using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Fusion;
using Fusion.Sockets;
using UnityEngine;
using OnlyScove.Scripts;

namespace Hallucinate.UI
{
    public class BasicSpawner : MonoBehaviour, INetworkRunnerCallbacks
    {
        private static BasicSpawner _instance;
        public static BasicSpawner Instance 
        { 
            get
            {
                if (_instance == null)
                {
                    _instance = UnityEngine.Object.FindFirstObjectByType<BasicSpawner>();
                }
                return _instance;
            }
        }

        private NetworkRunner _runner;
        public NetworkRunner Runner => _runner;

        private bool _isStarting = false;
        private bool _isInternalShutdown = false;

        public event Action<List<SessionInfo>> OnSessionListUpdatedEvent;
        public event Action<string> OnShutdownEvent;
        public event Action OnJoinStartedEvent;
        public event Action OnJoinFailedEvent;

        [Header("Prefabs")]
        [SerializeField] private NetworkPrefabRef _playerPrefab;
        [SerializeField] private NetworkPrefabRef _playerDataManagerPrefab;

        private void Awake()
        {
            if (_instance != null && _instance != this)
            {
                Destroy(gameObject);
                return;
            }
            _instance = this;
            
            // Ensure this is a root object so DontDestroyOnLoad works correctly
            transform.SetParent(null);
            DontDestroyOnLoad(gameObject);
        }

        public PlayerProfile LocalPlayerProfile { get; private set; }
        public void SetLocalPlayerProfile(PlayerProfile _profile)
        {
            LocalPlayerProfile = _profile;
        }

        private async Task EnsureRunnerExists()
        {
            if (_runner != null)
            {
                _isInternalShutdown = true;
                try 
                {
                    if (_runner.IsRunning)
                    {
                        Debug.Log("[BasicSpawner] Shutting down existing runner before recreation.");
                        await _runner.Shutdown();
                    }

                    // Check if it still exists (Unity pseudo-null check)
                    if (_runner != null)
                    {
                        // Only log if it's actually a valid object to destroy
                        // If it's already marked for destruction, Unity == null will be true soon
                        Destroy(_runner);
                    }
                    _runner = null;

                    await Task.Yield();
                }
                finally
                {
                    _isInternalShutdown = false;
                }
            }

            if (this == null) return; // BasicSpawner itself might be destroyed

            Debug.Log("[BasicSpawner] Creating new NetworkRunner component.");
            _runner = gameObject.AddComponent<NetworkRunner>();
            _runner.ProvideInput = true;
            _runner.AddCallbacks(this);
        }

        public async Task StartLobby()
        {
            if (_isStarting) return;
            
            // Nếu đã ở trong lobby rồi thì không cần làm gì
            if (_runner != null && _runner.IsRunning && _runner.LobbyInfo.IsValid) return;

            Debug.Log("[BasicSpawner] StartLobby called");
            _isStarting = true;

            try 
            {
                await EnsureRunnerExists();
                Debug.Log("[BasicSpawner] Joining Lobby...");
                var result = await _runner.JoinSessionLobby(SessionLobby.ClientServer);
                if (!result.Ok) 
                {
                    Debug.LogWarning($"Join lobby result: {result.ShutdownReason}");
                }
            }
            finally
            {
                _isStarting = false;
            }
        }

        public async Task<bool> StartHost(string sessionName, string displayName, string password = null)
        {
            // Wait for any existing startup process (like StartLobby) to finish
            while (_isStarting)
            {
                await Task.Yield();
            }

            _isStarting = true;

            try 
            {
                Debug.Log($"[BasicSpawner] StartHost called: {sessionName} ({displayName})");
                OnJoinStartedEvent?.Invoke();

                bool sceneExists = false;
                for (int i = 0; i < UnityEngine.SceneManagement.SceneManager.sceneCountInBuildSettings; i++)
                {
                    if (UnityEngine.SceneManagement.SceneUtility.GetScenePathByBuildIndex(i).Contains("Main Scene"))
                    {
                        sceneExists = true;
                        break;
                    }
                }

                if (!sceneExists)
                {
                    Debug.LogError("CRITICAL: 'Main Scene' is NOT in Build Settings!");
                    return false;
                }

                await EnsureRunnerExists();

                var customProps = new Dictionary<string, SessionProperty>();
                if (!string.IsNullOrEmpty(password))
                {
                    customProps.Add("pw", password);
                }
                customProps.Add("rn", displayName);

