using Newtonsoft.Json.Linq;
using OpenAC.MosswartMassacre.Infrastructure;
using OpenAC.MosswartMassacre.Tests.Fakes;

namespace OpenAC.MosswartMassacre.Tests;

/// <summary>A clock a test sets by hand.</summary>
internal sealed class FixedClock : IClock
{
    public DateTime UtcNow { get; set; } = new(2026, 9, 25, 8, 30, 15, 123, DateTimeKind.Utc);

    public DateTime Now { get; set; } = new(2026, 9, 25, 10, 30, 15, 123, DateTimeKind.Local);

    public void Advance(TimeSpan by)
    {
        UtcNow += by;
        Now += by;
    }
}

/// <summary>
/// The plugin built on a fake host and a fixed clock, logged in as a named
/// character with streaming on, and every frame it sends recorded.
/// </summary>
internal sealed class PluginHarness : IDisposable
{
    public PluginHarness(string characterName = "Mossy", bool webSocketEnabled = true, Action<FakeHost>? arrange = null)
    {
        Host.Automation.IsAvailable = true;
        Host.Automation.Character.Name = characterName;
        Host.Automation.Character.IsInWorld = false;
        Host.Automation.Character.ObjectId = 0x50000001;
        arrange?.Invoke(Host);
        Plugin.Initialize(Host);
        Plugin.Build(Host, Clock);
        Context.FrameTap = frame => Frames.Add(frame);
        // The stored settings keep streaming off so a login never opens a real
        // socket; Login() turns it on in memory afterwards, which is all the
        // frame gate reads.
        Context.Settings.Load(characterName);
        Context.Settings.Current.WebSocketEnabled = false;
        Context.Settings.Current.BackendUrl = "ws://127.0.0.1:1/unused/";
        Context.Settings.Save();
        _webSocketEnabled = webSocketEnabled;
    }

    private readonly bool _webSocketEnabled;

    public FakeHost Host { get; } = new();

    public FixedClock Clock { get; } = new();

    public MosswartMassacrePlugin Plugin { get; } = new();

    public MmContext Context => Plugin.Context!;

    public List<string> Frames { get; } = [];

    public IReadOnlyList<string> ChatLines => Host.ChatLines;

    /// <summary>Logs in without starting the socket.</summary>
    public void Login()
    {
        Host.Automation.Character.IsInWorld = true;
        Plugin.OnLogin();
        Context.Settings.Current.WebSocketEnabled = _webSocketEnabled;
    }

    /// <summary>Runs what the plugin runs right after the socket connects and registers.</summary>
    public void SimulateConnected() => Session.OnConnected(Clock.UtcNow);

    public OpenAC.MosswartMassacre.Backend.BackendSession Session =>
        Plugin.Features.OfType<OpenAC.MosswartMassacre.Backend.BackendSession>().Single();

    /// <summary>A frame as if the backend had sent it; routed on the next tick.</summary>
    public void Receive(string frame) => Session.Route(frame);

    public T Feature<T>() where T : IMmFeature => Plugin.Features.OfType<T>().Single();

    public void Tick(double seconds) => Host.Events.RaiseTick(seconds);

    /// <summary>Advances both the scheduler and the clock by <paramref name="seconds"/> in small steps.</summary>
    public void Run(double seconds, double step = 0.1)
    {
        for (double t = 0; t < seconds - 1e-9; t += step)
        {
            Clock.Advance(TimeSpan.FromSeconds(step));
            Tick(step);
        }
    }

    public IEnumerable<JObject> FramesOfType(string type) =>
        Frames.Select(JObject.Parse).Where(frame => (string?)frame["type"] == type);

    public void Dispose()
    {
        Plugin.OnLogoff();
        foreach (IMmFeature feature in Plugin.Features)
            feature.Dispose();
    }
}