feat: add profiler base

Signed-off-by: Octol1ttle <l1ttleofficial@outlook.com>

src/Octobot.cs

@@ -5,6 +5,7 @@ using Microsoft.Extensions.Logging;
 using Octobot.Commands;
 using Octobot.Commands.Events;
 using Octobot.Services;
+using Octobot.Services.Profiler;
 using Octobot.Services.Update;
 using Remora.Commands.Extensions;
 using Remora.Discord.API.Abstractions.Gateway.Commands;
@@ -86,6 +87,8 @@ public sealed class Octobot
                         .AddPreparationErrorEvent<LoggingPreparationErrorEvent>()
                         .AddPostExecutionEvent<ErrorLoggingPostExecutionEvent>()
                         // Services
+                        .AddTransient<Profiler>()
+                        .AddSingleton<ProfilerFactory>()
                         .AddSingleton<Utility>()
                         .AddSingleton<GuildDataService>()
                         .AddHostedService<GuildDataService>(provider => provider.GetRequiredService<GuildDataService>())

src/Services/Profiler/Profiler.cs

@@ -0,0 +1,114 @@
+using System.Diagnostics;
+using System.Text;
+using Microsoft.Extensions.Logging;
+using Remora.Results;
+
+// TODO: remove in future profiler PRs
+// ReSharper disable All
+
+namespace Octobot.Services.Profiler;
+
+/// <summary>
+/// Provides the ability to profile how long certain parts of code take to complete using <see cref="Stopwatch"/>es.
+/// </summary>
+/// <remarks>Resolve <see cref="ProfilerFactory"/> instead in singletons.</remarks>
+public sealed class Profiler
+{
+    private const int MaxProfilerTime = 1000; // milliseconds
+    private readonly List<ProfilerEvent> _events = [];
+    private readonly ILogger<Profiler> _logger;
+
+    public Profiler(ILogger<Profiler> logger)
+    {
+        _logger = logger;
+    }
+
+    /// <summary>
+    /// Pushes an event to the profiler.
+    /// </summary>
+    /// <param name="id">The ID of the event.</param>
+    public void Push(string id)
+    {
+        _events.Add(new ProfilerEvent
+        {
+            Id = id,
+            Stopwatch = Stopwatch.StartNew()
+        });
+    }
+
+    /// <summary>
+    /// Pops the last pushed event from the profiler.
+    /// </summary>
+    /// <exception cref="InvalidOperationException">Thrown if the profiler contains no events.</exception>
+    public void Pop()
+    {
+        if (_events.Count is 0)
+        {
+            throw new InvalidOperationException("Nothing to pop");
+        }
+
+        _events.Last().Stopwatch.Stop();
+    }
+
+    /// <summary>
+    /// If the profiler took too long to execute, this will log a warning with per-event time usage
+    /// </summary>
+    /// <exception cref="InvalidOperationException"></exception>
+    private void Report()
+    {
+        var main = _events[0];
+        if (main.Stopwatch.ElapsedMilliseconds < MaxProfilerTime)
+        {
+            return;
+        }
+
+        var unprofiled = main.Stopwatch.ElapsedMilliseconds;
+        var builder = new StringBuilder().AppendLine();
+        for (var i = 1; i < _events.Count; i++)
+        {
+            var profilerEvent = _events[i];
+            if (profilerEvent.Stopwatch.IsRunning)
+            {
+                throw new InvalidOperationException(
+                    $"Tried to report on a profiler with running stopwatches: {profilerEvent.Id}");
+            }
+
+            builder.AppendLine($"{profilerEvent.Id}: {profilerEvent.Stopwatch.ElapsedMilliseconds}ms");
+            unprofiled -= profilerEvent.Stopwatch.ElapsedMilliseconds;
+        }
+
+        builder.AppendLine($"<unprofiled>: {unprofiled}ms");
+
+        _logger.LogWarning("Profiler {ID} took {Elapsed} milliseconds to execute (max: {Max}ms):{Events}", main.Id,
+            main.Stopwatch.ElapsedMilliseconds, MaxProfilerTime, builder.ToString());
+    }
+
+    /// <summary>
+    /// <see cref="Pop"/> the profiler and <see cref="Report"/> on it afterwards.
+    /// </summary>
+    public void PopAndReport()
+    {
+        Pop();
+        Report();
+    }
+
+    /// <summary>
+    /// <see cref="PopAndReport"/> on the profiler and return a <see cref="Result{TEntity}"/>.
+    /// </summary>
+    /// <param name="result"></param>
+    /// <returns></returns>
+    public Result ReportWithResult(Result result)
+    {
+        PopAndReport();
+        return result;
+    }
+
+    /// <summary>
+    /// Calls <see cref="ReportWithResult"/> with <see cref="Result.FromSuccess"/>
+    /// </summary>
+    /// <returns>A successful result.</returns>
+    public Result ReportWithSuccess()
+    {
+        return ReportWithResult(Result.FromSuccess());
+    }
+}

src/Services/Profiler/ProfilerEvent.cs

@@ -0,0 +1,9 @@
+using System.Diagnostics;
+
+namespace Octobot.Services.Profiler;
+
+public struct ProfilerEvent
+{
+    public string Id { get; init; }
+    public Stopwatch Stopwatch { get; init; }
+}

src/Services/Profiler/ProfilerFactory.cs

@@ -0,0 +1,27 @@
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Octobot.Services.Profiler;
+
+/// <summary>
+/// Provides a method to create a <see cref="Profiler"/>. Useful in singletons.
+/// </summary>
+public sealed class ProfilerFactory
+{
+    private readonly IServiceScopeFactory _scopeFactory;
+
+    public ProfilerFactory(IServiceScopeFactory scopeFactory)
+    {
+        _scopeFactory = scopeFactory;
+    }
+
+    /// <summary>
+    /// Creates a new <see cref="Profiler"/>.
+    /// </summary>
+    /// <returns>A new <see cref="Profiler"/>.</returns>
+    // TODO: remove in future profiler PRs
+    // ReSharper disable once UnusedMember.Global
+    public Profiler Create()
+    {
+        return _scopeFactory.CreateScope().ServiceProvider.GetRequiredService<Profiler>();
+    }
+}