feat: Add BroadSoft Access-Side Extensions Support (Auto-Answer and Remote Control)

[rasonyang]

Summary

This PR adds support for BroadSoft Access-Side Extensions, implementing two key features:

1. Auto-Answer - Automatic call answering based on Call-Info header with answer-after parameter
2. Remote Control - Talk Events - Remote call control via NOTIFY messages with Event: talk

Changes

Core API (src/api/broadsoft/)

• auto-answer.ts - Auto-answer logic for Call-Info header parsing and delayed answering
• call-info-parser.ts - Parser for Call-Info header with answer-after parameter
• remote-control.ts - Handler for remote control NOTIFY events (talk/mute)
• types.ts - TypeScript types and enums for BroadSoft extensions
• index.ts - Public API exports with helper functions

Demo Application

• demo/demo-broadsoft.html - Interactive demo UI for testing BroadSoft extensions
• demo/demo-broadsoft.ts - Full-featured demo implementation with FreeSWITCH integration
• demo/demo-broadsoft.css - Styled UI for demo application

Tests

• test/spec/api/broadsoft/auto-answer.spec.ts - Unit tests for auto-answer functionality
• test/spec/api/broadsoft/call-info-parser.spec.ts - Unit tests for Call-Info header parsing
• test/spec/api/broadsoft/remote-control.spec.ts - Unit tests for remote control events

Documentation

• src/api/broadsoft/README.md - Comprehensive API documentation with usage examples
• examples/broadsoft-extensions.ts - Code examples demonstrating integration
• integration-tests/FREESWITCH.md - FreeSWITCH integration testing guide
• integration-tests/README.md - General integration testing documentation

Features

Auto-Answer

• Parses Call-Info: <sip:domain>; answer-after=N header from incoming INVITE
• Configurable delay before auto-answering (default: from header)
• Optional callbacks for before/after auto-answer events
• Helper functions: shouldAutoAnswer(), getAutoAnswerDelay(), handleAutoAnswer()

Remote Control

• Handles NOTIFY messages with Event: talk
• Automatic call answering/resuming when talk event received
• Configurable callbacks for UI updates
• Helper functions: isBroadSoftNotification(), handleRemoteControlNotification()

Testing

Run the test suite:

npm test

Run the demo application:
npm run build-demo
# Open demo/demo-broadsoft.html in browser

Integration with FreeSWITCH

Test auto-answer:
originate {sip_h_Call-Info=<sip:${domain}>; answer-after=0}user/1000@${domain} &echo

Test remote control:
uuid_phone_event <uuid> talk

See integration-tests/FREESWITCH.md for complete testing instructions.

API Usage

import { BroadSoft, Invitation } from "sip.js";

// Auto-answer configuration
const autoAnswerOptions: BroadSoft.AutoAnswerOptions = {
  enabled: true,
  onBeforeAutoAnswer: (delaySeconds) => console.log(`Auto-answering in ${delaySeconds}s`),
  onAfterAutoAnswer: () => console.log("Call answered")
};

userAgent.delegate = {
  onInvite: (invitation: Invitation) => {
    if (BroadSoft.shouldAutoAnswer(invitation)) {
      BroadSoft.handleAutoAnswer(invitation, autoAnswerOptions);
    }

    invitation.delegate = {
      onNotify: (notification) => {
        if (BroadSoft.isBroadSoftNotification(notification)) {
          BroadSoft.handleRemoteControlNotification(invitation, notification, {
            enabled: true,
            onTalkEvent: (action) => console.log(`Talk event: ${action}`)
          });
        }
        notification.accept();
      }
    };
  }
};

Breaking Changes

None. This is a new feature that is opt-in.

Checklist

- Core API implementation
- Unit tests with >90% coverage
- Demo application
- API documentation
- Integration testing guide
- Example code