feat(cli): table output formatter for audit events (#23 M8)

src/ScadaLink.CLI/Commands/AuditFormatter.cs

@@ -29,19 +29,16 @@ public sealed class JsonLinesAuditFormatter : IAuditFormatter
 }
 
 /// <summary>
-/// Resolves an <see cref="IAuditFormatter"/> for a given <c>--format</c> value. The
-/// table formatter is filled in by Bundle C; until then <c>--format table</c> falls back
-/// to JSONL with a one-time notice so the flag is wired but not silently broken.
+/// Resolves an <see cref="IAuditFormatter"/> for a given <c>--format</c> value:
+/// <c>table</c> renders a column-aligned text table (<see cref="TableAuditFormatter"/>),
+/// any other value (including <c>json</c>) renders JSONL.
 /// </summary>
 public static class AuditFormatterFactory
 {
     public static IAuditFormatter Create(string format, TextWriter notices)
     {
         if (string.Equals(format, "table", StringComparison.OrdinalIgnoreCase))
-        {
-            notices.WriteLine("note: 'table' output is not yet available; using json. (Bundle C)");
-            return new JsonLinesAuditFormatter();
-        }
+            return new TableAuditFormatter();
 
         return new JsonLinesAuditFormatter();
     }

src/ScadaLink.CLI/Commands/TableAuditFormatter.cs

@@ -0,0 +1,96 @@
+using System.Text.Json;
+
+namespace ScadaLink.CLI.Commands;
+
+/// <summary>
+/// Human-readable table formatter for <c>audit query --format table</c> (Audit Log
+/// #23 M8-T6). Renders each fetched page as a column-aligned text table with a fixed
+/// column set (<see cref="Columns"/>). Long free-text fields (Target, Actor) are
+/// truncated with an ellipsis so columns stay aligned regardless of payload size.
+/// </summary>
+/// <remarks>
+/// A header row is emitted once per page (matching the streamable, page-at-a-time
+/// contract of <see cref="IAuditFormatter"/>). An empty page emits the header only,
+/// so the column shape is visible even with zero results.
+/// </remarks>
+public sealed class TableAuditFormatter : IAuditFormatter
+{
+    /// <summary>JSON property name (camelCase, as the server serializes it) → column header.</summary>
+    private static readonly (string Property, string Header, int MaxWidth)[] Columns =
+    {
+        ("occurredAtUtc", "OccurredAtUtc", 24),
+        ("channel",       "Channel",       14),
+        ("kind",          "Kind",          18),
+        ("status",        "Status",        12),
+        ("target",        "Target",        32),
+        ("actor",         "Actor",         20),
+        ("durationMs",    "DurationMs",    10),
+        ("httpStatus",    "HttpStatus",    10),
+    };
+
+    public void WritePage(IReadOnlyList<JsonElement> events, TextWriter output)
+    {
+        // Build every cell first so column widths account for the actual data.
+        var rows = new List<string[]>(events.Count);
+        foreach (var evt in events)
+        {
+            var cells = new string[Columns.Length];
+            for (var i = 0; i < Columns.Length; i++)
+                cells[i] = Truncate(CellValue(evt, Columns[i].Property), Columns[i].MaxWidth);
+            rows.Add(cells);
+        }
+
+        var widths = new int[Columns.Length];
+        for (var i = 0; i < Columns.Length; i++)
+            widths[i] = Columns[i].Header.Length;
+        foreach (var row in rows)
+            for (var i = 0; i < Columns.Length; i++)
+                widths[i] = Math.Max(widths[i], row[i].Length);
+
+        WriteRow(output, Columns.Select(c => c.Header).ToArray(), widths);
+        foreach (var row in rows)
+            WriteRow(output, row, widths);
+    }
+
+    /// <summary>
+    /// Extracts a cell value for <paramref name="property"/> from an audit event.
+    /// A missing property or a JSON <c>null</c> renders as an empty string (never
+    /// the literal text "null").
+    /// </summary>
+    private static string CellValue(JsonElement evt, string property)
+    {
+        if (evt.ValueKind != JsonValueKind.Object
+            || !evt.TryGetProperty(property, out var value)
+            || value.ValueKind == JsonValueKind.Null)
+        {
+            return string.Empty;
+        }
+
+        return value.ValueKind == JsonValueKind.String
+            ? value.GetString() ?? string.Empty
+            : value.ToString();
+    }
+
+    /// <summary>
+    /// Truncates <paramref name="value"/> to <paramref name="maxWidth"/> characters,
+    /// replacing the tail with a single-character ellipsis so the column stays aligned.
+    /// </summary>
+    private static string Truncate(string value, int maxWidth)
+    {
+        if (maxWidth <= 0 || value.Length <= maxWidth)
+            return value;
+        if (maxWidth == 1)
+            return "…";
+        return value.Substring(0, maxWidth - 1) + "…";
+    }
+
+    private static void WriteRow(TextWriter output, IReadOnlyList<string> cells, int[] widths)
+    {
+        for (var i = 0; i < cells.Count; i++)
+        {
+            // Last column is not padded — avoids trailing whitespace at line end.
+            output.Write(i == cells.Count - 1 ? cells[i] : cells[i].PadRight(widths[i] + 2));
+        }
+        output.WriteLine();
+    }
+}