using System.Diagnostics;
using Shouldly;
using ZB.MOM.NatsNet.Server;

namespace ZB.MOM.NatsNet.Server.Tests.ImplBacklog;

public sealed class JetStreamClusterLongTests
{
    [Fact] // T:1219
    public void LongFileStoreEnforceMsgPerSubjectLimit_ShouldSucceed()
    {
        var root = Path.Combine(Path.GetTempPath(), $"impl-fs-long-{Guid.NewGuid():N}");
        Directory.CreateDirectory(root);

        JetStreamFileStore? fs = null;
        try
        {
            fs = JetStreamFileStore.NewFileStore(
                new FileStoreConfig { StoreDir = root, BlockSize = 1024 },
                new StreamConfig
                {
                    Name = "zzz",
                    Storage = StorageType.FileStorage,
                    Subjects = ["test.>"],
                    MaxMsgsPer = 1,
                    MaxMsgs = -1,
                    MaxBytes = -1,
                    Discard = DiscardPolicy.DiscardOld,
                    Retention = RetentionPolicy.LimitsPolicy,
                });

            const int keys = 4_000;
            const int rewriteCount = 30_000;

            for (var i = 0; i < keys; i++)
            {
                fs.StoreMsg($"test.{i:000000}", null, "seed"u8.ToArray(), 0).Seq.ShouldBeGreaterThan(0UL);
            }

            var sw = Stopwatch.StartNew();
            for (var i = 0; i < rewriteCount; i++)
            {
                var n = Random.Shared.Next(keys);
                fs.StoreMsg($"test.{n:000000}", null, "rewrite"u8.ToArray(), 0).Seq.ShouldBeGreaterThan(0UL);
            }
            sw.Stop();

            var totals = fs.SubjectsTotals("test.*");
            totals.Count.ShouldBe(keys);
            totals.Values.All(v => v <= 1UL).ShouldBeTrue();
            sw.Elapsed.ShouldBeLessThan(TimeSpan.FromSeconds(30));
        }
        finally
        {
            fs?.Stop();
            if (Directory.Exists(root))
                Directory.Delete(root, recursive: true);
        }
    }
}