// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Diagnostics.Metrics;
using Microsoft.AspNetCore.Shared;
 
namespace Microsoft.AspNetCore.Routing;
 
internal sealed class RoutingMetrics
{
    public const string MeterName = "Microsoft.AspNetCore.Routing";
 
     // Reuse boxed object for common values
    private static readonly object BoxedTrue = true;
    private static readonly object BoxedFalse = false;
 
    private readonly Meter _meter;
    private readonly Counter<long> _matchAttemptsCounter;
 
    public RoutingMetrics(IMeterFactory meterFactory)
    {
        _meter = meterFactory.Create(MeterName);
 
        _matchAttemptsCounter = _meter.CreateCounter<long>(
            "aspnetcore.routing.match_attempts",
            unit: "{match_attempt}",
            description: "Number of requests that were attempted to be matched to an endpoint.");
    }
 
    public bool MatchSuccessCounterEnabled => _matchAttemptsCounter.Enabled;
 
    public void MatchSuccess(string route, bool isFallback)
    {
        _matchAttemptsCounter.Add(1,
            new KeyValuePair<string, object?>("http.route", RouteDiagnosticsHelpers.ResolveHttpRoute(route)),
            new KeyValuePair<string, object?>("aspnetcore.routing.match_status", "success"),
            new KeyValuePair<string, object?>("aspnetcore.routing.is_fallback", isFallback ? BoxedTrue : BoxedFalse));
    }
 
    public void MatchFailure()
    {
        _matchAttemptsCounter.Add(1,
            new KeyValuePair<string, object?>("aspnetcore.routing.match_status", "failure"));
    }
}