I would like to understand the process of selecting the correct tile from a scaled Surface when I have information about the number of tiles on the x and y axes, the length of the Surface, and also considering the scroll factor

Firstly, I have the following variables:

WIDTH = 640
HEIGHT = 320
TILE_SIZE = 32
MAX_COL = WIDTH // TILE_SIZE
MAX_ROW = HEIGHT // TILE_SIZE

Then, I create the base Surface with screen = pg.display.set_mode((WIDTH, HEIGHT), pg.RESIZABLE), and a dummy Surface as follows: dummy = pg.Surface([WIDTH, HEIGHT]).

Next, I create grids using some clever math and a scroll variable (which changes when I press the D button, moving everything backward):

for v in range(MAX_COL):
    # vertical / col
    pg.draw.line(dummy, (0, 0, 0), (TILE_SIZE * v - scroll_x, 0), (TILE_SIZE * v - scroll_x, HEIGHT))
    # horizontal / row
for h in range(MAX_ROW):
    pg.draw.line(dummy, (0, 0, 0), (0 - scroll_x, TILE_SIZE * h), (MAX_COL * TILE_SIZE - scroll_x, TILE_SIZE * h))

Finally, I scale it (using tw and th, calculated dimensions to maintain aspect ratio, but for now, it can be anything):

f = pg.transform.scale(s, (tw, th))
screen.blit(f, (pad_x, pad_y)) # center the window

Now, I want to choose a tile so that when I click it, it shows on which field I currently am. I achieve this by dividing my mouse X and Y coordinates from pg.mouse.get_pos() with the size of a scaled tile, and the result looks something like this:

Now I can go ahead and print this tile as a tuple – (2, 2)

But the problem comes when I move with my map and everything changes its position:

To select a tile like this, I would normally use my scroll variable and manipulate it (such as adding that information to the mouse x coordinate). However, it seems a bit tricky because when I scale everything, my scroll isn’t accurate anymore, at least not for working with a mouse. So, I am wondering if someone knows how to maintain my coordinate system while also considering my scroll factor. For example here Id like to get (2, 2) as well but thats not what I get