#import operating system and the date
import os
from datetime import date

def main():
    check_files()
    loginMenu()

def check_files():
#check to see if the files exists.
    for i in ["stock","users","orders","customers"]:
#If it does'nt, create the missing file(s)
        if not os.path.isfile(i+".txt"):
#Let the user know that the files are being created
            print ("Creating the " + i + " file...")
            stockID = open(i+".txt", 'w')
#Let the user know that the file(s) have been created
            print(i + "file created!")

def loginMenu():
#Show the user a home screen
    print("""
##########################################################################
#                                                                        #
#                   Guild of the Ceramic Arts                            #
#                       Login Menu Below!                                #
#                                                                        #
##########################################################################

""")
#Run the verifyUser function
    verifyUser()

def verifyUser():
#Assign independant variables
    verifyUsername,verifyPassword = "",""
#Allow the user to enter their username and password
    username = str(input("\nPlease enter your username: \n"))
    password = str(input("\nPlease enter your password: \n"))

    while True:
        readUsers = open("users.txt","r")
#Read the files to verify user authentication
        lines = readUsers.readlines()
#Tell the user if the file is empty
        if len(lines) == 0:
            print("There are no Users in the file for you to search!\n")
#Sart the function newUser as there are no existing users
            newUser()
            continue
        verifyCounter = 0
        i = 0
#If there are users created, verify if the username and password match
        while i < len(lines):
            location = lines[i]

            verifyUsername = location [0:10]
            verifyUsername = verifyUsername.strip()
            verifyUsername = verifyUsername.lower()
            username = username.lower()

            verifyPassword = location[10:20]
            verifyPassword = verifyPassword.strip()
            verifyPassword = verifyPassword.lower()
            password = password.lower()

            if location == "":
                readUsers.close()
                break
#Allow the user to continue
            if verifyUsername == username and verifyPassword == password:
                verifyCounter = verifyCounter + 1
                mainMenu()
                break
            i += 1
#If the credentials are incorrect, allow the user to re-enter their username and password
        if verifyCounter ==0:
            print("\nThere is no user in the Users file with those login details.\n")
            loginMenu()
        else:
            break

def mainMenu():
    while True:
#Print a menu for the user
        print("""
##########################################################################
#                                                                        #
#                          Guild of Ceramic Arts                         #
#                                Main Menu                               #
#                                                                        #
#  What would you like to do?                                            #
#                                                                        #
#  1 - Add new User                                                      #
#  2 - Add new customer                                                  #
#  3 - Add new product                                                   #
#  4 - Delete product                                                    #
#  5 - Add new order                                                     #
#  6 - Review an Invoice
#  7 - Review an unpayed order
#                                                                        #
#  7 - Logout                                                            #
#  8 - Exit                                                              #
#                                                                        #
##########################################################################
""")
#Allow the user to choose an option
        mainMenu=input("What would like to do? Option '1', '2', '3', '4', '5' , '6' or '7'? ")
        if mainMenu =="1":
            newUser()
            break
        elif mainMenu =="2":
            newCustomer()
            break
        elif mainMenu =="3":
            newProduct()
            break
        elif mainMenu =="4":
            removeProduct()
            break
        elif mainMenu =="5":
            newOrder()
            break
        elif mainMenu =="6":
            printOrderInvoice()
            break
        elif mainMenu =="7":
            quit()
        elif mainMenu =="8":
#If the user enters an invalid option, tell the
        else:
            print("\nThat is not a valid entry, you must select '1', '2', '3', '4', '5' , '6' or '7'")



def newUser():
#Assign independant variables
    userName, password1, password2 = "", "", ""
    while True:
#Allow the user to enter a new username
        userName=input("\nInsert a Username for the new user (input '-1' to cancel and exit): ")
#Allow the user to leave the newUser function if they wish to
        if userName =="-1":
            mainMenu()
#Make sure the username is not over 10 characters long
        if len(userName)>10:
            print("\nUsername has to be between 1 and 10 characters!")
#Make sure the username only uses letters
        elif userName.isalpha()==False:
            print("\nYou need to use letters only!")
        else:
            break
    while True:
        password1=input("\nInput a password for the user (input '-1' to cancel and exit): ")
#Allow the user to leave the newUser function if they wish to
        if password1 =="-1":
            mainMenu()
#Make sure the password is not over 10 characters long
        if len(password1)>10:
            print("\nPassword has to be between 1 and 10 charcters!")
#Allow the user to re-enter their password
        password2=input("\nInput the password again (input '-1' to cancel and exit): ")
#Allow the user to leave the newUser function if they wish to
        if password2 =="-1":
            mainMenu()
#Make sure the second entry of the password is not over 10 characters long
        if len(password2)>10:
            print("\nPassword has to be between 1 and 10 charcters!")
#Ensure that both passwords match before creating a user
        if password1 != password2:
            print("\nThe passwords did not match!")
        else:
            break
#Change the username and password into lower case characters if possible
    userName=userName.lower()
    password1=password1.lower()
#Ensure that the username and password take up exactly ten spaces
    userNameStore=userName.ljust(10)
    password1Store=password1.ljust(10)
#Write the user credentials in the users text file
    store=open("users.txt","a")
    iStore=userNameStore+password1Store+"\n"
    store.write(iStore)

