using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

[DisallowMultipleComponent]
[ExecuteInEditMode]
public class SmoothMask:UIBehaviour,ICanvasRaycastFilter {

    [Range(0,1)]
    [SerializeField]
    private float m_Horizontal = 0f;
    public float horizontal { get { return m_Horizontal; } }

    [Range(0,1)]
    [SerializeField]
    private float m_Vertical = 0f;
    public float vertical { get { return m_Vertical; } }

    [SerializeField]
    private Material[] m_ImageMaterials;
    public Material[] imageMaterials { get { return m_ImageMaterials; } }

    [SerializeField]
    private Material[] m_TextMaterials;
    public Material[] textMaterials { get { return m_TextMaterials; } }

    [SerializeField]
    private CanvasScaler m_CanvasScaler;
    public CanvasScaler canvasScaler {
        get {
            return m_CanvasScaler ?? (m_CanvasScaler = GetComponentInParent<CanvasScaler>());
        }
    }

    public RectTransform rectTransform {
        get {
            return this.transform as RectTransform;
        }
    }
    private Vector2 leftBottom;
    private Vector2 rightTop;

    public bool IsRaycastLocationValid(Vector2 sp,Camera eventCamera) {
        return RectTransformUtility.RectangleContainsScreenPoint(rectTransform,sp,eventCamera);
    }

    void LateUpdate() {
        UpdateChildMaterialSmoothMask();
    }

    [ContextMenu("SetMaterial")]
    public void UpdateChildrenMaterial() {
        SetChildrenImageMaterial(this.transform);
        SetChildrenTextMaterial(this.transform);
    }

    private void SetChildrenImageMaterial(Transform _transform) {
        Image image;
        Transform transform;
        for(int i = 0;i < _transform.childCount;i++) {
            transform = _transform.GetChild(i);
            image = transform.GetComponent<Image>();
            if(image != null) {
                image.material = imageMaterials.Length > 0 ? imageMaterials[0] : null;
            }
            else
            {
                var imageex = transform.GetComponent<ImageEx>();
                if (imageex != null)
                {
                    imageex.material = imageMaterials.Length > 0 ? imageMaterials[0] : null;
                }
            }

            if(transform.childCount > 0) {
                SetChildrenImageMaterial(transform);
            }
        }
    }

    private void SetChildrenTextMaterial(Transform _parent) {
        Text text;
        Transform transform;
        for(int i = 0;i < _parent.childCount;i++) {
            transform = _parent.GetChild(i);
            text = transform.GetComponent<Text>();
            if(text != null) {
                text.material = textMaterials.Length > 0 ? textMaterials[0] : null;
            }

            if(transform.childCount > 0) {
                SetChildrenTextMaterial(transform);
            }
        }
    }

    private void UpdateChildMaterialSmoothMask() {
        var scaleX = canvasScaler.transform.localScale.x;
        var scaleY = canvasScaler.transform.localScale.y;

        leftBottom = scaleX == 0f ? Vector2.zero : rectTransform.GetMinWorldPosition() / scaleX;
        rightTop = scaleY == 0f ? Vector2.zero : rectTransform.GetMaxWorldPosition() / scaleY;

        if(imageMaterials != null) {
            for(int i = 0;i < imageMaterials.Length;i++) {
                SetSmoothMask(imageMaterials[i],leftBottom,rightTop,new Vector2(horizontal,vertical));
            }
        }

        if(textMaterials != null) {
            for(int i = 0;i < textMaterials.Length;i++) {
                SetSmoothMask(textMaterials[i],leftBottom,rightTop,new Vector2(horizontal,vertical));
            }
        }
    }

    static void SetSmoothMask(Material material,Vector2 leftBottom,Vector2 rightTop,Vector2 smoothRect) {
        material.SetVector("_LeftBottom",leftBottom);
        material.SetVector("_RightTop",rightTop);
        material.SetVector("_SmoothRect",smoothRect);
    }
}