
-
-export async function sendUnifiedPush(
-  record: SubscriptionRecord,
-  change: StateChange,
-): Promise<boolean> {
-  try {
-    const vapid = await getVapidKeys();
-    const payload = Buffer.from(JSON.stringify(buildPayload(record, change)), 'utf-8');
-    const result = await sendWebPush({
-      endpoint: record.endpoint,
-      p256dh: record.p256dh,
-      auth: record.auth,
-      payload,
-      vapid,
-      ttlSeconds: 60,
-      urgency: 'high',
-    });
-    if (!result.ok) {
-      logger.warn('push: unified-push delivery failed', {
-        status: result.status,
-        body: result.body,
-      });
-      return false;
-    }
-    return true;
-  } catch (error) {
-    logger.warn('push: unified-push delivery error', {
-      error: error instanceof Error ? error.message : 'Unknown error',
-    });
-    return false;
-  }
-}

lib/push/validation.ts

@@ -2,30 +2,9 @@ export function isValidSubscriptionId(id: unknown): id is string {
   return typeof id === 'string' && /^[A-Za-z0-9_-]{8,128}$/.test(id);
 }
 
-export function isValidPushEndpoint(url: unknown): url is string {
-  if (typeof url !== 'string' || url.length > 2048) return false;
-  try {
-    const parsed = new URL(url);
-    return parsed.protocol === 'https:' || parsed.protocol === 'http:';
-  } catch {
-    return false;
-  }
-}
-
-export function isBase64Url(value: unknown, minBytes: number, maxBytes: number): value is string {
-  if (typeof value !== 'string') return false;
-  if (!/^[A-Za-z0-9_-]+$/.test(value)) return false;
-  // base64url decoded length: floor(n * 3 / 4) where n is input length (no padding).
-  const decodedLen = Math.floor((value.length * 3) / 4);
-  return decodedLen >= minBytes && decodedLen <= maxBytes;
-}
-
-export function isValidP256dh(value: unknown): value is string {
-  // Uncompressed P-256 point is 65 bytes (0x04 || X || Y). base64url no padding.
-  return isBase64Url(value, 64, 66);
-}
-
-export function isValidAuthSecret(value: unknown): value is string {
-  // RFC 8291 requires 16 bytes.
-  return isBase64Url(value, 16, 16);
+export function isValidFcmToken(value: unknown): value is string {
+  // FCM registration tokens are opaque. In practice they're ~140–250 chars of
+  // [A-Za-z0-9:_-]. Be permissive on length; strict on charset to block
+  // obvious garbage without rejecting future token formats.
+  return typeof value === 'string' && value.length >= 64 && value.length <= 4096 && /^[A-Za-z0-9:_\-]+$/.test(value);
 }

