using UnityEngine;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Collections.Generic;


public class Player : MonoBehaviour
{
    public VoxelTreeManager voxelManager;

    public bool EnableDebug = false;

    int totalCastDone = 0;

    public float longitudeStep = 45f;
    public float lateralStep = 45f;

    int rayCount;

    // Start is called once before the first execution of Update after the MonoBehaviour is created
    void Start()
    {
        InitPrebuildArray();

        VoxelRaycastGPU.Ray[] rays = new VoxelRaycastGPU.Ray[rayCount];
        FillRaysArray(rays);
        voxelManager.gpuRayCaster.Init(rayCount, rays);
    }

    void Cast( ref VoxelRaycastGPU.BatchData[] batchData, int batchCount, int iIteration )
    {
        ComputeBuffer hitBuffer = new ComputeBuffer(rayCount * batchCount, Marshal.SizeOf(typeof(VoxelRaycastGPU.Hit)), ComputeBufferType.Append);

        Stopwatch sw = Stopwatch.StartNew();
        totalCastDone += batchCount * rayCount;
        VoxelRaycastGPU.BatchData[] hits = voxelManager.CastGpuRay(in batchData, batchCount);
        
        /*for( int i = 0; i < hits.Length; i++ )
        {
            GameObject sphere = GameObject.CreatePrimitive(PrimitiveType.Sphere);
            sphere.transform.position = hits[i].origin;
            sphere.transform.localScale = Vector3.one * 0.5f;
        }*/

        sw.Stop();
    }

    Vector3[] prebuildArrayDirection;

    void InitPrebuildArray()
    {
        var dirs = new List<Vector3>();

        const float EPS = 1e-6f;

        // Elevation (longitude in your naming): from -90 to +90 inclusive
        for (float lonDeg = -90f; lonDeg <= 90f + 1e-6f; lonDeg += longitudeStep)
        {
            float lonRad = lonDeg * Mathf.Deg2Rad;
            float cosLon = Mathf.Cos(lonRad);
            float sinLon = Mathf.Sin(lonRad);

            // If cosLon is ~0, we are at a pole: all azimuths collapse to the same vector.
            if (Mathf.Abs(cosLon) < EPS)
            {
                // Add a single pole direction (north or south)
                dirs.Add(new Vector3(0f, sinLon, 0f));
                continue; // skip azimuth loop for this elevation
            }

            // Otherwise loop over azimuth (lateral)
            for (float latDeg = 0f; latDeg < 360f - 1e-6f; latDeg += lateralStep)
            {
                float latRad = latDeg * Mathf.Deg2Rad;
                float cosLat = Mathf.Cos(latRad);
                float sinLat = Mathf.Sin(latRad);

                Vector3 dir = new Vector3(
                    cosLon * cosLat,
                    sinLon,
                    cosLon * sinLat
                );

                dirs.Add(dir.normalized);
            }
        }

        prebuildArrayDirection = dirs.ToArray();
        rayCount = dirs.Count;
    }

    void FillRaysArray( VoxelRaycastGPU.Ray[] rays )
    {
        for (int i = 0; i < prebuildArrayDirection.Length; i++)
        {
            rays[i].direction = prebuildArrayDirection[i];
        }
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.R))
        {
            //VoxelTreeRaycaster.HitInfo outHit;

            Vector3 origin = GetComponent<Transform>().position;

            UnityEngine.Debug.Log(origin);

            //int iNbCast = 0;

            /*Stopwatch sw = Stopwatch.StartNew();

            for (float el = -90f; el <= 90f; el += elStep)
            {
                for (float az = 0f; az < 360f; az += azStep)
                {
                    float elRad = el * Mathf.Deg2Rad;
                    float azRad = az * Mathf.Deg2Rad;

                    Vector3 dir = new Vector3(
                        Mathf.Cos(elRad) * Mathf.Cos(azRad),
                        Mathf.Sin(elRad),
                        Mathf.Cos(elRad) * Mathf.Sin(azRad)
                    ).normalized;

                    iNbCast++;
                    bool hit = voxelManager.CastRay(origin, dir, 100f, out outHit);
                }
            }

            sw.Stop();

            UnityEngine.Debug.Log($"RayCast done in {sw.Elapsed.TotalMilliseconds}ms for {iNbCast} casts");*/

            Stopwatch sw = Stopwatch.StartNew();

            totalCastDone = 0;

            VoxelRaycastGPU.Ray[] rays = new VoxelRaycastGPU.Ray[rayCount];
            VoxelRaycastGPU.BatchData[] batchDatas = new VoxelRaycastGPU.BatchData[1];

            batchDatas[0].origin = origin;
            batchDatas[0].maxDistance = 100;

            Cast(ref batchDatas, 1, 0);
            sw.Stop();

            UnityEngine.Debug.Log($"Gpu RayCast done in {sw.Elapsed.TotalMilliseconds}ms for {totalCastDone} casts");

        }
    }
}