using Godot;
using System;

public class WorldGrid : Node2D
{
    [Export]
    private PackedScene TileScene { get; set; }

    [Export]
    public int Size { get; set; }
    
    [Export]
    public int CellSize { get; set; }
    
    private struct Tile
    {
        public float data;
        public ShaderMaterial material;
    }
    private Tile[,] _tiles;

    // Called when the node enters the scene tree for the first time.
    public override void _Ready()
    {
        GenerateGrid(Size);
    }

    public override void _Process(float delta)
    {
        base._Process(delta);
        
        for (int x = 0; x < Size; x++)
        {
            for (int y = 0; y < Size; y++)
            {
                var tile = _tiles[x, y];
                var material = tile.material;
                material.SetShaderParam("c", tile.data);
            }
        }
    }
    
    public void GetGridPos(Vector2 position, out int x, out int y)
    {
        int GetCoord(float f) =>
            Mathf.Clamp(Mathf.FloorToInt(f / CellSize), 0, CellSize -1);

        x = GetCoord(position.x);
        y = GetCoord(position.y);
    }

    private void Clear()
    {
        _tiles = null;

        int children = this.GetChildCount();
        GD.Print(children);
        for (int i = 0; i < children; i++)
        {
            var child = this.GetChild(i);
            child.QueueFree();
        }
    }

    private void GenerateGrid(int size)
    {
        this.Clear();
        
        _tiles = new Tile[size, size];

        for (int x = 0; x < size; x++)
        {
            for (int y = 0; y < size; y++)
            {
                var tile = new Tile();
                tile.data = (float)(y * size + x) / 100f;
                
                var node = TileScene.Instance<Node2D>();
                this.AddChild(node);
                var position = new Vector2
                {
                    x = (x + .5f) * CellSize,
                    y = (y + .5f) * CellSize
                };
                node.Position = position;
                var canvasItem = (CanvasItem)node;
                tile.material = (ShaderMaterial)canvasItem.Material;
                
                _tiles[x, y] = tile;
            }
        }
    }
}