lib/push/vapid.ts

@@ -1,90 +0,0 @@
-import crypto from 'node:crypto';
-import { readFile, writeFile, mkdir } from 'node:fs/promises';
-import { existsSync } from 'node:fs';
-import path from 'node:path';
-import { b64uDecode, b64uEncode } from './base64url';
-
-interface StoredVapid {
-  publicKey: string;
-  privateKeyPem: string;
-  subject: string;
-}
-
-export interface VapidKeys {
-  publicKey: string;
-  publicKeyBuf: Buffer;
-  privateKeyPem: string;
-  subject: string;
-}
-
-function getVapidPath(): string {
-  const dir = process.env.PUSH_DATA_DIR || path.join(process.cwd(), 'data', 'push');
-  return path.join(dir, 'vapid.json');
-}
-
-function getSubject(): string {
-  return process.env.VAPID_SUBJECT?.trim() || 'mailto:admin@localhost';
-}
-
-// P-256 SPKI DER wraps a 26-byte algorithm identifier followed by a BIT STRING
-// containing the uncompressed point (0x04 || X || Y). Strip the header to get
-// the raw 65-byte public key that VAPID requires.
-function extractUncompressedPoint(spkiDer: Buffer): Buffer {
-  if (spkiDer.length < 65) throw new Error('SPKI DER too short for P-256');
-  return spkiDer.subarray(spkiDer.length - 65);
-}
-
-let cached: VapidKeys | null = null;
-let loading: Promise<VapidKeys> | null = null;
-
-async function loadOrCreate(): Promise<VapidKeys> {
-  const file = getVapidPath();
-  try {
-    const raw = await readFile(file, 'utf-8');
-    const parsed = JSON.parse(raw) as StoredVapid;
-    return {
-      publicKey: parsed.publicKey,
-      publicKeyBuf: b64uDecode(parsed.publicKey),
-      privateKeyPem: parsed.privateKeyPem,
-      subject: parsed.subject,
-    };
-  } catch (error) {
-    if ((error as NodeJS.ErrnoException).code !== 'ENOENT') throw error;
-  }
-
-  const { publicKey, privateKey } = crypto.generateKeyPairSync('ec', {
-    namedCurve: 'prime256v1',
-  });
-  const spki = publicKey.export({ format: 'der', type: 'spki' });
-  const uncompressed = extractUncompressedPoint(spki);
-  const privateKeyPem = privateKey.export({ format: 'pem', type: 'pkcs8' }) as string;
-  const stored: StoredVapid = {
-    publicKey: b64uEncode(uncompressed),
-    privateKeyPem,
-    subject: getSubject(),
-  };
-
-  const dir = path.dirname(file);
-  if (!existsSync(dir)) await mkdir(dir, { recursive: true });
-  const tmp = file + '.tmp';
-  await writeFile(tmp, JSON.stringify(stored, null, 2), 'utf-8');
-  await import('node:fs/promises').then((fs) => fs.rename(tmp, file));
-
-  return {
-    publicKey: stored.publicKey,
-    publicKeyBuf: uncompressed,
-    privateKeyPem: stored.privateKeyPem,
-    subject: stored.subject,
-  };
-}
-
-export async function getVapidKeys(): Promise<VapidKeys> {
-  if (cached) return cached;
-  if (!loading) {
-    loading = loadOrCreate().then((keys) => {
-      cached = keys;
-      return keys;
-    });
-  }
-  return loading;
-}

