using System.Collections.Generic;
using Unity.XR.CoreUtils;
using UnityEngine.XR.Interaction.Toolkit.Samples.ARStarterAssets;

namespace UnityEngine.XR.Templates.MR
{
    public class GazeTooltips : MonoBehaviour
    {
        [SerializeField]
        XROrigin m_XROrigin;

        [SerializeField]
        Transform m_Tooltip;

        [SerializeField]
        bool m_TapTooltip = true;

        Transform m_XRCameraTransform;
        LayerMask m_PlaneMask;
        ZoneScale m_ZoneScale;
        GameObject m_LastPlane = null;
        readonly List<ARContactSpawnTrigger> m_SpawnerContacts = new();

        const float k_SphereCastRadius = 0.1f;
        const string k_PlaneLayer = "Placeable Surface";

        void Start()
        {
            if (m_XROrigin == null)
            {
#if UNITY_2022_3_OR_NEWER
                m_XROrigin = FindFirstObjectByType<XROrigin>();
#else
                m_XROrigin = FindObjectOfType<XROrigin>();
#endif
            }

            m_XRCameraTransform = m_XROrigin.Camera.transform;
            m_XROrigin.GetComponentsInChildren(true, m_SpawnerContacts);
            m_ZoneScale = GetComponentInChildren<ZoneScale>(true);
            m_PlaneMask = LayerMask.GetMask(k_PlaneLayer);
        }

        void OnEnable()
        {
            m_Tooltip.gameObject.SetActive(false);
        }

        void LateUpdate()
        {
            PlaceTooltip();
        }

        void PlaceTooltip()
        {
            RaycastHit hitInfo;
            if (Physics.SphereCast(new Ray(m_XRCameraTransform.position, m_XRCameraTransform.forward), k_SphereCastRadius, out hitInfo, float.MaxValue, m_PlaneMask))
            {
                var spawnSurfaceFound = false;
                Vector3 surfacePosition = default;

                // plane tap tooltip
                if (m_TapTooltip)
                {
                    foreach (var spawnerContact in m_SpawnerContacts)
                    {
                        if (spawnerContact.isActiveAndEnabled && spawnerContact.TryGetSpawnSurfaceData(hitInfo.collider, out surfacePosition, out _))
                        {
                            spawnSurfaceFound = true;
                            break;
                        }
                    }
                }

                if (spawnSurfaceFound)
                {
                    m_Tooltip.position = surfacePosition;
                    var facePosition = m_XRCameraTransform.position;
                    var forward = facePosition - m_Tooltip.position;
                    var targetRotation = forward.sqrMagnitude > float.Epsilon ? Quaternion.LookRotation(forward, Vector3.up) : Quaternion.identity;
                    targetRotation *= Quaternion.Euler(new Vector3(0f, 180f, 0f));
                    var targetEuler = targetRotation.eulerAngles;
                    var currentEuler = m_Tooltip.rotation.eulerAngles;
                    targetRotation = Quaternion.Euler
                    (
                        currentEuler.x,
                        targetEuler.y,
                        currentEuler.z
                    );

                    m_Tooltip.rotation = targetRotation;

                    if (!m_Tooltip.gameObject.activeSelf)
                        m_Tooltip.gameObject.SetActive(true);

                    if (m_LastPlane != hitInfo.transform.gameObject)
                        m_ZoneScale.Snap();

                    m_LastPlane = hitInfo.transform.gameObject;
                }
                else
                {
                    if (m_Tooltip.gameObject.activeSelf)
                    {
                        m_Tooltip.gameObject.SetActive(false);
                    }
                }
            }
        }
    }
}