// 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.CodeAnalysis;
using Microsoft.AspNetCore.Diagnostics.Latency;
using Microsoft.Shared.DiagnosticIds;
using Microsoft.Shared.Diagnostics;
 
namespace Microsoft.Extensions.DependencyInjection;
 
/// <summary>
/// Extensions for enriching incoming HTTP request logs with latency telemetry.
/// </summary>
[Experimental(diagnosticId: DiagnosticIds.Experiments.HttpLogging, UrlFormat = DiagnosticIds.UrlFormat)]
public static class HttpLatencyTelemetryServiceCollectionExtensions
{
    /// <summary>
    /// Adds an enricher that appends latency information from the request's latency context to incoming HTTP request logs.
    /// </summary>
    /// <param name="services">The <see cref="IServiceCollection"/> to add to.</param>
    /// <returns>The value of <paramref name="services"/>.</returns>
    /// <exception cref="System.ArgumentNullException"><paramref name="services"/> is <see langword="null"/>.</exception>
    /// <remarks>
    /// The latency data this enricher reads is populated by the request latency telemetry services. Call
    /// <c>AddRequestLatencyTelemetry</c> and <c>AddRequestCheckpoint</c>, and add the corresponding middleware to the
    /// request pipeline, so that an <see cref="Microsoft.Extensions.Diagnostics.Latency.ILatencyContext"/> is available for each request.
    /// </remarks>
    [Experimental(diagnosticId: DiagnosticIds.Experiments.HttpLogging, UrlFormat = DiagnosticIds.UrlFormat)]
    public static IServiceCollection AddHttpLatencyTelemetry(this IServiceCollection services)
    {
        _ = Throw.IfNull(services);
        return services.AddHttpLogEnricher<HttpLatencyLogEnricher>();
    }
}