using UnityEditor;
using UnityEngine;

public class ReplaceGameobjectsEditor : EditorWindow
{
    public GameObject prefabToReplaceWith; // The prefab you want to use as a replacement
    public string targetTag = ""; // Tag of the GameObjects to replace (leave empty to replace selected)
    public string targetName = ""; // Name of the GameObjects to replace (leave empty to replace selected)

    [MenuItem("Tools/Replace GameObjects")]
    public static void ShowWindow()
    {
        GetWindow<ReplaceGameobjectsEditor>("Replace GameObjects");
    }

    private void OnGUI()
    {
        EditorGUILayout.LabelField("Replace GameObjects with Prefab", EditorStyles.boldLabel);

        prefabToReplaceWith = (GameObject)EditorGUILayout.ObjectField("Prefab to Replace With", prefabToReplaceWith, typeof(GameObject), false);

        EditorGUILayout.Space();
        EditorGUILayout.LabelField("Target Selection", EditorStyles.boldLabel);
        targetTag = EditorGUILayout.TagField("Target Tag (Optional)", targetTag);
        targetName = EditorGUILayout.TextField("Target Name (Optional)", targetName);

        EditorGUILayout.HelpBox("If both Tag and Name are empty, selected GameObjects in Hierarchy will be replaced.", MessageType.Info);

        if (GUILayout.Button("Replace!"))
        {
            ReplaceObjects();
        }
    }

    private void ReplaceObjects()
    {
        if (prefabToReplaceWith == null)
        {
            Debug.LogError("Please assign a Prefab to Replace With.");
            return;
        }

        GameObject[] objectsToReplace;

        if (!string.IsNullOrEmpty(targetTag))
        {
            objectsToReplace = GameObject.FindGameObjectsWithTag(targetTag);
        }
        else if (!string.IsNullOrEmpty(targetName))
        {
            // Find all GameObjects in the scene and filter by name
            objectsToReplace = FindObjectsOfType<GameObject>();
            System.Collections.Generic.List<GameObject> namedObjects = new System.Collections.Generic.List<GameObject>();
            foreach (GameObject go in objectsToReplace)
            {
                if (go.name == targetName)
                {
                    namedObjects.Add(go);
                }
            }
            objectsToReplace = namedObjects.ToArray();
        }
        else
        {
            objectsToReplace = Selection.gameObjects; // Replace currently selected GameObjects
        }

        if (objectsToReplace.Length == 0)
        {
            Debug.LogWarning("No GameObjects found to replace based on your criteria or selection.");
            return;
        }

        foreach (GameObject oldGameObject in objectsToReplace)
        {
            GameObject newGameObject = (GameObject)PrefabUtility.InstantiatePrefab(prefabToReplaceWith);
            newGameObject.transform.position = oldGameObject.transform.position;
            newGameObject.transform.rotation = oldGameObject.transform.rotation;
            newGameObject.transform.localScale = oldGameObject.transform.localScale;
            newGameObject.transform.parent = oldGameObject.transform.parent;

            // Optionally, copy component values if desired and compatible
            // For example, if both have a Rigidbody and you want to transfer velocity:
            // Rigidbody oldRb = oldGameObject.GetComponent<Rigidbody>();
            // Rigidbody newRb = newGameObject.GetComponent<Rigidbody>();
            // if (oldRb != null && newRb != null) { newRb.velocity = oldRb.velocity; }

            DestroyImmediate(oldGameObject);
        }
        Debug.Log($"Replaced {objectsToReplace.Length} GameObjects with instances of '{prefabToReplaceWith.name}'.");
    }
}