from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (QApplication, QWidget,
                             QVBoxLayout, QHBoxLayout,
                             QPushButton, QLabel,
                             QListWidget, QFileDialog)
from PyQt5.QtGui import QPixmap
from functools import partial
import os
from PIL import Image, ImageOps


app = QApplication([])
window = QWidget()
window.setWindowTitle("Редактор")
window.setFixedSize(700, 400) # resize(700, 400)

lb_image = QLabel("Картинка")
btn_dir = QPushButton("Папка")
lw_files = QListWidget()

btn_left = QPushButton("Лево")
btn_right = QPushButton("Право")
btn_flip = QPushButton("Зеркало")
btn_sharp = QPushButton("Резкость")
btn_bw = QPushButton("Ч/Б")
btn_save = QPushButton("Сохранить")
btn_reset = QPushButton("Сброс")

row = QHBoxLayout()
col1 = QVBoxLayout()
col2 = QVBoxLayout()
row1_tools = QHBoxLayout()
row2_tools = QHBoxLayout()

col1.addWidget(btn_dir)
col1.addWidget(lw_files)

col2.addWidget(lb_image, stretch=95)

row1_tools.addWidget(btn_left)
row1_tools.addWidget(btn_right)
row1_tools.addWidget(btn_flip)
row1_tools.addWidget(btn_sharp)
row1_tools.addWidget(btn_bw)

row2_tools.addWidget(btn_save)
row2_tools.addWidget(btn_reset)

col2.addLayout(row1_tools)
col2.addLayout(row2_tools)

row.addLayout(col1, stretch=20)
row.addLayout(col2, stretch=80)

window.setLayout(row)

# from PIL import Image

class ImageProcessor():
    def __init__(self):
        self.image = None
        self.dir = None
        self.filename = None
        self.save_dir = "Modified/"

    def load_image(self, dir, filename):
        self.dir = dir
        self.filename = filename
        image_path = os.path.join(dir, filename) # Downloads/original.jpg
        self.image = Image.open(image_path)

    def show_image(self, path):
        lb_image.hide()
        pixmapimage = QPixmap(path)
        w, h = lb_image.width(), lb_image.height()
        pixmapimage = pixmapimage.scaled(w, h, Qt.KeepAspectRatio)
        lb_image.setPixmap(pixmapimage)
        lb_image.show()

    def do_bw(self):
        self.image = ImageOps.grayscale(self.image)
        self.save_image()
        image_path = os.path.join(self.dir, self.save_dir, self.filename)
        self.show_image(image_path)

    def save_image(self):
        path = os.path.join(self.dir, self.save_dir)
        if not (os.path.exists(path) or os.path.isdir(path)):
            os.mkdir(path)
        image_path = os.path.join(path, self.filename)
        self.image.save(image_path)


workimage = ImageProcessor()

def show_chosen_image(workdir, index):
    if index >= 0:
        filename = lw_files.currentItem().text()
        workimage.load_image(workdir, filename)
        image_path = os.path.join(workimage.dir, workimage.filename)
        workimage.show_image(image_path)

def choose_workdir():
    try:
        workdir = QFileDialog.getExistingDirectory()
        if workdir:
            return workdir
        else:
            print("Папка не выбрана")
            return None
    except:
        return None

def filter(files):
    result = []
    extension = [".png", ".jpg", ".jpeg", ".gif", ".bmp"]
    for file in files:
        for ext in extension:
            if file.endswith(ext): # endswith("original.jpg") -> .jpg -> []
                result.append(file)
    return result

def show_filenames():
    dir = choose_workdir()
    files = filter(os.listdir(dir)) # ["name.docs", "1.xlsx", "2.pptx", "original.jpg"]
    lw_files.clear()
    for file in files:
        lw_files.addItem(file)

    lw_files.currentRowChanged.connect(partial(show_chosen_image, dir))

btn_bw.clicked.connect(workimage.do_bw)
btn_dir.clicked.connect(show_filenames)

window.show()
app.exec_()