    store.close()
#Let the user know that a new user has been
    print("\n" + userName + " has been created!")
    print("Username  :",userName)
    print("Password  : ********** ")

    mainMenu()

def newOrder():

    while True:
#Allow the user to insert a customer ID
        customerID = input("Please enter your customer ID: ")
        with open('customers.txt') as f:
#Verify if the user exists
            if customerID in f.read():
#Let the user know if the ID is valid or not
                print("\nThe customer ID is valid")
                break
            else:
                print("\nThat Customer ID does not exist. Please try again")
#Ask the user to input their order ID
    while True:
        orderID = input("Please enter a unique ID for your order (5 numbers): ")
        if orderID.isdigit()==False:
            print("\nYou can only use numbers for your unique ID")
        elif len(orderID) != 5:
                print("\nYou must use exactly 5 digits")
#Create a unique order ID for the customer
        else:
            print("Your unique ID is OR" + orderID)
            break
#Asks the user to input what product the customer would like to buy and ensures there are no errors
    while True:
        item_name = input("\nPlease type the name of the item the customer would like to purchase: ")
        with open('stock.txt') as f:
            if item_name in f.read():
#Tells the reader that the item has been added
                print("\nItem Added")
                break
#Lets the user know that they've spelt the item incorrectly
            elif item_name not in f.read():
                print("\nItem does not exist. Make sure it is spelt correctly!")

    while True:
#calculates the price of a single item
        readStock = open('stock.txt','r')
        location = readStock.readline()
        price = location[33:50]
        price = float(price)
#Allows the user to add more than one of the same item
        quantity = int(input("\nHow many of the singular product would the customer like to purchase?:  "))
        if quantity >100:
            print("\nThe customer cannot buy more than 100 items")
            break
        elif quantity <1:
            ("\nThe customer must buy a minimum of 1 item!")
#Calculates the final price
        finalPrice = (price*quantity)
        break
#If the price is over £50, adds a 5% discount
        if finalPrice >= 50:
            finalPrice *= 0.95
            readStock.close()
            break

#Ensures the order ID, final price, the date, whether it's been payed or not and the quantity are all ready to be stored in the orders file
    orderID = ("OR")+ orderID
    orderID=orderID.strip()
    orderID=orderID.lower()
    orderIDStore=orderID.ljust(13)
    customerID=customerID.strip()
    customerID=customerID.lower()
    customerIDStore=customerID.ljust(13)
    finalPrice=str(finalPrice)
    finalPrice=finalPrice.ljust(7)
    today = date.today()
    today = str(today)
    today = today.ljust(15)
    quantity = str(quantity)
    quantityStore = quantity.ljust(5)
    paid = " 0 "
#Stores the above into the orders file
    order_file = open('orders.txt', 'a')
    stock_file = open('stock.txt', 'r')
    for line in stock_file:
        if item_name in line:
            line = line.ljust(12)
            order_store = finalPrice + today + customerIDStore + quantityStore + orderIDStore + paid + line
            order_file.write(order_store + "\n")
#Shows the user that the chosen items hae been succesfully added
            print("\nThe chosen item(s) have been added to the order")
            order_file.close()
            stock_file.close()
            mainMenu()

def unpaidOrders():#checks if an order has been payed or not
    while True:
            order_ID = input("Please enter your order ID\n ")
            with open('orders.txt') as f: #opens the file
                if order_ID in f.read(): #if the orderID is in the file:
                    print("Thank you")
                    break

