Borrow_gui.py

import tkinter as t
from tkinter import scrolledtext as sct
from tkinter import messagebox,DoubleVar,ttk
import ListSplit_gui as ListSplit


#these widgets and variables are declared global because they are 
#used in multiple methods
global entry1
global entry2
global combo1
global scrollt
global btn
global btn1
global book_counter

window=t.Tk()

label=t.Label(window,text="Welcome to Library!")
label.grid(row=0,sticky="w" and "s",padx=20,pady=30)

#placing this window to center as per main window
windowWidth =250 #change this values to understand how it works
windowHeight =250 
positionRight = int(window.winfo_screenwidth()/2 - windowWidth/2)
positionDown = int(window.winfo_screenheight()/2 - windowHeight/2)

#positionDown,positionRight are the posotion co-ordinates of window
window.geometry("+{}+{}".format(positionRight, positionDown))

#150x100 is size of window
window.geometry("150x100")
window.withdraw()
window.deiconify()

#every global variable must be initialized before using
book_counter=0

entry1=t.Entry()
entry2=t.Entry()

btn=t.Button()
btn1=t.Button()

combo1=ttk.Combobox()
scrollt=sct.ScrolledText()

entry1_v=DoubleVar
entry2_v=DoubleVar

#accessing book details from Listsplit_gui.py in form of a List
book_list=ListSplit.listSplit()

#b_window method generates the window used for book borrowing 
def b_window():
    global entry1
    global entry2
    global combo1
    global scrollt
    global btn
    global btn1,book_counter
    
    book_counter=0

    window=t.Tk()
    window.geometry("350x450")
    window.title("Library management system")
    window.resizable(0,1)

    l1=t.Label(window,text="First Name",width=10).grid(row=0,pady=2,padx=4)

    entry1=t.Entry(window,width=30,textvariable=entry1_v)
    entry1.grid(row=0,column=1)

    l2=t.Label(window,text="Last Name",width=10).grid(row=1,pady=2,padx=4)

    entry2=t.Entry(window,width=30,textvariable=entry2_v)
    entry2.grid(row=1,column=1)

    btn=t.Button(window,text="Validate",command=validate,width=20)
    btn.grid(row=2,columnspan=2,pady=2,padx=4)

    combo1=ttk.Combobox(window,values=ListSplit.bookname,state="readonly" and t.DISABLED,width=30)
    combo1.grid(row=3,columnspan=3,padx=4,pady=2)
    combo1.current(0)
    #bind() is used to set method invokation when user selects any book from combobox
    combo1.bind("<<ComboboxSelected>>", onBookSelect)

    scrollt=sct.ScrolledText(window,width=35,height=10)
    scrollt.grid(row=4,rowspan=4,columnspan=3,padx=20,pady=2)

    btn1=t.Button(window,text="close",command=window.destroy,width=20)
    btn1.grid(row=8,columnspan=2,pady=2,padx=4)
  
    window.mainloop()

#validate method is used to validate the borrower name and create his file 
def validate():
    global entry1
    global entry2
    global combo1
    global scrollt
    global btn

    #retriving text entered in entry
    firstName=str(entry1.get())
    lastName=str(entry2.get())

    #checking if the firstname and lastname contains only charachters and not numbers 
    if firstName.isalpha() and lastName.isalpha():

        #btn is disabled in order to prevent user from creating multiple files at the same-time
        btn['state']=t.DISABLED
        combo1['state']=t.NORMAL
        
        t.messagebox.showinfo(message="Name Verified successfully")

        #Creating a file of borrower name in order to save the borrowed bookk details
        filename="F:\python projects\LMS\Borrow-"+firstName+" "+lastName+".txt"
        with open(filename,"w+") as f:
            f.write("               Library Management System  \n")
            f.write("                   Borrowed By: "+ firstName+" "+lastName+"\n")
            f.write("S.N. \t\t Bookname \t\t      Authorname \n" )

    else:
        t.messagebox.showwarning(message="please input only alphabets from A-Z")
     
#bookselect will be invoked when user will select a book from combobox 
def onBookSelect(event):
    global entry1
    global entry2
    global combo1
    global scrollt,book_counter
 
    firstName=str(entry1.get())
    lastName=str(entry2.get())


    filename="F:\python projects\LMS\Borrow-"+firstName+" "+lastName+".txt"
    #book_counter<=3 condition is defined to 
    #prevent user from borrowing more that 4 books
    #User will not be able to borrow more than 4 books.
    if book_counter<=3: 
        try:   
            a=combo1.current()
            try:
                #ListSplit.quantity[a])>0 condition checks if book is available or not
                if(int(ListSplit.quantity[a])>0):
                    t.messagebox.showinfo(message="book borrowed")
                    book_counter+=1

                    #Displaying borrowed book in scrolledtext 
                    scrollt.insert(t.INSERT,str(book_counter)+"."+ ListSplit.bookname[a]+"-"+ListSplit.authorname[a]+"\n")

                    #writing borrowed book details to borrowers file
                    with open(filename,"a") as f:
                        f.write(str(book_counter)+". \t\t"+ ListSplit.bookname[a]+"\t\t  "+ListSplit.authorname[a]+"\n")
                        
                    #substracting 1 book from quantity after borrowing
                    ListSplit.quantity[a]=int(ListSplit.quantity[a])-1

                    #rewritting the stocks file with new book quantity
                    with open("F:\python projects\LMS\Stock.txt","w+") as f:
                        for i in range(ListSplit.count1):
                            f.write(ListSplit.bookname[i]+","+ListSplit.authorname[i]+","+str(ListSplit.quantity[i])+","+"Rs"+ListSplit.cost[i]+"\n")
                else:
                    t.messagebox.showwarning(message="book not available")
            except IndexError:
                t.messagebox.showerror(message="error occured while selecting books")
        except ValueError:
            t.messagebox.showwarning(message="Invalid book selected")
    else:
        t.messagebox.showerror(title="Overflow",message="Can not borrow more than 4 books")