using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Chunk : ITickable
{
    public readonly int ChunkWidth = 20;
    public readonly int ChunkHeight = 125;
    public float _perlin;

    public Cube[,,] _Cubes;
    private int PosX;
    private int Posz;
    public Chunk(int px, int pz)
    {
        PosX = px;
        Posz = pz;
    }
    protected bool HasGenerated = false;
    public float GetHeight(float px, float pz, float py)
    {
        px += (PosX * ChunkWidth);
        pz += (Posz * ChunkWidth);

        float p1 = Mathf.PerlinNoise(px / GameManager.Sdx, pz / GameManager.Sdz) * GameManager.Smul;
        p1 *= (GameManager.Smy * py);

        return p1;
    }
    public void Start()
    {
        _Cubes = new Cube[ChunkWidth, ChunkHeight, ChunkWidth];

        for (int x = 0; x < ChunkWidth; x++)
        {
            for (int y = 0; y < ChunkHeight; y++)
            {
                System.Random m_rnd = new System.Random();
                for (int z = 0; z < ChunkWidth; z++)
                {
                    float perlin = GetHeight(x, z, y);
                    _perlin = perlin;

                    if (perlin > GameManager.Scutoff)
                    {
                        _Cubes[x, y, z] = Cube.Air;
                    }
                    else
                    {
                        if (y > 100)
                        {   // 10% chance of a cloud.
                            _Cubes[x, y, z]
                                = m_rnd.NextDouble() > 0.9
                                ? Cube.Cloud
                                : Cube.Air;
                        }

                        if (perlin > GameManager.Scutoff/ 1.1f)
                        {
                            _Cubes[x, y, z] = Cube.Grass;
                        }
                        else
                        {
                            _Cubes[x, y, z] = Cube.Stone;
                        }
                    }
                }
            }
        }

        HasGenerated = true;

    }

    public void Tick()
    {

    }

    protected bool HasDrawn = false;
    private MeshData data;
    protected bool DrawnLock = false;
    public void Update()
    {
        if (!HasDrawn && HasGenerated && !DrawnLock)
        {
            DrawnLock = true;
            data = new MeshData();
            for (int x = 0; x < ChunkWidth; x++)
            {
                for (int y = 0; y < ChunkHeight; y++)
                {
                    for (int z = 0; z < ChunkWidth; z++)
                    {
                        data.Merge(_Cubes[x, y, z].Draw(this, _Cubes, x, y, z));
                    }
                }
            }
            DrawnLock = false;
            HasDrawn = true;
        }
    }
    protected bool HasRendered = false;
    private GameObject go;
    public virtual void OnUnityUpdate()
    {
        if (HasGenerated && !HasRendered && HasDrawn)
        {
            HasRendered = true;
            Mesh mesh = data.ToMesh();
            if (go == null)
            {
                go = new GameObject();
            }

            Transform t = go.transform;

            if (t.gameObject.GetComponent<MeshFilter>() == null)
            {
                t.gameObject.AddComponent<MeshFilter>();
                t.gameObject.AddComponent<MeshRenderer>();
                t.gameObject.AddComponent<MeshCollider>();
                t.gameObject.GetComponent<MeshRenderer>().material = Resources.Load<Material>("ChunkMaterial");
                t.transform.position = new Vector3(PosX * ChunkWidth / 2, 0, Posz * ChunkWidth / 2);
                t.gameObject.layer = LayerMask.NameToLayer("Ground");
                Texture2D tmp = new Texture2D(0, 0);
                tmp.LoadImage(System.IO.File.ReadAllBytes("atlas.png"));
                tmp.filterMode = FilterMode.Point;
                t.gameObject.GetComponent<MeshRenderer>().material.mainTexture = tmp;
            }

            t.transform.GetComponent<MeshFilter>().sharedMesh = mesh;
            t.transform.GetComponent<MeshCollider>().sharedMesh = mesh;
        }
    }
}