/// by JCxYIS / Modded from Pico VR demo script
/// 20220410

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using Pvr_UnitySDKAPI;
using UnityEngine.SceneManagement;

/// <summary>
/// Pico 控制器與他的好朋友們
/// </summary>
[RequireComponent(typeof(Pvr_Controller))]
public class PicoVRcontroller : MonoBehaviour
{
    public static PicoVRcontroller Instance;

    /// <summary>
    /// 要看指到啥東西就把這個設 true
    /// </summary>
    public const bool PRINT_DEBUG = false;

    private GameObject controller0;
    private GameObject controller1;


    private Ray ray;
    public Ray Ray => ray;

    private GameObject currentController;

    private Transform lastHit;
    [SerializeField] private Transform currentHit;

    GameObject referenceObj;
    private bool isHasController = false;
    private RaycastHit hit;
    private GameObject rayLine;
    private GameObject dot;

    private Transform dragObj;

    private List<ITriggerManager> _triggerManagers = new List<ITriggerManager>();


    void Awake()
    {
        Instance = this;
    }

    void Start()
    {
        ray = new Ray();
        hit = new RaycastHit();

        Pvr_Controller pvr_Controller = GetComponent<Pvr_Controller>();
        controller0 = pvr_Controller.controller0;
        controller1 = pvr_Controller.controller1;

        if (Pvr_UnitySDKManager.SDK.isHasController)
        {
            Pvr_ControllerManager.PvrServiceStartSuccessEvent += ServiceStartSuccess;
            Pvr_ControllerManager.SetControllerStateChangedEvent += ControllerStateListener;
            isHasController = true;
#if UNITY_EDITOR
            currentController = controller1;
            dot = controller1.transform.Find("dot").gameObject;
            dot.SetActive(true);
            rayLine = controller1.transform.Find("ray_LengthAdaptive").gameObject;
            rayLine.SetActive(true);
#endif
        }
        referenceObj = new GameObject("ReferenceObj");

        _triggerManagers = FindObjectsOfInterfaces<ITriggerManager>();
    }

    void OnDestroy()
    {
        if (isHasController)
        {
            Pvr_ControllerManager.PvrServiceStartSuccessEvent -= ServiceStartSuccess;
            Pvr_ControllerManager.SetControllerStateChangedEvent -= ControllerStateListener;
        }
    }

    void Update()
    {        
        if (currentController == null)
        {
            Debug.LogWarning("No controller.");
            return;
        }

        ray.direction = currentController.transform.forward - currentController.transform.up * 0.25f;                
        ray.origin = currentController.transform.Find("start").position;

        if (Physics.Raycast(ray, out hit))
        {
            currentHit = hit.transform;

            if (currentHit != null && lastHit != null && currentHit != lastHit)
            {
                if (lastHit.GetComponent<Pvr_UIGraphicRaycaster>() && lastHit.transform.gameObject.activeInHierarchy && lastHit.GetComponent<Pvr_UIGraphicRaycaster>().enabled)
                {
                    lastHit.GetComponent<Pvr_UIGraphicRaycaster>().enabled = false;
                }
            }
            if (currentHit != null && lastHit != null && currentHit == lastHit)
            {
                if (currentHit.GetComponent<Pvr_UIGraphicRaycaster>() && !currentHit.GetComponent<Pvr_UIGraphicRaycaster>().enabled)
                {
                    currentHit.GetComponent<Pvr_UIGraphicRaycaster>().enabled = true;

                }
            }
        
            if (currentHit != null)
            {
                // Hover
                print("[PicoVRcontroller] Hover: "+currentHit.gameObject);
                _triggerManagers.ForEach(i => i.OnTriggerEnter(hit.collider));

                // Click
                if (Controller.UPvr_GetKeyDown(0, Pvr_KeyCode.Any) ||
                    Controller.UPvr_GetKeyDown(1, Pvr_KeyCode.Any) || Input.GetMouseButtonDown(0))
                {
                    print("[PicoVRcontroller] Click: "+currentHit.gameObject);
                    currentHit.GetComponent<IClickable>()?.OnClick();
                }

