using System.Collections.Generic;
using UnityEngine;

public class EnemySpawner : MonoBehaviour
{
    [Header("Spawn Configuration")]
    [SerializeField] private Enemy _enemyPrefab;
    [SerializeField] private int _maxAliveCount = 3;
    [SerializeField] private float _spawnInterval = 2f;
    [SerializeField] private float _initialDelay = 0f;

    [Header("Spawn Position")]
    [SerializeField] private Transform[] _spawnPoints;
    [SerializeField] private float _spawnRadius = 0f;
    [SerializeField] private Transform _enemyParent;

    [Header("Behavior")]
    [SerializeField] private bool _spawnOnStart = true;
    [SerializeField] private bool _respawnOnDeath = true;
    [SerializeField] private int _totalSpawnLimit = 0;

    private readonly List<Enemy> _aliveEnemies = new();
    private float _nextSpawnTime;
    private int _totalSpawned;
    private bool _active;

    private void Start()
    {
        if (_spawnOnStart) BeginSpawning();
    }

    public void BeginSpawning()
    {
        _active = true;
        _nextSpawnTime = Time.time + _initialDelay;
    }

    public void StopSpawning() => _active = false;

    public void ResetSpawner()
    {
        for (int i = _aliveEnemies.Count - 1; i >= 0; i--)
        {
            if (_aliveEnemies[i] != null)
                Destroy(_aliveEnemies[i].gameObject);
        }
        _aliveEnemies.Clear();
        _totalSpawned = 0;
        _nextSpawnTime = Time.time + _initialDelay;
    }

    private void Update()
    {
        if (!_active) return;

        _aliveEnemies.RemoveAll(e => e == null);

        if (!_respawnOnDeath && _aliveEnemies.Count == 0 && _totalSpawned > 0) return;
        if (_totalSpawnLimit > 0 && _totalSpawned >= _totalSpawnLimit) return;
        if (_aliveEnemies.Count >= _maxAliveCount) return;
        if (Time.time < _nextSpawnTime) return;
        if (_enemyPrefab == null) return;

        SpawnOne();
        _nextSpawnTime = Time.time + _spawnInterval;
    }

    public Enemy SpawnOne()
    {
        if (_enemyPrefab == null) return null;

        Vector3 spawnPos = GetSpawnPosition();
        Enemy enemy = Instantiate(_enemyPrefab, spawnPos, Quaternion.identity, _enemyParent);
        _aliveEnemies.Add(enemy);
        _totalSpawned++;
        return enemy;
    }

    private Vector3 GetSpawnPosition()
    {
        Vector3 basePos;
        if (_spawnPoints != null && _spawnPoints.Length > 0)
        {
            Transform pick = _spawnPoints[Random.Range(0, _spawnPoints.Length)];
            basePos = pick != null ? pick.position : transform.position;
        }
        else
        {
            basePos = transform.position;
        }

        if (_spawnRadius > 0f)
        {
            Vector2 offset = Random.insideUnitCircle * _spawnRadius;
            basePos.x += offset.x;
            basePos.y += offset.y;
        }

        return basePos;
    }

    private void OnDrawGizmosSelected()
    {
        Color pointColor = Color.cyan;
        Color radiusColor = new Color(0f, 1f, 1f, 0.25f);

        if (_spawnPoints != null && _spawnPoints.Length > 0)
        {
            foreach (var p in _spawnPoints)
            {
                if (p == null) continue;
                Gizmos.color = pointColor;
                Gizmos.DrawWireSphere(p.position, 0.3f);
                if (_spawnRadius > 0f)
                {
                    Gizmos.color = radiusColor;
                    Gizmos.DrawWireSphere(p.position, _spawnRadius);
                }
            }
        }
        else
        {
            Gizmos.color = pointColor;
            Gizmos.DrawWireSphere(transform.position, 0.3f);
            if (_spawnRadius > 0f)
            {
                Gizmos.color = radiusColor;
                Gizmos.DrawWireSphere(transform.position, _spawnRadius);
            }
        }
    }
}