using System.Diagnostics;
using Omika.Core.Configuration;
using Omika.Core.Observability;
using Omika.Core.Observability.Diagnostic;

namespace Omika.Tests.Observability.Diagnostic;

public class OmikaLocalDiagnosticsTests : IDisposable
{
    private readonly string _dir = DiagnosticTestHarness.CreateTempDirectory();

    [Fact]
    public async Task EndToEnd_EventWrittenWithSessionContext()
    {
        var host = new OmikaLocalDiagnostics(new LocalDiagnosticOptions { Directory = _dir });
        host.Start();

        host.Telemetry.Track(new TelemetryEvent { EventCode = TelemetryEventCodes.MobileAppStarted });

        await DiagnosticTestHarness.WaitUntilAsync(() => host.Queue.Count == 0);
        await host.StopAsync();

        string content = File.ReadAllText(Assert.Single(Directory.EnumerateFiles(_dir, "*.jsonl")));
        Assert.Contains(host.Session.SessionId.ToString("N"), content);
        Assert.Contains("\"sessionId\"", content);
    }

    [Fact]
    public async Task TelemetryDisabled_NoFileCreated()
    {
        var host = new OmikaLocalDiagnostics(
            new LocalDiagnosticOptions { Directory = _dir },
            new ObservabilityOptions { Enabled = false });
        host.Start();

        host.Telemetry.Track(new TelemetryEvent { EventCode = TelemetryEventCodes.MobileAppStarted });

        await Task.Delay(150);
        await host.StopAsync();

        Assert.Empty(Directory.EnumerateFiles(_dir, "*.jsonl"));
    }

    [Fact]
    public async Task StopAsync_IsBounded_AndNeverThrows()
    {
        var host = new OmikaLocalDiagnostics(new LocalDiagnosticOptions
        {
            Directory = _dir,
            FlushTimeout = TimeSpan.FromMilliseconds(100)
        });
        host.Start();

        for (int i = 0; i < 20; i++)
        {
            host.Telemetry.Track(new TelemetryEvent { EventCode = TelemetryEventCodes.MobileAppStarted });
        }

        var stopwatch = Stopwatch.StartNew();
        await host.StopAsync();
        stopwatch.Stop();

        Assert.True(stopwatch.Elapsed < TimeSpan.FromSeconds(2));
    }

    [Fact]
    public async Task Saturation_100kEvents_Bounded_NoException()
    {
        var host = new OmikaLocalDiagnostics(new LocalDiagnosticOptions { Directory = _dir });
        host.Start();

        for (int i = 0; i < 100_000; i++)
        {
            host.Telemetry.Track(new TelemetryEvent { EventCode = TelemetryEventCodes.MobileAppStarted });
        }

        await host.StopAsync();

        Assert.True(Directory.EnumerateFiles(_dir, "*.jsonl").Count() <= 5);
    }

    public void Dispose() => DiagnosticTestHarness.DeleteDirectory(_dir);
}