    today = datetime.datetime.now() #detecting Current Date

    with open('orders.txt') as orders:
        expired = []
        dates = [[datetime.datetime.strptime(i[36:62].strip(), '%Y-%m-%d %H:%M:%S.%f'),i[12:24]] for i in orders.readlines()]
        for i in dates: #check and print expired invoices
            if today > i[0] + datetime.timedelta(28): #checks if the date is later than the date saved in the file
                expired.append(i)
        if len (expired) >0:
            print("Late orders:\n" + "\n".join([("Order ID: " + i[1] + " Date: " + i[0]) for i in[[str(i[0]),i[1]] for i in expired]]))#prints the order which is late and the date of  the order
        else:
            print("There are currently no late orders")

    mainMenu()

def payOrder():
    while True:
        order_ID = input("Please enter your order ID\n ")
        with open('orders.txt') as f: #opens the file
            if order_ID in f.read(): #Checks if the order is in the file
                print("Thank you")
                break
    while True:
        pay_file = open("paid.txt","a")
        orders_file = open('orders.txt', 'r')
        for line in orders_file:
            if order_ID in line:
                line = line.ljust(12) #gives room at the end of the line
                pay_file.write(line + "\n") #writes the line into the paid flie
        break

    while True:
        with open("orders.txt","r") as f:
            f.seek(0)
            total = 0
            for line in f:
                if order_ID in line:
                    total_price = line[24:36]
                    total += float(total_price)

        if total>50:
            total = float(total-(total*0.05))
            total = str(total)
            print("\nYour order total is:     ",total + " (Including 5% discount)")
            break
        else:
            print("\nYour order total is:     ",total)
            break

def newCustomer():
    customerID,customerForeName,customerLastName,customerTown,customerHouseNumber,customerPostcode,customerPhoneNumberNumber ="","","","","","",""
    while True:
#Allows the user to input and save the customers forename, surname, town, building number, postcode and phone number
        customerForeName=input("\nInput the Customers Forename: ")
        if len(customerForeName)>20:
            print("\nThe Customers Forename must be between 1 and 20 characters")
        elif customerForeName.isalpha()==False:
            print("\nYou can only use letters for the customers Forename.")
        else:
            break
    while True:
        customerLastName=input("\nInput the customers Surname: ")
        if len(customerLastName)>20:
            print("\nCustomer Surname has to be between 1 and 20 characters")
        elif customerLastName.isalpha()==False:
            print("\nYou must only use letters for the customers Surname")
        else:
            break
    while True:
        customerTown=input("\nInput the customers Town: ")
        if len(customerTown)>20:
            print("\nThe Customers Town name must be between 1 and 20 characters")
        else:
            break
    while True:
        customerHouseNumber=input("\nInput the Customers Building Number: ")
        if len(customerHouseNumber)>5:
            print("\nThe Customers Building Number must be less than 5 characters")
        else:
            break
    while True:
        customerPostcode=input("\nInput the Customers Postcode: ")
        if len(customerPostcode)>8:
            print("\nThe customers Postcode must be less than 8 characters")
        else:
            break
    while True:
        customerPhoneNumber=input("\nInput the customers Phone Number: ")
        if len(customerPhoneNumber)>11:
            print("\nThe Customer Phone Number must be less than 11 numbers")
        elif customerPhoneNumber.isdigit()!=True:
            print("\nYou can only use numbers for the customers Phone Number")
        else:
            break
#Stores the above in the customers file
    customerHouseNumber=customerHouseNumber.strip()
    customerPostcode=customerPostcode.replace(" ", "")
    customerID=(customerHouseNumber)+(customerPostcode)
    customerID=customerID.strip()
    customerID=customerID.lower()
    customerIDStore=customerID.ljust(12)
    customerForeNameStore=customerForeName.ljust(20)
    customerLastNameStore=customerLastName.ljust(20)
    customerTownStore=customerTown.ljust(20)
    customerHouseNumberStore=customerHouseNumber.ljust(5)
    customerPostcodeStore=customerPostcode.ljust(8)
    customerPhoneNumberStore=customerPhoneNumber.ljust(11)
    store=open("customers.txt","a")
    iStore=customerIDStore+customerForeNameStore+customerLastNameStore+customerTownStore+customerHouseNumberStore+customerPostcodeStore+customerPhoneNumberStore+"\n"
    store.write(iStore)
    store.close()
#Lets the user know that the customer has been stored succesfully
    print("\nA new customer has been succesfully created!")
    print("Customer ID:             ",customerIDStore)
    print("Customer Forename:       ",customerForeNameStore)
    print("Customer Surname:        ",customerLastNameStore)
    print("Customer Town:           ",customerTownStore)
    print("Customer House Number:   ",customerHouseNumberStore)
    print("Customer Posecode:       ",customerPostcodeStore)
    print("Customer Phone Number:   ",customerPhoneNumberStore)
    mainMenu()

def newProduct():
    productID,productPrice,productName = "","",""

