using UnityEngine;
using Unity.Netcode;

namespace Colosseum.Skills
{
    /// <summary>
    /// 스킬 투사체. 충돌 시 연결된 효과를 적용합니다.
    /// 서버에서만 이동/충돌을 처리하며, NetworkTransform으로 위치를 동기화합니다.
    /// </summary>
    [RequireComponent(typeof(Rigidbody))]
    public class SkillProjectile : NetworkBehaviour
    {
        [Header("이동 설정")]
        [Min(0f)] [SerializeField] private float speed = 15f;
        [Min(0f)] [SerializeField] private float lifetime = 5f;

        [Header("관통 설정")]
        [SerializeField] private bool penetrate = false;
        [SerializeField] private int maxPenetration = 1;

        [Header("충돌 이펙트")]
        [SerializeField] private GameObject hitEffect;
        [SerializeField] private float hitEffectDuration = 2f;

        [Header("트레일 이펙트")]
        [Tooltip("투사체 트레일 프리팹 (TrailRenderer가 포함된 프리팹). 미설정 시 트레일 없음.")]
        [SerializeField] private GameObject trailPrefab;
        [Tooltip("투사체 파괴 후 트레일이 남는 시간 (초)")]
        [Min(0.1f)] [SerializeField] private float trailDuration = 0.3f;

        private GameObject caster;
        private SkillEffect sourceEffect;
        private int penetrationCount;
        private Rigidbody rb;
        private bool initialized;
        private GameObject trailInstance;

        /// <summary>
        /// 투사체 초기화
        /// </summary>
        public void Initialize(GameObject caster, SkillEffect sourceEffect)
        {
            this.caster = caster;
            this.sourceEffect = sourceEffect;
            initialized = true;

            rb = GetComponent<Rigidbody>();
            if (rb != null)
            {
                rb.useGravity = false;
                rb.collisionDetectionMode = CollisionDetectionMode.ContinuousDynamic;
            }

            // caster 및 자식 콜라이더와의 충돌 무시
            var myColliders = GetComponents<Collider>();
            foreach (var cc in caster.GetComponentsInChildren<Collider>())
                foreach (var mc in myColliders)
                    Physics.IgnoreCollision(mc, cc);
        }

        public override void OnNetworkSpawn()
        {
            // 트레일 생성 (서버/클라이언트 양쪽에서 실행)
            if (trailPrefab != null)
            {
                trailInstance = Instantiate(trailPrefab, transform);
                trailInstance.transform.localPosition = Vector3.zero;
                trailInstance.transform.localRotation = Quaternion.identity;
            }
        }

        private void Start()
        {
            // 서버에서만 수명 관리
            if (IsServer)
                Invoke(nameof(ServerDespawn), lifetime);
        }

        private void FixedUpdate()
        {
            // 서버에서만 이동 처리
            if (!IsServer || !initialized || rb == null) return;
            rb.linearVelocity = transform.forward * speed;
        }

        private void OnTriggerEnter(Collider other)
        {
            // 서버에서만 충돌 처리
            if (!IsServer || !initialized || sourceEffect == null) return;
            if (other.gameObject == caster) return;

            // 유효한 타겟인지 확인
            if (!sourceEffect.IsValidTarget(caster, other.gameObject))
                return;

            // 충돌 이펙트 (서버 + 클라이언트 모두 표시)
            if (hitEffect != null)
            {
                var effect = Instantiate(hitEffect, transform.position, transform.rotation);
                Destroy(effect, hitEffectDuration);
                HitEffectClientRpc(transform.position, transform.rotation.eulerAngles);
            }

            // 효과 적용
            sourceEffect.ExecuteOnHit(caster, other.gameObject);

            penetrationCount++;

            if (!penetrate || penetrationCount >= maxPenetration)
            {
                ServerDespawn();
            }
        }

        private void ServerDespawn()
        {
            if (!IsServer || !IsSpawned) return;

            // 트레일을 월드에 남겨서 자연스럽게 사라지게 함
            if (trailInstance != null)
            {
                trailInstance.transform.SetParent(null);
                Destroy(trailInstance, trailDuration);
                trailInstance = null;
            }

            NetworkObject.Despawn(true);
        }

        public void SetDirection(Vector3 direction)
        {
            transform.rotation = Quaternion.LookRotation(direction.normalized);
        }

        /// <summary>
        /// 클라이언트에 충돌 이펙트 표시
        /// </summary>
        [Rpc(SendTo.NotServer)]
        private void HitEffectClientRpc(Vector3 position, Vector3 eulerAngles)
        {
            if (hitEffect != null)
            {
                var effect = Instantiate(hitEffect, position, Quaternion.Euler(eulerAngles));
                Destroy(effect, hitEffectDuration);
            }
        }
    }
}