PenguinsTwoChase/Assets/Scripts/Core/Network/ConnectionManager.cs

using PashaBibko.PenguinChase.Extensions;
using Unity.Netcode;
using UnityEngine;

namespace PashaBibko.PenguinChase.Core.Network
{
    public class ConnectionManager : MonoBehaviour
    {
        private static ConnectionManager sInstance;

        [SerializeField] private GameObject PrefabForEachClient;
        public static GameObject ClientPrefab => sInstance?.PrefabForEachClient;

        private void Start()
        {
            // Stops overlapping instances
            if (sInstance is not null)
            {
                Debug.LogError($"Multiple of [{nameof(ConnectionManager)}] cannot exist.");
                Destroy(gameObject);
                return;
            }

            sInstance = this;
        }

        public static void CreateNetworkConnectionManager()
        {
            NetworkManager.Singleton.OnClientConnectedCallback += OnClientJoin;
            OnClientJoin(0); // Has to be manually called for local client
        }

        public static void DestroyNetworkConnectionManager()
        {
            NetworkManager.Singleton.OnClientConnectedCallback -= OnClientJoin;
            sInstance.DestroyAllChildren();
        }

        private static void OnClientJoin(ulong id)
        {
            GameObject client = Instantiate(ClientPrefab);
            DontDestroyOnLoad(client);
            
            NetworkObject networkObject = client.GetComponent<NetworkObject>();
            networkObject.SpawnAsPlayerObject(id);
        }
    }
}