feat(call, voicemail, ivr): add voicemail and IVR call flows with DTMF handling, prompt playback, recording, and dashboard management

ts/sip/helpers.ts

@@ -188,3 +188,54 @@ export function parseSdpEndpoint(sdp: string): { address: string; port: number }
   }
   return addr && port ? { address: addr, port } : null;
 }
+
+// ---------------------------------------------------------------------------
+// MWI (Message Waiting Indicator) — RFC 3842
+// ---------------------------------------------------------------------------
+
+/**
+ * Build a SIP NOTIFY request for Message Waiting Indicator.
+ *
+ * Sent out-of-dialog to notify a device about voicemail message counts.
+ * Uses the message-summary event package per RFC 3842.
+ */
+export interface IMwiOptions {
+  /** Proxy LAN IP and port (Via / From / Contact). */
+  proxyHost: string;
+  proxyPort: number;
+  /** Target device URI (e.g. "sip:user@192.168.5.100:5060"). */
+  targetUri: string;
+  /** Account URI for the voicebox (used in the From header). */
+  accountUri: string;
+  /** Number of new (unheard) voice messages. */
+  newMessages: number;
+  /** Number of old (heard) voice messages. */
+  oldMessages: number;
+}
+
+/**
+ * Build the body and headers for an MWI NOTIFY (RFC 3842 message-summary).
+ *
+ * Returns the body string and extra headers needed. The caller builds
+ * the SipMessage via SipMessage.createRequest('NOTIFY', ...).
+ */
+export function buildMwiBody(newMessages: number, oldMessages: number, accountUri: string): {
+  body: string;
+  contentType: string;
+  extraHeaders: [string, string][];
+} {
+  const hasNew = newMessages > 0;
+  const body =
+    `Messages-Waiting: ${hasNew ? 'yes' : 'no'}\r\n` +
+    `Message-Account: ${accountUri}\r\n` +
+    `Voice-Message: ${newMessages}/${oldMessages}\r\n`;
+
+  return {
+    body,
+    contentType: 'application/simple-message-summary',
+    extraHeaders: [
+      ['Event', 'message-summary'],
+      ['Subscription-State', 'terminated;reason=noresource'],
+    ],
+  };
+}