using ProjectM.Simulation;
using Unity.Entities;
using Unity.NetCode;
using UnityEngine;

namespace ProjectM.Client
{
    /// <summary>
    /// Minimal IMGUI Host / Join (+ IP) panel for the M4 LAN flow — the connection entry point for player
    /// builds, where there is no editor auto-host. Writes a <see cref="ConnectionConfig"/> request into the
    /// relevant netcode world(s): <b>Host</b> makes the server world listen and the local client join over
    /// loopback; <b>Join</b> makes the client world connect to the typed IP. Hides itself once the client
    /// world has a connection. Direct IP/LAN only — Unity Relay is deferred to a later pass. In the editor
    /// the <c>EditorAutoHostSystem</c> usually connects first, so this panel just shows "Connected".
    /// </summary>
    public class ConnectionUI : MonoBehaviour
    {
        [SerializeField] ushort _port = 7979;

        string _ipField = "127.0.0.1";

        void OnGUI()
        {
            if (IsClientConnected())
            {
                GUILayout.BeginArea(new Rect(10, 10, 220, 26));
                GUILayout.Label("Net: Connected");
                GUILayout.EndArea();
                return;
            }

            GUILayout.BeginArea(new Rect(10, 10, 240, 150), GUI.skin.box);
            GUILayout.Label("Project M — LAN co-op");

            // Host is only possible where a server world exists (editor or a ClientServer/host build).
            if (ClientServerBootstrap.ServerWorld is { IsCreated: true })
            {
                if (GUILayout.Button("Host"))
                {
                    Seed(ClientServerBootstrap.ServerWorld, ConnectionMode.Host, "0.0.0.0", _port);
                    Seed(ClientServerBootstrap.ClientWorld, ConnectionMode.Join, "127.0.0.1", _port);
                }
                GUILayout.Space(6);
            }

            GUILayout.Label("Join host IP:");
            _ipField = GUILayout.TextField(_ipField);
            if (GUILayout.Button("Join"))
                Seed(ClientServerBootstrap.ClientWorld, ConnectionMode.Join, _ipField, _port);

            GUILayout.EndArea();
        }

        static bool IsClientConnected()
        {
            var world = ClientServerBootstrap.ClientWorld;
            if (world is not { IsCreated: true })
                return false;
            using var q = world.EntityManager.CreateEntityQuery(ComponentType.ReadOnly<NetworkId>());
            return !q.IsEmpty;
        }

        static void Seed(World world, ConnectionMode mode, string address, ushort port)
        {
            if (world is not { IsCreated: true })
                return;
            var em = world.EntityManager;
            using var q = em.CreateEntityQuery(ComponentType.ReadWrite<ConnectionConfig>());
            Entity e = q.IsEmpty ? em.CreateEntity(typeof(ConnectionConfig)) : q.GetSingletonEntity();
            em.SetComponentData(e, new ConnectionConfig
            {
                Mode = mode,
                Address = address,
                Port = port,
                Requested = true,
            });
        }
    }
}