using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using BITFALL.Bullet;
using UnityEngine;
using BITKit;
using BITKit.Entities;
using Cysharp.Threading.Tasks;
using Unity.Mathematics;
using UnityEditor;
using UnityEngine.Animations;
using UnityEngine.UIElements;

namespace BITFALL
{
    [Serializable]
    public record InstanceBullet : SpawnBullet
    {
        public Vector3 GraphicsPosition;
        public Vector3 Velocity;
        public Vector3 CurrentPos;
        public float CurrentSpeed = 64;
        public float ElapsedTime; 
    }
    [Serializable]
    public class BulletServiceSingleton : IBulletService
    {
            public void Spawn(SpawnBullet bullet)=>BulletService.Spawn?.Invoke(bullet);
    }
    public class BulletService : MonoBehaviour, IBulletService
    {
        public static Action<SpawnBullet> Spawn;
        
        [Header(Constant.Header.Settings)]
        [SerializeField] private LayerMask layerMask;
        [SerializeField] private Material material;
        [SerializeField] private Optional<float> bulletLerpSpeed;
        [SerializeField] private Optional<AnimationCurve> bulletScaleCurve;
        
        [Header(Constant.Header.Prefabs)]
        [SerializeField] private Mesh rectangleMesh;
        [SerializeField] private Mesh quadMesh;

        [Header(Constant.Header.Providers)]
        [SerializeField, SerializeReference, SubclassSelector]
        private IEntitiesService entitiesService;
        [SerializeField, SerializeReference, SubclassSelector]
        private INetProvider netProvider;
        [SerializeField, SerializeReference, SubclassSelector]
        private IDamageService damageService;
        
        [Header(Constant.Header.InternalVariables)]
        private readonly List<InstanceBullet> instances = new();
        private readonly RaycastHit[] _raycastHits = new RaycastHit[16];

        private const float dragCoefficient = 0.045f; // 子弹的阻力系数
        private const float bulletMass = 0.015f; // 子弹的质量，单位：千克
        
        private readonly Queue<(Vector3 Position,Vector3 Forward,Quaternion StartRotation,float ElaspedTime,Vector3 StartPosition)> DrawQueue=new();

        private readonly Queue<InstanceBullet> _newBulletQueue = new();

        private readonly Queue<InstanceBullet> _removeBulletQueue = new();

        private void Start()
        {
            Spawn += SpawnBullet;
        }
        private void OnDestroy()
        {
            Spawn -= SpawnBullet;
        }
        private void Update()
        {
            var camera = Camera.main;
            if (!camera) return;
            var cameraTransform = camera.transform;
            //var rot = camera.transform.rotation * Quaternion.Euler(0, 180, 0);
            foreach (var bullet in instances.ToArray())
            {
                if (bullet.ElapsedTime < 0.04f) continue;
                
                bullet.GraphicsPosition =
                    Vector3.MoveTowards(bullet.GraphicsPosition, bullet.CurrentPos, bullet.StartSpeed*Time.deltaTime);
                
                DrawQueue.Enqueue((bullet.GraphicsPosition,bullet.Forward,bullet.Rotation,bullet.ElapsedTime,bullet.Position));
            }

            while (DrawQueue.TryDequeue(out var queue))
            {
                var direction = camera.transform.position - queue.Position;

                var rot = Quaternion.LookRotation(queue.Position + queue.Forward, direction);
                // 获取目标方向

                var mesh = rectangleMesh;

                //if (MathV.InFovRange(cameraTransform.position, cameraTransform.forward, bullet.CurrentPos,8))
                if (Vector3.Angle(cameraTransform.forward, queue.Forward) < 8)
                {
                    if (Vector3.Distance(queue.StartPosition, queue.Position) < 3.2f)
                        continue;
                    
                    mesh = quadMesh;
                    rot = cameraTransform.rotation * Quaternion.Euler(0, 180, 0);
                }
                const int count = 1;
                var matrix = Matrix4x4.TRS(
                    queue.Position,
                    rot,
                    Vector3.one * 
                    Mathf.Lerp(
                        0,1,Vector3.Distance(queue.StartPosition,queue.Position)
                        )
                    + Vector3.one *
                    (bulletScaleCurve.Allow ? bulletScaleCurve.Value.Evaluate(queue.ElaspedTime) : 0)
                );
                Graphics.DrawMesh(mesh, matrix, material,
                    LayerMask.NameToLayer("TransparentFX"));
            }
        }

        private void FixedUpdate()
        {
            foreach (var bullet in instances)
            {
                if (destroyCancellationToken.IsCancellationRequested) return;
                var size = Physics.RaycastNonAlloc(bullet.CurrentPos, bullet.Velocity, _raycastHits, Vector3.Distance(default,bullet.Velocity) * Time.fixedDeltaTime, layerMask);
                var validHit = false;
                RaycastHit hit=default;
                foreach (var raycastHit in _raycastHits.Take(size).OrderBy(x => Vector3.Distance(bullet.Position, x.point)))
                {
                    if (!IsValidHit(raycastHit, bullet,out hit))
                        continue;
                    validHit = true;
                    break;
                }

                if (validHit || bullet.CurrentSpeed <= 0 || bullet.Velocity.sqrMagnitude <= 0.01f ||
                    bullet.ElapsedTime >= 8)
                {
                    _removeBulletQueue.Enqueue(bullet);

                    if (validHit)
                    {
                        DrawQueue.Enqueue((hit.point - bullet.Velocity.normalized * 0.5f, bullet.Forward, bullet.Rotation,
                            bullet.ElapsedTime,bullet.Position));
                    }
                    else
                    {
                        DrawQueue.Enqueue((bullet.CurrentPos + bullet.Velocity * 0.5f, bullet.Forward, bullet.Rotation,
                            bullet.ElapsedTime,bullet.Position));
                    }

