using System.Net;
using System.Net.Sockets;
using System.Threading.Tasks;
using Xunit;
using XWorld.Framework.Protocol;
using XWorld.Server.Gateway;

namespace XWorld.Server.Gateway.Tests
{
    public class DevDiscoveryResponderTests
    {
        private static async Task<DevDiscoveryReply?> QueryAsync(int port, string token, uint nonce, int timeoutMs)
        {
            using var client = new UdpClient(AddressFamily.InterNetwork);
            byte[] q = DevDiscoveryCodec.EncodeQuery(new DevDiscoveryQuery
            {
                ProtoVersion = DevDiscovery.ProtoVersion,
                Nonce = nonce,
                Token = token,
            });
            await client.SendAsync(q, q.Length, new IPEndPoint(IPAddress.Loopback, port));

            var recv = client.ReceiveAsync();
            var done = await Task.WhenAny(recv, Task.Delay(timeoutMs));
            if (done != recv) return null;
            UdpReceiveResult result = await recv;
            if (!DevDiscoveryCodec.TryDecodeReply(result.Buffer, out var reply)) return null;
            return reply;
        }

        [Fact]
        public async Task ValidQuery_ReceivesReply_WithAdvertisedAddresses()
        {
            var responder = new DevDiscoveryResponder(
                "dev-pc", "ws://192.168.1.23:5005/ws", "http://192.168.1.23:15081/minigame/",
                token: "secret", listenPort: 0);
            responder.Start();
            try
            {
                var reply = await QueryAsync(responder.Port, "secret", nonce: 7, timeoutMs: 2000);
                Assert.NotNull(reply);
                Assert.Equal("ws://192.168.1.23:5005/ws", reply.Value.GatewayUrl);
                Assert.Equal("http://192.168.1.23:15081/minigame/", reply.Value.ResourceBaseUrl);
                Assert.Equal("dev-pc", reply.Value.ServerName);
                Assert.Equal(7u, reply.Value.Nonce);
            }
            finally { await responder.StopAsync(); }
        }

        [Fact]
        public async Task WrongToken_NoReply()
        {
            var responder = new DevDiscoveryResponder("dev-pc", "ws://x", "http://y", token: "secret", listenPort: 0);
            responder.Start();
            try
            {
                var reply = await QueryAsync(responder.Port, "WRONG", nonce: 1, timeoutMs: 800);
                Assert.Null(reply);
            }
            finally { await responder.StopAsync(); }
        }

        [Fact]
        public async Task GarbagePacket_Ignored_LoopStillAnswers()
        {
            var responder = new DevDiscoveryResponder("dev-pc", "ws://x", "http://y", token: "secret", listenPort: 0);
            responder.Start();
            try
            {
                using (var raw = new UdpClient(AddressFamily.InterNetwork))
                {
                    byte[] junk = { 1, 2, 3 };
                    await raw.SendAsync(junk, junk.Length, new IPEndPoint(IPAddress.Loopback, responder.Port));
                }
                var reply = await QueryAsync(responder.Port, "secret", nonce: 9, timeoutMs: 2000);
                Assert.NotNull(reply);
                Assert.Equal(9u, reply.Value.Nonce);
            }
            finally { await responder.StopAsync(); }
        }
    }
}