using System;
using Unity.Collections;
using Unity.Netcode;
using Unity.Netcode.Transports.UTP;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace Colosseum.Network
{
    /// <summary>
    /// 로비 상태 관리. NetworkBehaviour로 플레이어 목록을 모든 클라이언트에 동기화.
    /// NetworkManager가 있는 오브젝트와 별개로 배치하거나 NetworkObject 컴포넌트 필요.
    /// </summary>
    public class LobbyManager : NetworkBehaviour
    {
        public static LobbyManager Instance { get; private set; }

        [Header("Game Scene")]
        [SerializeField] private string gameSceneName = "Test";

        // 모든 클라이언트에 동기화되는 플레이어 목록
        private NetworkList<LobbyPlayerData> _players;

        public event Action OnPlayersChanged;

        // ─── 초기화 ───────────────────────────────────────────────
        private void Awake()
        {
            if (Instance != null && Instance != this)
            {
                Destroy(gameObject);
                return;
            }
            Instance = this;

            _players = new NetworkList<LobbyPlayerData>();
        }

        public override void OnNetworkSpawn()
        {
            _players.OnListChanged += _ => OnPlayersChanged?.Invoke();

            if (IsServer)
            {
                NetworkManager.Singleton.OnClientConnectedCallback += OnClientConnected;
                NetworkManager.Singleton.OnClientDisconnectCallback += OnClientDisconnected;
            }
        }

        public override void OnNetworkDespawn()
        {
            if (IsServer)
            {
                NetworkManager.Singleton.OnClientConnectedCallback -= OnClientConnected;
                NetworkManager.Singleton.OnClientDisconnectCallback -= OnClientDisconnected;
            }
        }

        // ─── 연결 제어 (클라이언트에서 호출) ─────────────────────
        /// <summary>호스트 시작</summary>
        public void StartHost(string ip, ushort port)
        {
            SetTransport(ip, port);
            NetworkManager.Singleton.StartHost();
        }

        /// <summary>클라이언트로 접속</summary>
        public void StartClient(string ip, ushort port)
        {
            SetTransport(ip, port);
            NetworkManager.Singleton.StartClient();
        }

        public void Disconnect()
        {
            NetworkManager.Singleton?.Shutdown();
        }

        // ─── 플레이어 목록 ────────────────────────────────────────
        public int PlayerCount => _players.Count;

        public LobbyPlayerData GetPlayer(int index) => _players[index];

        private void OnClientConnected(ulong clientId)
        {
            AddPlayer(clientId);
        }

        private void OnClientDisconnected(ulong clientId)
        {
            for (int i = 0; i < _players.Count; i++)
            {
                if (_players[i].ClientId == clientId)
                {
                    _players.RemoveAt(i);
                    return;
                }
            }
        }

        private void AddPlayer(ulong clientId)
        {
            _players.Add(new LobbyPlayerData
            {
                ClientId = clientId,
                PlayerName = new FixedString32Bytes($"Player {clientId}"),
                IsReady = false
            });
        }

        // ─── 준비 상태 ────────────────────────────────────────────
        [Rpc(SendTo.Server)]
        public void SetReadyRpc(bool isReady, RpcParams rpcParams = default)
        {
            ulong clientId = rpcParams.Receive.SenderClientId;
            for (int i = 0; i < _players.Count; i++)
            {
                if (_players[i].ClientId == clientId)
                {
                    var data = _players[i];
                    data.IsReady = isReady;
                    _players[i] = data;
                    return;
                }
            }
        }

        // ─── 게임 시작 ────────────────────────────────────────────
        /// <summary>호스트만 호출 가능. 모든 플레이어가 준비되어야 활성화 권장.</summary>
        public void StartGame()
        {
            if (!IsHost) return;
            NetworkManager.Singleton.SceneManager.LoadScene(gameSceneName, LoadSceneMode.Single);
        }

        // ─── 유틸 ─────────────────────────────────────────────────
        private void SetTransport(string ip, ushort port)
        {
            var transport = NetworkManager.Singleton?.GetComponent<UnityTransport>();
            if (transport != null)
                transport.SetConnectionData(ip, port);
        }
    }
}