using UnityEngine;
using UnityEngine.UI;

public static class UGUIUtility
{
    public static Vector2 WorldToScreenPoint(Camera worldCam, CanvasScaler scaler, Vector3 worldPoint)
    {
        if (worldCam == null)
            return new Vector2(worldPoint.x, worldPoint.y);

        Vector2 screenPoint = (Vector2) worldCam.WorldToScreenPoint(worldPoint);

        if (scaler != null)
        {
            screenPoint.x /= (Screen.width / scaler.referenceResolution.x);
            screenPoint.y /= (Screen.height / scaler.referenceResolution.y);
        }

        return screenPoint;
    }

    public static Vector2 WorldToScreenPoint(Camera worldCam, Camera uiCam, CanvasScaler scaler, Vector3 worldPoint)
    {
        if (uiCam == null)
            return WorldToScreenPoint(worldCam, scaler, worldPoint);

        if (worldCam == null)
            return new Vector2(worldPoint.x, worldPoint.y);

        Vector2 viewportPoint = (Vector2) worldCam.WorldToViewportPoint(worldPoint);

        viewportPoint.x -= 0.5f;
        viewportPoint.y -= 0.5f;

        Vector3 screenPoint = new Vector3(uiCam.pixelWidth * viewportPoint.x, uiCam.pixelHeight * viewportPoint.y, 0);

        if (scaler != null)
        {
            screenPoint.x /= (Screen.width / scaler.referenceResolution.x);
            screenPoint.y /= (Screen.height / scaler.referenceResolution.y);
        }

        return screenPoint;
    }

    public static bool WorldToScreenPoint(Camera worldCam, CanvasScaler scaler, Vector3 worldPoint, out Vector2 screenPoint)
    {
        if (worldCam == null)
        {
            screenPoint = Vector2.zero;
            return false;
        }

        Vector3 pos = worldCam.WorldToScreenPoint(worldPoint);
        if (pos.z < 0)
        {
            screenPoint = Vector2.zero;
            return false;
        }

        screenPoint = (Vector2) pos;
        if (scaler != null)
        {
            screenPoint.x /= (Screen.width / scaler.referenceResolution.x);
            screenPoint.y /= (Screen.height / scaler.referenceResolution.y);
        }

        return true;
    }

    public static bool WorldToScreenPoint(Camera worldCam, Camera uiCam, CanvasScaler scaler, Vector3 worldPoint, out Vector2 screenPoint)
    {
        if (worldCam == null || uiCam == null)
        {
            screenPoint = Vector2.zero;
            return false;
        }

        Vector3 viewportPoint = worldCam.WorldToViewportPoint(worldPoint);
        if (viewportPoint.z < 0)
        {
            screenPoint = Vector2.zero;
            return false;
        }

        viewportPoint.x -= 0.5f;
        viewportPoint.y -= 0.5f;

        screenPoint = new Vector2(uiCam.pixelWidth * viewportPoint.x, uiCam.pixelHeight * viewportPoint.y);

        if (scaler != null)
        {
            screenPoint.x /= (Screen.width / scaler.referenceResolution.x);
            screenPoint.y /= (Screen.height / scaler.referenceResolution.y);
        }

        return true;
    }
}