#!/usr/bin/env python
import tkinter as tk
import tkinter.filedialog
import tkinter.messagebox
from io import BytesIO
from pathlib import Path
from pprint import pprint
from functools import partial

from Crypto.Cipher import AES
from PIL import (
    ImageTk,
    Image
)

import config as cfg


class MainWin(tk.Tk):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.title('Mein Titel ;-)')
        self.menubar = tk.Menu(self)
        self.config(menu=self.menubar)
        self.filemenu = tk.Menu(self.menubar, tearoff=False)
        self.menubar.add_cascade(label='File', menu=self.filemenu)
        self.filemenu.add_command(label='Open Plain', command=self.open_plain)
        self.filemenu.add_command(label='Save Plain', command=self.save_plain)
        self.filemenu.add_command(label='Open Crypt', command=self.open_crypt)
        self.filemenu.add_command(label='Save Crypt', command=self.save_crypt)
        self.filemenu.add_command(label='Exit', command=self.destroy)
        self.filename = tk.Label(self, relief=tk.SUNKEN)
        self.filename.pack(side=tk.TOP, fill=tk.X)
        self.canvas = tk.Canvas(self)
        self.canvas.pack(side=tk.TOP, fill=tk.BOTH, expand=True)
        self.image = None
        self.filepath = None
        tk.messagebox.showwarning(
            title='Achtung!',
            message='Dieses Programm benutzt eine unsichere Verschlüsselung!\n'
            'Ein besserer Nonce ist notwendig!'
        )

    def on_resize(self, *args, **kwargs):
        self.display_file()

    def open_plain(self, *args, **kwargs):
        self.filepath = Path(tk.filedialog.askopenfilename(master=self, title='Verzeichnis?', initialdir=cfg.DIR_PLAIN))
        if self.filepath:
            with open(self.filepath, 'rb') as ifh: data = BytesIO(ifh.read())
            self.image = Image.open(data)
            self.display_file()

    def save_plain(self, *args, **kwargs):
        newfilepath = Path(tk.filedialog.asksaveasfilename(master=self, title='Verzeichnis?', initialdir=cfg.DIR_PLAIN))
        if self.filepath:
            self.image.save(newfilepath)

    def save_crypt(self, *args, **kwargs):
        newfilepath = Path(tk.filedialog.asksaveasfilename(master=self, title='Verzeichnis?', initialdir=cfg.DIR_CRYPT))
        if self.filepath:
            buf = BytesIO()
            self.image.save(buf, format=self.image.format)
            ### for a real application, use a better nonce
            cipher = AES.new(
                cfg.CRYPT_KEY.encode(),
                AES.MODE_EAX,
                nonce=cfg.CRYPT_KEY.encode()  # HERE BE DRAGONS!
            )
            encrypted = cipher.decrypt(buf.getvalue())
            newfilepath.write_bytes(encrypted)

    def open_crypt(self, *args, **kwargs):
        self.filepath = Path(tk.filedialog.askopenfilename(master=self, title='Verzeichnis?', initialdir=cfg.DIR_CRYPT))
        if self.filepath:
            with open(self.filepath, 'rb') as ifh:
                data = BytesIO(ifh.read())
            ### for a real application, use a better nonce
            cipher = AES.new(
                cfg.CRYPT_KEY.encode(),
                AES.MODE_EAX,
                nonce=cfg.CRYPT_KEY.encode()  # HERE BE DRAGONS!
            )
            decrypted = cipher.decrypt(data.read())
            data = BytesIO(decrypted)
            try:
                self.image = Image.open(data)
            except:
                Path('1.img').write_bytes(decrypted)    
            self.display_file()

    def display_file(self):
        self.canvas.update()
        width = self.canvas.winfo_width()
        height = self.canvas.winfo_height()
        image = self.image.copy()
        image.thumbnail((width, height), Image.Resampling.LANCZOS)
        img = ImageTk.PhotoImage(image=image)
        self.canvas.create_image(1, 1, anchor=tk.NW, image=img)
        self.canvas.image = img
        self.filename.config(text=str(self.filepath.name))

        
if __name__ == '__main__':
    MainWin().mainloop()