using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

namespace XRTool.WorldUI
{
    /// <summary>
    /// Simple event system using physics raycasts.
    /// </summary>
    [AddComponentMenu("Event/XR Physics Raycaster")]
    [RequireComponent(typeof(Camera))]
    public class XRPhysicsRaycaster : PhysicsRaycaster
    {
        private RaycastResult minResult;
        private PhysicsRayConf layerConf;

        public PhysicsRayConf LayerConf { get => layerConf; set => layerConf = value; }

        protected override void Start()
        {
            base.Start();
            LayerConf = Resources.Load<PhysicsRayConf>("PhysicsRayConf");
            eventCamera.cullingMask = LayerConf.eventMask;
            eventMask = LayerConf.eventMask;
        }

        public override void Raycast(PointerEventData eventData, List<RaycastResult> resultAppendList)
        {
            if (resultAppendList != null && resultAppendList.Count > 0)
            {
                float minDis = float.MaxValue;
                int minIndex = 0;
                for (int i = 0; i < resultAppendList.Count; i++)
                {
                    RaycastResult result = resultAppendList[i];
                    if (result.distance < minDis)
                    {
                        minDis = result.distance;
                        minIndex = i;
                    }
                }
                minResult = resultAppendList[minIndex];
                resultAppendList.Clear();
                resultAppendList.Add(minResult);
                base.Raycast(eventData, resultAppendList);
            }
            else
            {
                base.Raycast(eventData, resultAppendList);
            }
        }
    }
}