using UnityEditor.PackageManager.UI;
using UnityEngine;

public class TerrainGenerator : MonoBehaviour
{
    public int height = 5;
    public int length = 1000;
    public int width = 1000;
    public int heightmapResolution = 1025;

    public float hillsRate = 0.5f;
    public float slope = 0.5f;

    public TerrainLayer[] terrainLayers;

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

    }

    private void OnEnable()
    {
        var terrain = GetComponent<Terrain>();
        var terrainCollider = terrain.GetComponent<TerrainCollider>();

        var terrainData = new TerrainData()
        {
            size = new Vector3(length, height, width),
            heightmapResolution = heightmapResolution
        };

        var map = new float[terrainData.heightmapResolution, terrainData.heightmapResolution];

        for (int i = 0; i < terrainData.heightmapResolution; i++)
        {
            for (int j = 0; j < terrainData.heightmapResolution; j++)
            {
                var prevHeight = j == 0
                    ? i == 0
                        ? Random.Range(-slope, slope)
                        : map[i - 1, 0]
                    : map[i, j - 1];

                var isSlope = Random.value <= hillsRate;

                if (isSlope)
                {
                    map[i, j] = Random.Range(-slope, slope); // prevHeight * (1 + Random.Range(-slope, slope));
                }
                else
                {
                    map[i, j] = 0;
                }
            }
        }

        terrainData.SetHeights(0, 0, map);
        terrain.terrainData = terrainData;
        terrainCollider.terrainData = terrainData;
        terrainData.terrainLayers = terrainLayers;
        Debug.Log(terrain.terrainData.size);
    }

    // Update is called once per frame
    void Update()
    {
        
    }
}