refactor(audit): consolidate query-param parsers; widen CLI export to multi-value

tests/ScadaLink.CLI.Tests/Commands/AuditExportCommandTests.cs

@@ -63,8 +63,8 @@ public class AuditExportCommandTests
             Until = "2026-05-20T12:00:00Z",
             Format = "jsonl",
             Output = "/tmp/x",
-            Channel = "Notification",
-            Site = "site-9",
+            Channel = new[] { "Notification" },
+            Site = new[] { "site-9" },
         };
         var qs = AuditExportHelpers.BuildQueryString(args, now);
         var parsed = HttpUtility.ParseQueryString(qs.TrimStart('?'));
@@ -76,6 +76,90 @@ public class AuditExportCommandTests
         Assert.Equal("2026-05-20T12:00:00.0000000+00:00", parsed["toUtc"]);
     }
 
+    [Fact]
+    public void BuildQueryString_MultiValueFilters_EmitOneKeyPerValue()
+    {
+        var now = DateTimeOffset.Parse("2026-05-20T12:00:00Z");
+        var args = new AuditExportArgs
+        {
+            Since = "1h",
+            Until = "2026-05-20T12:00:00Z",
+            Format = "csv",
+            Output = "/tmp/x",
+            Channel = new[] { "ApiOutbound", "DbOutbound" },
+            Kind = new[] { "ApiCall", "DbWrite" },
+            Status = new[] { "Failed", "Parked" },
+            Site = new[] { "site-1", "site-2" },
+        };
+        var qs = AuditExportHelpers.BuildQueryString(args, now);
+        var parsed = HttpUtility.ParseQueryString(qs.TrimStart('?'));
+
+        Assert.Equal(new[] { "ApiOutbound", "DbOutbound" }, parsed.GetValues("channel"));
+        Assert.Equal(new[] { "ApiCall", "DbWrite" }, parsed.GetValues("kind"));
+        Assert.Equal(new[] { "Failed", "Parked" }, parsed.GetValues("status"));
+        Assert.Equal(new[] { "site-1", "site-2" }, parsed.GetValues("sourceSiteId"));
+    }
+
+    [Fact]
+    public void BuildQueryString_OmitsUnsetMultiValueFilters()
+    {
+        var now = DateTimeOffset.Parse("2026-05-20T12:00:00Z");
+        var args = new AuditExportArgs
+        {
+            Since = "1h",
+            Until = "0h",
+            Format = "csv",
+            Output = "/tmp/x",
+        };
+        var qs = AuditExportHelpers.BuildQueryString(args, now);
+        var parsed = HttpUtility.ParseQueryString(qs.TrimStart('?'));
+
+        Assert.Null(parsed["channel"]);
+        Assert.Null(parsed["kind"]);
+        Assert.Null(parsed["status"]);
+        Assert.Null(parsed["sourceSiteId"]);
+    }
+
+    [Fact]
+    public void Export_MultipleChannelValues_SingleToken_AreAccepted()
+    {
+        // AllowMultipleArgumentsPerToken: --channel A B parses as two values.
+        var root = AuditCommandTestHarness.BuildRoot();
+        var parse = root.Parse(new[]
+        {
+            "audit", "export", "--since", "1h", "--until", "0h",
+            "--format", "csv", "--output", "/tmp/out.csv",
+            "--channel", "ApiOutbound", "DbOutbound",
+        });
+        Assert.Empty(parse.Errors);
+    }
+
+    [Fact]
+    public void Export_MultipleChannelValues_RepeatedFlag_AreAccepted()
+    {
+        var root = AuditCommandTestHarness.BuildRoot();
+        var parse = root.Parse(new[]
+        {
+            "audit", "export", "--since", "1h", "--until", "0h",
+            "--format", "csv", "--output", "/tmp/out.csv",
+            "--channel", "ApiOutbound", "--channel", "Notification",
+        });
+        Assert.Empty(parse.Errors);
+    }
+
+    [Fact]
+    public void Export_MultiValueChannel_WithOneInvalidName_FailsFast()
+    {
+        // AcceptOnlyFromAmong validates EACH value of the multi-value option.
+        var root = AuditCommandTestHarness.BuildRoot();
+        var (exit, _, err) = AuditCommandTestHarness.Invoke(
+            root, "audit", "export", "--since", "1h", "--until", "0h",
+            "--format", "csv", "--output", "/tmp/out.csv",
+            "--channel", "ApiOutbound", "OutboundApi");
+        Assert.NotEqual(0, exit);
+        Assert.NotEqual("", err);
+    }
+
     // ---- Streaming export to file -----------------------------------------
 
