using System.Collections.Generic;
using UnityEngine;

// 敵のスポナー
public class EnemySpawner : MonoBehaviour
{
    [SerializeField] private Enemy enemyPrefab;
    [SerializeField] private Transform[] spawnPoints;
    [SerializeField] private float spawnInterval = 1.5f;
    [SerializeField] private int maxAliveCount = 20;

    private readonly List<Enemy>
        _aliveEnemies = new();
    private float _spawnTimer;

    private void Update()
    {
        CleanupDestroyedEnemies();
        _spawnTimer += Time.deltaTime;
        if (_spawnTimer < spawnInterval)
            return;
        _spawnTimer = 0f;
        Spawn();
    }
    private void Spawn()
    {
        if (_aliveEnemies.Count >= maxAliveCount)
            return;
        var spawnPoint =
            spawnPoints[Random.Range(
                0,
                spawnPoints.Length)];

        var enemy = Instantiate(
            enemyPrefab,
            spawnPoint.position,
            spawnPoint.rotation);

        _aliveEnemies.Add(enemy);
    }

    private void CleanupDestroyedEnemies()
    {
        _aliveEnemies.RemoveAll(enemy => enemy == null);
    }
}