using System;
using System.Collections.Generic;
using UnityEngine;
using Unity.Netcode;
using Unity.Behavior;
using Colosseum.Stats;

namespace Colosseum.Enemy
{
    /// <summary>
    /// 보스 캐릭터. 페이즈 시스템과 동적 AI 전환을 지원합니다.
    /// Unity Behavior 패키지를 사용하여 Behavior Tree 기반 AI를 구현합니다.
    /// </summary>
    
    public class BossEnemy : EnemyBase
    {
        [Header("Boss Settings")]
        [Tooltip("보스 페이즈 데이터 목록 (순서대로 전환)")]
        [SerializeField] private List<BossPhaseData> phases = new();
        
        [Tooltip("초기 Behavior Graph")]
        [SerializeField] private BehaviorGraph initialBehaviorGraph;

        [Header("Phase Settings")]
        [Tooltip("페이즈 전환 시 무적 시간")]
        [Min(0f)] [SerializeField] private float phaseTransitionInvincibilityTime = 2f;
        
        [Tooltip("페이즈 전환 연출 시간")]
        [Min(0f)] [SerializeField] private float phaseTransitionDuration = 3f;

        [Header("Debug")]
        [SerializeField] private bool debugMode = true;

        // 컴포넌트
        private BehaviorGraphAgent behaviorAgent;

        // 페이즈 상태
        private int currentPhaseIndex = 0;
        private bool isTransitioning = false;
        private float phaseStartTime;
        private float phaseElapsedTime;
        private bool isInvincible = false;

        // 커스텀 조건 딕셔너리
        private Dictionary<string, bool> customConditions = new Dictionary<string, bool>();

        // 이벤트
        public event System.Action<int> OnPhaseChanged; // phaseIndex
        public event System.Action<float> OnPhaseTransitionStart; // transitionDuration
        public event System.Action OnPhaseTransitionEnd;
        // 정적 이벤트 (UI 자동 연결용)
        /// <summary>
        /// 보스 스폰 시 발생하는 정적 이벤트
        /// </summary>
        public static event System.Action<BossEnemy> OnBossSpawned;
        
        /// <summary>
        /// 현재 활성화된 보스 (Scene에 하나만 존재한다고 가정)
        /// </summary>
        public static BossEnemy ActiveBoss { get; private set; }

        // Properties
        public int CurrentPhaseIndex => currentPhaseIndex;
        public BossPhaseData CurrentPhase => phases.Count > currentPhaseIndex ? phases[currentPhaseIndex] : null;
        public int TotalPhases => phases.Count;
        public bool IsTransitioning => isTransitioning;
        public float PhaseElapsedTime => phaseElapsedTime;

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

            // BehaviorGraphAgent 컴포넌트 확인/추가
            behaviorAgent = GetComponent<BehaviorGraphAgent>();
            if (behaviorAgent == null)
            {
                behaviorAgent = gameObject.AddComponent<BehaviorGraphAgent>();
            }

            // 초기 AI 설정
            if (IsServer && initialBehaviorGraph != null)
            {
                behaviorAgent.Graph = initialBehaviorGraph;
            }
            
            // 정적 이벤트 발생 (UI 자동 연결용)
            ActiveBoss = this;
            OnBossSpawned?.Invoke(this);
            
            if (debugMode)
            {
                Debug.Log($"[Boss] Boss spawned: {name}");
            }
        }


        protected override void InitializeStats()
        {
            base.InitializeStats();
            phaseStartTime = Time.time;
            phaseElapsedTime = 0f;
            currentPhaseIndex = 0;
            isTransitioning = false;
            isInvincible = false;
            customConditions.Clear();
        }

        protected override void OnServerUpdate()
        {
            if (isTransitioning) return;

            phaseElapsedTime = Time.time - phaseStartTime;
            CheckPhaseTransition();
        }

        /// <summary>
        /// 페이즈 전환 조건 확인
        /// </summary>
        private void CheckPhaseTransition()
        {
            int nextPhaseIndex = currentPhaseIndex + 1;
            if (nextPhaseIndex >= phases.Count)
                return;

            BossPhaseData nextPhase = phases[nextPhaseIndex];
            if (nextPhase == null)
                return;

            if (nextPhase.CheckTransitionCondition(this, phaseElapsedTime))
            {
                StartPhaseTransition(nextPhaseIndex);
            }
        }

        /// <summary>
        /// 페이즈 전환 시작
        /// </summary>
        private void StartPhaseTransition(int newPhaseIndex)
        {
            if (newPhaseIndex >= phases.Count || isTransitioning)
                return;

            isTransitioning = true;
            isInvincible = true;

