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

public class ReturnToStart : MonoBehaviour
{

    private Vector3 m_StartPos;
    private Quaternion m_StartRot;
    private VRTK_InteractableObject m_interactable;
    private Rigidbody m_rigid;


    // Start is called before the first frame update
    void Awake()
    {
        m_StartPos = transform.position;
        m_StartRot = transform.rotation;
        //Set up some variables on start
        m_interactable = GetComponent<VRTK_InteractableObject>();
        m_rigid = GetComponentInChildren<Rigidbody>();
    }

    private void OnEnable()
    {
        RegisterEvents(true);
    }


    private void OnDisable()
    {
        RegisterEvents(false);
    }

    private void OnGrab(object sender, InteractableObjectEventArgs args)
    {
        StopAllCoroutines();
        m_rigid.isKinematic = false;
    }


    private void OnDrop(object sender, InteractableObjectEventArgs args)
    {
        //other hand might still be grabbed
        if (!m_interactable.IsGrabbed())
        {
            StopAllCoroutines();
            StartCoroutine(LerpToPosition(m_StartPos, m_StartRot, 2.0f));
        }
    }


    private void OnSnap(object sender, InteractableObjectEventArgs args)
    {
        StopAllCoroutines();
        //m_rigid.isKinematic = true;
    }


    private void RegisterEvents(bool value)
    {
        if (value)
        {
            m_interactable.InteractableObjectSnappedToDropZone += OnSnap;
            m_interactable.InteractableObjectGrabbed += OnGrab;
            m_interactable.InteractableObjectUngrabbed += OnDrop;
        }
        else
        {
            m_interactable.InteractableObjectSnappedToDropZone -= OnSnap;
            m_interactable.InteractableObjectGrabbed -= OnGrab;
            m_interactable.InteractableObjectUngrabbed -= OnDrop;
        }
    }

    #region Coroutines
    /// <summary>
    /// Lerps object to a position over an amount of time
    /// </summary>
    /// <param name="SnapPos">End position</param>
    /// <param name="SnapRot">End rotation</param>
    /// <param name="snapTime">Time it takes to lerp</param>
    private IEnumerator LerpToPosition(Vector3 SnapPos, Quaternion SnapRot, float snapTime)
    {
        Debug.Log("Lerp to position");
        //This is based off of SteamVR Lerping code
        float dropTimer = -1;
        m_rigid.isKinematic = false;


        //once again this is all steamVR
        while (dropTimer < 1)
        {
            float t = Mathf.Pow(35, dropTimer);

            m_rigid.velocity = Vector3.Lerp(m_rigid.velocity, Vector3.zero, Time.fixedDeltaTime * 4);
            if (m_rigid.useGravity)
                m_rigid.AddForce(-Physics.gravity);

            transform.position = Vector3.Lerp(transform.position, SnapPos, Time.fixedDeltaTime * t * 3);
            transform.rotation = Quaternion.Slerp(transform.rotation, SnapRot, Time.fixedDeltaTime * t * 5);

            yield return new WaitForFixedUpdate();
            dropTimer += Time.fixedDeltaTime / (snapTime / 2);
        }

        //#Audio: object has just arrived at where it was lerping to

        //set correct transform in case object stuck
        m_rigid.isKinematic = true;
        transform.position = SnapPos;
        transform.rotation = SnapRot;
    }
    #endregion Coroutines

}