using Fleet.Core;
using Fleet.Hosting;
using MoShiro.Protocol;

namespace MoShiro.Probe.Tests;

public sealed class ProbeTests
{
    [Fact]
    public void AgentDirectory_DualStack_PersistsBothPaths_AndRemovingIpv6KeepsIpv4()
    {
        string directory = NewDirectory();
        try
        {
            var agents = new AgentDirectory(new ConfigStore(directory), directory, NullNodeLog.Instance);
            ProbeAgentList list = List(1, "agt_dual");
            list.Agents[0].Ipv6Host = "2001:db8::1";
            agents.Apply(list);
            Assert.Equal(new[] { "ipv4", "ipv6" }, agents.Agents.Select(a => a.IpVersion));
            var reloaded = new AgentDirectory(new ConfigStore(directory), directory, NullNodeLog.Instance);
            Assert.Equal(2, reloaded.Agents.Count);
            Assert.Equal("2001:db8::1", reloaded.Agents[1].Host);
            list.Version = 2;
            list.Agents[0].Ipv6Host = null;
            reloaded.Apply(list);
            Assert.Equal("ipv4", Assert.Single(reloaded.Agents).IpVersion);
        }
        finally
        {
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void ClockEstimator_UsesTheSampleWithTheShortestRoundTrip()
    {
        var clock = new ClockEstimator();
        Assert.False(clock.HasEstimate);

        // Offset 1000 with a 50 ms round trip, offset 5000 with a 2 ms round trip (symmetry assumption is far better here)
        clock.Add(sendUs: 0, agentUs: 25_000 + 1000, receiveUs: 50_000);
        clock.Add(sendUs: 100_000, agentUs: 101_000 + 5000, receiveUs: 102_000);
        Assert.True(clock.HasEstimate);
        Assert.Equal(5000, clock.OffsetUs);

        // Slow samples do not displace the good one
        clock.Add(sendUs: 200_000, agentUs: 300_000, receiveUs: 400_000);
        Assert.Equal(5000, clock.OffsetUs);
    }

    private static string NewDirectory()
    {
        string path = Path.Combine(Path.GetTempPath(), "probe-tests-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(path);
        return path;
    }

    private static ProbeAgentList List(long version, params string[] ids) => new()
    {
        Version = version,
        Agents = [.. ids.Select(id => new AgentEndpoint { AgentId = new NodeId(id), Host = id + ".example", TcpPort = 7443, PublicKey = "c3BraQ==" })],
    };

    [Fact]
    public void AgentDirectory_StartsEmpty_IgnoresStaleLists_PersistsChanges_AndReloadsThem()
    {
        string directory = NewDirectory();
        try
        {
            var directoryA = new AgentDirectory(new ConfigStore(directory), directory, NullNodeLog.Instance);
            int changes = 0;
            directoryA.Changed += () => changes++;
            Assert.Empty(directoryA.Agents);

            directoryA.Apply(List(5, "agt_1", "agt_2"));
            Assert.Equal(1, changes);
            Assert.Equal(["agt_1", "agt_2"], directoryA.Agents.Select(a => a.AgentId));

            directoryA.Apply(List(4, "agt_old")); // out-of-order older push
            directoryA.Apply(List(5, "agt_1", "agt_2")); // same version and content
            Assert.Equal(1, changes);
            Assert.Equal(5, directoryA.Version);

            // The next start uses the saved list while the panel is not reachable yet
            var directoryB = new AgentDirectory(new ConfigStore(directory), directory, NullNodeLog.Instance);
            Assert.Equal(["agt_1", "agt_2"], directoryB.Agents.Select(a => a.AgentId));
            Assert.Equal(5, directoryB.Version);
        }
        finally
        {
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void AgentDirectory_StartsEmpty_WhenTheSavedFileIsCorrupt()
    {
        string directory = NewDirectory();
        try
        {
            new ConfigStore(directory).Write(AgentDirectory.FileName, "{ not json"u8.ToArray());
            var loaded = new AgentDirectory(new ConfigStore(directory), directory, NullNodeLog.Instance);
            Assert.Empty(loaded.Agents);
        }
        finally
        {
            Directory.Delete(directory, recursive: true);
        }
    }

    [Fact]
    public void ConfigStore_CreatesSubdirectories_ForFreshVolumes()
    {
        // 新建的命名卷里没有 update/：面板转来的更新清单要能写进去
        string directory = NewDirectory();
        try
        {
            new ConfigStore(directory).Write("update/offer.manifest", "{}"u8.ToArray());
            Assert.True(File.Exists(Path.Combine(directory, "update", "offer.manifest")));
        }
        finally
        {
            Directory.Delete(directory, recursive: true);
        }
    }
}