using System;

using UnityEngine;
using Unity.Netcode;

using Colosseum.Stats;

namespace Colosseum.Weapons
{
    /// <summary>
    /// 무기 장착을 관리하는 컴포넌트.
    /// 무기 장착 시 스탯 보너스를 적용하고 배율을 제공하며, 무기 외형을 표시합니다.
    /// 메시 이름으로 소켓을 자동 검색합니다.
    /// </summary>
    public class WeaponEquipment : NetworkBehaviour
    {
        [Header("References")]
        [Tooltip("CharacterStats 컴포넌트 (없으면 자동 검색)")]
        [SerializeField] private CharacterStats characterStats;

        [Header("Socket Names (메시 이름)")]
        [Tooltip("오른손 메시 이름")]
        [SerializeField] private string rightHandName = "Hand_R";
        [Tooltip("왼손 메시 이름")]
        [SerializeField] private string leftHandName = "Hand_L";
        [Tooltip("등 메시 이름")]
        [SerializeField] private string backName = "Spine";
        [Tooltip("허리 메시 이름")]
        [SerializeField] private string hipName = "Hip";
        [Tooltip("양손 메시 이름 (기본값: 오른손 사용)")]
        [SerializeField] private string twoHandedName = "";

        [Header("Starting Weapon")]
        [Tooltip("시작 무기 (선택)")]
        [SerializeField] private WeaponData startingWeapon;

        [Header("Starting Offhand")]
        [Tooltip("시작 보조 무기 (선택)")]
        [SerializeField] private WeaponData startingOffhandWeapon;

        [Header("네트워크 동기화")]
        [Tooltip("이 장착 시스템이 사용하는 모든 WeaponData 목록. 서버→클라이언트 무기 동기화에 사용됩니다.")]
        [SerializeField] private System.Collections.Generic.List<WeaponData> registeredWeapons = new();

        [Header("네트워크 동기화 (보조손)")]
        [Tooltip("보조손 WeaponData 목록. 서버→클라이언트 동기화에 사용됩니다.")]
        [SerializeField] private System.Collections.Generic.List<WeaponData> registeredOffhands = new();

        // 캐싱된 소켓 Transform들
        private Transform rightHandSocket;
        private Transform leftHandSocket;
        private Transform backSocket;
        private Transform hipSocket;
        private Transform twoHandedSocket;

        // 현재 장착 중인 무기
        private WeaponData currentWeapon;

        // 현재 생성된 무기 인스턴스
        private GameObject currentWeaponInstance;

        // 현재 적용된 스탯 수정자들 (해제 시 제거용)
        private readonly System.Collections.Generic.Dictionary<StatType, StatModifier> activeModifiers
            = new System.Collections.Generic.Dictionary<StatType, StatModifier>();

        // 보조손 무기
        private WeaponData currentOffhandWeapon;
        private GameObject currentOffhandWeaponInstance;
        private readonly System.Collections.Generic.Dictionary<StatType, StatModifier> activeOffhandModifiers
            = new System.Collections.Generic.Dictionary<StatType, StatModifier>();

        // 보조손 네트워크 동기화 (registeredOffhands 인덱스, -1 = 없음)
        private NetworkVariable<int> equippedOffhandId = new NetworkVariable<int>(-1);

        // 무기 장착 상태 동기화 (registeredWeapons 인덱스, -1 = 없음)
        private NetworkVariable<int> equippedWeaponId = new NetworkVariable<int>(-1);

        public WeaponData CurrentWeapon => currentWeapon;
        public bool HasWeaponEquipped => currentWeapon != null;
        public GameObject CurrentWeaponInstance => currentWeaponInstance;

        // 배율 프로퍼티 (무기 없으면 기본값 1.0)
        public float DamageMultiplier => currentWeapon != null ? currentWeapon.DamageMultiplier : 1f;
        public float RangeMultiplier => currentWeapon != null ? currentWeapon.RangeMultiplier : 1f;
        public float ManaCostMultiplier => currentWeapon != null ? currentWeapon.ManaCostMultiplier : 1f;

        // 보조손 프로퍼티
        public WeaponData CurrentOffhandWeapon => currentOffhandWeapon;
        public bool HasOffhandEquipped => currentOffhandWeapon != null;

        /// <summary>
        /// 현재 장착된 무기(메인+보조)의 특성 합산
        /// </summary>
        public WeaponTrait EquippedWeaponTraits
        {
            get
            {
                WeaponTrait traits = currentWeapon != null ? currentWeapon.WeaponTrait : WeaponTrait.None;
                if (currentOffhandWeapon != null)
                    traits |= currentOffhandWeapon.WeaponTrait;
                return traits;
            }
        }