                    //pool.Return(bullet.model);
                }
                else
                {
                    // // 计算子弹的下坠距离
                    // float distance =Mathf.Clamp(
                    //     0.5f * Physics.gravity.y * bullet.ElapsedTime * bullet.ElapsedTime,
                    //     Physics.gravity.y
                    //     ,0
                    //     ) ;
                    //
                    // bullet.currentSpeed -= bullet.startSpeed * Time.fixedDeltaTime;
                    // bullet.currentPos += (Vector3)bullet.forward * (bullet.currentSpeed * Time.fixedDeltaTime);
                    // bullet.currentPos += Vector3.up * distance;
                    // bullet.model.transform.position = bullet.currentPos;
                    //
                    // bullet.ElapsedTime += Time.fixedDeltaTime;
                    
                    // 计算重力下坠
                    
                    bullet.ElapsedTime+=Time.fixedDeltaTime;
                    
                    bullet.Velocity+= Physics.gravity * (Time.fixedDeltaTime * bullet.ElapsedTime);

                    // // 计算空气阻力
                    // float airDragForce = 0.5f * dragCoefficient * 1.225f * bullet.Velocity.magnitude * bullet.Velocity.magnitude;
                    //
                    // if (float.IsNaN(airDragForce))
                    // {
                    //     bullet.Velocity=Vector3.zero;
                    //     continue;
                    // }
                    //
                    // Vector3 airDragDirection = -bullet.Velocity.normalized;
                    // Vector3 airDrag = airDragDirection * airDragForce / bulletMass;
                    
                    var newVelocity =bullet.Velocity * Time.fixedDeltaTime;
                    
                    bullet.CurrentPos+=newVelocity;
                 
                    float CalculateElevationAngle(float distance)
                    {
                        float g = Mathf.Abs(Physics.gravity.y);
                        float angle = 0.5f * Mathf.Asin(distance * g / (bullet.StartSpeed * bullet.StartSpeed));
                        return angle * Mathf.Rad2Deg;
                    }
                }
            }

            while (_removeBulletQueue.TryDequeue(out var removeBullet))
            {
                instances.Remove(removeBullet);
            }
            while (_newBulletQueue.TryDequeue(out var newBullet))
            {
                instances.Add(newBullet);
            }
        }
        private async void RpcSpawnBullet(SpawnBullet x)
        {
            await UniTask.SwitchToMainThread();
            InstanceBullet bullet = new()
            {
                Initiator = x.Initiator,
                CurrentPos = x.Position,
                StartSpeed = x.StartSpeed,
                Position = x.Position,
                GraphicsPosition=x.Position,
                Rotation = x.Rotation,
                Forward = x.Forward,
                InitialDamage = x.InitialDamage,
                InitialForce = x.InitialForce,
                Velocity =x.Forward * x.StartSpeed,
                Token = x.Token
            };
            // InstanceBullet bullet = x with
            // {
            //
            // };
            _newBulletQueue.Enqueue(bullet);
            //instances.Add(bullet);
        }
        private void SpawnBullet(SpawnBullet x)
        {
            RpcSpawnBullet(x);
        }

        private bool IsValidHit(RaycastHit raycastHit, InstanceBullet bullet,out RaycastHit hit)
        {
            hit = default;
            if (layerMask.Includes(raycastHit.collider.gameObject.layer) is false) return false;
            raycastHit.collider.TryGetComponentAny<IPhysicsInfo>(out var physicsInfo);
            var force = (raycastHit.point - (Vector3)bullet.Position).normalized * (physicsInfo?.AddForceMultiple ?? 64);
            if (raycastHit.collider.TryGetComponent<IDamagable>(out var damagable))
            {
                if (damagable.UnityEntity?.Id == bullet.Initiator) return false;
                if (layerMask.Includes(raycastHit.collider.gameObject.layer) is false) return false;
                var msg = new DamageMessage()
                {
                    Target = damagable.UnityEntity,
                    Hit = damagable,
                    Damage = bullet.InitialDamage,
                };
                if (damagable is IEntityComponent)
                {
                    damageService.Execute(msg);
                }
                else
                {
                    damagable.GiveDamage(msg);
                }
             
            }

            var _rigidbody = (raycastHit.rigidbody,damagable?.Rigidbody) switch
            {
                (null, null) => null,
                (null, not null) => damagable?.Rigidbody,
                (not null, null) => raycastHit.rigidbody,
                (not null, not null) => damagable?.Rigidbody,
            };
            if (_rigidbody && _rigidbody.gameObject.layer is not 0)
            {
                _rigidbody.AddForceAtPositionAsync(force, raycastHit.point, ForceMode.Impulse).Forget();
            }
           

            List<string> tags = new()
            {
                "BulletHit",
            };
            if (raycastHit.collider.TryGetComponent<ITag>(out var _tag))
            {
                tags.AddRange(_tag.GetTags());
            }

            Location location = new()
            {
                position = raycastHit.point,
                forward = tags.Contains("IgnoreRotation") ? bullet.Forward : Quaternion.LookRotation(raycastHit.normal) * Vector3.forward,
            };
            var vfx = DI.Get<VFXService>().Spawn(location, tags.ToArray());
            if (_rigidbody is not null && tags.Contains("Fixed") is false)
            {
                vfx.SetParentConstraint(_rigidbody.transform);
            }
            else
            {
                vfx.gameObject.RemoveComponent<ParentConstraint>();
            }

            hit = raycastHit;
            return true;
        }

        void IBulletService.Spawn(SpawnBullet bullet) => SpawnBullet(bullet);
        
        
    }
}