using System.Diagnostics.Metrics;
using System.Net;
using System.Text;
using ItWorx.KnowledgeHub.Application.Operations;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Hosting.Server;
using Microsoft.AspNetCore.Hosting.Server.Features;
using Microsoft.Extensions.DependencyInjection;
using OpenTelemetry;
using OpenTelemetry.Exporter;
using OpenTelemetry.Metrics;

namespace ItWorx.KnowledgeHub.IntegrationTests.Operations;

public sealed class OtlpExportTests
{
    [Fact]
    public async Task Platform_metrics_are_exported_over_real_OTLP_HTTP_without_private_labels()
    {
        var received = new TaskCompletionSource<byte[]>(TaskCreationOptions.RunContinuationsAsynchronously);
        var builder = WebApplication.CreateSlimBuilder();
        builder.WebHost.ConfigureKestrel(server => server.Listen(IPAddress.Loopback, 0));
        await using var collector = builder.Build();
        collector.MapPost("/v1/metrics", async context =>
        {
            using var body = new MemoryStream();
            await context.Request.Body.CopyToAsync(body);
            received.TrySetResult(body.ToArray());
            context.Response.ContentType = "application/x-protobuf";
            context.Response.StatusCode = 200;
        });
        await collector.StartAsync();
        var address = collector.Services.GetRequiredService<IServer>()
            .Features.Get<IServerAddressesFeature>()!.Addresses.Single();
        using var metrics = new PlatformMetrics();
        using var provider = Sdk.CreateMeterProviderBuilder().AddMeter("ItWorx.KnowledgeHub.Platform")
            .AddOtlpExporter(options =>
            {
                options.Endpoint = new Uri(new Uri(address), "/v1/metrics");
                options.Protocol = OtlpExportProtocol.HttpProtobuf;
            }).Build();
        metrics.Record("private-document-title", "secret-token", .125, 2);
        metrics.SetQueueState(2, 1, 0, 90);
        metrics.SetOperationalAges(30, 60, 120);
        Assert.True(provider.ForceFlush(10_000));
        var payload = Encoding.UTF8.GetString(await received.Task.WaitAsync(TimeSpan.FromSeconds(10)));
        Assert.Contains("platform_operations_total", payload, StringComparison.Ordinal);
        Assert.Contains("platform_evidence_age_seconds", payload, StringComparison.Ordinal);
        Assert.DoesNotContain("private-document-title", payload, StringComparison.Ordinal);
        Assert.DoesNotContain("secret-token", payload, StringComparison.Ordinal);
        await collector.StopAsync();
    }
}