using System.Collections;

namespace UnityEngine.XR.Templates.MR
{
    // Original source: AR Mobile Template project

    public class FadePlaneMaterial : MonoBehaviour
    {
        // attached game object for fading
        public GameObject Plane;

        // fade speed length
        public float fadeSpeed = 1f;

        // fade alpha speed length
        public float fadeAlphaSpeed = 0.5f;

        // view radius
        public float viewRadius = 2.5f;

        // alpha
        public float alpha = 0.5f;

        Coroutine m_FadeDotsCoroutine;
        Coroutine m_FadeAlphaCoroutine;
        static readonly int k_DotViewRadius = Shader.PropertyToID("_DotViewRadius");
        static readonly int k_Alpha = Shader.PropertyToID("_Alpha");

        void Awake()
        {
            Renderer rend = Plane.transform.GetComponent<Renderer>();
            rend.material.SetFloat(k_DotViewRadius, 0f);
            rend.material.SetFloat(k_Alpha, 0f);
            FadePlane(true);
        }

        public void FadePlane(bool visible)
        {
            if (m_FadeDotsCoroutine != null)
                StopCoroutine(m_FadeDotsCoroutine);

            if (m_FadeAlphaCoroutine != null)
                StopCoroutine(m_FadeAlphaCoroutine);

            m_FadeAlphaCoroutine = StartCoroutine(FadeAlpha(visible));
            m_FadeDotsCoroutine = StartCoroutine(FadeDots(visible));
        }

        //Fade Coroutine
        public IEnumerator FadeDots(bool visible)
        {
            yield return new WaitForSeconds(fadeAlphaSpeed);

            Renderer rend = Plane.transform.GetComponent<Renderer>();
            float viewRadiusValue = rend.material.GetFloat(k_DotViewRadius);

            if (!visible)
            {
                //while loop to deincrement Alpha value until object is invisible
                while (rend.material.GetFloat(k_DotViewRadius) > 0f)
                {
                    viewRadiusValue -= Time.deltaTime / fadeSpeed;
                    rend.material.SetFloat(k_DotViewRadius, viewRadiusValue);
                    yield return null;
                }
                rend.material.SetFloat(k_DotViewRadius, 0f);
            }
            else if (visible)
            {
                //while loop to increment object Alpha value until object is opaque
                while (rend.material.GetFloat(k_DotViewRadius) < viewRadius)
                {
                    viewRadiusValue += Time.deltaTime / fadeSpeed;
                    rend.material.SetFloat(k_DotViewRadius, viewRadiusValue);
                    yield return null;
                }
                rend.material.SetFloat(k_DotViewRadius, viewRadius);
            }
        }

        public IEnumerator FadeAlpha(bool visible)
        {
            Renderer rend = Plane.transform.GetComponent<Renderer>();
            float alphaValue = rend.material.GetFloat(k_Alpha);

            if (!visible)
            {
                //while loop to deincrement Alpha value until object is invisible
                while (rend.material.GetFloat(k_Alpha) > 0f)
                {
                    alphaValue -= Time.deltaTime / fadeAlphaSpeed;
                    rend.material.SetFloat(k_DotViewRadius, alphaValue);
                    yield return null;
                }
                rend.material.SetFloat(k_Alpha, 0f);
            }
            else if (visible)
            {
                //while loop to increment object Alpha value until object is opaque
                while (rend.material.GetFloat(k_Alpha) < alpha)
                {
                    alphaValue += Time.deltaTime / fadeAlphaSpeed;
                    rend.material.SetFloat(k_Alpha, alphaValue);
                    yield return null;
                }
                rend.material.SetFloat(k_Alpha, alpha);
            }
        }
    }
}