using System.Collections.Generic;
using UnityEngine;

public class LevelBuilder : MonoBehaviour
{
    [Header("Tile Settings")]
    [SerializeField] private GameObject[] tilePrefabs;
    [SerializeField] private float tileLength = 6f;
    [SerializeField] private int numberOfTiles = 20;
    [SerializeField] private Transform playerTransform;

    [Header("Environment Settings")]
    [SerializeField] private GameObject[] treePrefabs;

    [SerializeField] private float sideOffset = 10f;
    [SerializeField] private float treeRandomSpread = 2f;

    private readonly List<GameObject> _activeTiles = new();
    private readonly List<GameObject> _activeEnvironment = new();
    private float _spawnZ;

    private void Start()
    {
        for (var i = 0; i < numberOfTiles; i++)
        {
            SpawnTile(i < 5 ? 0 : Random.Range(0, tilePrefabs.Length));
        }
    }

    private void Update()
    {
        if (playerTransform.position.z - 35 > _spawnZ - numberOfTiles * tileLength)
        {
            SpawnTile(Random.Range(0, tilePrefabs.Length));
            DeleteTile();
        }
    }

    private void SpawnTile(int tileIndex)
    {
        var tile = Instantiate(tilePrefabs[tileIndex], transform.forward * _spawnZ, transform.rotation);
        _activeTiles.Add(tile);

        SpawnEnvironment(_spawnZ);

        _spawnZ += tileLength;
    }

    private void SpawnEnvironment(float zPos)
    {
        var envContainer = new GameObject("EnvGroup_" + zPos);
        envContainer.transform.SetParent(transform);

        CreateTree(-sideOffset, zPos, envContainer.transform);
        CreateTree(sideOffset, zPos, envContainer.transform);

        _activeEnvironment.Add(envContainer);
    }

    private void CreateTree(float xOffset, float zPos, Transform parent)
    {
        if (treePrefabs.Length == 0) return;

        var finalX = xOffset + Random.Range(-treeRandomSpread, treeRandomSpread);
        var finalZ = zPos + Random.Range(-treeRandomSpread, treeRandomSpread);
        var spawnPos = new Vector3(finalX, 0, finalZ);

        var treePrefab = treePrefabs[Random.Range(0, treePrefabs.Length)];
        var tree = Instantiate(treePrefab, spawnPos, Quaternion.Euler(0, Random.Range(0, 360), 0));
        
        tree.transform.SetParent(parent);
    }

    private void DeleteTile()
    {
        Destroy(_activeTiles[0]);
        _activeTiles.RemoveAt(0);

        Destroy(_activeEnvironment[0]);
        _activeEnvironment.RemoveAt(0);
    }
}