feat: Implement OFREP default evaluation response (#468)

Signed-off-by: André Silva <[email protected]>

Author: askpt

src/OpenFeature.Providers.Ofrep/Client/OfrepClient.cs

@@ -258,9 +258,9 @@ private async Task<OfrepResponse<T>> ProcessBadRequestResponse<T>(string flagKey
     private async Task<OfrepResponse<T>> ProcessOkResponseAsync<T>(string flagKey, T defaultValue,
         HttpResponseMessage response, CancellationToken cancellationToken = default)
     {
-        var evaluationResponse = await response.Content
-            .ReadFromJsonAsync<OfrepResponse<T>>(JsonOptions, cancellationToken).ConfigureAwait(false);
-        if (evaluationResponse == null)
+        var rawResponse = await response.Content
+            .ReadFromJsonAsync<OfrepResponse<JsonElement>>(JsonOptions, cancellationToken).ConfigureAwait(false);
+        if (rawResponse == null)
         {
             this.LogNullResponse(flagKey);
             return new OfrepResponse<T>(flagKey, defaultValue)
@@ -270,6 +270,41 @@ private async Task<OfrepResponse<T>> ProcessOkResponseAsync<T>(string flagKey, T
             };
         }
 
+        var hasValue = rawResponse.Value.ValueKind != JsonValueKind.Undefined &&
+                       rawResponse.Value.ValueKind != JsonValueKind.Null;
+
+        T resolvedValue;
+        if (hasValue)
+        {
+            try
+            {
+                resolvedValue = rawResponse.Value.Deserialize<T>(JsonOptions) ?? defaultValue;
+            }
+            catch (JsonException ex)
+            {
+                this.LogJsonParseError(flagKey, ex.Message, ex);
+                return HandleEvaluationError(flagKey, ex, defaultValue);
+            }
+        }
+        else
+        {
+            resolvedValue = defaultValue;
+        }
+
+        var evaluationResponse = new OfrepResponse<T>(rawResponse.Key ?? flagKey, resolvedValue)
+        {
+            ErrorCode = rawResponse.ErrorCode,
+            ErrorMessage = rawResponse.ErrorMessage,
+            Reason = rawResponse.Reason,
+            Variant = rawResponse.Variant,
+            Metadata = rawResponse.Metadata
+        };
+
+        if (!hasValue)
+        {
+            evaluationResponse.Reason ??= Reason.Default;
+        }
+
         return evaluationResponse;
     }
 

test/OpenFeature.Providers.Ofrep.Test/Client/OfrepClientTest.cs

@@ -11,6 +11,7 @@
 using OpenFeature.Providers.Ofrep.Configuration;
 using OpenFeature.Providers.Ofrep.Models;
 using OpenFeature.Providers.Ofrep.Test.Helpers;
+using OpenFeature.Constant;
 using Xunit;
 
 namespace OpenFeature.Providers.Ofrep.Test.Client;
@@ -248,6 +249,53 @@ public async Task EvaluateFlag_WithNullResponse_ShouldReturnParsingError()
         Assert.Contains("null or empty response", result.ErrorMessage);
     }
 
+    [Fact]
+    public async Task EvaluateFlag_WhenResponseDefersToCodeDefault_ShouldUseDefaultValue()
+    {
+        // Arrange
+        const string flagKey = "code-default";
+        const bool defaultValue = true;
+
+        const string jsonResponse = "{\"key\":\"code-default\",\"variant\":\"control\",\"metadata\":{\"traceId\":\"abc-123\"}}";
+        this._mockHandler.SetupResponse(HttpStatusCode.OK, jsonResponse);
+
+        using var client = new OfrepClient(this._configuration, this._mockHandler, this._mockLogger);
+
+        // Act
+        var result = await client.EvaluateFlag(flagKey, defaultValue, EvaluationContext.Empty);
+
+        // Assert
+        Assert.Equal(defaultValue, result.Value);
+        Assert.Equal(Reason.Default, result.Reason);
+        Assert.Equal("control", result.Variant);
+
+        Assert.NotNull(result.Metadata);
+        Assert.True(result.Metadata!.TryGetValue("traceId", out var traceId));
+        var traceIdElement = Assert.IsType<JsonElement>(traceId);
+        Assert.Equal("abc-123", traceIdElement.GetString());
+    }
+
+    [Fact]
+    public async Task EvaluateFlag_WhenCodeDefaultResponseIncludesReason_ShouldPreserveServerReason()
+    {
+        // Arrange
+        const string flagKey = "code-default-reason";
+        const int defaultValue = 7;
+
+        const string jsonResponse = "{\"key\":\"code-default-reason\",\"reason\":\"STATIC\"}";
+        this._mockHandler.SetupResponse(HttpStatusCode.OK, jsonResponse);
+
+        using var client = new OfrepClient(this._configuration, this._mockHandler, this._mockLogger);
+
+        // Act
+        var result = await client.EvaluateFlag(flagKey, defaultValue, EvaluationContext.Empty);
+
+        // Assert
+        Assert.Equal(defaultValue, result.Value);
+        Assert.Equal("STATIC", result.Reason);
+        Assert.Null(result.Metadata);
+    }
+
     [Fact]
     public async Task EvaluateFlag_WithEvaluationContext_ShouldIncludeContextInRequest()
     {