using UnityEngine;
using UnityEngine.AI;
using System;

public class MonsterClass : MonoBehaviour, IDamageable
{
    [Header("스탯")]
    [SerializeField] protected float maxHP = 100f;
    protected float currentHP;
    public event Action<float, float> OnHealthChanged;

    [Header("피격 / 사망 애니메이션")]
    [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;
    protected bool isDead;

    [Header("경험치")]
    [SerializeField] protected int expReward = 10;
    public static System.Action<int> OnMonsterKilled;

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

    [Header("--- 드랍 설정 ---")]
    [SerializeField] private GameObject potionPrefab;
    [SerializeField][Range(0f, 100f)] private float potionDropChance = 30f;

    [Space(10)]
    [SerializeField] private GameObject[] weaponPrefabs;
    [SerializeField][Range(0f, 100f)] private float weaponDropChance = 5f;

    protected virtual void Start()
    {
        currentHP = maxHP;
        animator = GetComponent<Animator>();
        agent = GetComponent<NavMeshAgent>();
        audioSource = GetComponent<AudioSource>();
        OnHealthChanged?.Invoke(currentHP, maxHP);
    }

    // ⭐ [애니메이션 버그 해결] 매 프레임 속도를 체크해서 애니메이터에 전달합니다.
    protected virtual void Update()
    {
        if (isDead) return;

        if (agent != null && animator != null)
        {
            // 에이전트의 현재 이동 속도를 가져와서 "Speed" 파라미터에 넣어줍니다.
            float currentSpeed = agent.velocity.magnitude;
            animator.SetFloat("Speed", currentSpeed);
        }
    }

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

    public virtual void OnDamaged(float damage)
    {
        if (isDead) return;
        currentHP -= damage;
        OnHealthChanged?.Invoke(currentHP, maxHP);

        if (currentHP <= 0) { Die(); return; }
        if (!isHit) StartHit();
    }

    protected virtual void StartHit()
    {
        isHit = true;
        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);
    }

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

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

        // 아이템 날아감 방지: 몬스터 시체의 충돌을 끕니다.
        Collider col = GetComponent<Collider>();
        if (col != null) col.enabled = false;

        OnMonsterKilled?.Invoke(expReward);
        TryDropItems();

        if (agent && agent.isOnNavMesh) { agent.isStopped = true; agent.velocity = Vector3.zero; }
        animator.Play(Monster_Die, 0, 0f);
        if (deathSound) audioSource.PlayOneShot(deathSound);

        Destroy(gameObject, 1.5f);
    }

    private void TryDropItems()
    {
        if (potionPrefab != null && UnityEngine.Random.Range(0f, 100f) <= potionDropChance)
        {
            SpawnItem(potionPrefab);
        }

        if (weaponPrefabs != null && weaponPrefabs.Length > 0 && UnityEngine.Random.Range(0f, 100f) <= weaponDropChance)
        {
            int randomIndex = UnityEngine.Random.Range(0, weaponPrefabs.Length);
            SpawnItem(weaponPrefabs[randomIndex]);
        }
    }

    private void SpawnItem(GameObject prefab)
    {
        Vector3 spawnPos = transform.position + Vector3.up * 0.5f;
        GameObject item = Instantiate(prefab, spawnPos, Quaternion.identity);

        // ✅ [유저 요청] 배율 없이 프리팹의 원래 크기를 100% 그대로 적용
        item.transform.localScale = prefab.transform.localScale;

        if (item.TryGetComponent<Rigidbody>(out var rb))
        {
            // 튀어오르는 힘은 유저님이 설정하신 0.02f 유지
            Vector3 popDir = Vector3.up * 0.02f + UnityEngine.Random.insideUnitSphere * 0.02f;
            rb.AddForce(popDir, ForceMode.Impulse);

            if (prefab != potionPrefab)
            {
                rb.AddTorque(UnityEngine.Random.insideUnitSphere * 0.3f, ForceMode.Impulse);
            }
        }
    }

    public void OnDeathAnimEnd() { }
}