                // Drag
                if (Controller.UPvr_GetKeyDown(0, Pvr_KeyCode.TOUCHPAD) || Controller.UPvr_GetKeyDown(1, Pvr_KeyCode.TOUCHPAD) || Input.GetMouseButtonDown(0))
                {
                    referenceObj.transform.position = hit.point;
                    dragObj = currentHit;
                    print("[PicoVRcontroller] DragStart: "+currentHit.gameObject);
                }
                if (Controller.UPvr_GetKey(0, Pvr_KeyCode.TOUCHPAD) || Controller.UPvr_GetKey(1, Pvr_KeyCode.TOUCHPAD) || Input.GetMouseButton(0))
                {
                    if (currentHit == dragObj.transform)
                    {
                        print("[PicoVRcontroller] Drag: "+currentHit.gameObject);
                        currentHit.GetComponent<IDragable>()?.OnDrag();
                    }
                }
            }

            // Exit from last stuff (if hit changes)
            if (lastHit != null && lastHit != currentHit) 
            {
                print("[PicoVRcontroller] Exit: "+lastHit.transform.gameObject);
                _triggerManagers.ForEach(i => i.OnTriggerExit(lastHit.GetComponent<Collider>()));
            }
            lastHit = currentHit;
#if UNITY_EDITOR
            Debug.DrawLine(ray.origin, hit.point, Color.red);
#endif
            currentController.transform.Find("dot").position = hit.point;
            if (Pvr_ControllerManager.Instance.LengthAdaptiveRay)
            {
                float scale = 0.178f * currentController.transform.Find("dot").localPosition.z / 3.3f;
                Mathf.Clamp(scale, 0.05f, 0.178f);
                currentController.transform.Find("dot").localScale = new Vector3(scale, scale, 1);
            }
        }
        else // hit nothing
        {
            if (lastHit != null)
            {
                print("[PicoVRcontroller] Exit: "+lastHit.transform.gameObject);
                _triggerManagers.ForEach(i => i.OnTriggerExit(lastHit.GetComponent<Collider>()));
            }

            lastHit = null;
            currentHit = null;

            if(Pvr_ControllerManager.Instance.LengthAdaptiveRay)
            {
                currentController.transform.Find("dot").localScale = new Vector3(0.178f, 0.178f, 1);
            }
        }
#if UNITY_EDITOR
        rayLine.GetComponent<LineRenderer>().SetPosition(0,currentController.transform.TransformPoint(0, 0, 0.072f));
        rayLine.GetComponent<LineRenderer>().SetPosition(1, dot.transform.position);
#endif                
    }
    
    private void ServiceStartSuccess()
    {
        if (Controller.UPvr_GetMainHandNess() == 0)
        {
            currentController = controller0;
        }
        if (Controller.UPvr_GetMainHandNess() == 1)
        {
            currentController = controller1;
        }
    }

    private void ControllerStateListener(string data)
    {
        if (Controller.UPvr_GetMainHandNess() == 0)
        {
            currentController = controller0;
        }
        if (Controller.UPvr_GetMainHandNess() == 1)
        {
            currentController = controller1;
        }
    }

    /// <summary>
    /// https://answers.unity.com/questions/863509/how-can-i-find-all-objects-that-have-a-script-that.html
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <returns></returns>
    public static List<T> FindObjectsOfInterfaces<T>(  )
    {
        List<T> interfaces = new List<T>();
        GameObject[] rootGameObjects = SceneManager.GetActiveScene().GetRootGameObjects();
        foreach( var rootGameObject in rootGameObjects )
        {
            T[] childrenInterfaces = rootGameObject.GetComponentsInChildren<T>();
            foreach( var childInterface in childrenInterfaces )
            {
                interfaces.Add(childInterface);
            }
        }
        return interfaces;
    }



    new void print(object obj)
    {
        if(PRINT_DEBUG)
            Debug.Log(obj);
    }
}