            StartCoroutine(PhaseTransitionCoroutine(newPhaseIndex));
        }

        private System.Collections.IEnumerator PhaseTransitionCoroutine(int newPhaseIndex)
        {
            BossPhaseData newPhase = phases[newPhaseIndex];

            // 전환 이벤트
            OnPhaseTransitionStart?.Invoke(phaseTransitionDuration);

            // 전환 연출
            yield return PlayPhaseTransitionEffect(newPhase);

            // AI 그래프 교체
            if (newPhase.BehaviorGraph != null && behaviorAgent != null)
            {
                behaviorAgent.End();
                behaviorAgent.Graph = newPhase.BehaviorGraph;
            }

            // 페이즈 전환 완료
            currentPhaseIndex = newPhaseIndex;
            phaseStartTime = Time.time;
            phaseElapsedTime = 0f;

            // 무적 해제
            yield return new WaitForSeconds(phaseTransitionInvincibilityTime);
            isInvincible = false;
            isTransitioning = false;

            OnPhaseTransitionEnd?.Invoke();
            OnPhaseChanged?.Invoke(currentPhaseIndex);

            if (debugMode)
            {
                Debug.Log($"[Boss] Phase transition: {currentPhaseIndex} ({newPhase.PhaseName})");
            }
        }

        /// <summary>
        /// 페이즈 전환 연출 재생
        /// </summary>
        private System.Collections.IEnumerator PlayPhaseTransitionEffect(BossPhaseData newPhase)
        {
            // 애니메이션 재생
            if (animator != null && newPhase.PhaseStartAnimation != null)
            {
                animator.Play(newPhase.PhaseStartAnimation.name);
            }

            // 이펙트 생성
            if (newPhase.PhaseTransitionEffect != null)
            {
                var effect = Instantiate(newPhase.PhaseTransitionEffect, transform.position, transform.rotation);
                Destroy(effect, phaseTransitionDuration);
            }

            // 전환 시간 대기
            yield return new WaitForSeconds(phaseTransitionDuration);
        }

        /// <summary>
        /// 대미지 적용 (무적 상태 고려)
        /// </summary>
        public override float TakeDamage(float damage, object source = null)
        {
            if (isInvincible)
                return 0f;

            return base.TakeDamage(damage, source);
        }

        /// <summary>
        /// 커스텀 조건 설정
        /// </summary>
        public void SetCustomCondition(string conditionId, bool value)
        {
            customConditions[conditionId] = value;
        }

        /// <summary>
        /// 커스텀 조건 확인
        /// </summary>
        public bool CheckCustomCondition(string conditionId)
        {
            return customConditions.TryGetValue(conditionId, out bool value) && value;
        }

        /// <summary>
        /// 수동으로 페이즈 전환
        /// </summary>
        public void ForcePhaseTransition(int phaseIndex)
        {
            if (!IsServer)
                return;

            if (phaseIndex >= 0 && phaseIndex < phases.Count && phaseIndex != currentPhaseIndex)
            {
                StartPhaseTransition(phaseIndex);
            }
        }

        /// <summary>
        /// 현재 페이즈 재시작
        /// </summary>
        public void RestartCurrentPhase()
        {
            if (!IsServer)
                return;

            phaseStartTime = Time.time;
            phaseElapsedTime = 0f;

            if (behaviorAgent != null)
            {
                behaviorAgent.Restart();
            }
        }

        protected override void HandleDeath()
        {
            // 마지막 페이즈에서만 사망 처리
            if (currentPhaseIndex < phases.Count - 1 && !isTransitioning)
            {
                // 아직 페이즈가 남아있으면 강제로 다음 페이즈로
                StartPhaseTransition(currentPhaseIndex + 1);
                return;
            }

            // AI 완전 중단 (순서 중요: enabled=false를 먼저 호출하여 Update() 차단)
            if (behaviorAgent != null)
            {
                behaviorAgent.enabled = false;  // 가장 먼저: Update() 호출 방지
                behaviorAgent.End();
                behaviorAgent.Graph = null;
            }
            behaviorAgent = null;

            base.HandleDeath();
        }

        #region Debug

        private void OnDrawGizmosSelected()
        {
            if (!debugMode)
                return;

            // 현재 페이즈 정보 표시
            #if UNITY_EDITOR
            if (phases != null && currentPhaseIndex < phases.Count)
            {
                var phase = phases[currentPhaseIndex];
                if (phase != null)
                {
                    UnityEditor.Handles.Label(
                        transform.position + Vector3.up * 3f,
                        $"Phase {currentPhaseIndex + 1}/{phases.Count}\n{phase.PhaseName}"
                    );
                }
            }
            #endif
        }

        #endregion
    }
}