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utils/e2ee.js

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+/**
+ * E2EE helpers — server never decrypts; only detects envelopes and opaques previews.
+ */
+
+const E2EE_PREVIEW = '🔒 پیام رمزنگاری‌شده'
+
+function isE2eeEnvelope(content) {
+  if (!content || typeof content !== 'string') return false
+  const trimmed = content.trim()
+  if (!trimmed.startsWith('{')) return false
+  try {
+    const parsed = JSON.parse(trimmed)
+    return Boolean(parsed && parsed.e2ee === true && parsed.ciphertext)
+  } catch {
+    return false
+  }
+}
+
+function opaquePreview(content, maxLen = 80) {
+  if (isE2eeEnvelope(content)) return E2EE_PREVIEW
+  const text = String(content || 'پیام')
+  return text.slice(0, maxLen)
+}
+
+module.exports = {
+  E2EE_PREVIEW,
+  isE2eeEnvelope,
+  opaquePreview
+}