using System.Net;
using System.Net.Sockets;
using System.Text;

namespace Nonemm.Keying.Tests;

/// The sender is tested against a socket that speaks cwdaemon's side of the
/// protocol, so what goes on the wire is what is asserted.
public class CwDaemonSenderTests : IDisposable
{
    private readonly UdpClient daemon = new(new IPEndPoint(IPAddress.Loopback, 0));

    private int Port => ((IPEndPoint)daemon.Client.LocalEndPoint!).Port;

    public void Dispose()
    {
        daemon.Dispose();
        GC.SuppressFinalize(this);
    }

    private async Task<byte[]> NextDatagram(Func<Task> send)
    {
        Task<UdpReceiveResult> receiving = daemon.ReceiveAsync();
        await send();
        UdpReceiveResult received = await receiving.WaitAsync(TimeSpan.FromSeconds(5));
        return received.Buffer;
    }

    [Fact]
    public async Task TextGoesOutInUpperCaseBehindAReplyRequest()
    {
        using CwDaemonSender sender = new("127.0.0.1", Port);
        await sender.SendAsync("cq test de dl1abc");

        // one receive at a time: two at once can take the datagrams in either order
        UdpReceiveResult request = await daemon.ReceiveAsync().WaitAsync(TimeSpan.FromSeconds(5));
        UdpReceiveResult text = await daemon.ReceiveAsync().WaitAsync(TimeSpan.FromSeconds(5));
        Assert.Equal("\u001bhnonemm", Encoding.ASCII.GetString(request.Buffer));
        Assert.Equal("CQ TEST DE DL1ABC", Encoding.ASCII.GetString(text.Buffer));
    }

    /// cwdaemon answers with `h` and the text of the reply request once the
    /// message has been played.
    [Fact]
    public async Task TheReplySaysTheMessageHasGoneOut()
    {
        using CwDaemonSender sender = new("127.0.0.1", Port);
        TaskCompletionSource finished = new();
        sender.Finished += (_, _) => finished.TrySetResult();

        Task<UdpReceiveResult> request = daemon.ReceiveAsync();
        await sender.SendAsync("test");
        UdpReceiveResult from = await request.WaitAsync(TimeSpan.FromSeconds(5));
        await daemon.SendAsync(Encoding.ASCII.GetBytes("hnonemm\r\n"), from.RemoteEndPoint);

        await finished.Task.WaitAsync(TimeSpan.FromSeconds(5));
    }

    [Fact]
    public async Task AReplyForSomebodyElseIsPassedOver()
    {
        using CwDaemonSender sender = new("127.0.0.1", Port);
        TaskCompletionSource finished = new();
        sender.Finished += (_, _) => finished.TrySetResult();

        Task<UdpReceiveResult> request = daemon.ReceiveAsync();
        await sender.SendAsync("test");
        UdpReceiveResult from = await request.WaitAsync(TimeSpan.FromSeconds(5));
        await daemon.SendAsync(Encoding.ASCII.GetBytes("hsomebodyelse\r\n"), from.RemoteEndPoint);

        await Assert.ThrowsAsync<TimeoutException>(
            () => finished.Task.WaitAsync(TimeSpan.FromMilliseconds(300)));
    }

    [Fact]
    public async Task AbortIsTheEscapeFourCommand()
    {
        using CwDaemonSender sender = new("127.0.0.1", Port);
        byte[] sent = await NextDatagram(() => sender.AbortAsync());
        Assert.Equal([0x1B, (byte)'4'], sent);
    }

    [Fact]
    public async Task SpeedIsTheEscapeTwoCommand()
    {
        using CwDaemonSender sender = new("127.0.0.1", Port);
        byte[] sent = await NextDatagram(() => sender.SetSpeedAsync(32));
        Assert.Equal([0x1B, (byte)'2', (byte)'3', (byte)'2'], sent);
    }
}