feat: implement janus-client class for core sip client functionality

* Introduces JanusClient class as the central component for SIP calls.
* Manages connection to Janus server, plugin attachment, and SIP
registration.
* Handles call creation and management through CallAgent.
* Provides methods for connecting, making calls, getting calls, and setting
remote media element.
* Includes event handling for listening to call events.
* Implements stubs for enabling/disabling webcam and disconnection (to be
completed).

BREAKING CHANGE: Introduces a new class for core functionality, potentially
affecting code organization and usage.

packages/js/src/Modules/Janus/Client.ts

@@ -0,0 +1,108 @@
+import { Call } from './Call';
+import { Connection } from './Connection';
+import { deRegister, register } from './Handler';
+import KeepAliveAgent from './KeepAliveAgent';
+import { SIPRegistrationAgent } from './SIPRegistrationAgent';
+import { transactionManager } from './TransactionManager';
+import { Environment } from './constants';
+import { IClientOptions } from './interfaces';
+import { AttachSipPluginTransaction } from './transactions/AttachSIPPlugin';
+import { CreateSessionTransaction } from './transactions/CreateSession';
+import CallAgent from './CallAgent';
+import { ICallOptions } from 'src/utils/interfaces';
+
+export default class JanusClient {
+  private _gatewaySessionId: number | null = null;
+  private _gatewayHandleId: number | null = null;
+  private _connection: Connection;
+  private _options: IClientOptions;
+  private _sipRegistrationAgent: SIPRegistrationAgent;
+  private _keepAliveAgent: KeepAliveAgent;
+  private _callAgent: CallAgent;
+
+  static telnyxStateCall(call: Call) {
+    return call;
+  }
+  constructor(options: IClientOptions) {
+    this._connection = new Connection({
+      environment: Environment.production,
+    });
+    this._options = options;
+  }
+
+  public async connect() {
+    this._connection.connect();
+
+    const { sessionId } = await transactionManager.execute(
+      new CreateSessionTransaction()
+    );
+
+    this._gatewaySessionId = sessionId;
+
+    const { handleId } = await transactionManager.execute(
+      new AttachSipPluginTransaction({
+        sessionId: this._gatewaySessionId,
+      })
+    );
+    this._gatewayHandleId = handleId;
+
+    this._keepAliveAgent = new KeepAliveAgent({
+      connection: this._connection,
+      gatewaySessionId: this._gatewaySessionId,
+    });
+
+    this._sipRegistrationAgent = new SIPRegistrationAgent({
+      connection: this._connection,
+      options: this._options,
+      sessionId: this._gatewaySessionId,
+      handleId: this._gatewayHandleId,
+    });
+
+    this._callAgent = new CallAgent({
+      gatewayHandleId: this._gatewayHandleId,
+      gatewaySessionId: this._gatewaySessionId,
+      connection: this._connection,
+    });
+
+    await this._sipRegistrationAgent.register();
+    this._keepAliveAgent.start();
+  }
+
+  async newCall(options: ICallOptions) {
+    const call = await this._callAgent.Outbound({
+      ...options,
+      handleId: this._gatewayHandleId,
+      sessionId: this._gatewaySessionId,
+    });
+    return call;
+  }
+
+  get calls() {
+    return this._callAgent.calls;
+  }
+  public disconnect() {
+    // TODO - implement
+  }
+
+  public enableWebcam() {
+    // TODO - implement
+    return true;
+  }
+  public disableWebcam() {
+    // TODO - implement
+    return true;
+  }
+
+  set remoteElement(
+    element: HTMLMediaElement | string | (() => HTMLMediaElement)
+  ) {
+    this._callAgent.remoteElement = element;
+  }
+
+  on(eventName: string, callback: Function) {
+    register(eventName, callback);
+  }
+  off(eventName: string, callback: Function) {
+    deRegister(eventName, callback);
+  }
+}

packages/js/src/Modules/Janus/index.ts

@@ -0,0 +1 @@
+export * from './Client'

packages/js/src/TelnyxRTC.ts

@@ -1,5 +1,4 @@
 /* eslint-disable no-useless-constructor */
-import TelnyxRTCClient from './Modules/Verto';
 import { ICallOptions, IClientOptions } from './utils/interfaces';
 import {
   getWebRTCInfo,
@@ -11,6 +10,7 @@ import {
 } from './Modules/Verto/webrtc/interfaces';
 
 import * as pkg from '../package.json';
+import JanusClient from './Modules/Janus/Client';
 
 /**
  * The `TelnyxRTC` client connects your application to the Telnyx backend,
@@ -49,7 +49,7 @@ import * as pkg from '../package.json';
  *
  * @category Client
  */
-export class TelnyxRTC extends TelnyxRTCClient {
+export class TelnyxRTC extends JanusClient {
   /**
    * Creates a new `TelnyxRTC` instance with the provided options.
    *
@@ -153,7 +153,7 @@ export class TelnyxRTC extends TelnyxRTCClient {
    * // => `destinationNumber is required`
    * ```
    */
-  newCall(options: ICallOptions) {
+  newCall = (options: ICallOptions) => {
     return super.newCall(options);
   }