ObjectsSelector

using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
using System.Collections.Generic;
#endif

[ExecuteAlways]
public class ObjectsSelector : MonoBehaviour
{
    [SerializeField] private Color selectedColor = Color.green;
    [SerializeField] private Color unselectedColor = new Color(0f, 0.5f, 0.5f, 0.6f); // corretto: verde scuro trasparente
    [SerializeField, Range(0f, 25f)] private float lineThickness = 2f;

    [SerializeField, HideInInspector] private Vector3 cubeSize;
    [Header("Use the context menu\n (right mouse button on the title)\n to select or parent the objects inside the cube")]
    [SerializeField] private string parentName = "GroupedObjects";

    private BoxCollider _boxCollider;

    private void OnEnable()
    {
        EnsureBoxColliderExists();
    }

    private void OnValidate()
    {
        EnsureBoxColliderExists();
    }

    private void EnsureBoxColliderExists()
    {
        _boxCollider = GetComponent<BoxCollider>();
        if (_boxCollider == null)
        {
            _boxCollider = gameObject.AddComponent<BoxCollider>();
            _boxCollider.isTrigger = true;
        }
    }

    private void OnDrawGizmos()
    {
        if (_boxCollider == null)
            EnsureBoxColliderExists();

        if (_boxCollider == null) return;

        Vector3 worldCenter = transform.TransformPoint(_boxCollider.center);
        Vector3 size = _boxCollider.size;
        cubeSize = size;

        Color drawColor = GetDrawColor();
        DrawWireCube(worldCenter, size, drawColor, lineThickness);
    }

    private Color GetDrawColor()
    {
#if UNITY_EDITOR
        if (Selection.activeGameObject == gameObject)
            return selectedColor;
#endif
        return unselectedColor;
    }

    void DrawWireCube(Vector3 center, Vector3 size, Color color, float thickness)
    {
        Vector3 half = size * 0.5f;

        Vector3[] corners = new Vector3[8]
        {
            center + new Vector3(-half.x, -half.y, -half.z),
            center + new Vector3( half.x, -half.y, -half.z),
            center + new Vector3( half.x, -half.y,  half.z),
            center + new Vector3(-half.x, -half.y,  half.z),
            center + new Vector3(-half.x,  half.y, -half.z),
            center + new Vector3( half.x,  half.y, -half.z),
            center + new Vector3( half.x,  half.y,  half.z),
            center + new Vector3(-half.x,  half.y,  half.z)
        };

        int[,] edges = new int[,]
        {
            {0,1}, {1,2}, {2,3}, {3,0},
            {4,5}, {5,6}, {6,7}, {7,4},
            {0,4}, {1,5}, {2,6}, {3,7}
        };

        for (int i = 0; i < edges.GetLength(0); i++)
        {
            DrawThickLine(corners[edges[i, 0]], corners[edges[i, 1]], color, thickness);
        }
    }

    void DrawThickLine(Vector3 start, Vector3 end, Color color, float thickness)
    {
#if UNITY_EDITOR
        Handles.color = color;
        Handles.DrawAAPolyLine(thickness, new Vector3[] { start, end });
#endif
    }

#if UNITY_EDITOR
    [ContextMenu("Select Active Objects Inside Trigger")]
    void SelectActiveObjectsInTrigger()
    {
        if (_boxCollider == null)
        {
            Debug.LogWarning("No BoxCollider found!");
            return;
        }

        List<GameObject> activeObjects = new List<GameObject>();

        Collider[] overlapping = Physics.OverlapBox(transform.TransformPoint(_boxCollider.center),
            _boxCollider.size * 0.5f,
            transform.rotation,
            ~0,
            QueryTriggerInteraction.Collide
        );

        foreach (var col in overlapping)
        {
            GameObject go = col.gameObject;
            // Ignora self e oggetti disattivati
            if (go == gameObject) continue;
            if (!go.activeInHierarchy) continue;

            activeObjects.Add(go);
        }

        if (activeObjects.Count == 0)
        {
            Debug.Log("No active objects found inside the trigger.");
            Selection.objects = new Object[0];
        }
        else
        {
            Selection.objects = activeObjects.ToArray();
            Debug.Log($"Selected {activeObjects.Count} active object(s).");
        }
    }

    [ContextMenu("Group Selected Objects Under New Parent")]
    void GroupSelectedObjects()
    {
        GameObject[] selected = Selection.gameObjects;
        if (selected.Length == 0)
        {
            Debug.LogWarning("No objects selected.");
            return;
        }

        string name = string.IsNullOrEmpty(parentName) ? "GroupedObjects" : parentName;

        GameObject parent = new GameObject(name);

        Undo.RegisterCreatedObjectUndo(parent, "Create Group Parent");

        foreach (GameObject go in selected)
        {
            Undo.SetTransformParent(go.transform, parent.transform, "Parent Selected Objects");
        }

        Selection.activeObject = parent;
    }
#endif
}