import PySimpleGUI as sg
from tkinterdnd2 import TkinterDnD, DND_FILES

#----------------------- tkinterdnd2 specific -------------------------------------#

def dnd_init():
    # Make a TkinterDnD dummy window and hide it
    root = TkinterDnD.Tk()
    root.attributes('-alpha', 0)
    root.withdraw()
    dnd_init.root = root

def dnd_exit():
    dnd_init.root.destroy()

def register_element_dnd(element:sg.Element):
    element.widget.drop_target_register(DND_FILES)
    element.widget.dnd_bind("<<Drop>>", on_drop)

#-------------------------PySimpleGUI code ----------------------------------------#


def on_drop(event):
    # Called when a drop event happens
    filepath = event.data.replace("{", "").replace("}", "")    # remove {}  filenames with spaces are in format "{filename with spaces}"
    window["-FILE-"].update(filepath)


dnd_init()

layout = [[sg.Text("Drag & Drop a File Here", key="-DROP-")],
          [sg.Input("", key="-FILE-")],
          [sg.Button("OK"), sg.Button("Cancel")]]

# layout = [[sg.Column(layout, p=0, k='-COL-')]]        # if want to make the entire window the target

window = sg.Window("File Drop", layout, finalize=True)

register_element_dnd(window['-FILE-'])          # register the Input element as the target
# register_element_dnd(window['-COL-'])         # register the column element that contains the entire window as the target

while True:
    event, values = window.read()
    print(event, values)
    if event in (sg.WIN_CLOSED, "Cancel"):
        break

window.close()

dnd_exit()          # being a good citizen and cleaning up the dummy window. May be able to get away with not destroying it