     private sealed class BodyHandler : HttpMessageHandler

tests/ScadaLink.CLI.Tests/Commands/AuditQueryCommandTests.cs

@@ -76,7 +76,7 @@ public class AuditQueryCommandTests
         Assert.Equal("ApiCallCached", parsed["kind"]);
         Assert.Equal("Delivered", parsed["status"]);
         Assert.Equal("site-1", parsed["sourceSiteId"]);
-        // --instance was dropped: AuditLogQueryFilter has no instance column.
+        // The CLI audit query has no --instance flag, so no instance param is emitted.
         Assert.Null(parsed["instance"]);
         Assert.Equal("weather-api", parsed["target"]);
         Assert.Equal("multi-role", parsed["actor"]);

tests/ScadaLink.Commons.Tests/Types/AuditQueryParamParsersTests.cs

@@ -0,0 +1,75 @@
+using ScadaLink.Commons.Types.Audit;
+using ScadaLink.Commons.Types.Enums;
+
+namespace ScadaLink.Commons.Tests.Types;
+
+/// <summary>
+/// Audit Log #23 (M8): tests for the shared lax multi-value query-param parsers
+/// used by the ManagementService + CentralUI audit endpoints and the
+/// <c>AuditLogPage</c> drill-in parser. The contract under test: parse each
+/// repeated value independently, silently drop unparseable/blank elements, and
+/// collapse an empty result to <c>null</c>.
+/// </summary>
+public class AuditQueryParamParsersTests
+{
+    [Fact]
+    public void ParseEnumList_NullInput_ReturnsNull()
+    {
+        Assert.Null(AuditQueryParamParsers.ParseEnumList<AuditChannel>(null));
+    }
+
+    [Fact]
+    public void ParseEnumList_EmptyInput_ReturnsNull()
+    {
+        Assert.Null(AuditQueryParamParsers.ParseEnumList<AuditChannel>(Array.Empty<string?>()));
+    }
+
+    [Fact]
+    public void ParseEnumList_AllValuesValid_ParsesEverything()
+    {
+        var result = AuditQueryParamParsers.ParseEnumList<AuditChannel>(
+            new[] { "ApiOutbound", "DbOutbound" });
+        Assert.Equal(new[] { AuditChannel.ApiOutbound, AuditChannel.DbOutbound }, result);
+    }
+
+    [Fact]
+    public void ParseEnumList_IsCaseInsensitive()
+    {
+        var result = AuditQueryParamParsers.ParseEnumList<AuditChannel>(new[] { "apioutbound" });
+        Assert.Equal(new[] { AuditChannel.ApiOutbound }, result);
+    }
+
+    [Fact]
+    public void ParseEnumList_DropsUnparseableElement_KeepsTheRest()
+    {
+        var result = AuditQueryParamParsers.ParseEnumList<AuditChannel>(
+            new[] { "ApiOutbound", "NotAChannel", "Notification" });
+        Assert.Equal(new[] { AuditChannel.ApiOutbound, AuditChannel.Notification }, result);
+    }
+
+    [Fact]
+    public void ParseEnumList_AllValuesUnparseable_ReturnsNull()
+    {
+        Assert.Null(AuditQueryParamParsers.ParseEnumList<AuditStatus>(new[] { "Bogus", "" }));
+    }
+
+    [Fact]
+    public void ParseStringList_NullInput_ReturnsNull()
+    {
+        Assert.Null(AuditQueryParamParsers.ParseStringList(null));
+    }
+
+    [Fact]
+    public void ParseStringList_TrimsValuesAndDropsBlanks()
+    {
+        var result = AuditQueryParamParsers.ParseStringList(
+            new[] { "  site-1 ", "", "   ", "site-2", null });
+        Assert.Equal(new[] { "site-1", "site-2" }, result);
+    }
+
+    [Fact]
+    public void ParseStringList_AllBlank_ReturnsNull()
+    {
+        Assert.Null(AuditQueryParamParsers.ParseStringList(new[] { "", "  ", null }));
+    }
+}