        // 이벤트
        public event Action<WeaponData> OnWeaponEquipped;
        public event Action<WeaponData> OnWeaponUnequipped;
        public event Action<WeaponData> OnOffhandWeaponEquipped;
        public event Action<WeaponData> OnOffhandWeaponUnequipped;

        private void Awake()
        {
            // CharacterStats 참조 확인
            if (characterStats == null)
            {
                characterStats = GetComponent<CharacterStats>();
            }

            // 소켓 자동 검색
            CacheSockets();
        }

        public override void OnNetworkSpawn()
        {
            equippedWeaponId.OnValueChanged += HandleEquippedWeaponChanged;
            equippedOffhandId.OnValueChanged += HandleEquippedOffhandChanged;

            if (IsServer && startingWeapon != null)
            {
                EquipWeapon(startingWeapon);
            }
            else if (!IsServer && equippedWeaponId.Value >= 0)
            {
                // 늦게 접속한 클라이언트: 현재 장착된 무기 시각화
                SpawnWeaponVisualsLocal(equippedWeaponId.Value);
            }

            if (IsServer && startingOffhandWeapon != null)
            {
                EquipOffhandWeapon(startingOffhandWeapon);
            }
            else if (!IsServer && equippedOffhandId.Value >= 0)
            {
                SpawnOffhandVisualsLocal(equippedOffhandId.Value);
            }
        }

        public override void OnNetworkDespawn()
        {
            equippedWeaponId.OnValueChanged -= HandleEquippedWeaponChanged;
            equippedOffhandId.OnValueChanged -= HandleEquippedOffhandChanged;
        }

        /// <summary>
        /// 메시 이름으로 소켓 Transform 캐싱
        /// </summary>
        private void CacheSockets()
        {
            rightHandSocket = FindDeepChild(rightHandName);
            leftHandSocket = FindDeepChild(leftHandName);
            backSocket = FindDeepChild(backName);
            hipSocket = FindDeepChild(hipName);

            // 양손은 별도 이름 없으면 오른손 사용
            if (!string.IsNullOrEmpty(twoHandedName))
            {
                twoHandedSocket = FindDeepChild(twoHandedName);
            }
            else
            {
                twoHandedSocket = rightHandSocket;
            }

            Debug.Log($"[WeaponEquipment] Sockets cached - R:{rightHandSocket != null}, L:{leftHandSocket != null}, Back:{backSocket != null}, Hip:{hipSocket != null}");
        }

        /// <summary>
        /// 이름으로 자식 Transform 재귀 검색
        /// </summary>
        private Transform FindDeepChild(string name)
        {
            if (string.IsNullOrEmpty(name)) return null;

            // BFS로 검색
            var queue = new System.Collections.Generic.Queue<Transform>();
            queue.Enqueue(transform);

            while (queue.Count > 0)
            {
                Transform current = queue.Dequeue();

                if (current.name == name)
                {
                    return current;
                }

                foreach (Transform child in current)
                {
                    queue.Enqueue(child);
                }
            }

            return null;
        }

        private void HandleEquippedWeaponChanged(int oldValue, int newValue)
        {
            if (IsServer) return; // 서버는 EquipWeapon/UnequipWeapon에서 직접 처리

            if (newValue == -1)
                UnequipWeaponInternal();
            else
                SpawnWeaponVisualsLocal(newValue);
        }


        /// <summary>
        /// 무기 장착 (서버에서만 호출)
        /// </summary>
        public void EquipWeapon(WeaponData weapon)
        {
            if (weapon == null)
            {
                Debug.LogWarning("[WeaponEquipment] EquipWeapon called with null weapon");
                return;
            }

            if (!IsServer)
            {
                Debug.LogWarning("[WeaponEquipment] EquipWeapon can only be called on server");
                return;
            }

            // 기존 무기 해제
            if (currentWeapon != null)
            {
                UnequipWeapon();
            }

            currentWeapon = weapon;

            // 스탯 보너스 적용
            ApplyStatBonuses(weapon);

            // 무기 외형 생성 및 부착
            SpawnWeaponVisuals(weapon);

            // registeredWeapons 인덱스로 동기화
            equippedWeaponId.Value = registeredWeapons.IndexOf(weapon);
            if (equippedWeaponId.Value < 0)
                Debug.LogWarning($"[WeaponEquipment] '{weapon.WeaponName}' is not in registeredWeapons. Add it to sync to clients.");

            // 이벤트 발생
            OnWeaponEquipped?.Invoke(weapon);

