using System.Collections.Generic;
using Colosseum.Network;
using TMPro;
using Unity.Netcode;
using UnityEngine;
using UnityEngine.UI;

namespace Colosseum.UI
{
    /// <summary>
    /// 로비 씬 UI 제어.
    /// 두 패널 구조:
    ///   connectPanel  — IP/포트 입력 후 Host 또는 Join
    ///   lobbyPanel    — 대기실 (플레이어 목록, 준비, 게임 시작)
    /// </summary>
    public class LobbyUI : MonoBehaviour
    {
        // ─── Connect Panel ────────────────────────────────────────
        [Header("Connect Panel")]
        [SerializeField] private GameObject connectPanel;
        [SerializeField] private TMP_InputField ipInput;
        [SerializeField] private TMP_InputField portInput;
        [SerializeField] private Button hostButton;
        [SerializeField] private Button joinButton;
        [SerializeField] private TextMeshProUGUI connectStatusText;

        // ─── Lobby Panel ──────────────────────────────────────────
        [Header("Lobby Panel")]
        [SerializeField] private GameObject lobbyPanel;
        [SerializeField] private Transform playerListParent;
        [SerializeField] private GameObject playerSlotPrefab;   // TextMeshProUGUI 하나 포함
        [SerializeField] private Button readyButton;
        [SerializeField] private Button startButton;            // 호스트만 표시
        [SerializeField] private Button disconnectButton;

        // ─── 내부 ─────────────────────────────────────────────────
        private readonly List<GameObject> _slots = new();
        private bool _isReady;

        // ─── 초기화 ───────────────────────────────────────────────
        private void Start()
        {
            ipInput.text = "127.0.0.1";
            portInput.text = "7777";

            hostButton.onClick.AddListener(OnHostClicked);
            joinButton.onClick.AddListener(OnJoinClicked);
            readyButton.onClick.AddListener(OnReadyClicked);
            startButton.onClick.AddListener(OnStartClicked);
            disconnectButton.onClick.AddListener(OnDisconnectClicked);

            ShowConnectPanel();
        }

        private void OnEnable()
        {
            if (NetworkManager.Singleton == null) return;
            NetworkManager.Singleton.OnClientConnectedCallback += OnConnectionEvent;
            NetworkManager.Singleton.OnClientDisconnectCallback += OnConnectionEvent;
        }

        private void OnDisable()
        {
            if (NetworkManager.Singleton != null)
            {
                NetworkManager.Singleton.OnClientConnectedCallback -= OnConnectionEvent;
                NetworkManager.Singleton.OnClientDisconnectCallback -= OnConnectionEvent;
            }
        }

        // ─── Connect Panel 버튼 ───────────────────────────────────
        private void OnHostClicked()
        {
            if (!TryGetAddress(out string ip, out ushort port)) return;
            LobbyManager.Instance.StartHost(ip, port);
            LobbyManager.Instance.OnPlayersChanged += RefreshPlayerList;
            ShowLobbyPanel();
        }

        private void OnJoinClicked()
        {
            if (!TryGetAddress(out string ip, out ushort port)) return;
            SetConnectStatus("Connecting...");
            joinButton.interactable = false;
            hostButton.interactable = false;

            LobbyManager.Instance.StartClient(ip, port);

            // 연결 성공/실패 대기
            NetworkManager.Singleton.OnClientConnectedCallback += OnJoinSuccess;
            NetworkManager.Singleton.OnTransportFailure += OnJoinFailed;
        }

        private void OnJoinSuccess(ulong clientId)
        {
            if (clientId != NetworkManager.Singleton.LocalClientId) return;

            NetworkManager.Singleton.OnClientConnectedCallback -= OnJoinSuccess;
            NetworkManager.Singleton.OnTransportFailure -= OnJoinFailed;