lib/push/web-push.ts

@@ -1,149 +0,0 @@
-import crypto from 'node:crypto';
-import { b64uDecode, b64uEncode } from './base64url';
-import type { VapidKeys } from './vapid';
-
-// RFC 5869 HKDF-Extract + HKDF-Expand using SHA-256.
-function hkdf(salt: Buffer, ikm: Buffer, info: Buffer, length: number): Buffer {
-  const prk = crypto.createHmac('sha256', salt).update(ikm).digest();
-  const out = Buffer.alloc(length);
-  let previous = Buffer.alloc(0);
-  let offset = 0;
-  let counter = 1;
-  while (offset < length) {
-    const hmac = crypto.createHmac('sha256', prk);
-    hmac.update(previous);
-    hmac.update(info);
-    hmac.update(Buffer.from([counter]));
-    previous = hmac.digest();
-    const copyLen = Math.min(previous.length, length - offset);
-    previous.subarray(0, copyLen).copy(out, offset);
-    offset += copyLen;
-    counter++;
-  }
-  return out;
-}
-
-// RFC 8291 aes128gcm Web Push content encoding (single record).
-export function encryptAes128gcm(params: {
-  p256dh: Buffer;
-  auth: Buffer;
-  payload: Buffer;
-}): Buffer {
-  const ecdh = crypto.createECDH('prime256v1');
-  const serverPublic = ecdh.generateKeys();
-  const sharedSecret = ecdh.computeSecret(params.p256dh);
-  const salt = crypto.randomBytes(16);
-
-  // RFC 8291 §3.3: PRK_key = HMAC-SHA-256(auth_secret, IKM)
-  //                IKM = ECDH shared secret
-  //                info = "WebPush: info\0" || ua_public || as_public
-  const keyInfo = Buffer.concat([
-    Buffer.from('WebPush: info\0', 'utf-8'),
-    params.p256dh,
-    serverPublic,
-  ]);
-  const prkKey = hkdf(params.auth, sharedSecret, keyInfo, 32);
-
-  // RFC 8188 §2.2: derive CEK and nonce from PRK_key with salt.
-  const cek = hkdf(salt, prkKey, Buffer.from('Content-Encoding: aes128gcm\0', 'utf-8'), 16);
-  const nonce = hkdf(salt, prkKey, Buffer.from('Content-Encoding: nonce\0', 'utf-8'), 12);
-
-  // Single-record padding: plaintext || 0x02 (end-of-last-record delimiter).
-  const padded = Buffer.concat([params.payload, Buffer.from([0x02])]);
-
-  const cipher = crypto.createCipheriv('aes-128-gcm', cek, nonce);
-  const ciphertext = Buffer.concat([cipher.update(padded), cipher.final()]);
-  const tag = cipher.getAuthTag();
-
-  // Per RFC 8188 §2.1: salt (16) || rs (4 BE) || idlen (1) || keyid || ciphertext+tag.
-  const rsBuf = Buffer.alloc(4);
-  rsBuf.writeUInt32BE(4096, 0);
-  const idlenBuf = Buffer.from([serverPublic.length]);
-
-  return Buffer.concat([salt, rsBuf, idlenBuf, serverPublic, ciphertext, tag]);
-}
-
-// ECDSA DER → raw r||s (64 bytes) for ES256 signature encoding used by JWT.
-function derEs256ToRaw(der: Buffer): Buffer {
-  if (der[0] !== 0x30) throw new Error('Invalid DER signature');
-  let offset = 2;
-  if (der[1] & 0x80) offset += der[1] & 0x7f;
-  if (der[offset] !== 0x02) throw new Error('Invalid DER r marker');
-  const rLen = der[offset + 1];
-  let r = der.subarray(offset + 2, offset + 2 + rLen);
-  offset += 2 + rLen;
-  if (der[offset] !== 0x02) throw new Error('Invalid DER s marker');
-  const sLen = der[offset + 1];
-  let s = der.subarray(offset + 2, offset + 2 + sLen);
-  const pad = (buf: Buffer) => {
-    if (buf.length === 32) return buf;
-    if (buf.length === 33 && buf[0] === 0x00) return buf.subarray(1);
-    if (buf.length > 32) throw new Error('ECDSA component > 32 bytes');
-    const out = Buffer.alloc(32);
-    buf.copy(out, 32 - buf.length);
-    return out;
-  };
-  return Buffer.concat([pad(r), pad(s)]);
-}
-
-function buildVapidJwt(endpoint: string, vapid: VapidKeys): string {
-  const audience = new URL(endpoint).origin;
-  const header = b64uEncode(Buffer.from(JSON.stringify({ typ: 'JWT', alg: 'ES256' })));
-  const claims = b64uEncode(
-    Buffer.from(
-      JSON.stringify({
-        aud: audience,
-        exp: Math.floor(Date.now() / 1000) + 12 * 3600,
-        sub: vapid.subject,
-      }),
-    ),
-  );
-  const signingInput = `${header}.${claims}`;
-  const der = crypto.createSign('SHA256').update(signingInput).sign(vapid.privateKeyPem);
-  return `${signingInput}.${b64uEncode(derEs256ToRaw(der))}`;
-}
-
-export interface WebPushResult {
-  ok: boolean;
-  status: number;
-  body?: string;
-}
-
-export async function sendWebPush(params: {
-  endpoint: string;
-  p256dh: string;
-  auth: string;
-  payload: Buffer;
-  vapid: VapidKeys;
-  ttlSeconds?: number;
-  urgency?: 'very-low' | 'low' | 'normal' | 'high';
-  topic?: string;
-}): Promise<WebPushResult> {
-  const body = encryptAes128gcm({
-    p256dh: b64uDecode(params.p256dh),
-    auth: b64uDecode(params.auth),
-    payload: params.payload,
-  });
-  const jwt = buildVapidJwt(params.endpoint, params.vapid);
-  const headers: Record<string, string> = {
-    'content-type': 'application/octet-stream',
-    'content-encoding': 'aes128gcm',
-    'content-length': String(body.length),
-    ttl: String(params.ttlSeconds ?? 60),
-    urgency: params.urgency ?? 'high',
-    authorization: `vapid t=${jwt}, k=${params.vapid.publicKey}`,
-  };
-  if (params.topic) headers.topic = params.topic;
-
-  const res = await fetch(params.endpoint, {
-    method: 'POST',
-    headers,
-    body: new Uint8Array(body),
-  });
-  const ok = res.status >= 200 && res.status < 300;
-  return {
-    ok,
-    status: res.status,
-    body: ok ? undefined : await res.text().catch(() => undefined),
-  };
-}