Update callflow-for-customer-interactions-csharp.md

add recognize code and testing the application

Author: valindrae

articles/communication-services/quickstarts/voice-video-calling/includes/call-automation/callflow-for-customer-interactions-csharp.md

@@ -78,20 +78,16 @@ From the Azure portal, locate your Communication Service resource and click on t
 Using the minimal API feature in .NET 6, we can easily add an HTTP POST map and answer the call. A callback URI is required so the service knows how to contact your web server for subsequent calls state events such as `CallConnected` and `PlayCompleted`.  
 
 NOTE: The code sample also illustrates how you can control the callback URI by setting your own context/ID when you answer the call. All events generated by the call will be sent to the specific route you provide when answering an inbound call and the same applies to when you place an outbound call.
-```csharp
+``` csharp
 using Azure.Communication;
 using Azure.Communication.CallingServer;
 using Azure.Messaging.EventGrid;
 using Microsoft.AspNetCore.Mvc;
 using System.Text.Json;
-
 var builder = WebApplication.CreateBuilder(args);
-
 var client = new CallAutomationClient(builder.Configuration["ACS:ConnectionString"]);
 var callbackUriBase = "<YOUR_NGROK_FQDN>"; // i.e. https://someguid.ngrok.io
-
 var app = builder.Build();
-
 app.MapPost("/api/incomingCall", async (
     [FromBody] EventGridEvent[] eventGridEvents) =>
     {
@@ -110,16 +106,14 @@ app.MapPost("/api/incomingCall", async (
                     return Results.Ok(responseData);
                 }
             }
-
             var jsonObject = JsonNode.Parse(eventGridEvent.Data).AsObject();
             var incomingCallContext = (string)jsonObject["incomingCallContext"];
             var callbackUri = new Uri(callbackUriBase + $"/api/calls/{Guid.NewGuid()}");
             AnswerCallResult answerCallResult = await client.AnswerCallAsync(incomingCallContext, callbackUri);
         }
-
         return Results.Ok();
     });
-
+    
 app.MapPost("/api/calls/{contextId}", async (
     [FromBody] CloudEvent[] cloudEvents,
     [FromRoute] string contextId) =>
@@ -129,24 +123,30 @@ app.MapPost("/api/calls/{contextId}", async (
         CallAutomationEventBase @event = CallAutomationEventParser.Parse(cloudEvent);
         if (@event == typeof(CallConnected))
         {
-            // play audio file to caller
+            // recognize pin input of 123
             var playSource = new FileSource("<INSERT_AUDIO_FILE_URI>");
-            var playOptions = new PlayOptions() { Loop = true };
+            var recognizeOptions = new CallMediaRecognizeDtmfOptions(new PhoneNumberIdentifier("<Target-Participant-Phone-Number>"), 3)
+            {
+                InterruptPrompt = true,
+                InterToneTimeoutInSeconds = TimeSpan.FromSeconds(10),
+                StopTones = new DtmfTone[] { DtmfTone.Pound },
+                InitialSilenceTimeoutInSeconds = TimeSpan.FromSeconds(5),
+                RecognizeOptions = recognizeOptions,
+                Prompt = playSource
+            }
             await client.GetCallConnection(@event.CallConnectionId)
                 .GetCallMedia()
-                .PlayToAllAsync(playSource, playOptions);
+                .StartRecognizingAsync(recognizeOptions);
         }
-        if (@event == typeof(PlayCompleted))
-        {            
-            // add ACS user as a participant to the call after audio has completed playing
+        if @event == typeof(RecognizeCompleted))
+        {
             await client.GetCallConnection(@event.CallConnectionId)
                 .AddParticipantsAsync(new List<CommunicationIdentifier>() { new CommunicationUserIdentifier("<ACS_USER_ID>")});
         }
     }
-
+    
     return Results.Ok();
 }).Produces(StatusCodes.Status200OK);
-
 app.Run();
 ```
 
@@ -155,5 +155,5 @@ app.Run();
 1. Place a call to the number you acquired in the Azure portal (see prerequisites above).
 2. Your Event Grid subscription to the `IncomingCall` should execute and call your web server.
 3. The call will be answered, and an asynchronous web hook callback will be sent to the NGROK callback URI.
-4. When the call is connected, a `CallConnected` event will be sent to your web server, wrapped in a `CloudEvent` schema and can be easily deserialized using the Call Automation SDK parser. At this point, the application will request audio to be played in a loop to all participants on the call.
-5. When the audio file has played, a `PlayCompleted` event is received, and the web server will make a request to add a participant to the call.
+4. When the call is connected, a `CallConnected` event will be sent to your web server, wrapped in a `CloudEvent` schema and can be easily deserialized using the Call Automation SDK parser. At this point the application will request audio to be played and input from a targeted phone number.
+5. When the input has been received and recognized, the web server will make a request to add a participant to the call.