using System.Diagnostics.Metrics;

namespace StellaOps.Graph.Api.Services;

public interface IGraphMetrics : IDisposable
{
    Counter<long> BudgetDenied { get; }
    Histogram<double> QueryLatencySeconds { get; }
    Counter<long> OverlayCacheHit { get; }
    Counter<long> OverlayCacheMiss { get; }
    Histogram<double> ExportLatencySeconds { get; }
    Meter Meter { get; }
}

public sealed class GraphMetrics : IGraphMetrics
{
    private readonly Meter _meter;

    public GraphMetrics()
    {
        _meter = new Meter("StellaOps.Graph.Api", "1.0.0");
        BudgetDenied = _meter.CreateCounter<long>("graph_query_budget_denied_total");
        QueryLatencySeconds = _meter.CreateHistogram<double>("graph_tile_latency_seconds", unit: "s");
        OverlayCacheHit = _meter.CreateCounter<long>("graph_overlay_cache_hits_total");
        OverlayCacheMiss = _meter.CreateCounter<long>("graph_overlay_cache_misses_total");
        ExportLatencySeconds = _meter.CreateHistogram<double>("graph_export_latency_seconds", unit: "s");
    }

    public Counter<long> BudgetDenied { get; }
    public Histogram<double> QueryLatencySeconds { get; }
    public Counter<long> OverlayCacheHit { get; }
    public Counter<long> OverlayCacheMiss { get; }
    public Histogram<double> ExportLatencySeconds { get; }
    public Meter Meter => _meter;

    public void Dispose()
    {
        _meter.Dispose();
    }
}