using UnityEditor;
using UnityEditor.UI;
using UnityEngine;
using UnityEngine.UI;

public class PinchZoomImageEditor : GraphicEditor
{
    private static GameObject getCanvas()
    {
        if (Selection.activeGameObject)
            return Selection.activeGameObject;

        Canvas[] canvases = FindObjectsOfType<Canvas>();
        foreach (Canvas canvas in canvases)
        {
            if (canvas.gameObject.activeInHierarchy)
                return canvas.gameObject;
        }
        return null;
    }
    private static GameObject createCanvas()
    {
        GameObject result = new GameObject("Canvas");
        Canvas canvas = result.AddComponent<Canvas>();
        canvas.renderMode = RenderMode.ScreenSpaceOverlay;
        result.AddComponent<CanvasScaler>();
        result.AddComponent<GraphicRaycaster>();
        return result;
    }
    [MenuItem("GameObject/UI/Pinch and Zoom Image", false, 0)]
    public static void CreateGameObject()
    {        
        GameObject parent = getCanvas();
        if(parent == null)
            parent = createCanvas();                
        
        RectTransform parentCanvasRenderer = parent.GetComponent<RectTransform>();
        if (parentCanvasRenderer)
        {
            GameObject go = new GameObject("Pinch and Zoom Image");
            go.transform.SetParent(parent.transform, false);
            go.AddComponent<RectTransform>();
            go.AddComponent<RawImage>();
            go.AddComponent<PinchZoomImage>();
            Selection.activeGameObject = go;
        }
        else
        {
            EditorUtility.DisplayDialog("Pinch and Zoom Image", "You must make the Pinch and Zoom Image component as a child of a Canvas.", "Ok");
        }
    }
}