using Unity.Netcode;
using UnityEngine;

namespace Northbound
{
    /// <summary>
    /// 적대 유닛 (적대세력 또는 몬스터)
    /// </summary>
    [RequireComponent(typeof(Collider))]
    public class EnemyUnit : NetworkBehaviour, IDamageable, ITeamMember, IHealthProvider
    {
        [Header("Fog of War Visibility")]
        [Tooltip("전장의 안개에 의한 가시성 제어 활성화")]
        public bool enableFogVisibility = true;

        [Tooltip("가시성 체크 주기 (초)")]
        public float visibilityCheckInterval = 0.1f;
        [Header("Team Settings")]
        [Tooltip("이 유닛의 팀 (Hostile = 적대세력, Monster = 몬스터)")]
        public TeamType enemyTeam = TeamType.Hostile;

        [Header("Combat")]
        public int maxHealth = 100;

        [Header("Visual")]
        public GameObject damageEffectPrefab;
        public GameObject destroyEffectPrefab;

        [Header("Health Bar")]
        public bool showHealthBar = true;
        public GameObject healthBarPrefab;

        private NetworkVariable<int> _currentHealth = new NetworkVariable<int>(
            0,
            NetworkVariableReadPermission.Everyone,
            NetworkVariableWritePermission.Server
        );

        private NetworkVariable<TeamType> _team = new NetworkVariable<TeamType>(
            TeamType.Neutral,
            NetworkVariableReadPermission.Everyone,
            NetworkVariableWritePermission.Server
        );

        private NetworkVariable<bool> _isInvulnerable = new NetworkVariable<bool>(
            false,
            NetworkVariableReadPermission.Everyone,
            NetworkVariableWritePermission.Server
        );

        /// <summary>
        /// 사망 시 발생하는 이벤트 (매개변수: killerId)
        /// </summary>
        public event System.Action<ulong> OnDeath;

        /// <summary>
        /// 데미지를 받았을 때 발생하는 이벤트 (매개변수: attackerId, damage)
        /// </summary>
        public event System.Action<ulong, int> OnDamageTaken;

        private UnitHealthBar _healthBar;

        // 전장의 안개 가시성
        private Renderer[] _renderers;
        private float _visibilityTimer;
        private bool _lastVisibleState = true;
        private bool _initializedVisibility = false;
        private ulong _localPlayerId = ulong.MaxValue;

        public override void OnNetworkSpawn()
        {
            base.OnNetworkSpawn();

            // 렌더러 캐시 (가시성 제어용)
            _renderers = GetComponentsInChildren<Renderer>();

            if (IsServer)
            {
                _currentHealth.Value = maxHealth;
                _team.Value = enemyTeam;
            }

            // 체력 변경 이벤트 구독
            _currentHealth.OnValueChanged += OnHealthChanged;

            // 체력바 생성
            if (showHealthBar && healthBarPrefab != null)
            {
                CreateHealthBar();
            }

            // 클라이언트에서는 기본적으로 렌더러 비활성화
            if (enableFogVisibility && IsClient)
            {
                SetRenderersEnabled(false);
            }
        }

        public override void OnNetworkDespawn()
        {
            _currentHealth.OnValueChanged -= OnHealthChanged;
            base.OnNetworkDespawn();
        }

        private void Update()
        {
            // 클라이언트에서만 가시성 체크 (호스트 포함)
            if (enableFogVisibility && IsClient)
            {
                UpdateFogVisibility();
            }
        }

        /// <summary>
        /// 전장의 안개에 따른 가시성 업데이트 (클라이언트 전용)
        /// </summary>
        private void UpdateFogVisibility()
        {
            _visibilityTimer += Time.deltaTime;
            if (_visibilityTimer < visibilityCheckInterval) return;
            _visibilityTimer = 0f;

