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

public class RecursiveBacktrackerChris : MonoBehaviour
{
    private MyTile[,] levelTiles;

    private GameObject level;
    private Vector2Int currentPos;
    private Stack<Vector2Int> positions;
    public GameObject Ground;
    public GameObject Wall;
    public int MapSize;
    public int StepLength;

    private void Awake()
    {
        level = new GameObject("Level");
        positions = new Stack<Vector2Int>();

        CreateLevel(MapSize);
        MakeMaze();
    }

    private void CreateLevel(int size)
    {
        levelTiles = new MyTile[size, size];

        for (int i = 0; i < size; i++)
        {
            for (int j = 0; j < size; j++)
            {
                //GameObject temp = GameObject.Instantiate(Wall);
                GameObject temp = GameObject.CreatePrimitive(PrimitiveType.Cube); //kann verwendet werden, wenn du keine eigenen Assets für Wall hast.
                temp.transform.position = new Vector3(i, j, 0);
                temp.transform.SetParent(level.transform);
                levelTiles[i, j] = temp.AddComponent<MyTile>();

                // frame as ground  can’t dig there
                if (i == 0 || j == 0 || i == size - 1 || j == size - 1)
                {
                    levelTiles[i, j].type = MyTile.TileType.Ground;
                }
            }
        }
    }

    private void MakeMaze()
    {
        currentPos = GetRandomStartPosition();
        SetTileType(currentPos, MyTile.TileType.Ground);
        positions.Push(currentPos);

        while (positions.Count > 0)
        {
            Vector2Int digDirection = GetRandomDirection(currentPos);
            while (digDirection == Vector2Int.zero)
            {
                positions.Pop();
                if (positions.Count == 0)
                    return;
                currentPos = positions.Peek();
                digDirection = GetRandomDirection(currentPos);
            }
            currentPos = DigDirection(currentPos, digDirection, StepLength);
            positions.Push(currentPos);
        }
    }

    // zufälligen Startpunkt wählen
    private Vector2Int GetRandomStartPosition()
    {
        int startX = Random.Range(1, MapSize - 1);
        int startY = Random.Range(1, MapSize - 1);

        startX = startX % 2 == 0 ? startX - 1 : startX;
        startY = startY % 2 == 0 ? startY - 1 : startY;

        Vector2Int startPos = new Vector2Int(startX, startY);
        return startPos;
    }

    private MyTile GetNeighbor(Vector2Int position, Vector2Int direction)
    {
        MyTile temp = null;
        try
        {
            temp = levelTiles[position.x + StepLength * direction.x,
            position.y + StepLength * direction.y];

            if (temp.type == MyTile.TileType.Ground)
            {
                temp = null;
            }
        }
        catch (System.IndexOutOfRangeException e)
        {
            Debug.LogWarning(e.Message);
        }
        return temp;
    }

    private Vector2Int DigDirection(Vector2Int position, Vector2Int direction, int stepLength)
    {
        for (int i = 0; i <= stepLength; i++)
        {
            SetTileType(position + i * direction, MyTile.TileType.Ground);
        }
        return position + stepLength * direction;
    }

    private void SetTileType(Vector2Int position, MyTile.TileType tileType)
    {
        try
        {
            levelTiles[position.x, position.y].type = tileType;
            if (tileType == MyTile.TileType.Ground)
            {
                Destroy(levelTiles[position.x, position.y].gameObject);
                GameObject temp = GameObject.Instantiate(Ground,
                new Vector3(position.x, position.y, 0),
                Quaternion.identity);
                temp.transform.SetParent(level.transform);
            }
        }
        catch (System.IndexOutOfRangeException e)
        {
            Debug.LogWarning($"{e.Message}: position = {position}");
        }
    }

    // zufällige Richtung graben
    private Vector2Int GetRandomDirection(Vector2Int position)
    {
        List<Vector2Int> directions = new List<Vector2Int>();

        if (GetNeighbor(position, Vector2Int.right) != null)
        {
            directions.Add(Vector2Int.right);
        }
        if (GetNeighbor(position, Vector2Int.left) != null)
        {
            directions.Add(Vector2Int.left);
        }
        if (GetNeighbor(position, Vector2Int.down) != null)
        {
            directions.Add(Vector2Int.down);
        }
        if (GetNeighbor(position, Vector2Int.up) != null)
        {
            directions.Add(Vector2Int.up);
        }

        // wenn Sackgasse, Position vom Stack nehmen
        if (directions.Count == 0)
        {
            // keine Nachbarn gefunden
            return Vector2Int.zero;
        }
        else
        {
            return directions[Random.Range(0, directions.Count)];
        }
    }
}