public struct Cell {
    public readonly int X;
    public readonly int Y;
    public readonly char Symbol;
    public readonly ConsoleColor ColorBG;
    public readonly ConsoleColor ColorFG;

    public Cell(
        Int32 x,
        Int32 y,
        Char c = ' ',
        ConsoleColor bg = ConsoleColor.Black,
        ConsoleColor fg = ConsoleColor.White) {
        X = x;
        Y = y;
        Symbol = c;
        ColorBG = bg;
        ColorFG = fg;
    }

    public override Boolean Equals([NotNullWhen(true)] Object? obj) {
        if(obj is not Cell other)
            return false;

        return
            X == other.X
            && Y == other.Y
            && Symbol == other.Symbol
            && ColorBG == other.ColorBG
            && ColorFG == other.ColorFG;
    }
}

public class FrameBuffer {
    private Cell[,] _buffer;
    private uint _width;
    private uint _height;

    public FrameBuffer(uint width, uint height) {
        _width = width;
        _height = height;
        _buffer = new Cell[_height, _width];
    }

    public uint Width => _width;
    public uint Height => _height;

    public Cell this[int x, int y] => GetCell(x, y);
    public ref Cell GetCell(int x, int y) => ref _buffer[y, x];
    public void SetCell(Cell c) => _buffer[c.Y, c.X] = c;
    public void ClearAll() => Array.Clear(_buffer);

    public override String ToString() {
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i < _height; i++) {
            for(int j = 0; j < _width; j++) {
                sb.Append(GetCell(j, i).Symbol);
            }
            sb.AppendLine();
        }
        return sb.ToString();
    }

    public void CopyTo(FrameBuffer other) {
        Array.Copy(_buffer, other._buffer, _buffer.Length);
    }
}

public class Renderer {
    FrameBuffer _current;
    FrameBuffer _next;
    FrameBuffer _previous;

    public Renderer(uint width, uint heigth) {
        _current = new(width, heigth);
        _next = new(width, heigth);
        _previous = new(width, heigth);
        Console.CursorVisible = false;
        Console.OutputEncoding = System.Text.Encoding.UTF8;
    }

    public void BeginDraw() => _next.ClearAll();

    public void EndDraw() {
        (_next, _current) = (_current, _next);
        Render();
        _current.CopyTo(_previous);
    }

    public FrameBuffer DrawBuffer => _next;

    private void Render() {
        for(int i = 0; i < _current.Width; i++) {
            for(int j = 0; j < _current.Height; j++) {

                ref Cell current = ref _current.GetCell(i, j);
                ref Cell previous = ref _previous.GetCell(i, j);

                if(!current.Equals(previous)) {
                    Console.SetCursorPosition(previous.X, previous.Y);
                    Console.BackgroundColor = ConsoleColor.Black;
                    Console.ForegroundColor = ConsoleColor.Black;
                    Console.Write(' ');
                    Console.SetCursorPosition(current.X, current.Y);
                    Console.BackgroundColor = current.ColorBG;
                    Console.ForegroundColor = current.ColorFG;
                    Console.Write(current.Symbol);
                }
            }
            Console.ResetColor();
        }
    }
}