using UnityEngine;
using UnityEngine.AI;
using System.Collections;
using System;

/// <summary>
/// 몬스터 기본 클래스 (공통 기능만)
/// - 공격 방식은 자식 클래스에서 구현
/// </summary>
public abstract class MonsterClass : MonoBehaviour, IDamageable
{
    [Header("--- 최적화 설정 ---")]
    protected Renderer mobRenderer;
    protected Transform playerTransform;
    [SerializeField] protected float optimizationDistance = 40f;

    [Header("몬스터 기본 스탯")]
    [SerializeField] protected float maxHP = 100f;
    [SerializeField] protected float attackDamage = 10f;
    [SerializeField] protected int expReward = 10;
    [SerializeField] protected float moveSpeed = 3.5f;

    protected float currentHP;
    public event Action<float, float> OnHealthChanged;

    [Header("전투 / 무기 (선택사항)")]
    // ⭐ 근접 몬스터가 사용할 무기 (원거리 몬스터는 비워둬도 됨)
    [SerializeField] protected MonsterWeapon myWeapon;

    [Header("피격 / 사망 / 대기 애니메이션")]
    [SerializeField] protected string Monster_Idle = "Monster_Idle";
    [SerializeField] protected string Monster_GetDamage = "Monster_GetDamage";
    [SerializeField] protected string Monster_Die = "Monster_Die";

    protected Animator animator;
    protected NavMeshAgent agent;
    protected AudioSource audioSource;
    protected bool isHit, isDead, isAttacking;

    public bool IsAggroed { get; protected set; }

    [Header("AI 설정")]
    [SerializeField] protected float attackRestDuration = 1.5f;
    protected bool isResting;

    public static System.Action<int> OnMonsterKilled;

    [Header("공통 사운드/이펙트")]
    [SerializeField] protected AudioClip hitSound, deathSound;
    [SerializeField] protected GameObject deathEffectPrefab;
    [SerializeField] protected ParticleSystem hitEffect;
    [SerializeField] protected Transform impactSpawnPoint;

    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
    // 생명주기
    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    protected virtual void Awake()
    {
        mobRenderer = GetComponentInChildren<Renderer>();
        animator = GetComponent<Animator>();
        agent = GetComponent<NavMeshAgent>();
        audioSource = GetComponent<AudioSource>();
        if (agent != null) agent.speed = moveSpeed;
    }

    protected virtual void OnEnable()
    {
        playerTransform = GameObject.FindGameObjectWithTag("Player")?.transform;
        if (mobRenderer != null) mobRenderer.enabled = true;
        Init();
        if (MobUpdateManager.Instance != null) MobUpdateManager.Instance.RegisterMob(this);
    }

    protected virtual void OnDisable()
    {
        if (MobUpdateManager.Instance != null) MobUpdateManager.Instance.UnregisterMob(this);
    }

    public void ResetStats()
    {
        isDead = false;
        IsAggroed = false;
        currentHP = maxHP;
        OnHealthChanged?.Invoke(currentHP, maxHP);

        Collider col = GetComponent<Collider>();
        if (col != null) col.enabled = true;

        OnResetStats();
    }

    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
    // 추상 메서드 (자식이 반드시 구현)
    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    protected virtual void Init() { }
    protected abstract void ExecuteAILogic();
    protected virtual void OnResetStats() { }

    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
    // 공통 기능
    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    public virtual void Reactivate()
    {
        if (agent != null && agent.isOnNavMesh)
        {
            agent.isStopped = false;
            if (IsAggroed && playerTransform != null)
            {
                agent.SetDestination(playerTransform.position);
            }
        }
        if (mobRenderer != null) mobRenderer.enabled = true;
    }

    public void OnManagedUpdate()
    {
        if (isDead || playerTransform == null || !gameObject.activeInHierarchy) return;

        float distance = Vector3.Distance(transform.position, playerTransform.position);

        if (distance > optimizationDistance && !IsAggroed)
        {
            StopMovement();
            if (mobRenderer != null && mobRenderer.enabled) mobRenderer.enabled = false;
            return;
        }

        if (mobRenderer != null && !mobRenderer.enabled) mobRenderer.enabled = true;
        if (mobRenderer != null && !mobRenderer.isVisible) { StopMovement(); return; }
        if (agent != null && agent.isOnNavMesh && agent.isStopped) agent.isStopped = false;

        ExecuteAILogic();
    }

    protected void StopMovement()
    {
        if (agent != null && agent.isOnNavMesh)
        {
            agent.isStopped = true;
            agent.velocity = Vector3.zero;
        }
        if (animator != null)
        {
            animator.SetFloat("Speed", 0f);
            animator.Play(Monster_Idle);
        }
    }

    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
    // 피격 / 사망
    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    public virtual void TakeDamage(float amount)
    {
        OnDamaged(amount);
    }

    public virtual void OnDamaged(float damage)
    {
        if (isDead) return;
        IsAggroed = true;
        currentHP -= damage;
        OnHealthChanged?.Invoke(currentHP, maxHP);
        if (currentHP <= 0) { Die(); return; }
        if (!isHit) StartHit();
    }

    protected virtual void StartHit()
    {
        isHit = true;
        isAttacking = false;
        isResting = false;
        StopAllCoroutines();

        OnStartHit();

        if (agent && agent.isOnNavMesh)
        {
            agent.isStopped = true;
            agent.velocity = Vector3.zero;
        }

        animator.Play(Monster_GetDamage, 0, 0f);
        if (hitEffect) hitEffect.Play();
        if (hitSound) audioSource.PlayOneShot(hitSound);
    }

    protected virtual void OnStartHit() { }

    public virtual void OnHitEnd()
    {
        isHit = false;
        if (agent && agent.isOnNavMesh) agent.isStopped = false;
    }

    protected virtual void Die()
    {
        if (isDead) return;
        isDead = true;
        IsAggroed = false;

        OnDie();

        OnMonsterKilled?.Invoke(expReward);
        Collider col = GetComponent<Collider>();
        if (col != null) col.enabled = false;

        if (agent && agent.isOnNavMesh)
        {
            agent.isStopped = true;
            agent.velocity = Vector3.zero;
        }

        animator.Play(Monster_Die, 0, 0f);
        if (deathSound) audioSource.PlayOneShot(deathSound);
        Invoke("ReturnToPool", 1.5f);
    }

    protected virtual void OnDie() { }

    public bool IsDead => isDead;
    protected void ReturnToPool() => gameObject.SetActive(false);

    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
    // ⭐ 공격 이벤트 (여기가 중요!)
    // ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

    /// <summary>
    /// 애니메이션 이벤트: 공격 시작
    /// - 부모는 기본적으로 무기를 켬
    /// - 자식(원거리)은 이걸 Override 해서 화살 발사로 바꿈
    /// </summary>
    public virtual void OnAttackStart()
    {
        isAttacking = true;
        isResting = false;

        if (myWeapon != null)
        {
            myWeapon.EnableHitBox();
        }
    }

    public virtual void OnAttackEnd()
    {
        if (myWeapon != null)
        {
            myWeapon.DisableHitBox();
        }

        isAttacking = false;
        if (!isDead && !isHit) StartCoroutine(RestAfterAttack());
    }

    protected virtual IEnumerator RestAfterAttack()
    {
        isResting = true;
        yield return new WaitForSeconds(attackRestDuration);
        isResting = false;
    }
}