using System.Diagnostics.Metrics;
public sealed class EvidenceLog : ILoggerProvider {
    private readonly object sync=new(); private readonly Queue<string> messages=new();
    public string[] Snapshot() { lock(sync) return messages.ToArray(); }
    public ILogger CreateLogger(string categoryName)=>new Writer(this,categoryName);
    public void Dispose() { }
    private void Add(string category,string text) { if(category=="ProductionPrivacy") lock(sync) { if(messages.Count==32) messages.Dequeue(); messages.Enqueue(text); } Console.WriteLine(text); }
    private sealed class Writer(EvidenceLog owner,string category):ILogger {
        public IDisposable? BeginScope<TState>(TState state) where TState:notnull=>null;
        public bool IsEnabled(LogLevel level)=>category=="Microsoft.Hosting.Lifetime"||category=="ProductionPrivacy";
        public void Log<TState>(LogLevel level,EventId id,TState state,Exception? exception,Func<TState,Exception?,string> formatter) { if(IsEnabled(level)) owner.Add(category,formatter(state,exception)); }
    }
}
public sealed class PrivacySignals : IDisposable {
    private readonly Meter meter=new("SharpRune.ProductionPrivacy"); private readonly MeterListener listener=new(); private readonly Counter<long> counter;
    private readonly object sync=new(); private readonly HashSet<string> labels=new(StringComparer.Ordinal); private int disposed;
    public PrivacySignals() {
        counter=meter.CreateCounter<long>("production.operations");
        listener.InstrumentPublished=(instrument,value)=> { if(instrument.Meter.Name=="SharpRune.ProductionPrivacy") value.EnableMeasurementEvents(instrument); };
        listener.SetMeasurementEventCallback<long>((instrument,value,tags,state)=> { foreach(var tag in tags) if(tag.Key=="operation"&&tag.Value is string label) lock(sync) labels.Add(label); }); listener.Start();
    }
    public string Record(string raw) { string operation=raw is "quote" or "search" ? raw : "other"; counter.Add(1,new KeyValuePair<string,object?>("operation",operation)); return operation; }
    public string[] Labels() { lock(sync) return labels.OrderBy(x=>x,StringComparer.Ordinal).ToArray(); }
    public void Dispose() { if(Interlocked.Exchange(ref disposed,1)!=0)return; listener.Dispose(); meter.Dispose(); }
}