            Debug.Log($"[WeaponEquipment] Equipped: {weapon.WeaponName} at {weapon.WeaponSlot}");
        }

        /// <summary>
        /// 무기 해제 (서버에서만 호출)
        /// </summary>
        public void UnequipWeapon()
        {
            if (currentWeapon == null) return;

            if (!IsServer)
            {
                Debug.LogWarning("[WeaponEquipment] UnequipWeapon can only be called on server");
                return;
            }

            WeaponData previousWeapon = currentWeapon;

            // 스탯 보너스 제거
            RemoveStatBonuses();

            // 무기 외형 제거
            DespawnWeaponVisuals();

            currentWeapon = null;
            equippedWeaponId.Value = -1;

            // 이벤트 발생
            OnWeaponUnequipped?.Invoke(previousWeapon);

            Debug.Log($"[WeaponEquipment] Unequipped: {previousWeapon.WeaponName}");
        }

        #region 보조손

        private void HandleEquippedOffhandChanged(int oldValue, int newValue)
        {
            if (IsServer) return;

            if (newValue == -1)
                UnequipOffhandWeaponInternal();
            else
                SpawnOffhandVisualsLocal(newValue);
        }

        /// <summary>
        /// 보조손 무기 장착 (서버에서만 호출)
        /// </summary>
        public void EquipOffhandWeapon(WeaponData weapon)
        {
            if (weapon == null)
            {
                Debug.LogWarning("[WeaponEquipment] EquipOffhandWeapon called with null weapon");
                return;
            }

            if (!IsServer)
            {
                Debug.LogWarning("[WeaponEquipment] EquipOffhandWeapon can only be called on server");
                return;
            }

            if (currentOffhandWeapon != null)
            {
                UnequipOffhandWeapon();
            }

            currentOffhandWeapon = weapon;

            ApplyOffhandStatBonuses(weapon);
            SpawnOffhandVisuals(weapon);

            equippedOffhandId.Value = registeredOffhands.IndexOf(weapon);
            if (equippedOffhandId.Value < 0)
                Debug.LogWarning($"[WeaponEquipment] '{weapon.WeaponName}' is not in registeredOffhands. Add it to sync to clients.");

            OnOffhandWeaponEquipped?.Invoke(weapon);

            Debug.Log($"[WeaponEquipment] Equipped offhand: {weapon.WeaponName}");
        }

        /// <summary>
        /// 보조손 무기 해제 (서버에서만 호출)
        /// </summary>
        public void UnequipOffhandWeapon()
        {
            if (currentOffhandWeapon == null) return;

            if (!IsServer)
            {
                Debug.LogWarning("[WeaponEquipment] UnequipOffhandWeapon can only be called on server");
                return;
            }

            WeaponData previousWeapon = currentOffhandWeapon;

            RemoveOffhandStatBonuses();
            DespawnOffhandVisuals();

            currentOffhandWeapon = null;
            equippedOffhandId.Value = -1;

            OnOffhandWeaponUnequipped?.Invoke(previousWeapon);

            Debug.Log($"[WeaponEquipment] Unequipped offhand: {previousWeapon.WeaponName}");
        }

        /// <summary>
        /// 보조손 내부 해제 로직 (클라이언트 동기화용)
        /// </summary>
        private void UnequipOffhandWeaponInternal()
        {
            if (currentOffhandWeaponInstance == null && currentOffhandWeapon == null) return;

            WeaponData previousWeapon = currentOffhandWeapon;
            DespawnOffhandVisualsLocal();

            OnOffhandWeaponUnequipped?.Invoke(previousWeapon);
        }

        /// <summary>
        /// 보조손 무기의 스탯 보너스 적용
        /// </summary>
        private void ApplyOffhandStatBonuses(WeaponData weapon)
        {
            if (characterStats == null) return;

            foreach (StatType statType in System.Enum.GetValues(typeof(StatType)))
            {
                int bonus = weapon.GetStatBonus(statType);
                if (bonus != 0)
                {
                    var stat = characterStats.GetStat(statType);
                    if (stat != null)
                    {
                        var modifier = new StatModifier(bonus, StatModType.Flat, weapon);
                        stat.AddModifier(modifier);
                        activeOffhandModifiers[statType] = modifier;

                        Debug.Log($"[WeaponEquipment] Applied offhand {statType} +{bonus}");
                    }
                }
            }
        }