            // 로컬 플레이어 ID 캐시
            if (_localPlayerId == ulong.MaxValue)
            {
                _localPlayerId = GetLocalPlayerId();
                if (_localPlayerId == ulong.MaxValue)
                {
                    // 로컬 플레이어를 찾지 못함 - 기본적으로 숨김
                    if (_initializedVisibility) return;
                    _initializedVisibility = true;
                    SetRenderersEnabled(false);
                    return;
                }
            }

            // FogOfWarSystem이 없으면 항상 보임
            if (FogOfWarSystem.Instance == null)
            {
                if (_initializedVisibility) return;
                _initializedVisibility = true;
                SetRenderersEnabled(true);  // FogOfWar가 없으면 항상 보임
                return;
            }

            // FogOfWar가 비활성화되어 있으면 항상 보임
            if (!FogOfWarSystem.Instance.gameObject.activeInHierarchy)
            {
                if (_initializedVisibility) return;
                _initializedVisibility = true;
                SetRenderersEnabled(true);
                return;
            }

            // 현재 위치의 가시성 확인
            FogOfWarState state = FogOfWarSystem.Instance.GetVisibilityState(_localPlayerId, transform.position);
            bool shouldBeVisible = (state == FogOfWarState.Visible);

            // 초기화되지 않은 경우 강제로 설정
            if (!_initializedVisibility)
            {
                _initializedVisibility = true;
                _lastVisibleState = shouldBeVisible;
                SetRenderersEnabled(shouldBeVisible);
                return;
            }

            // 상태가 변경된 경우에만 렌더러 업데이트
            if (shouldBeVisible != _lastVisibleState)
            {
                _lastVisibleState = shouldBeVisible;
                SetRenderersEnabled(shouldBeVisible);
            }
        }

        /// <summary>
        /// 로컬 플레이어의 실제 ID 가져오기
        /// </summary>
        private ulong GetLocalPlayerId()
        {
            if (NetworkManager.Singleton == null)
            {
                return ulong.MaxValue;
            }

            // 방법 1: SpawnManager에서 찾기
            var localPlayer = NetworkManager.Singleton.SpawnManager.GetLocalPlayerObject();

            // 방법 2: LocalClient에서 찾기
            if (localPlayer == null && NetworkManager.Singleton.LocalClient != null)
            {
                localPlayer = NetworkManager.Singleton.LocalClient.PlayerObject;
            }

            // 방법 3: 직접 검색 (IsLocalPlayer인 플레이어 찾기)
            if (localPlayer == null)
            {
                var allPlayers = FindObjectsByType<NetworkPlayerController>(FindObjectsSortMode.None);
                foreach (var player in allPlayers)
                {
                    if (player.IsLocalPlayer)
                    {
                        localPlayer = player.GetComponent<NetworkObject>();
                        break;
                    }
                }
            }

            if (localPlayer == null)
            {
                return ulong.MaxValue;
            }

            var playerController = localPlayer.GetComponent<NetworkPlayerController>();
            if (playerController == null)
            {
                return ulong.MaxValue;
            }

            return playerController.OwnerPlayerId;
        }

        /// <summary>
        /// 모든 렌더러 활성화/비활성화
        /// </summary>
        private void SetRenderersEnabled(bool enabled)
        {
            if (_renderers == null) return;

            foreach (var renderer in _renderers)
            {
                if (renderer != null)
                {
                    renderer.enabled = enabled;
                }
            }

            // 체력바도 함께 처리
            if (_healthBar != null)
            {
                _healthBar.gameObject.SetActive(enabled);
            }
        }

        private void OnHealthChanged(int previousValue, int newValue)
        {
            if (_healthBar != null)
            {
                _healthBar.UpdateHealth();
            }
        }

        private void CreateHealthBar()
        {
            if (_healthBar != null)
                return;

            if (healthBarPrefab == null)
                return;

            GameObject healthBarObj = Instantiate(healthBarPrefab, transform);
            _healthBar = healthBarObj.GetComponent<UnitHealthBar>();

            if (_healthBar != null)
            {
                _healthBar.Initialize(this);
            }
        }

