Pennington.Tui.BoundedSequenceLog

namespace Pennington.Tui;

/// Thread-safe bounded queue of sequence-tagged entries. Producers run on arbitrary threads (Kestrel workers, the ILogger pipeline); the TUI drains new rows each tick on the terminal thread by tracking the last-seen sequence. Trims the oldest when capacity is exceeded; the minimum floor of 50 keeps the dashboard from rendering empty on a busy page even if a caller passes 0.
public class BoundedSequenceLog
{
    /// Thread-safe bounded queue of sequence-tagged entries. Producers run on arbitrary threads (Kestrel workers, the ILogger pipeline); the TUI drains new rows each tick on the terminal thread by tracking the last-seen sequence. Trims the oldest when capacity is exceeded; the minimum floor of 50 keeps the dashboard from rendering empty on a busy page even if a caller passes 0.
    
public sealed class BoundedSequenceLog<T>(int capacity)
{
    private readonly ConcurrentQueue<T> _entries = new();
    private readonly int _capacity = Math.Max(50, capacity);
    private long _sequence;

    /// <summary>Assign the next sequence id, hand it to <paramref name="factory"/>, and enqueue the result.</summary>
    public void Append(Func<long, T> factory)
    {
        var seq = Interlocked.Increment(ref _sequence);
        _entries.Enqueue(factory(seq));
        while (_entries.Count > _capacity && _entries.TryDequeue(out _)) { }
    }

    /// <summary>Snapshot of current entries, oldest first.</summary>
    public IReadOnlyList<T> Snapshot() => [.. _entries];
}

    /// Assign the next sequence id, hand it to factory, and enqueue the result.
    
public void Append(Func<long, T> factory);

    /// Snapshot of current entries, oldest first.
    
public IReadOnlyList<T> Snapshot();
}