Refactor IntegrationHandlerResult to provide more detail around failures (#6736)

* Refactor IntegrationHandlerResult to provide more detail around failures

* ServiceUnavailable now retryable, more explicit http status handling, more consistency with different handlers, additional xmldocs

* Address PR feedback

test/Core.Test/AdminConsole/Models/Data/EventIntegrations/IntegrationHandlerResultTests.cs

@@ -0,0 +1,128 @@
+using Bit.Core.AdminConsole.Models.Data.EventIntegrations;
+using Bit.Test.Common.AutoFixture.Attributes;
+using Xunit;
+
+namespace Bit.Core.Test.AdminConsole.Models.Data.EventIntegrations;
+
+public class IntegrationHandlerResultTests
+{
+    [Theory, BitAutoData]
+    public void Succeed_SetsSuccessTrue_CategoryNull(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Succeed(message);
+
+        Assert.True(result.Success);
+        Assert.Null(result.Category);
+        Assert.Equal(message, result.Message);
+        Assert.Null(result.FailureReason);
+    }
+
+    [Theory, BitAutoData]
+    public void Fail_WithCategory_SetsSuccessFalse_CategorySet(IntegrationMessage message)
+    {
+        var category = IntegrationFailureCategory.AuthenticationFailed;
+        var failureReason = "Invalid credentials";
+
+        var result = IntegrationHandlerResult.Fail(message, category, failureReason);
+
+        Assert.False(result.Success);
+        Assert.Equal(category, result.Category);
+        Assert.Equal(failureReason, result.FailureReason);
+        Assert.Equal(message, result.Message);
+    }
+
+    [Theory, BitAutoData]
+    public void Fail_WithDelayUntil_SetsDelayUntilDate(IntegrationMessage message)
+    {
+        var delayUntil = DateTime.UtcNow.AddMinutes(5);
+
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.RateLimited,
+            "Rate limited",
+            delayUntil
+        );
+
+        Assert.Equal(delayUntil, result.DelayUntilDate);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_RateLimited_ReturnsTrue(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.RateLimited,
+            "Rate limited"
+        );
+
+        Assert.True(result.Retryable);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_TransientError_ReturnsTrue(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.TransientError,
+            "Temporary network issue"
+        );
+
+        Assert.True(result.Retryable);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_AuthenticationFailed_ReturnsFalse(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.AuthenticationFailed,
+            "Invalid token"
+        );
+
+        Assert.False(result.Retryable);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_ConfigurationError_ReturnsFalse(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.ConfigurationError,
+            "Channel not found"
+        );
+
+        Assert.False(result.Retryable);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_ServiceUnavailable_ReturnsTrue(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.ServiceUnavailable,
+            "Service is down"
+        );
+
+        Assert.True(result.Retryable);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_PermanentFailure_ReturnsFalse(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Fail(
+            message,
+            IntegrationFailureCategory.PermanentFailure,
+            "Permanent failure"
+        );
+
+        Assert.False(result.Retryable);
+    }
+
+    [Theory, BitAutoData]
+    public void Retryable_SuccessCase_ReturnsFalse(IntegrationMessage message)
+    {
+        var result = IntegrationHandlerResult.Succeed(message);
+
+        Assert.False(result.Retryable);
+    }
+}