using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[ExecuteInEditMode]
public class AutoScaler : MonoBehaviour {

    [SerializeField]
    [TooltipAttribute("Adjust the final scale by 2^scaleFactor.")]
    [Range(-2, 2)]
    float scaleFactor = 0;

    [Header("Semi Auto Fields")]
    [SerializeField]
    Camera referenceCamera;

    [SerializeField]
    Canvas canvas;

    [SerializeField]
    AVProQuad avproQuad;

    [SerializeField]
    float pixelsPerUnit = 100;

    void Start () {
		if(referenceCamera == null)
            referenceCamera = Camera.main;
        if (canvas == null)
            canvas = FindObjectOfType<Canvas>().GetComponent<Canvas>();

        avproQuad = GetComponent<AVProQuad>();

        SpriteRenderer spriteRenderer = GetComponent<SpriteRenderer>();
        if (spriteRenderer != null)
            pixelsPerUnit = spriteRenderer.sprite.pixelsPerUnit;
    }

    void Update()
    {
//#if UNITY_EDITOR
        if (canvas == null || referenceCamera == null)
            return;

        Vector3 heading = transform.position - referenceCamera.transform.position;
        Vector3 d = Vector3.one * Vector3.Dot(heading, referenceCamera.transform.forward) * pixelsPerUnit;
        if (avproQuad != null)
        {
            d.x = d.x * avproQuad.Size.x / pixelsPerUnit;
            d.y = d.y * avproQuad.Size.y / pixelsPerUnit;
        }
        float scale = Mathf.Pow(2, scaleFactor);
        transform.localScale = d / canvas.planeDistance * scale;
//#endif
    }
}