#!python
"""
Simple Image Viewer on PySimpleGUI
"""
import PySimpleGUI as sg
from PIL import Image, ImageTk
import io
import sys
# import os

img_types = (".png", ".jpg", "jpeg", ".tiff", ".bmp")

status_text = ''
fname = None
if not len(sys.argv) == 1:
    fname = sys.argv[1]

if fname:
    if not fname.lower().endswith(img_types):
        sg.popup("Cancel", fname + " is Not image file")
        raise SystemExit("Canceling: Not image file")


def get_img_data(f, maxsize=(1200, 850), first=False):
    """Generate image data using PIL."""
    global status_text
    im = Image.open(f)
    status_text = "%d x %d" % im.size  # original image size
    im.thumbnail(maxsize)
    status_text += " (%d x %d)" % im.size  # thumbnail image size
    if first:
        bio = io.BytesIO()
        im.save(bio, format="PNG")
        del im
        return bio.getvalue()
    return ImageTk.PhotoImage(im)


# layout
firstfg = True
if fname:
    image_elem = sg.Image(data=get_img_data(fname, first=firstfg))
    fname_elem = sg.InputText(size=(80, 1), enable_events=True,
                              default_text=fname)
    firstfg = False
else:
    image_elem = sg.Image()
    fname_elem = sg.InputText(size=(80, 1), enable_events=True)
status_elem = sg.Text(key='-STATUS-', size=(64, 1))

layout = [
    [fname_elem, sg.FileBrowse(key='-FILENAME-')],
    [status_elem],
    [image_elem]
]

# create window
window = sg.Window('Image Viewer', layout, return_keyboard_events=True,
                   location=(0, 0), use_default_focus=False)

# event loop
while True:
    event, values = window.read()
    if event in (None, 'Exit'):
        break

    if values['-FILENAME-'] != '':
        # filename select
        fname = values['-FILENAME-']
        if fname.lower().endswith(img_types):
            # load image
            image_elem.update(data=get_img_data(fname, first=firstfg))
            fname_elem.update(fname)
            status_elem.update(status_text)
            firstfg = False

window.close()