#!/usr/bin/env python
import tkinter as tk
from tkinter.filedialog import askopenfilename, asksaveasfilename

class BtnFrame(tk.Frame):
    def __init__(self, master, *args, **kwargs):
        super().__init__(master, *args, **kwargs)
        self.btn_open = tk.Button(self, text="Open", command=master.open_file)
        self.btn_save = tk.Button(self, text="Save As...", command=master.save_file)
        self.btn_open.grid(row=0, column=0, sticky="ew", padx=5, pady=5)
        self.btn_save.grid(row=1, column=0, sticky="ew", padx=5)

class MainWin(tk.Tk):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.title("Simple Text Editor")
        self.rowconfigure(0, minsize=800, weight=1)
        self.columnconfigure(1, minsize=800, weight=1)
      
        self.txt_edit = tk.Text(self)
        self.frm_buttons = BtnFrame(self)
        self.frm_buttons.grid(row=0, column=0, sticky="ns")
        self.txt_edit.grid(row=0, column=1, sticky="nsew")

    def open_file(self):
        """Open a file for editing."""
        filepath = askopenfilename(
            filetypes=[("Text Files", "*.txt"), ("All Files", "*.*")]
        )
        if not filepath:
            return
        self.txt_edit.delete("1.0", tk.END)
        with open(filepath, mode="r", encoding="utf-8") as input_file:
            text = input_file.read()
            self.txt_edit.insert(tk.END, text)
        self.title(f"Simple Text Editor - {filepath}")
    
    def save_file(self):
        """Save the current file as a new file."""
        filepath = asksaveasfilename(
            defaultextension=".txt",
            filetypes=[("Text Files", "*.txt"), ("All Files", "*.*")],
        )
        if not filepath:
            return
        with open(filepath, mode="w", encoding="utf-8") as output_file:
            text = self.txt_edit.get("1.0", tk.END)
            output_file.write(text)
        self.title(f"Simple Text Editor - {filepath}")


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