public class EnemySpawner01 : MonoBehaviour
{
    public GameObject enemyPrefab;
    public float width = 10;
    public float height = 5;
    public float speed = 5.0f;
    public float padding = 0;
    public float SpawnDelay = 1;
    public float Timer;
    public Transform TrainingBoss;

    private int direction = 1;
    private float boundaryRightEdge, boundaryLeftEdge;
    void Start()
    {
        Camera camera = Camera.main;
        float distance = transform.position.z - camera.transform.position.z;
        boundaryLeftEdge = camera.ViewportToWorldPoint(new Vector3(0, 0, distance)).x + padding;
        boundaryRightEdge = camera.ViewportToWorldPoint(new Vector3(1, 1, distance)).x - padding;
        SpawnUntilFull();
    }
    void SpawnEnemies()
    {
        foreach (Transform child in transform)
        {
            GameObject enemy = Instantiate(enemyPrefab, child.transform.position, Quaternion.identity) as GameObject;
            enemy.transform.parent = child;
        }
    }
    void SpawnUntilFull()
    {
        Transform FreePosition = NextFreePosition();
        if (FreePosition)
        {
            GameObject enemy = Instantiate(enemyPrefab, FreePosition.position, Quaternion.identity) as GameObject;
            enemy.transform.parent = FreePosition;
        }
        if (NextFreePosition())
        {
            Invoke("SpawnUntilFull", SpawnDelay);
        }
    }
    void OnDrawGizmos()
    {
        float xmin, xmax, ymin, ymax;
        xmin = transform.position.x - 0.5f * width;
        xmax = transform.position.x + 0.5f * width;
        ymin = transform.position.y - 0.5f * height;
        ymax = transform.position.y + 0.5f * height;
        Gizmos.DrawLine(new Vector3(xmin, ymin, 0), new Vector3(xmin, ymax));
        Gizmos.DrawLine(new Vector3(xmin, ymax, 0), new Vector3(xmax, ymax));
        Gizmos.DrawLine(new Vector3(xmax, ymax, 0), new Vector3(xmax, ymin));
        Gizmos.DrawLine(new Vector3(xmax, ymin, 0), new Vector3(xmin, ymin));
    }
    void Update()
    {
        float formationRightEdge = transform.position.x + 0.5f * width;
        float formationLeftEdge = transform.position.x - 0.5f * width;
        if (formationRightEdge > boundaryRightEdge)
        {
            direction = -1;
        }
        if (formationLeftEdge < boundaryLeftEdge)
        {
            direction = 1;
        }
        transform.position += new Vector3(direction * speed * Time.deltaTime, 0, 0);
        if (AllMembersDead())
        {
            SpawnUntilFull();
        }

            if (Timer > 0)
            {
                Timer -= Time.deltaTime;
            }
            else
            {
                Destroy(gameObject);
            if (TrainingBoss.gameObject.activeInHierarchy == false)
            {
                TrainingBoss.gameObject.SetActive(true);
            }
            else
            {
                TrainingBoss.gameObject.SetActive(false);
            }
        }

    }
    Transform NextFreePosition()
    {
        foreach (Transform childPositionGameObject in transform)
        {
            if (childPositionGameObject.childCount == 0)
            {
                return childPositionGameObject;
            }
        }
        return null;
    }

    bool AllMembersDead()
    {
        foreach (Transform childPositionGameObject in transform)
        {
            if (childPositionGameObject.childCount > 0)
            {
                return false;
            }
        }
        return true;
    }
}