                // Re-create or find SceneManager to ensure it matches the new runner
                var sceneManager = gameObject.GetComponent<NetworkSceneManagerDefault>();
                if (sceneManager == null) sceneManager = gameObject.AddComponent<NetworkSceneManagerDefault>();

                var result = await _runner.StartGame(new StartGameArgs()
                {
                    GameMode = GameMode.Host,
                    SessionName = sessionName,
                    SessionProperties = customProps,
                    PlayerCount = 2,
                    SceneManager = sceneManager
                });

                if (result.Ok)
                {
                    Debug.Log("[BasicSpawner] StartHost SUCCESS");
                    if (_runner.IsServer && _playerDataManagerPrefab.IsValid)
                    {
                        if (FindFirstObjectByType<PlayerDataManager>() == null)
                        {
                            Debug.Log("[BasicSpawner] Spawning PlayerDataManager");
                            _runner.Spawn(_playerDataManagerPrefab, Vector3.zero, Quaternion.identity, null);
                        }
                    }
                    return true;
                }
                else
                {
                    Debug.LogError($"[BasicSpawner] Fusion StartHost Failed: {result.ShutdownReason}.");
                    OnJoinFailedEvent?.Invoke();
                    return false;
                }
            }
            finally
            {
                _isStarting = false;
            }
        }

        public async Task<bool> StartClient(string sessionName, string password = null)
        {
            if (_isStarting) return false;
            _isStarting = true;

            try 
            {
                OnJoinStartedEvent?.Invoke();
                await EnsureRunnerExists();

                var sceneManager = gameObject.GetComponent<NetworkSceneManagerDefault>();
                if (sceneManager == null) sceneManager = gameObject.AddComponent<NetworkSceneManagerDefault>();

                var result = await _runner.StartGame(new StartGameArgs()
                {
                    GameMode = GameMode.Client,
                    SessionName = sessionName,
                    SceneManager = sceneManager
                });

                if (result.Ok)
                {
                    return true;
                }
                else
                {
                    Debug.LogError($"[BasicSpawner] Fusion StartClient Failed: {result.ShutdownReason}");
                    OnJoinFailedEvent?.Invoke();
                    return false;
                }
            }
            finally
            {
                _isStarting = false;
            }
        }


        private Dictionary<PlayerRef, NetworkObject> _spawnedCharacters = new Dictionary<PlayerRef, NetworkObject>();

        public void OnPlayerJoined(NetworkRunner runner, PlayerRef player)
        {
            if (player == runner.LocalPlayer)
            {
                SendLocalMetaData(player);
            }
        }

        private async void SendLocalMetaData(PlayerRef player)
        {
            PlayerDataManager pdm = null;
            int retries = 0;
            while (pdm == null && retries < 20)
            {
                pdm = FindFirstObjectByType<PlayerDataManager>();
                if (pdm != null) break;
                await Task.Delay(500);
                retries++;
            }

            if (pdm != null)
            {
                string playerName = LocalPlayerProfile != null ? LocalPlayerProfile.Name : "Player " + player.PlayerId;
                
                // Thêm hậu tố (HOST) nếu là server để dễ phân biệt
                if (_runner.IsServer) playerName += " (HOST)";

                _Role playerRole = _Role.Seeker;

                var metaData = new _PlayerMetaData()
                {
                    Name = playerName,
                    Role = playerRole,
                    IsReady = false
                };
                pdm.RPC_UpdatePlayerMetaData(player, metaData);
            }
            else
            {
                Debug.LogError("[BasicSpawner] Could not find PlayerDataManager after retries. Data will not sync.");
            }
        }

        public void StartGame()
        {
            if (_runner != null && _runner.IsServer)
            {
                _runner.LoadScene("Main Scene");
            }
        }

        public void OnPlayerLeft(NetworkRunner runner, PlayerRef player)
        {
            if (_spawnedCharacters.TryGetValue(player, out NetworkObject networkObject))
            {
                runner.Despawn(networkObject);
                _spawnedCharacters.Remove(player);
            }

            // Logic Reassign Leader (Logical)
            if (runner.IsServer && PlayerDataManager.Instance != null && PlayerDataManager.Instance.Leader == player)
            {
                var nextLeader = runner.ActivePlayers.FirstOrDefault();
                if (nextLeader != PlayerRef.None)
                {
                    PlayerDataManager.Instance.Leader = nextLeader;
                    Debug.Log($"[BasicSpawner] Leader left. New logical leader: {nextLeader}");
                }
            }

            if (runner.IsServer && player == runner.LocalPlayer) 
            {
                runner.Shutdown();
            }
        }

        public void OnShutdown(NetworkRunner runner, ShutdownReason shutdownReason)
        {
            Debug.LogWarning($"[Fusion] Shutdown occurred. Reason: {shutdownReason}");
            OnShutdownEvent?.Invoke(shutdownReason.ToString());
            
