using System.Collections.Generic;
using UnityEngine;
using DG.Tweening;
using System;

namespace NBF
{
    /// <summary>
    /// 抛竿输入参数
    /// </summary>
    [Serializable]
    public struct ThrowInput
    {
        [Range(0, 1)] public float power;           // 力度 0-1
        [Range(5, 50)] public float lureWeight;     // 钓饵重量 g
        [Range(0.1f, 1f)] public float lineDiameter; // 线直径 mm
        public Vector3 windDirection;
        public float windStrength;
    }

    /// <summary>
    /// 路亚抛竿轨迹控制器
    /// 使用预计算轨迹 + DOTween动画，实现确定性抛竿
    /// </summary>
    public class LureThrowTrajectory : IDisposable
    {
        // 物理常量
        private const float AirDensity = 1.225f;

        // 默认参数
        protected float _minThrowPower = 15f;
        protected float _maxThrowPower = 45f;
        private float _dragCoefficient = 0.2f;
        private float _lureArea = 0.001f;
        private float _timeStep = 0.02f;
        private int _maxSteps = 500;

        private Sequence _throwSequence;
        private List<Vector3> _trajectory;

        public bool IsPlaying => _throwSequence != null && _throwSequence.IsPlaying();
        public List<Vector3> Trajectory => _trajectory;

        /// <summary>
        /// 计算抛竿轨迹
        /// </summary>
        public List<Vector3> CalculateTrajectory(ThrowInput input, Vector3 startPos, Vector3 throwDirection)
        {
            _trajectory = new List<Vector3>();

            Vector3 position = startPos;
            Vector3 direction = throwDirection.normalized;
            float throwPower = Mathf.Lerp(_minThrowPower, _maxThrowPower, input.power);
            Vector3 velocity = direction * throwPower;

            float lureMass = input.lureWeight / 1000f;
            Vector3 windDir = input.windDirection.normalized;
            float windStrength = input.windStrength;

            float currentTime = 0f;
            int steps = 0;

            while (currentTime < 10f && steps < _maxSteps)
            {
                if (position.y <= 0f) break;

                // 风力影响
                float windInfluenceFactor = Mathf.Clamp01(currentTime / 1.5f);
                Vector3 windVelocity = windDir * windStrength * windInfluenceFactor;
                Vector3 relVelocity = velocity - windVelocity;

                // 空气阻力
                float dragMag = 0.5f * AirDensity * relVelocity.sqrMagnitude * _dragCoefficient * _lureArea;

                // 钓线阻力
                float lineLength = Vector3.Distance(
                    new Vector3(position.x, 0, position.z),
                    new Vector3(startPos.x, 0, startPos.z));
                float lineRadius = input.lineDiameter / 2000f;
                float lineArea = lineLength * (lineRadius * 2f);
                float lineDragMag = 0.5f * AirDensity * velocity.sqrMagnitude * _dragCoefficient * lineArea;
                Vector3 lineDragForce = -velocity.normalized * lineDragMag;

                Vector3 dragForce = -relVelocity.normalized * dragMag;
                Vector3 totalForce = dragForce + lineDragForce;
                Vector3 acceleration = Physics.gravity + totalForce / lureMass;

                velocity += acceleration * _timeStep;
                position += velocity * _timeStep;

                _trajectory.Add(position);
                currentTime += _timeStep;
                steps++;
            }

            return _trajectory;
        }

        /// <summary>
        /// 执行抛竿动画
        /// </summary>
        public void ExecuteThrow(
            Transform lureTransform,
            Rigidbody lureRigidbody,
            List<Vector3> trajectory,
            float duration,
            Action onComplete = null)
        {
            if (trajectory == null || trajectory.Count < 2)
            {
                onComplete?.Invoke();
                return;
            }

            // 停止之前的动画
            Kill();

            // 设置为运动学模式
            lureRigidbody.isKinematic = true;
            lureRigidbody.useGravity = false;

            // 创建路径动画
            _throwSequence = DOTween.Sequence();

            // 使用 DOPath 沿路径移动
            var pathArray = trajectory.ToArray();
            _throwSequence.Append(
                lureTransform.DOPath(pathArray, duration, PathType.Linear, PathMode.Full3D)
                    .SetEase(Ease.Linear)
                    .SetLookAt(0.01f) // 让Lure朝向运动方向
            );

            _throwSequence.OnComplete(() =>
            {
                // 动画结束，恢复物理
                lureRigidbody.isKinematic = false;
                lureRigidbody.useGravity = true;
                lureRigidbody.linearVelocity = Vector3.zero;
                lureRigidbody.angularVelocity = Vector3.zero;
                onComplete?.Invoke();
            });
        }

        /// <summary>
        /// 计算合适的飞行时间（基于轨迹长度）
        /// </summary>
        public float CalculateDuration(List<Vector3> trajectory, float speedFactor = 1f)
        {
            if (trajectory == null || trajectory.Count < 2) return 1f;

            float totalLength = 0f;
            for (int i = 1; i < trajectory.Count; i++)
            {
                totalLength += Vector3.Distance(trajectory[i - 1], trajectory[i]);
            }

            // 根据轨迹长度计算时间，越长越慢
            return Mathf.Clamp(totalLength / (20f * speedFactor), 0.5f, 3f);
        }

        /// <summary>
        /// 使用简化轨迹（减少点位，优化性能）
        /// </summary>
        public List<Vector3> SimplifyTrajectory(List<Vector3> points, float tolerance = 0.1f)
        {
            if (points == null || points.Count < 3) return new List<Vector3>(points ?? new List<Vector3>());

            var result = new List<Vector3>();
            SimplifySection(points, 0, points.Count - 1, tolerance, result);
            result.Add(points[points.Count - 1]);
            return result;
        }

        private void SimplifySection(List<Vector3> points, int start, int end, float tolerance, List<Vector3> result)
        {
            if (end <= start + 1) return;

            float maxDistance = -1f;
            int index = -1;

            for (int i = start + 1; i < end; i++)
            {
                float distance = PerpendicularDistance(points[i], points[start], points[end]);
                if (distance > maxDistance)
                {
                    maxDistance = distance;
                    index = i;
                }
            }

            if (maxDistance > tolerance)
            {
                SimplifySection(points, start, index, tolerance, result);
                result.Add(points[index]);
                SimplifySection(points, index, end, tolerance, result);
            }
        }

        private float PerpendicularDistance(Vector3 point, Vector3 lineStart, Vector3 lineEnd)
        {
            if (lineStart == lineEnd) return Vector3.Distance(point, lineStart);
            Vector3 projected = Vector3.Project(point - lineStart, lineEnd - lineStart);
            return Vector3.Distance(point, lineStart + projected);
        }

        public void Kill()
        {
            if (_throwSequence != null)
            {
                _throwSequence.Kill();
                _throwSequence = null;
            }
        }

        public void Dispose()
        {
            Kill();
            _trajectory?.Clear();
        }

        /// <summary>
        /// 设置抛竿力度范围
        /// </summary>
        public void SetPowerRange(float min, float max)
        {
            _minThrowPower = min;
            _maxThrowPower = max;
        }
    }
}