using System.Numerics;
using System.Runtime.InteropServices;
using CounterStrikeSharp.API;
using CounterStrikeSharp.API.Core;
using CounterStrikeSharp.API.Modules.Entities.Constants;
using CounterStrikeSharp.API.Modules.Memory;
using CounterStrikeSharp.API.Modules.Utils;
using Vector = CounterStrikeSharp.API.Modules.Utils.Vector;

namespace RayTraceAPI
{
#region Native Structs (matching C++ layout exactly)
    [Flags]
	public enum InteractionLayers: ulong
	{
		None = 0,
		Solid = 0x1,
		Hitboxes = 0x2,
		Trigger = 0x4,
		Sky = 0x8,
		PlayerClip = 0x10,
		NPCClip = 0x20,
		BlockLOS = 0x40,
		BlockLight = 0x80,
		Ladder = 0x100,
		Pickup = 0x200,
		BlockSound = 0x400,
		NoDraw = 0x800,
		Window = 0x1000,
		PassBullets = 0x2000,
		WorldGeometry = 0x4000,
		Water = 0x8000,
		Slime = 0x10000,
		TouchAll = 0x20000,
		Player = 0x40000,
		NPC = 0x80000,
		Debris = 0x100000,
		Physics_Prop = 0x200000,
		NavIgnore = 0x400000,
		NavLocalIgnore = 0x800000,
		PostProcessingVolume = 0x1000000,
		UnusedLayer3 = 0x2000000,
		CarriedObject = 0x4000000,
		PushAway = 0x8000000,
		ServerEntityOnClient = 0x10000000,
		CarriedWeapon = 0x20000000,
		StaticLevel = 0x40000000,
		csgo_team1 = 0x80000000,
		csgo_team2 = 0x100000000,
		csgo_grenadeclip = 0x200000000,
		csgo_droneclip = 0x400000000,
		csgo_moveable = 0x800000000,
		csgo_opaque = 0x1000000000,
		csgo_monster = 0x2000000000,
		csgo_thrown_grenade = 0x8000000000,

		MASK_SHOT_PHYSICS = Solid | PlayerClip | Window | PassBullets | Player | NPC | Physics_Prop,
		MASK_SHOT_HITBOX = Hitboxes | Player | NPC,
		MASK_SHOT_FULL = MASK_SHOT_PHYSICS | Hitboxes,
		MASK_WORLD_ONLY = Solid | Window | PassBullets,
		MASK_GRENADE = Solid | Window | Physics_Prop | PassBullets,
		MASK_BRUSH_ONLY = Solid | Window,
		MASK_PLAYER_MOVE = Solid | Window | PlayerClip | PassBullets,
		MASK_NPC_MOVE = Solid | Window | NPCClip | PassBullets
	}

	[StructLayout(LayoutKind.Explicit, Size = 32)]
	public unsafe struct TraceOptions
	{
		[FieldOffset(0)] public ulong InteractsAs;
		[FieldOffset(8)] public ulong InteractsWith;
		[FieldOffset(16)] public ulong InteractsExclude;
		[FieldOffset(24)] public int DrawBeam;

		public TraceOptions()
		{
		  InteractsAs = 0;
			InteractsWith = (ulong)InteractionLayers.MASK_SHOT_PHYSICS;
			InteractsExclude = 0;
			DrawBeam = 0;
		}

		public TraceOptions(InteractionLayers interactsAs, InteractionLayers interactsWith, InteractionLayers interactsExclude = 0, bool drawBeam = false)
		{
		  InteractsAs = (ulong)interactsAs;
			InteractsWith = (ulong)interactsWith;
			InteractsExclude = (ulong)interactsExclude;
			DrawBeam = drawBeam ? 1 : 0;
		}
	}

	[StructLayout(LayoutKind.Explicit, Size = 136)]
	public unsafe struct TraceResult
	{
		[FieldOffset(0)] public float StartPosX;
		[FieldOffset(4)] public float StartPosY;
		[FieldOffset(8)] public float StartPosZ;

		[FieldOffset(12)] public float EndPosX;
		[FieldOffset(16)] public float EndPosY;
		[FieldOffset(20)] public float EndPosZ;

		[FieldOffset(24)] public float HitPointX;
		[FieldOffset(28)] public float HitPointY;
		[FieldOffset(32)] public float HitPointZ;

		[FieldOffset(36)] public float NormalX;
		[FieldOffset(40)] public float NormalY;
		[FieldOffset(44)] public float NormalZ;

		[FieldOffset(48)] public float Fraction;
		[FieldOffset(52)] public float HitOffset;

		[FieldOffset(56)] public int TriangleIndex;
		[FieldOffset(60)] public int HitboxBoneIndex;

		[FieldOffset(64)] public int Contents;
		[FieldOffset(68)] public int RayType;

		[FieldOffset(72)] public int AllSolid;
		[FieldOffset(76)] public int ExactHitPoint;

		// pointer section
		[FieldOffset(80)] public nint HitEntityPtr;
		[FieldOffset(88)] public nint HitboxPtr;
		[FieldOffset(96)] public nint SurfacePropsPtr;
		[FieldOffset(104)] public nint BodyHandle;
		[FieldOffset(112)] public nint ShapeHandle;

		// thread safe heap pointer section
		[FieldOffset(120)] public nint BodyTransformPtr;
		[FieldOffset(128)] public nint ShapeAttributesPtr;

		public unsafe ref T GetRef<T>(nint ptr) where T : unmanaged
		{
			if (ptr == 0)
				throw new NullReferenceException();

			return ref *(T*)ptr;
		}

		public T? GetObject<T>(nint ptr) where T : class
		{
			if (ptr == 0)
				return null;

			return (T)Activator.CreateInstance(typeof(T), ptr)!;
		}

	    public Vector3 StartPos => new(StartPosX, StartPosY, StartPosZ);
        public Vector3 EndPos => new(EndPosX, EndPosY, EndPosZ);
        public Vector3 HitPoint => new(HitPointX, HitPointY, HitPointZ);
        public Vector3 Normal => new(NormalX, NormalY, NormalZ);

	    public bool DidHit => Fraction < 1.0f;
	    public bool IsAllSolid => AllSolid != 0;
	    public bool HasExactHit => ExactHitPoint != 0;

		public CEntityInstance? HitEntity => GetObject<CEntityInstance>(HitEntityPtr);
	}
#endregion

    public interface CRayTraceInterface
    {
        public unsafe bool TraceShape(Vector origin, QAngle angles, CBaseEntity? ignoreEntity, TraceOptions options,
            out TraceResult result);

        public unsafe bool TraceEndShape(Vector origin, Vector endOrigin, CBaseEntity? ignoreEntity,
            TraceOptions options, out TraceResult result);

        public unsafe bool TraceHullShape(Vector vecStart, Vector vecEnd, Vector hullMins, Vector hullMaxs,
            CBaseEntity? ignoreEntity, TraceOptions options, out TraceResult result);
    }
}