using NATS.Server.JetStream.Storage;
using System.Text;

namespace NATS.Server.JetStream.Tests;

public class JetStreamFileStoreBlockParityTests
{
    [Fact]
    public async Task File_store_rolls_blocks_and_recovers_index_without_full_file_rewrite()
    {
        var dir = Path.Combine(Path.GetTempPath(), $"nats-js-filestore-block-{Guid.NewGuid():N}");
        var options = new FileStoreOptions
        {
            Directory = dir,
            BlockSizeBytes = 512,
        };

        await using (var store = new FileStore(options))
        {
            for (var i = 0; i < 5000; i++)
                await store.AppendAsync("orders.created", Encoding.UTF8.GetBytes($"payload-{i}"), default);

            store.BlockCount.ShouldBeGreaterThan(1);
        }

        await using var reopened = new FileStore(options);
        var state = await reopened.GetStateAsync(default);
        state.Messages.ShouldBe((ulong)5000);
    }
}
