using System;
using UnityEngine;

// ReSharper disable once CheckNamespace
namespace BlueWaterProject
{
    [Serializable]
    public class TargetInfo
    {
        public Transform transform;
        public Collider collider;
        public IAiStat iAiStat;
        
        public TargetInfo()
        {
            transform = null;
            collider = null;
            iAiStat = null;
        }

        public TargetInfo(Transform transform, Collider collider, IAiStat iAiStat)
        {
            this.transform = transform;
            this.collider = collider;
            this.iAiStat = iAiStat;
        }

        public void SetTargetInfo(Transform targetTransform, Collider collider, IAiStat targetIAiStat)
        {
            transform = targetTransform;
            this.collider = collider;
            iAiStat = targetIAiStat;
        }

        public void DefaultSetting()
        {
            transform = null;
            collider = null;
            iAiStat = null;
        }
    }
    
    public class FieldOfView : MonoBehaviour
    {
        #region Property and variable

        [Header("타겟 및 시야 설정")]
        [SerializeField] private bool drawGizmo = true;
        
        [SerializeField] private LayerMask targetLayer;
        
        [Tooltip("시야 각도\n상대를 감지하는 0~360도 사이의 시야각")]
        [Range(0f, 360f)]
        [SerializeField] private float viewAngle = 360f;
        
        [Tooltip("시야 길이\n상대를 감지하는 최대 길이, 부채꼴 혹은 원의 반지름 길이")]
        [Range(0f, 50f)]
        [SerializeField] private float viewRadius;
        
        [Header("시야 내 타겟 정보")]
        [SerializeField] private Collider[] colliderWithinRange = new Collider[TARGET_MAX_SIZE];
        [SerializeField] private TargetInfo targetInfo = new();

        private Collider targetCollider;
        private IAiStat iAiStat;
        
        private const int TARGET_MAX_SIZE = 20;

        #endregion

        #region Unity built-in Function

#if UNITY_EDITOR
        public void OnDrawGizmosSelected()
        {
            if (!drawGizmo) return;

            var myPos = transform.position;

            Gizmos.color = Color.green;
            Gizmos.DrawWireSphere(myPos, viewRadius);

            if (targetInfo.transform == null) return;
            
            Debug.DrawLine(myPos, targetInfo.transform.position, Color.red);
        }
#endif  

        private void LateUpdate()
        {
            Array.Clear(colliderWithinRange, 0, TARGET_MAX_SIZE);
            
            var myPos = transform.position;
            var maxColliderCount = Physics.OverlapSphereNonAlloc(myPos, viewRadius, colliderWithinRange, 
                targetLayer, QueryTriggerInteraction.Collide);

            if (maxColliderCount <= 0)
            {
                targetInfo.DefaultSetting();
                return;
            }
            
            iAiStat = colliderWithinRange[0].GetComponent<IAiStat>();

            float nearestDistance;
            Transform nearestTargetTransform;
            
            if (iAiStat.GetCurrentHp() <= 0)
            {
                nearestDistance = float.PositiveInfinity;
                nearestTargetTransform = null;
            }
            else
            {
                nearestDistance = Vector3.Distance(colliderWithinRange[0].transform.position, myPos);
                nearestTargetTransform = colliderWithinRange[0].transform;
            }

            for (var i = 1; i < maxColliderCount; i++)
            {
                var distance = Vector3.Distance(colliderWithinRange[i].transform.position, myPos);

                if (nearestDistance < distance) continue;

                iAiStat = colliderWithinRange[i].GetComponent<IAiStat>();
                
                if (iAiStat.GetCurrentHp() <= 0) continue;

                nearestDistance = distance;
                nearestTargetTransform = colliderWithinRange[i].transform;
            }

            if (nearestTargetTransform)
            {
                targetCollider = nearestTargetTransform.GetComponent<Collider>();
                iAiStat = nearestTargetTransform.GetComponent<IAiStat>();
                targetInfo.SetTargetInfo(nearestTargetTransform, targetCollider, iAiStat);
                
                var targetPos = targetInfo.transform.position;
                targetPos.y = transform.position.y;
                transform.LookAt(targetPos);
            }
            else
            {
                targetInfo.DefaultSetting();
            }
        }

        #endregion

        #region Custom Function

        public int GetTargetLayer() => targetLayer;
        public TargetInfo GetTargetInfo() => targetInfo;

        #endregion
    }
}