GridManager

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

public class GridManager : MonoBehaviour
{
    [SerializeField] Vector2Int gridSize; // specifies x width & y height of 2D grid
    [Tooltip("World Grid Size -  should match UnityEditror snap settings.")]
    [SerializeField] int unityGridSize = 10;
    public int UnityGridSize { get { return unityGridSize; } }
    Dictionary<Vector2Int, Node> grid = new Dictionary<Vector2Int, Node>();
    public Dictionary<Vector2Int, Node> Grid{get {return grid;}}

    void Awake() {
        {
            CreateGrid();
        }
    }

    public Node GetNode(Vector2Int coordinates)
    {
        if(grid.ContainsKey(coordinates))
        {
            return grid[coordinates];
        }
        return null;
    }

    public void BlockNode(Vector2Int coordinates)
    {
        if(grid.ContainsKey(coordinates))
        {
            grid[coordinates].isWalkable = false;
        }
    }

    public Vector2Int GetCoordinatesFromPosition(Vector3 position)
    {
        Vector2Int coordinates = new Vector2Int();
        coordinates.x = Mathf.RoundToInt(position.x/ unityGridSize);
        coordinates.y = Mathf.RoundToInt(position.z/ unityGridSize );

        return coordinates;
    }

    public Vector3 GetPositionFromCoordinates(Vector2Int coordinates)
    {
        Vector3 position = new Vector3();
        position.x = coordinates.x * unityGridSize;
        position.z = coordinates.y * unityGridSize;

        return position;
    }

    void CreateGrid()
    {
        for(int x = 0; x < gridSize.x; x++)
        {
            for(int y = 0; y < gridSize.y; y++)
            {
                Vector2Int coordinates = new Vector2Int(x,y);
                grid.Add(coordinates, new Node(coordinates, true));
                // Dictionary here; uses a Key and a Description.
                //the value of coords in vect2Int .info contained in value
                // The [coordinates] is the key, and .coordinates + .isWalkable is the information/description.
                // Debug.Log(grid[coordinates].coordinates + " = " + grid[coordinates].isWalkable);
            }
        }
    }
}