            // Nếu shutdown là do hệ thống chủ động hủy để tạo runner mới, KHÔNG quay về Menu
            if (_isInternalShutdown)
            {
                Debug.Log("[BasicSpawner] Internal shutdown detected, skipping Menu routing.");
                return;
            }

            // Nếu đang trong quá trình Host Migration, đừng quay về menu
            if (shutdownReason == ShutdownReason.HostMigration)
            {
                Debug.Log("[BasicSpawner] Shutdown due to Host Migration. Waiting for recovery...");
                return;
            }

            if (UIManager.Instance != null)
            {
                UIManager.Instance.OnBackToMenu();
            }
        }

        public void OnSessionListUpdated(NetworkRunner runner, List<SessionInfo> sessionList)
        {
            OnSessionListUpdatedEvent?.Invoke(sessionList);
        }

        public void OnInput(NetworkRunner runner, NetworkInput input)
        {
            // var data = new PlayerInputData();
            // if (PlayerStateMachine.Local != null && PlayerStateMachine.Local.Input != null)
            // {
            //     data.Direction = PlayerStateMachine.Local.Input.MoveInput;
            //     data.sprint = PlayerStateMachine.Local.Input.IsSprintHeld;
            //     data.jump = PlayerStateMachine.Local.Input.ConsumeJumpInput();
            //     if (PlayerStateMachine.Local.Cam != null)
            //         data.rot = PlayerStateMachine.Local.Cam.PlanarRotation;
            // }
            // input.Set(data);
        }

        public void OnConnectedToServer(NetworkRunner runner) { }
        public void OnDisconnectedFromServer(NetworkRunner runner, NetDisconnectReason reason) { }
        public void OnConnectRequest(NetworkRunner runner, NetworkRunnerCallbackArgs.ConnectRequest request, byte[] token) { }
        public void OnConnectFailed(NetworkRunner runner, NetAddress remoteAddress, NetConnectFailedReason reason) { }
        public void OnUserSimulationMessage(NetworkRunner runner, SimulationMessagePtr message) { }
        public void OnReliableDataReceived(NetworkRunner runner, PlayerRef player, ReliableKey key, ArraySegment<byte> data) { }
        public void OnReliableDataProgress(NetworkRunner runner, PlayerRef player, ReliableKey key, float progress) { }
        public void OnInputMissing(NetworkRunner runner, PlayerRef player, NetworkInput input) { }
        public void OnObjectExitAOI(NetworkRunner runner, NetworkObject obj, PlayerRef player) { }
        public void OnObjectEnterAOI(NetworkRunner runner, NetworkObject obj, PlayerRef player) { }
        public void OnCustomAuthenticationResponse(NetworkRunner runner, Dictionary<string, object> data) { }
        
        public async void OnHostMigration(NetworkRunner runner, HostMigrationToken hostMigrationToken) 
        { 
            Debug.Log("[BasicSpawner] OnHostMigration triggered!");
            
            // 1. Shutdown existing runner properly
            await runner.Shutdown(false);

            // 2. Create new runner
            await EnsureRunnerExists();

            // 3. Restart as new Host/Server using the migration token
            var result = await _runner.StartGame(new StartGameArgs()
            {
                HostMigrationToken = hostMigrationToken,
                SceneManager = gameObject.GetComponent<NetworkSceneManagerDefault>() ?? gameObject.AddComponent<NetworkSceneManagerDefault>()
            });

            if (result.Ok)
            {
                Debug.Log("[BasicSpawner] Host Migration SUCCESSFUL");
            }
            else
            {
                Debug.LogError($"[BasicSpawner] Host Migration FAILED: {result.ShutdownReason}");
                UIManager.Instance?.OnBackToMenu();
            }
        }
        
        public void OnSceneLoadDone(NetworkRunner runner)
        {
            string currentSceneName = UnityEngine.SceneManagement.SceneManager.GetActiveScene().name;
            if (runner.IsServer && currentSceneName == "Main Scene")
            {
                foreach (var player in runner.ActivePlayers)
                {
                    Vector2 spawnPosition = (player == runner.LocalPlayer) ? new Vector2(-8, 0) : new Vector2(8, 0);
                    var networkPlayerObject = runner.Spawn(_playerPrefab, spawnPosition, Quaternion.identity, player);
                    _spawnedCharacters.Add(player, networkPlayerObject);
                }
            }
            if (currentSceneName == "Main Scene")
            {
                UIManager.Instance?.OnGameStarted();
            }
        }


        public void OnSceneLoadStart(NetworkRunner runner) { }
    }
}