feat(devices): pure RustPlusErrorCode -> DeviceReachability mapper

Author: HandyS11

src/RustPlusBot.Features.Connections/Listening/ReachabilityMapping.cs

@@ -0,0 +1,27 @@
+using RustPlusApi.Data;
+using RustPlusBot.Abstractions.Connections;
+
+namespace RustPlusBot.Features.Connections.Listening;
+
+/// <summary>Maps a Rust+ response outcome to <see cref="DeviceReachability"/>. The ONLY place RustPlusErrorCode is interpreted.</summary>
+internal static class ReachabilityMapping
+{
+    /// <summary>Reachable on success; Removed for not_found; NoPrivilege for access_denied; NoResponse otherwise.</summary>
+    /// <param name="isSuccess">Whether the Rust+ response succeeded.</param>
+    /// <param name="errorCode">The error code if the response failed, or null.</param>
+    /// <returns>The mapped <see cref="DeviceReachability"/> state.</returns>
+    public static DeviceReachability FromResponse(bool isSuccess, RustPlusErrorCode? errorCode)
+    {
+        if (isSuccess)
+        {
+            return DeviceReachability.Reachable;
+        }
+
+        return errorCode switch
+        {
+            RustPlusErrorCode.NotFound => DeviceReachability.Removed,
+            RustPlusErrorCode.AccessDenied => DeviceReachability.NoPrivilege,
+            _ => DeviceReachability.NoResponse,
+        };
+    }
+}

tests/RustPlusBot.Features.Connections.Tests/ReachabilityMappingTests.cs

@@ -0,0 +1,25 @@
+using RustPlusApi.Data;
+using RustPlusBot.Abstractions.Connections;
+using RustPlusBot.Features.Connections.Listening;
+
+namespace RustPlusBot.Features.Connections.Tests;
+
+public sealed class ReachabilityMappingTests
+{
+    [Fact]
+    public void Success_IsReachable() =>
+        Assert.Equal(DeviceReachability.Reachable, ReachabilityMapping.FromResponse(true, null));
+
+    [Theory]
+    [InlineData(RustPlusErrorCode.NotFound, DeviceReachability.Removed)]
+    [InlineData(RustPlusErrorCode.AccessDenied, DeviceReachability.NoPrivilege)]
+    [InlineData(RustPlusErrorCode.Unknown, DeviceReachability.NoResponse)]
+    [InlineData(RustPlusErrorCode.ServerError, DeviceReachability.NoResponse)]
+    [InlineData(RustPlusErrorCode.RateLimit, DeviceReachability.NoResponse)]
+    public void Failure_MapsByCode(RustPlusErrorCode code, DeviceReachability expected) =>
+        Assert.Equal(expected, ReachabilityMapping.FromResponse(false, code));
+
+    [Fact]
+    public void Failure_NullCode_IsNoResponse() =>
+        Assert.Equal(DeviceReachability.NoResponse, ReachabilityMapping.FromResponse(false, null));
+}