#Allows the user to create a product name and a product ID
    while True:
        productName = input("\nInput the product name you would like to add: ")
        productName.strip()
        productName.lower()
        if len(productName)>25:
            print("\nProduct name must be between 1 and 25 characters! Try Again! ")
        else:
            break
    while True:
        productID = input("\nInput the product ID of the product you want to add (5 Numbers): ")
        productID.strip()
        if len(productID)>5:
            print("\nThe product ID, '"+str(productID)+"' exceeds the allowed amount of digits")
        elif productID.isdigit()!=True:
            print("\nYou can only use numbers for the product ID!")
        else:
            break


    productPrice=float(input("\nInput the price of the your product(numbers only!): "))
    productPrice=str(productPrice)
    productID = "PT"+productID
    productID.strip()
    productID.lower()
    productIDStore = productID.ljust(8)
    productName.strip()
    productName.lower()
    productNameStore = productName.ljust(25)
#Stores the new product in the stock file
    store= open("stock.txt","a")
    istore= productNameStore + productIDStore + productPrice+ "\n"
    store.write(istore)

    store.close()
#tells the user that the new product has been added and repeats the details
    print("\nFinished adding the new product")
    print("Product ID:             ",productIDStore)
    print("Product Name:       ",productNameStore)
    print("Product Price:        ",productPrice)
    mainMenu()

def removeProduct():
#Asks the user what product they would like to delete, locates the product and deletes it
    product = input("What product would you like to delete (Insert Name)? ")
    f = open("stock.txt","r+")
    r = open("stock.txt","w")
    deleted = 0
    for line in f:
        stock = line [0:25]
        stock = stock.lower()
        stock = stock.strip()
        if product == stock:
            deleted = deleted + 1
            line = ""
        r.write(line+'\n')
    f.close()
    r.close()
    if deleted == 1:
        print("\nProduct name '"+str(product)+"' has been deleted!")
    tidyUpProduct()

def printOrderInvoice():
#Allows the user to chose what order they would like to view
    while True:
        orderID = input("Please enter the orderID of the invoice you wish to view\n")
        with open('orders.txt') as f:
            if orderID in f.read():
                print("Thank you")
                break
            else:
                print("The orderID entered was invalid")
                printOrderInvoice()
#Locates the order and prints all the details based on line location
    with open("orders.txt","r+") as f:
        f.seek(0)
        for line in f:
            if orderID in line:
                finalPrice = line[0:7]
                date = line[7:22]
                customerID = line[22:35]
                quantity = line[35:40]
                orderID = line[40:53]
                paid = line[53:55]
                orderName = line[55:80]
                productID = line[80:88]
#shows the user the invoice that has been chosen
                print("\n#########################################")
                print("#  Invoice for Order ID: " +orderID+("  #"))
                print("#  Date of order: " +date+("       #"))
                print("#  Customer ID: " +customerID+("           #"))
                print("#  Product quantity: "+quantity+("              #"))
                print("#  Paid or unpaid? (1:0): "+paid+("            #"))
                print("#  Order Name: "+orderName+("#"))
                print("#  Product ID: "+productID+("                 #"))
                print("#########################################")
                mainMenu()

def payOrder():
    while True:
        order_ID = input("Please enter your order ID\n ")
        with open('orders.txt') as f: #opens the file
            if order_ID in f.read(): #if the order ID is in the text file:
                print("Thank you")
                break
    while True:
        pay_file = open("paid.txt","a") #opens the paid file in append mode
        orders_file = open('orders.txt', 'r') #opens the orders file in read mode
        for line in orders_file: #for each line in the orders file:
            if order_ID in line: #if the order ID is in the line:
                line = line.ljust(12) #gives room at the end of the line
                pay_file.write(line + "\n") #writes the line into the paid flie
        break
    while True:
        with open("orders.txt","r") as f:
            f.seek(0)
            total = 0
            for line in f:
                if order_ID in line:
                    total_price = line[24:36]
                    total += float(total_price)
        if total>50:
            total = float(total-(total*0.05))
            total = str(total)
            print("\nYour order total is:     ",total + " (Including 5% discount)")
            break
        else:
            print("\nYour order total is:     ",total)
            break

main()