CounterDroneBackend/src/CounterDrone.Core/Simulation/MunitionEntity.cs

using CounterDrone.Core.Algorithms;
using CounterDrone.Core.Models;

namespace CounterDrone.Core.Simulation
{
    public class MunitionEntity
    {
        public string Id { get; }
        public PlatformType LaunchMode { get; }
        public AerosolType AerosolType { get; }
        public float PosX { get; private set; }
        public float PosY { get; private set; }
        public float PosZ { get; private set; }
        public float TargetX { get; }
        public float TargetY { get; }
        public float TargetZ { get; }
        public float ReleaseAltitude { get; }
        public bool HasArrived { get; private set; }

        private readonly float _muzzleVelocity;
        private float _time;
        private readonly float _launchAngle;
        private readonly float _azimuth;
        private readonly float _startX, _startY, _startZ;

        private bool _hasExceededReleaseAltitude;

        public MunitionEntity(string id, PlatformType launchMode, AerosolType aerosolType,
            float startX, float startY, float startZ,
            float targetX, float targetY, float targetZ,
            float muzzleVelocity, float releaseAltitude)
        {
            Id = id;
            LaunchMode = launchMode;
            AerosolType = aerosolType;
            _startX = startX; _startY = startY; _startZ = startZ;
            PosX = startX; PosY = startY; PosZ = startZ;
            TargetX = targetX; TargetY = targetY; TargetZ = targetZ;
            _muzzleVelocity = muzzleVelocity;
            ReleaseAltitude = releaseAltitude;

            // 根据目标距离反算发射角（取低弹道）
            var dx = targetX - startX;
            var dz = targetZ - startZ;
            var horizontalDist = (float)System.Math.Sqrt(dx * dx + dz * dz);
            _azimuth = horizontalDist > 0.001f ? (float)System.Math.Atan2(dx, dz) : 0;

            _launchAngle = Kinematics.CalculateLaunchAngle(horizontalDist, muzzleVelocity, releaseAltitude);
        }

        public void Update(float deltaTime)
        {
            if (HasArrived) return;
            _time += deltaTime;

            if (LaunchMode == PlatformType.GroundBased)
            {
                (float x, float y, float z) = Kinematics.ParabolicPosition(
                    _startX, _startY, _startZ, _launchAngle, _azimuth, _muzzleVelocity, _time);
                PosX = x; PosY = y; PosZ = z;

                // 必须先从上方越过释放高度，再回落时才触发
                if (PosY > ReleaseAltitude)
                    _hasExceededReleaseAltitude = true;

                if (_hasExceededReleaseAltitude && PosY <= ReleaseAltitude)
                {
                    PosY = ReleaseAltitude;
                    HasArrived = true;
                }
            }
            else
            {
                // 空基投放：自由落体
                PosY -= 9.81f * deltaTime;
                PosX += (TargetX - PosX) * 0.1f;
                PosZ += (TargetZ - PosZ) * 0.1f;

                if (PosY <= ReleaseAltitude)
                {
                    PosY = ReleaseAltitude;
                    HasArrived = true;
                }
            }
        }
    }
}