// Copyright 2012-2026 The NATS Authors
// Licensed under the Apache License, Version 2.0

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

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

public sealed class ConsumerFileStoreTests
{
    [Fact]
    public void UpdateDelivered_UpdateAcks_AndReload_ShouldPersistState()
    {
        var root = Path.Combine(Path.GetTempPath(), $"cfs-{Guid.NewGuid():N}");
        Directory.CreateDirectory(root);
        try
        {
            var fs = NewStore(root);
            var cfg = new ConsumerConfig { Durable = "D", AckPolicy = AckPolicy.AckExplicit };
            var cs = (ConsumerFileStore)fs.ConsumerStore("D", DateTime.UtcNow, cfg);

            cs.SetStarting(0);
            cs.UpdateDelivered(1, 1, 1, 123);
            cs.UpdateDelivered(2, 2, 1, 456);
            cs.UpdateAcks(1, 1);

            var (state, err) = cs.State();
            err.ShouldBeNull();
            state.ShouldNotBeNull();
            state!.Delivered.Consumer.ShouldBe(2UL);
            state.AckFloor.Consumer.ShouldBe(1UL);

            cs.Stop();

            var odir = Path.Combine(root, FileStoreDefaults.ConsumerDir, "D");
            var loaded = new ConsumerFileStore(
                fs,
                new FileConsumerInfo { Name = "D", Created = DateTime.UtcNow, Config = cfg },
                "D",
                odir);

            var (loadedState, loadedErr) = loaded.State();
            loadedErr.ShouldBeNull();
            loadedState.ShouldNotBeNull();
            loadedState!.Delivered.Consumer.ShouldBe(2UL);
            loadedState.AckFloor.Consumer.ShouldBe(1UL);

            loaded.Delete();
            Directory.Exists(odir).ShouldBeFalse();
            fs.Stop();
        }
        finally
        {
            if (Directory.Exists(root))
                Directory.Delete(root, recursive: true);
        }
    }

    private static JetStreamFileStore NewStore(string root)
    {
        return new JetStreamFileStore(
            new FileStoreConfig { StoreDir = root },
            new FileStreamInfo
            {
                Created = DateTime.UtcNow,
                Config = new StreamConfig
                {
                    Name = "S",
                    Storage = StorageType.FileStorage,
                    Subjects = ["foo"],
                },
            });
    }
}