Added JsonStringEnumMemberConverter & updated models to use it.

Author: lvukadinovic-ib

src/Infobip.Api.Client/Client/JsonStringEnumMemberConverter.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Runtime.Serialization;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Infobip.Api.Client
+{
+
+    /// <summary>
+    ///     System.Text.Json converter that serializes and deserializes enums using their <see cref="EnumMemberAttribute"/> values if present, else their names.
+    ///     Ensures proper enum (de)serialization for API models where JSON uses string values defined by <see cref="EnumMemberAttribute"/>.
+    /// </summary>
+    /// <typeparam name="T">Enum type to convert.</typeparam>
+    public class JsonStringEnumMemberConverter<T> : JsonConverter<T> where T : struct, Enum
+    {
+        private readonly Dictionary<string, T> _fromValue;
+        private readonly Dictionary<T, string> _toValue;
+
+        /// <summary>
+        ///     Initializes a new instance of <see cref="JsonStringEnumMemberConverter{T}"/>.
+        ///     Builds internal mappings of enum values to their <see cref="EnumMemberAttribute"/> strings.
+        /// </summary>
+        public JsonStringEnumMemberConverter()
+        {
+            _fromValue = new Dictionary<string, T>(StringComparer.OrdinalIgnoreCase);
+            _toValue = new Dictionary<T, string>();
+            foreach (var field in typeof(T).GetFields(BindingFlags.Public | BindingFlags.Static))
+            {
+                var enumValue = (T)field.GetValue(null);
+                var enumMemberAttr = field.GetCustomAttribute<EnumMemberAttribute>();
+                var strValue = enumMemberAttr?.Value ?? field.Name;
+                _fromValue[strValue] = enumValue;
+                _toValue[enumValue] = strValue;
+            }
+        }
+
+        /// <summary>
+        ///     Reads and converts the JSON string value to the corresponding enum value,
+        ///     interpreting <see cref="EnumMemberAttribute.Value"/> if present.
+        /// </summary>
+        /// <param name="reader">The reader to read from.</param>
+        /// <param name="typeToConvert">The type being converted.</param>
+        /// <param name="options">Serialization options to use.</param>
+        /// <returns>The converted enum value.</returns>
+        /// <exception cref="JsonException">Thrown if JSON token is not a string or cannot be mapped to enum.</exception>
+        public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType == JsonTokenType.String)
+            {
+                var enumString = reader.GetString();
+                if (_fromValue.TryGetValue(enumString, out var value))
+                    return value;
+                throw new JsonException($"Unknown value '{enumString}' for enum '{typeof(T).Name}'");
+            }
+            throw new JsonException($"Unexpected token parsing enum. Expected String, got {reader.TokenType}.");
+        }
+
+        /// <summary>
+        ///     Writes the enum value as a JSON string, preferring the <see cref="EnumMemberAttribute.Value"/> if present.
+        /// </summary>
+        /// <param name="writer">The writer to write to.</param>
+        /// <param name="value">The enum value to write.</param>
+        /// <param name="options">Serialization options to use.</param>
+        public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
+        {
+            if (_toValue.TryGetValue(value, out var stringValue))
+                writer.WriteStringValue(stringValue);
+            else
+                writer.WriteStringValue(value.ToString());
+        }
+    }   
+}

src/Infobip.Api.Client/Model/CallDirection.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -21,7 +20,7 @@ namespace Infobip.Api.Client.Model
     /// </summary>
     /// <value>Call direction.</value>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallDirection>))]
     public enum CallDirection
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallEndpointType.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -20,7 +19,7 @@ namespace Infobip.Api.Client.Model
     ///     Defines CallEndpointType.
     /// </summary>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallEndpointType>))]
     public enum CallEndpointType
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallRoutingCriteriaType.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -20,7 +19,7 @@ namespace Infobip.Api.Client.Model
     ///     Defines CallRoutingCriteriaType.
     /// </summary>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallRoutingCriteriaType>))]
     public enum CallRoutingCriteriaType
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallRoutingDestinationType.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -20,7 +19,7 @@ namespace Infobip.Api.Client.Model
     ///     Defines CallRoutingDestinationType.
     /// </summary>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallRoutingDestinationType>))]
     public enum CallRoutingDestinationType
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallRoutingEndpointType.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -20,7 +19,7 @@ namespace Infobip.Api.Client.Model
     ///     Defines CallRoutingEndpointType.
     /// </summary>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallRoutingEndpointType>))]
     public enum CallRoutingEndpointType
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallRoutingRecordingType.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -21,7 +20,7 @@ namespace Infobip.Api.Client.Model
     /// </summary>
     /// <value>Recording type.</value>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallRoutingRecordingType>))]
     public enum CallRoutingRecordingType
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallState.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -21,7 +20,7 @@ namespace Infobip.Api.Client.Model
     /// </summary>
     /// <value>Call state.</value>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallState>))]
     public enum CallState
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallVoice.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -25,7 +24,7 @@ namespace Infobip.Api.Client.Model
     ///     [here](https://www.infobip.com/docs/voice-and-video/getting-started#text-to-speech).
     /// </value>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallVoice>))]
     public enum CallVoice
     {
         /// <summary>

src/Infobip.Api.Client/Model/CallsActionStatus.cs

@@ -10,7 +10,6 @@
 
 
 using System.Runtime.Serialization;
-using System.Text.Json.Serialization;
 using Newtonsoft.Json.Converters;
 using JsonConverterAttribute = Newtonsoft.Json.JsonConverterAttribute;
 
@@ -21,7 +20,7 @@ namespace Infobip.Api.Client.Model
     /// </summary>
     /// <value>Action status.</value>
     [JsonConverter(typeof(StringEnumConverter))]
-    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumConverter))]
+    [System.Text.Json.Serialization.JsonConverter(typeof(JsonStringEnumMemberConverter<CallsActionStatus>))]
     public enum CallsActionStatus
     {
         /// <summary>