        #region IDamageable Implementation

        public void TakeDamage(int damage, ulong attackerId)
        {
            if (!IsServer) return;
            if (_currentHealth.Value <= 0) return;

            // 무적 상태면 데미지 무시
            if (_isInvulnerable.Value) return;

            // 공격자의 팀 확인
            if (NetworkManager.Singleton.SpawnManager.SpawnedObjects.TryGetValue(attackerId, out NetworkObject attackerObj))
            {
                var attackerTeamMember = attackerObj.GetComponent<ITeamMember>();
                if (attackerTeamMember != null)
                {
                    if (!TeamManager.CanAttack(attackerTeamMember, this))
                    {
                        return;
                    }
                }
            }

            int actualDamage = Mathf.Min(damage, _currentHealth.Value);
            _currentHealth.Value -= actualDamage;

            // 데미지 이펙트
            ShowDamageEffectClientRpc();

            // 데미지 받음 이벤트 발생 (AI 어그로 시스템용)
            OnDamageTaken?.Invoke(attackerId, actualDamage);

            // 체력이 0이 되면 파괴
            if (_currentHealth.Value <= 0)
            {
                DestroyUnit(attackerId);
            }
        }

        private void DestroyUnit(ulong attackerId)
        {
            if (!IsServer) return;

            // 사망 이벤트 발생 (애니메이션 등)
            OnDeath?.Invoke(attackerId);

            // 파괴 이펙트
            ShowDestroyEffectClientRpc();

            // 네트워크 오브젝트 파괴
            Invoke(nameof(DespawnUnit), 3.0f);
        }

        private void DespawnUnit()
        {
            if (IsServer && NetworkObject != null)
            {
                NetworkObject.Despawn(true);
            }
        }

        [Rpc(SendTo.ClientsAndHost)]
        private void ShowDamageEffectClientRpc()
        {
            if (damageEffectPrefab != null)
            {
                GameObject effect = Instantiate(damageEffectPrefab, transform.position, Quaternion.identity);
                Destroy(effect, 2f);
            }
        }

        [Rpc(SendTo.ClientsAndHost)]
        private void ShowDestroyEffectClientRpc()
        {
            if (destroyEffectPrefab != null)
            {
                GameObject effect = Instantiate(destroyEffectPrefab, transform.position, Quaternion.identity);
                Destroy(effect, 3f);
            }
        }

        #endregion

        #region ITeamMember Implementation

        public bool IsDead() => _currentHealth.Value <= 0;

        public TeamType GetTeam() => _team.Value;

        public void SetTeam(TeamType team)
        {
            if (!IsServer) return;
            _team.Value = team;
        }

        #endregion

        #region IHealthProvider Implementation

        public int GetCurrentHealth() => _currentHealth.Value;

        public int GetMaxHealth() => maxHealth;

        public float GetHealthPercentage()
        {
            int max = GetMaxHealth();
            return max > 0 ? (float)_currentHealth.Value / max : 0f;
        }

        #endregion

        #region Invulnerability & Healing

        public bool IsInvulnerable() => _isInvulnerable.Value;

        public void SetInvulnerable(bool value)
        {
            if (!IsServer) return;
            _isInvulnerable.Value = value;
        }

        public void HealToFull()
        {
            if (!IsServer) return;
            _currentHealth.Value = maxHealth;
        }

        #endregion

        private void OnDrawGizmosSelected()
        {
            #if UNITY_EDITOR
            if (Application.isPlaying)
            {
                UnityEditor.Handles.Label(transform.position + Vector3.up * 2f, 
                    $"Team: {TeamManager.GetTeamName(_team.Value)}\nHP: {_currentHealth.Value}/{maxHealth}");
            }
            else
            {
                UnityEditor.Handles.Label(transform.position + Vector3.up * 2f, 
                    $"Team: {TeamManager.GetTeamName(enemyTeam)}");
            }
            #endif
        }
    }
}