KBW

import tkinter as tk
from tkinter import messagebox


btnCRUDROW = 1
ACCOUNTROW = 2
PASSWORDROW = 3
btnLOGINROW = 4

user_Info = {'admin':'pass01', 'manage':'pass02'}


def open_main_window(old_page):
    # btn pixel
    X_PIXEL01 = 0
    X_PIXEL02 = 80
    X_PIXEL03 = 160
    Y_PIXEL01 = 20
    Y_PIXEL02 = 50
    Y_PIXEL03 = 80
    global G_user_name

    old_page.destroy()
    win_main = tk.Tk()
    win_main.title("main page")
    win_main.geometry('300x200')
    label_Lusername = tk.Label(win_main, text="User Name:").place(x=0,y=0)
    label_username = tk.Label(win_main,text=G_user_name).place(x=80, y=0)
    btn_open_page01 = tk.Button(win_main, text='products', command= lambda:open_page01_window(win_main)).place(x=X_PIXEL01,y=Y_PIXEL01)
    btn_open_page02 = tk.Button(win_main, text='page02', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL02,y=Y_PIXEL01)
    btn_open_page03 = tk.Button(win_main, text='page03', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL03,y=Y_PIXEL01)
    btn_open_page04 = tk.Button(win_main, text='page04', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL01,y=Y_PIXEL02)
    btn_open_page05 = tk.Button(win_main, text='page05', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL02,y=Y_PIXEL02)
    btn_open_page06 = tk.Button(win_main, text='page06', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL03,y=Y_PIXEL02)
    btn_open_page07 = tk.Button(win_main, text='page07', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL01,y=Y_PIXEL03)
    btn_open_page08 = tk.Button(win_main, text='page08', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL02,y=Y_PIXEL03)
    btn_open_page09 = tk.Button(win_main, text='page09', command=lambda: open_page01_window(win_main)).place(x=X_PIXEL03,y=Y_PIXEL03)

def open_page01_window(old_page):
    LABEL_YPIXEL = 20
    NAME_XPIXEL = 0
    STOCK_XPIXEL = 80
    PRICE_XPIXEL = 160
    PURCHASE_XPIXEL = 240
    EFFECT_XPIXEL = 350
    ORIGIN_XPIXEL = 430
    RETURNS_XPIXEL = 500
    old_page.destroy()
    win_products = tk.Tk()
    win_products.title("page01")
    win_products.geometry('600x400')

    label_Lusername = tk.Label(win_products, text="User Name:").place(x=0, y=0)
    label_username = tk.Label(win_products, text=G_user_name).place(x=80, y=0)
    label_Lname = tk.Label(win_products, text="Name").place(x=NAME_XPIXEL, y=LABEL_YPIXEL)
    label_Lstock = tk.Label(win_products, text="Stock").place(x=STOCK_XPIXEL, y=LABEL_YPIXEL)
    label_Lprice = tk.Label(win_products, text="Price").place(x=PRICE_XPIXEL, y=LABEL_YPIXEL)
    label_Lpurchase = tk.Label(win_products, text="Purchase").place(x=PURCHASE_XPIXEL, y=LABEL_YPIXEL)
    label_Leffectivedate = tk.Label(win_products, text="Date").place(x=EFFECT_XPIXEL, y=LABEL_YPIXEL)
    label_Lorigin = tk.Label(win_products, text="Origin").place(x=ORIGIN_XPIXEL, y=LABEL_YPIXEL)
    label_Lreturns = tk.Label(win_products, text="Returns").place(x=RETURNS_XPIXEL, y=LABEL_YPIXEL)
    btn_open_main = tk.Button(win_products, text='return', command=lambda:open_main_window(win_products)).pack(side="bottom")


def usr_login():
    global var_account
    global var_password
    global win_login
    global G_user_name
    usr_name = var_account.get()
    usr_pwd = var_password.get()
    if usr_name in user_Info:
        if usr_pwd == user_Info[usr_name]:
            G_user_name = usr_name
            messagebox.showinfo(title='Welcome', message='How are you?' + usr_name)
            open_main_window(win_login)
        else:
            messagebox.showerror(message='Error, your password is wrong, try again.')
    else:
        messagebox.askyesno('Welcome','You have not sign up yet. Sign up today?')

def login_frame():
    global var_account
    global var_password
    global win_login
    win_login = tk.Tk()
    win_login.title("Log in")
    var_account = tk.StringVar()
    var_password = tk.StringVar()

    label=tk.Label(win_login, text="Log in!")
    label_account=tk.Label(win_login, text="account")
    label_password=tk.Label(win_login, text="password")
    entry_account=tk.Entry(win_login, textvariable=var_account)
    entry_password=tk.Entry(win_login, show='*', textvariable=var_password)
    btn_login=tk.Button(win_login, text="Log in", command=usr_login)
    label.grid(column=0,row=0)


    label_account.grid(column=0,row =ACCOUNTROW)
    entry_account.grid(column=1,row =ACCOUNTROW)
    label_password.grid(column=0,row =PASSWORDROW)
    entry_password.grid(column=1,row =PASSWORDROW)
    btn_login.grid(row = btnLOGINROW)

    win_login.mainloop()

login_frame()