using Microsoft.Extensions.Options;
using TermRemoteCtl.Agent.Configuration;
using TermRemoteCtl.Agent.History;
using TermRemoteCtl.Agent.Sessions;
using TermRemoteCtl.Agent.Terminal;

namespace TermRemoteCtl.Agent.Tests.Terminal;

public class PowerShellSessionHostTests
{
    [Fact]
    public async Task ResizeAsync_Forwards_To_ConPty_Session()
    {
        var factory = new FakeConPtySessionFactory();
        using var harness = HostHarness.Create(factory);
        await using var host = harness.Host;

        await host.StartAsync("alpha", CancellationToken.None);
        await host.ResizeAsync("alpha", 120, 40, CancellationToken.None);

        Assert.Equal((120, 40), factory.Session.ResizeCalls.Single());
    }

    [Fact]
    public async Task Session_Output_Is_Captured_In_Registry_History()
    {
        var factory = new FakeConPtySessionFactory();
        using var harness = HostHarness.Create(factory, lineLimit: 3);
        var session = harness.Registry.Create("Shell", DateTimeOffset.UtcNow);
        await using var host = harness.Host;

        await host.StartAsync(session.SessionId, CancellationToken.None);
        factory.Session.EmitOutput(session.SessionId, "one\ntwo\nthree\n");

        var history = harness.Registry.GetHistory(session.SessionId, 2);

        Assert.Equal(["two", "three"], history.Lines);
        Assert.True(history.HasMoreAbove);
    }

    private sealed class HostHarness : IDisposable
    {
        private HostHarness(string dataRoot, SessionRegistry registry, PowerShellSessionHost host)
        {
            DataRoot = dataRoot;
            Registry = registry;
            Host = host;
        }

        public string DataRoot { get; }

        public SessionRegistry Registry { get; }

        public PowerShellSessionHost Host { get; }

        public static HostHarness Create(FakeConPtySessionFactory factory, int lineLimit = 4000)
        {
            var dataRoot = Path.Combine(Path.GetTempPath(), "TermRemoteCtl.Tests", Guid.NewGuid().ToString("N"));
            Directory.CreateDirectory(dataRoot);

            var options = Options.Create(new AgentOptions
            {
                DataRoot = dataRoot,
                RingBufferLineLimit = lineLimit,
            });
            var registry = new SessionRegistry(new SessionHistoryStore(dataRoot), options);
            var host = new PowerShellSessionHost(factory, registry);

            return new HostHarness(dataRoot, registry, host);
        }

        public void Dispose()
        {
            if (Directory.Exists(DataRoot))
            {
                Directory.Delete(DataRoot, true);
            }
        }
    }

    private sealed class FakeConPtySessionFactory : IConPtySessionFactory
    {
        public FakeConPtySession Session { get; } = new();

        public IConPtySession Create(string sessionId)
        {
            Session.SessionId = sessionId;
            return Session;
        }
    }

    private sealed class FakeConPtySession : IConPtySession
    {
        public string SessionId { get; set; } = string.Empty;

        public event EventHandler<TerminalOutputEventArgs>? OutputReceived;

        public List<(int Columns, int Rows)> ResizeCalls { get; } = new();

        public Task StartAsync(CancellationToken cancellationToken)
        {
            return Task.CompletedTask;
        }

        public Task WriteInputAsync(string input, CancellationToken cancellationToken)
        {
            return Task.CompletedTask;
        }

        public Task ResizeAsync(int columns, int rows, CancellationToken cancellationToken)
        {
            ResizeCalls.Add((columns, rows));
            return Task.CompletedTask;
        }

        public void EmitOutput(string sessionId, string chunk)
        {
            OutputReceived?.Invoke(this, new TerminalOutputEventArgs(sessionId, chunk));
        }

        public ValueTask DisposeAsync()
        {
            return ValueTask.CompletedTask;
        }
    }
}