#!/usr/bin/env python
import PySimpleGUI as sg
import os

'''
    Simple Image Browser 
    
    This is an early demo program, so perhaps not quite as sophisticated as later ones.
    
    Copyright 2021-2023 PySimpleSoft, Inc. and/or its licensors. All rights reserved.
    
    Redistribution, modification, or any other use of PySimpleGUI or any portion thereof is subject to the terms of the PySimpleGUI License Agreement available at https://eula.pysimplegui.com.
    
    You may not redistribute, modify or otherwise use PySimpleGUI or its contents except pursuant to the PySimpleGUI License Agreement.
'''


def main():

    # Get the folder containing the images from the user
    folder = sg.popup_get_folder('Image folder to open')
    if folder is None:
        sg.popup_cancel('Cancelling')
        return

    # get list of PNG files in folder
    png_files = [os.path.join(folder, f) for f in os.listdir(folder) if f.lower().endswith('.png')]
    filenames_only = [f for f in os.listdir(folder) if f.lower().endswith('.png')]

    if len(png_files) == 0:
        sg.popup('No PNG images in folder')
        return

    # define menu layout
    menu = [['File', ['Open Folder', 'Exit']], ['Help', ['About', ]]]

    # define layout, show and read the window
    col = [[sg.Text(png_files[0], size=(80, 3), key='-FILENAME-')],
           [sg.Image(filename=png_files[0], key='-IMAGE-', expand_x=True, expand_y=True)],
           [sg.Button('Next', size=(8, 2)), sg.Button('Prev', size=(8, 2)),
               sg.Text('File 1 of {}'.format(len(png_files)), size=(15, 1), key='-FILENUM-')]]

    col_files = [[sg.Listbox(values=filenames_only, size=(60, 30), key='-LISTBOX-', enable_events=True)],
                 [sg.Text('Select a file.  Use scrollwheel or arrow keys on keyboard to scroll through files one by one.')]]

    layout = [[sg.Menu(menu)], [sg.Col(col_files), sg.Col(col, expand_x=True, expand_y=True)]]

    window = sg.Window('Image Browser', layout, return_keyboard_events=True, use_default_focus=False)

    # loop reading the user input and displaying image, filename
    filenum, filename = 0, png_files[0]
    while True:

        event, values = window.read()
        # --------------------- Button & Keyboard ---------------------
        if event == sg.WIN_CLOSED:
            break
        elif event in ('Next', 'MouseWheel:Down', 'Down:40', 'Next:34') and filenum < len(png_files)-1:
            filenum += 1
            filename = os.path.join(folder, filenames_only[filenum])
            window['-LISTBOX-'].update(set_to_index=filenum, scroll_to_index=filenum)
        elif event in ('Prev', 'MouseWheel:Up', 'Up:38', 'Prior:33') and filenum > 0:
            filenum -= 1
            filename = os.path.join(folder, filenames_only[filenum])
            window['-LISTBOX-'].update(set_to_index=filenum, scroll_to_index=filenum)
        elif event == 'Exit':
            break
        elif event == '-LISTBOX-':
            filename = os.path.join(folder, values['-LISTBOX-'][0])
            filenum = png_files.index(filename)
        # ----------------- Menu choices -----------------
        if event == 'Open Folder':
            newfolder = sg.popup_get_folder('New folder', no_window=True)
            if newfolder is None:
                continue

            folder = newfolder
            png_files = [os.path.join(folder, f) for f in os.listdir(folder) if f.lower().endswith('.png')]
            filenames_only = [f for f in os.listdir(folder) if f.lower().endswith('.png')]

            window['-LISTBOX-'].update(values=filenames_only)
            window.refresh()

            filenum = 0
        elif event == 'About':
            sg.popup('Demo PNG Viewer Program',
                     'Please give PySimpleGUI a try!')

        # update window with new image
        window['-IMAGE-'].update(filename=filename)
        # update window with filename
        window['-FILENAME-'].update(filename)
        # update page display
        window['-FILENUM-'].update('File {} of {}'.format(filenum + 1, len(png_files)))

    window.close()

if __name__ == '__main__':
    main()