using UnityEngine;

namespace _Project.Scripts.PlayerUtils
{
    [RequireComponent(typeof(Rigidbody), typeof(CapsuleCollider))]
    public class EnemyAI : MonoBehaviour, IDamageable
    {
        [Header("Класс и Профиль Врага")]
        public BodyClass enemyClass = BodyClass.Trooper;
        [Tooltip("Если не назначен, сгенерируется автоматически под выбранный класс")]
        public BodyProfile profile;

        [Header("Настройки ИИ")]
        [SerializeField] private float detectionRange = 30f;
        [SerializeField] private float eyeHeight = 1.5f;
        [SerializeField] private LayerMask obstacleMask = ~0;

        public float CurrentHealth { get; private set; }
        public bool IsDead { get; private set; }

        // Можно вселяться в любого живого врага (или если у него осталось мало ХП — на твой выбор)
        public bool CanBePossessed => !IsDead;

        private Rigidbody _rb;
        private Transform _playerTransform;
        private float _fireTimer;
        private float _strafeTimer;
        private int _strafeDir = 1;
        private LineRenderer _sniperLaser;

        private void Awake()
        {
            _rb = GetComponent<Rigidbody>();
            _rb.freezeRotation = true;
        }

        private void Start()
        {
            if (Player.Instance != null)
                _playerTransform = Player.Instance.transform;

            if (profile == null || profile.bodyClass != enemyClass)
            {
                profile = BodyProfile.CreateDefault(enemyClass);
            }

            CurrentHealth = profile.maxHealth;

            if (enemyClass == BodyClass.Sniper && _sniperLaser == null)
            {
                SetupSniperLaser();
            }
        }

        private void SetupSniperLaser()
        {
            _sniperLaser = gameObject.AddComponent<LineRenderer>();
            _sniperLaser.startWidth = 0.02f;
            _sniperLaser.endWidth = 0.02f;
            _sniperLaser.material = new Material(Shader.Find("Sprites/Default"));
            _sniperLaser.startColor = new Color(1f, 0f, 0f, 0.7f);
            _sniperLaser.endColor = new Color(1f, 0f, 0f, 0.1f);
            _sniperLaser.enabled = false;
        }

        private void Update()
        {
            if (IsDead || _playerTransform == null) return;

            _fireTimer -= Time.deltaTime;
            _strafeTimer -= Time.deltaTime;
            if (_strafeTimer <= 0f)
            {
                _strafeDir = Random.value > 0.5f ? 1 : -1;
                _strafeTimer = Random.Range(0.6f, 1.5f);
            }

            Vector3 eyePos = transform.position + Vector3.up * eyeHeight;
            Vector3 targetPos = _playerTransform.position + Vector3.up * 1.0f;
            Vector3 toPlayer = targetPos - eyePos;
            float dist = toPlayer.magnitude;

            if (dist > detectionRange || !HasLineOfSight(eyePos, targetPos, dist))
            {
                if (_sniperLaser != null) _sniperLaser.enabled = false;
                return;
            }

            // Поворот лицом к игроку по горизонтали
            Vector3 flatDir = new Vector3(toPlayer.x, 0f, toPlayer.z).normalized;
            if (flatDir.sqrMagnitude > 0.001f)
            {
                transform.rotation = Quaternion.Slerp(
                    transform.rotation, Quaternion.LookRotation(flatDir), Time.deltaTime * 10f);
            }

            // Лазер снайпера виден за 0.5 сек до выстрела
            if (_sniperLaser != null)
            {
                _sniperLaser.enabled = _fireTimer < 0.5f;
                if (_sniperLaser.enabled)
                {
                    _sniperLaser.SetPosition(0, eyePos);
                    _sniperLaser.SetPosition(1, targetPos);
                }
            }

            // Стрельба по игроку
            if (dist <= profile.weaponRange && _fireTimer <= 0f)
            {
                ShootAtPlayer(eyePos, toPlayer.normalized);
            }
        }

        private void FixedUpdate()
        {
            if (IsDead || _playerTransform == null) return;

            Vector3 eyePos = transform.position + Vector3.up * eyeHeight;
            Vector3 targetPos = _playerTransform.position + Vector3.up * 1.0f;
            Vector3 toPlayer = targetPos - eyePos;
            float dist = toPlayer.magnitude;

            if (dist > detectionRange || !HasLineOfSight(eyePos, targetPos, dist))
            {
                _rb.linearVelocity = new Vector3(0f, _rb.linearVelocity.y, 0f);
                return;
            }

            Vector3 forward = new Vector3(toPlayer.x, 0f, toPlayer.z).normalized;
            Vector3 right = Vector3.Cross(Vector3.up, forward);
            Vector3 moveDir = Vector3.zero;

            // Тактика передвижения зависит от класса!
            switch (enemyClass)
            {
                case BodyClass.Scout:
                    // Агрессивно сближается зигзагами
                    if (dist > 3.5f) moveDir = (forward + right * (_strafeDir * 0.65f)).normalized;
                    else moveDir = right * _strafeDir;
                    break;

                case BodyClass.Trooper:
                    // Держит среднюю дистанцию (8-14м) и стрейфит
                    if (dist > 14f) moveDir = forward + right * (_strafeDir * 0.3f);
                    else if (dist < 7f) moveDir = -forward + right * (_strafeDir * 0.5f);
                    else moveDir = right * _strafeDir;
                    moveDir.Normalize();
                    break;

                case BodyClass.Juggernaut:
                    // Медленно и неотвратимо идёт напролом
                    if (dist > 4f) moveDir = forward;
                    break;

                case BodyClass.Sniper:
                    // Держится далеко (отступает, если игрок ближе 15м)
                    if (dist < 15f) moveDir = -forward + right * (_strafeDir * 0.25f);
                    else if (dist > 28f) moveDir = forward;
                    moveDir.Normalize();
                    break;
            }

            Vector3 vel = moveDir * (profile.moveSpeed * 0.8f);
            _rb.linearVelocity = new Vector3(vel.x, _rb.linearVelocity.y, vel.z);
        }

        private bool HasLineOfSight(Vector3 from, Vector3 to, float dist)
        {
            Vector3 dir = (to - from).normalized;
            if (Physics.Raycast(from, dir, out RaycastHit hit, dist, obstacleMask, QueryTriggerInteraction.Ignore))
            {
                if (hit.transform == _playerTransform || hit.transform.root == _playerTransform)
                    return true;
                return false;
            }
            return true;
        }

        private void ShootAtPlayer(Vector3 origin, Vector3 baseDir)
        {
            _fireTimer = profile.fireRate * 1.6f;

            int pellets = Mathf.Max(1, profile.pelletsPerShot);
            float spread = Mathf.Max(1.5f, profile.spreadAngle + 1.5f);

            // Сдвигаем точку вылета чуть вперёд от глаз врага
            Vector3 muzzlePos = origin + baseDir * 0.6f;

            for (int i = 0; i < pellets; i++)
            {
                Vector3 dir = Quaternion.Euler(
                    Random.Range(-spread, spread),
                    Random.Range(-spread, spread), 0f) * baseDir;

                Projectile.Spawn(muzzlePos, dir, profile, false, gameObject, obstacleMask);
            }
        }

        public void TakeDamage(float amount)
        {
            if (IsDead) return;
            CurrentHealth -= amount;

            if (CurrentHealth <= 0f)
            {
                IsDead = true;
                Destroy(gameObject);
            }
        }
    }
}