[ACS][Common] OPS - Added Routing Logic Based on Scopes (#47609)

* added routing logic

* fixed comments

* reverted back optional scope param

* fixed tests

sdk/communication/Azure.Communication.Common/CHANGELOG.md

@@ -3,6 +3,7 @@
 ## 1.4.0-beta.1 (Unreleased)
 
 ### Features Added
+- Introduced support for `Azure.Core.TokenCredential` with `EntraCommunicationTokenCredentialOptions`, enabling Entra users to authorize Communication Services and allowing an Entra user with a Teams license to use Teams Phone Extensibility features through the Azure Communication Services resource.
 
 ### Breaking Changes
 

sdk/communication/Azure.Communication.Common/README.md

@@ -105,24 +105,46 @@ using var tokenCredential = new CommunicationTokenCredential(
 ### Create a credential with a token credential capable of obtaining an Entra user token
 
 For scenarios where an Entra user can be used with Communication Services, you need to initialize any implementation of [Azure.Core.TokenCredential](https://docs.microsoft.com/dotnet/api/azure.core.tokencredential?view=azure-dotnet) and provide it to the ``EntraCommunicationTokenCredentialOptions``.
-Along with this, you must provide the URI of the Azure Communication Services resource and the scopes required for the Entra user token. These scopes determine the permissions granted to the token:
-
+Along with this, you must provide the URI of the Azure Communication Services resource and the scopes required for the Entra user token. These scopes determine the permissions granted to the token.
+If the scopes are not provided, by default, it sets the scopes to `https://communication.azure.com/clients/.default`.
 ```C# 
 var options = new InteractiveBrowserCredentialOptions
     {
         TenantId = "<your-tenant-id>",
         ClientId = "<your-client-id>",
-        RedirectUri = new Uri("<your-redirect-uri>"),
-        AuthorityHost = new Uri("https://login.microsoftonline.com/<your-tenant-id>")
+        RedirectUri = new Uri("<your-redirect-uri>")
     };
 var entraTokenCredential = new InteractiveBrowserCredential(options);
 
 var entraTokenCredentialOptions = new EntraCommunicationTokenCredentialOptions(
     resourceEndpoint: "https://<your-resource>.communication.azure.com",
-    entraTokenCredential: entraTokenCredential
-){
+    entraTokenCredential: entraTokenCredential)
+    {
       Scopes = new[] { "https://communication.azure.com/clients/VoIP" }
-};
+    };
+
+var credential = new CommunicationTokenCredential(entraTokenCredentialOptions);
+
+```
+
+The same approach can be used for authorizing an Entra user with a Teams license to use Teams Phone Extensibility features through your Azure Communication Services resource.
+This requires providing the `https://auth.msft.communication.azure.com/TeamsExtension.ManageCalls` scope
+```C# 
+var options = new InteractiveBrowserCredentialOptions
+    {
+        TenantId = "<your-tenant-id>",
+        ClientId = "<your-client-id>",
+        RedirectUri = new Uri("<your-redirect-uri>")
+    };
+var entraTokenCredential = new InteractiveBrowserCredential(options);
+
+var entraTokenCredentialOptions = new EntraCommunicationTokenCredentialOptions(
+    resourceEndpoint: "https://<your-resource>.communication.azure.com",
+    entraTokenCredential: entraTokenCredential)
+    )
+    {
+      Scopes = new[] { "https://auth.msft.communication.azure.com/TeamsExtension.ManageCalls" }
+    };
 
 var credential = new CommunicationTokenCredential(entraTokenCredentialOptions);
 

sdk/communication/Azure.Communication.Common/src/EntraTokenCredential.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -15,8 +16,16 @@ namespace Azure.Communication
     /// </summary>
     internal sealed class EntraTokenCredential : ICommunicationTokenCredential
     {
+        private const string TeamsExtensionScopePrefix = "https://auth.msft.communication.azure.com/";
+        private const string ComunicationClientsScopePrefix = "https://communication.azure.com/clients/";
+        private const string TeamsExtensionEndpoint = "/access/teamsPhone/:exchangeAccessToken";
+        private const string TeamsExtensionApiVersion = "2025-03-02-preview";
+        private const string ComunicationClientsEndpoint = "/access/entra/:exchangeAccessToken";
+        private const string ComunicationClientsApiVersion = "2024-04-01-preview";
+
         private HttpPipeline _pipeline;
         private string _resourceEndpoint;
+        private string[] _scopes { get; set; }
         private readonly ThreadSafeRefreshableAccessTokenCache _accessTokenCache;
 
         /// <summary>
@@ -27,6 +36,7 @@ internal sealed class EntraTokenCredential : ICommunicationTokenCredential
         public EntraTokenCredential(EntraCommunicationTokenCredentialOptions options, HttpPipelineTransport pipelineTransport = null)
         {
             this._resourceEndpoint = options.ResourceEndpoint;
+            this._scopes = options.Scopes;
             _pipeline = CreatePipelineFromOptions(options, pipelineTransport);
             _accessTokenCache = new ThreadSafeRefreshableAccessTokenCache(
                     ExchangeEntraToken,
@@ -99,14 +109,9 @@ private async ValueTask<AccessToken> ExchangeEntraTokenAsync(bool async, Cancell
 
         private HttpMessage CreateRequestMessage()
         {
-            var uri = new RequestUriBuilder();
-            uri.Reset(new Uri(_resourceEndpoint));
-            uri.AppendPath("/access/entra/:exchangeAccessToken", false);
-            uri.AppendQuery("api-version", "2024-04-01-preview", true);
-
             var message = _pipeline.CreateMessage();
             var request = message.Request;
-            request.Uri = uri;
+            request.Uri = CreateRequestUri();
             request.Method = RequestMethod.Post;
             request.Headers.Add("Accept", "application/json");
             request.Headers.Add("Content-Type", "application/json");
@@ -115,6 +120,37 @@ private HttpMessage CreateRequestMessage()
             return message;
         }
 
+        private RequestUriBuilder CreateRequestUri()
+        {
+            var uri = new RequestUriBuilder();
+            uri.Reset(new Uri(_resourceEndpoint));
+
+            var (endpoint, apiVersion) = DetermineEndpointAndApiVersion();
+            uri.AppendPath(endpoint, false);
+            uri.AppendQuery("api-version", apiVersion, true);
+            return uri;
+        }
+
+        private (string Endpoint, string ApiVersion) DetermineEndpointAndApiVersion()
+        {
+            if (_scopes == null || !_scopes.Any())
+            {
+                throw new ArgumentException($"Scopes validation failed. Ensure all scopes start with either {TeamsExtensionScopePrefix} or {ComunicationClientsScopePrefix}.", nameof(_scopes));
+            }
+            else if (_scopes.All(item => item.StartsWith(TeamsExtensionScopePrefix)))
+            {
+                return (TeamsExtensionEndpoint, TeamsExtensionApiVersion);
+            }
+            else if (_scopes.All(item => item.StartsWith(ComunicationClientsScopePrefix)))
+            {
+                return (ComunicationClientsEndpoint, ComunicationClientsApiVersion);
+            }
+            else
+            {
+                throw new ArgumentException($"Scopes validation failed. Ensure all scopes start with either {TeamsExtensionScopePrefix} or {ComunicationClientsScopePrefix}.", nameof(_scopes));
+            }
+        }
+
         private AccessToken ParseAccessTokenFromResponse(Response response)
         {
             switch (response.Status)