        /// <summary>
        /// 보조손 무기의 스탯 보너스 제거
        /// </summary>
        private void RemoveOffhandStatBonuses()
        {
            if (characterStats == null) return;

            foreach (StatType statType in System.Enum.GetValues(typeof(StatType)))
            {
                var stat = characterStats.GetStat(statType);
                if (stat != null && activeOffhandModifiers.TryGetValue(statType, out StatModifier modifier))
                {
                    stat.RemoveModifier(modifier);
                    Debug.Log($"[WeaponEquipment] Removed offhand {statType} modifier");
                }
            }

            activeOffhandModifiers.Clear();
        }

        /// <summary>
        /// 보조손 무기 외형 생성 및 부착 (서버). 항상 왼손에 장착합니다.
        /// </summary>
        private void SpawnOffhandVisuals(WeaponData weapon)
        {
            if (weapon == null || weapon.WeaponPrefab == null) return;

            if (leftHandSocket == null)
            {
                Debug.LogWarning("[WeaponEquipment] No left hand socket found for offhand weapon");
                return;
            }

            currentOffhandWeaponInstance = Instantiate(weapon.WeaponPrefab, leftHandSocket);
            currentOffhandWeaponInstance.transform.localPosition = weapon.PositionOffset;
            currentOffhandWeaponInstance.transform.localRotation = Quaternion.Euler(weapon.RotationOffset);
            currentOffhandWeaponInstance.transform.localScale = weapon.Scale;

            Debug.Log($"[WeaponEquipment] Spawned offhand visual: {weapon.WeaponName}");
        }

        /// <summary>
        /// 클라이언트: registeredOffhands 인덱스로 보조손 무기 외형 생성
        /// </summary>
        private void SpawnOffhandVisualsLocal(int weaponIndex)
        {
            if (weaponIndex < 0 || weaponIndex >= registeredOffhands.Count || registeredOffhands[weaponIndex] == null)
            {
                Debug.LogWarning($"[WeaponEquipment] Offhand weapon index {weaponIndex} not found in registeredOffhands.");
                return;
            }

            var weapon = registeredOffhands[weaponIndex];
            if (weapon.WeaponPrefab == null) return;

            DespawnOffhandVisualsLocal();

            if (leftHandSocket == null)
            {
                Debug.LogWarning("[WeaponEquipment] No left hand socket found for offhand weapon");
                return;
            }

            currentOffhandWeaponInstance = Instantiate(weapon.WeaponPrefab, leftHandSocket);
            currentOffhandWeaponInstance.transform.localPosition = weapon.PositionOffset;
            currentOffhandWeaponInstance.transform.localRotation = Quaternion.Euler(weapon.RotationOffset);
            currentOffhandWeaponInstance.transform.localScale = weapon.Scale;
            currentOffhandWeapon = weapon;
        }

        /// <summary>
        /// 보조손 무기 외형 제거 (서버)
        /// </summary>
        private void DespawnOffhandVisuals()
        {
            if (currentOffhandWeaponInstance == null) return;
            Destroy(currentOffhandWeaponInstance);
            currentOffhandWeaponInstance = null;
        }

        /// <summary>
        /// 보조손 무기 외형 제거 (클라이언트)
        /// </summary>
        private void DespawnOffhandVisualsLocal()
        {
            if (currentOffhandWeaponInstance == null) return;
            Destroy(currentOffhandWeaponInstance);
            currentOffhandWeaponInstance = null;
            currentOffhandWeapon = null;
        }

        #endregion

        /// <summary>
        /// 내부 해제 로직 (클라이언트 동기화용)
        /// </summary>
        private void UnequipWeaponInternal()
        {
            if (currentWeaponInstance == null && currentWeapon == null) return;

            WeaponData previousWeapon = currentWeapon;
            DespawnWeaponVisualsLocal();

            OnWeaponUnequipped?.Invoke(previousWeapon);
        }

        /// <summary>
        /// 무기의 스탯 보너스 적용
        /// </summary>
        private void ApplyStatBonuses(WeaponData weapon)
        {
            if (characterStats == null) return;

            // 모든 스탯 타입에 대해 보너스 적용
            foreach (StatType statType in System.Enum.GetValues(typeof(StatType)))
            {
                int bonus = weapon.GetStatBonus(statType);
                if (bonus != 0)
                {
                    var stat = characterStats.GetStat(statType);
                    if (stat != null)
                    {
                        var modifier = new StatModifier(bonus, StatModType.Flat, weapon);
                        stat.AddModifier(modifier);
                        activeModifiers[statType] = modifier;

                        Debug.Log($"[WeaponEquipment] Applied {statType} +{bonus}");
                    }
                }
            }
        }