            LobbyManager.Instance.OnPlayersChanged += RefreshPlayerList;
            ShowLobbyPanel();
        }

        private void OnJoinFailed()
        {
            NetworkManager.Singleton.OnClientConnectedCallback -= OnJoinSuccess;
            NetworkManager.Singleton.OnTransportFailure -= OnJoinFailed;

            SetConnectStatus("Connection failed. Check IP/Port.");
            joinButton.interactable = true;
            hostButton.interactable = true;
        }

        // ─── Lobby Panel 버튼 ─────────────────────────────────────
        private void OnReadyClicked()
        {
            _isReady = !_isReady;
            LobbyManager.Instance.SetReadyRpc(_isReady);
            readyButton.GetComponentInChildren<TextMeshProUGUI>().text =
                _isReady ? "Ready!" : "Ready";
        }

        private void OnStartClicked()
        {
            LobbyManager.Instance.StartGame();
        }

        private void OnDisconnectClicked()
        {
            LobbyManager.Instance.OnPlayersChanged -= RefreshPlayerList;
            LobbyManager.Instance.Disconnect();
            _isReady = false;
            ShowConnectPanel();
        }

        // ─── 패널 전환 ────────────────────────────────────────────
        private void ShowConnectPanel()
        {
            connectPanel.SetActive(true);
            lobbyPanel.SetActive(false);
            SetConnectStatus("");
            hostButton.interactable = true;
            joinButton.interactable = true;
        }

        private void ShowLobbyPanel()
        {
            connectPanel.SetActive(false);
            lobbyPanel.SetActive(true);

            bool isHost = NetworkManager.Singleton.IsHost;
            startButton.gameObject.SetActive(isHost);
            readyButton.gameObject.SetActive(!isHost);

            RefreshPlayerList();
        }

        // ─── 플레이어 목록 갱신 ───────────────────────────────────
        private void OnConnectionEvent(ulong _) => RefreshPlayerList();

        private void RefreshPlayerList()
        {
            if (LobbyManager.Instance == null) return;

            // 슬롯 수 맞추기
            int count = LobbyManager.Instance.PlayerCount;
            while (_slots.Count < count)
            {
                var slot = Instantiate(playerSlotPrefab, playerListParent);
                _slots.Add(slot);
            }
            while (_slots.Count > count)
            {
                Destroy(_slots[^1]);
                _slots.RemoveAt(_slots.Count - 1);
            }

            for (int i = 0; i < count; i++)
            {
                var data = LobbyManager.Instance.GetPlayer(i);
                var label = _slots[i].GetComponentInChildren<TextMeshProUGUI>();
                if (label != null)
                    label.text = $"{data.PlayerName}  {(data.IsReady ? "[Ready]" : "")}";
            }

            // 호스트: 모두 준비됐을 때만 시작 활성화
            if (NetworkManager.Singleton.IsHost)
            {
                bool allReady = AllPlayersReady();
                startButton.interactable = allReady && count >= 1;
            }
        }

        private bool AllPlayersReady()
        {
            if (LobbyManager.Instance == null) return false;
            int count = LobbyManager.Instance.PlayerCount;
            for (int i = 0; i < count; i++)
            {
                // 호스트 본인은 준비 체크 면제
                if (LobbyManager.Instance.GetPlayer(i).ClientId ==
                    NetworkManager.Singleton.LocalClientId) continue;

                if (!LobbyManager.Instance.GetPlayer(i).IsReady) return false;
            }
            return count > 0;
        }

        // ─── 유틸 ─────────────────────────────────────────────────
        private bool TryGetAddress(out string ip, out ushort port)
        {
            ip = ipInput.text.Trim();
            if (string.IsNullOrEmpty(ip)) ip = "127.0.0.1";

            if (!ushort.TryParse(portInput.text.Trim(), out port))
            {
                port = 7777;
                SetConnectStatus("Invalid port number.");
                return false;
            }
            return true;
        }

        private void SetConnectStatus(string msg)
        {
            if (connectStatusText != null)
                connectStatusText.text = msg;
        }
    }
}