using UnityEngine;

namespace Funique
{
    /// <summary>
    /// Degree of freedom behaviour <br />
    /// ------------------------------------------------ <br />
    /// 自由角 行為
    /// </summary>
    [AddComponentMenu("Funique/Core/DOF")]
    public class DOF : MonoBehaviour
    {
        // 變數
        #region Field
        [SerializeField] Transform HeadsetTransform;
        [SerializeField] public float Scale = 1.5f;
        [SerializeField] public float Len;
        [SerializeField] public bool Resize;
        [SerializeField] public bool DebugSwitch;
        [SerializeField] public bool IslookAtHeadset;
        public float dis { private set; get; }
        float sixDoflimit = 1.74f;
        float min = 1.7f;
        #endregion


        // Unity 事件
        #region Unity Event
        private void Start()
        {
            //headsetTransform = Singleton<Main>.Instance.HeadSet.transform;
        }
        private void Update()
        {
            //Len = Singleton<Main>.Instance.XRManager.Len;
            Fade();
            if (Resize)
            {
                ScaleByDistance();
                if (IslookAtHeadset)
                {
                    LookAtHeadset();
                }
            }
        }
        #endregion


        // 功能
        #region Utility
        private void LookAtHeadset()
        {
            transform.LookAt(HeadsetTransform);
            transform.eulerAngles = new Vector3(transform.eulerAngles.x, transform.eulerAngles.y - 90f, transform.eulerAngles.z);
        }
        private void Fade()
        {
            float num = Vector3.Distance(transform.position - transform.right * transform.localScale.x, HeadsetTransform.transform.position);
            if (num < sixDoflimit)
            {
                Color color = GetComponent<Renderer>().material.color;
                float a = MinMax(num, sixDoflimit, min, 1f, 0f);
                GetComponent<Renderer>().material.color = new Color(color.r, color.g, color.b, a);
            }
            else
            {
                GetComponent<Renderer>().material.color = Color.white;
            }
        }
        public float MinMax(float x, float max, float min, float new_max, float new_min)
        {
            x = (x - min) / (max - min);
            x *= new_max - new_min;
            x += new_min;
            return x;
        }
        private void ScaleByDistance()
        {
            if (DebugSwitch)
            {
                MonoBehaviour.print(Vector3.Distance(HeadsetTransform.transform.position, transform.position));
            }
            dis = Mathf.Lerp(Scale + 1f, 1f, Vector3.Distance(HeadsetTransform.transform.position, transform.position) / Len);
            if (Vector3.Distance(HeadsetTransform.transform.position, transform.position) > Len)
            {
                dis = Mathf.Max(0f, Mathf.Lerp(0f - Scale + 1f, 1f, Len / Vector3.Distance(HeadsetTransform.transform.position, transform.position)));
            }
            transform.localScale = new Vector3(dis, dis, dis);
        }
        #endregion
    }
}