        /// <summary>
        /// 무기의 스탯 보너스 제거
        /// </summary>
        private void RemoveStatBonuses()
        {
            if (characterStats == null) return;

            // 각 스탯에서 무기로부터 추가된 수정자 제거
            foreach (StatType statType in System.Enum.GetValues(typeof(StatType)))
            {
                var stat = characterStats.GetStat(statType);
                if (stat != null && activeModifiers.TryGetValue(statType, out StatModifier modifier))
                {
                    stat.RemoveModifier(modifier);
                    Debug.Log($"[WeaponEquipment] Removed {statType} modifier");
                }
            }

            activeModifiers.Clear();
        }

        /// <summary>
        /// 무기 외형 생성 및 부착 (서버)
        /// </summary>
        private void SpawnWeaponVisuals(WeaponData weapon)
        {
            if (weapon == null || weapon.WeaponPrefab == null) return;

            Transform socket = GetSocketForSlot(weapon.WeaponSlot);
            if (socket == null)
            {
                Debug.LogWarning($"[WeaponEquipment] No socket found for slot: {weapon.WeaponSlot}");
                return;
            }

            currentWeaponInstance = Instantiate(weapon.WeaponPrefab, socket);
            currentWeaponInstance.transform.localPosition = weapon.PositionOffset;
            currentWeaponInstance.transform.localRotation = Quaternion.Euler(weapon.RotationOffset);
            currentWeaponInstance.transform.localScale = weapon.Scale;

            Debug.Log($"[WeaponEquipment] Spawned weapon visual: {weapon.WeaponName}");
        }

        /// <summary>
        /// 클라이언트: registeredWeapons 인덱스로 무기 외형 생성
        /// </summary>
        private void SpawnWeaponVisualsLocal(int weaponIndex)
        {
            if (weaponIndex < 0 || weaponIndex >= registeredWeapons.Count || registeredWeapons[weaponIndex] == null)
            {
                Debug.LogWarning($"[WeaponEquipment] Weapon index {weaponIndex} not found in registeredWeapons.");
                return;
            }

            var weapon = registeredWeapons[weaponIndex];
            if (weapon.WeaponPrefab == null) return;

            DespawnWeaponVisualsLocal();

            Transform socket = GetSocketForSlot(weapon.WeaponSlot);
            if (socket == null)
            {
                Debug.LogWarning($"[WeaponEquipment] No socket found for slot: {weapon.WeaponSlot}");
                return;
            }

            currentWeaponInstance = Instantiate(weapon.WeaponPrefab, socket);
            currentWeaponInstance.transform.localPosition = weapon.PositionOffset;
            currentWeaponInstance.transform.localRotation = Quaternion.Euler(weapon.RotationOffset);
            currentWeaponInstance.transform.localScale = weapon.Scale;
            currentWeapon = weapon;
        }

        /// <summary>
        /// 무기 외형 제거 (서버)
        /// </summary>
        private void DespawnWeaponVisuals()
        {
            if (currentWeaponInstance == null) return;
            Destroy(currentWeaponInstance);
            currentWeaponInstance = null;
        }

        /// <summary>
        /// 무기 외형 제거 (클라이언트)
        /// </summary>
        private void DespawnWeaponVisualsLocal()
        {
            if (currentWeaponInstance == null) return;
            Destroy(currentWeaponInstance);
            currentWeaponInstance = null;
            currentWeapon = null;
        }

        /// <summary>
        /// 슬롯 타입에 맞는 소켓 Transform 반환
        /// </summary>
        private Transform GetSocketForSlot(WeaponSlot slot)
        {
            return slot switch
            {
                WeaponSlot.RightHand => rightHandSocket,
                WeaponSlot.LeftHand => leftHandSocket,
                WeaponSlot.Back => backSocket,
                WeaponSlot.Hip => hipSocket,
                WeaponSlot.TwoHanded => twoHandedSocket != null ? twoHandedSocket : rightHandSocket,
                _ => rightHandSocket,
            };
        }

        /// <summary>
        /// 서버에 무기 장착 요청
        /// </summary>
        [Rpc(SendTo.Server)]
        public void RequestEquipWeaponRpc(int weaponInstanceId)
        {
            // TODO: WeaponDatabase에서 ID로 WeaponData 조회 후 EquipWeapon 호출
            Debug.Log($"[WeaponEquipment] Client requested weapon equip: {weaponInstanceId}");
        }

        /// <summary>
        /// 서버에 무기 해제 요청
        /// </summary>
        [Rpc(SendTo.Server)]
        public void RequestUnequipWeaponRpc()
        {
            UnequipWeapon();
        }
    }
}