#-----Imported Functions---------------------------------------------#
#
# Below are various import statements for helpful functions.  You
# should be able to complete this assignment using these
# functions only.  Note that not all of these functions are
# needed to successfully complete this assignment.
#

# The function for opening a web document given its URL.
# (You WILL need to use this function in your solution,
# either directly or via our "download" function.)
from urllib.request import urlopen

# Import the standard Tkinter functions. (You WILL need to use
# these functions in your solution.)
from tkinter import *

# Functions for finding all occurrences of a pattern
# defined via a regular expression, as well as
# the "multiline" and "dotall" flags.  (You do NOT need to
# use these functions in your solution, because the problem
# can be solved with the string "find" function, but it will
# be difficult to produce a concise and robust solution
# without using regular expressions.)
from re import findall, finditer, MULTILINE, DOTALL

# Import the standard SQLite functions (just in case they're
# needed).
from sqlite3 import *

#
#--------------------------------------------------------------------#



#-----Downloader Function--------------------------------------------#
#
# This is our function for downloading a web page's content and both
# saving it on a local file and returning its source code
# as a Unicode string. The function tries to produce
# a meaningful error message if the attempt fails.  WARNING: This
# function will silently overwrite the target file if it
# already exists!  NB: You should change the filename extension to
# "xhtml" when downloading an XML document.  (You do NOT need to use
# this function in your solution if you choose to call "urlopen"
# directly, but it is provided for your convenience.)
#
def download(url = 'http://www.wikipedia.org/',
             target_filename = 'download',
             filename_extension = 'html'):

    # Import an exception raised when a web server denies access
    # to a document
    from urllib.error import HTTPError

    # Open the web document for reading
    try:
        web_page = urlopen(url)
    except ValueError:
        raise Exception("Download error - Cannot find document at URL '" + url + "'")
    except HTTPError:
        raise Exception("Download error - Access denied to document at URL '" + url + "'")
    except:
        raise Exception("Download error - Something went wrong when trying to download " + \
                        "the document at URL '" + url + "'")

    # Read its contents as a Unicode string
    try:
        web_page_contents = web_page.read().decode('UTF-8')
    except UnicodeDecodeError:
        raise Exception("Download error - Unable to decode document at URL '" + \
                        url + "' as Unicode text")

    # Write the contents to a local text file as Unicode
    # characters (overwriting the file if it
    # already exists!)
    try:
        text_file = open(target_filename + '.' + filename_extension,
                         'w', encoding = 'UTF-8')
        text_file.write(web_page_contents)
        text_file.close()
    except:
        raise Exception("Download error - Unable to write to file '" + \
                        target_file + "'")

    # Return the downloaded document to the caller
    return web_page_contents

#
#--------------------------------------------------------------------#



#-----Student's Solution---------------------------------------------#
#
# Put your solution at the end of this file.
#

#download('https://www.amazon.com.au/gp/rss/bestsellers/books', 'amazon_books', 'html')
#download('http://www.beaversportswear.com/rss.php?type=rss', 'beaver_sportswear', 'html')

# Backend Web Functions
def currency_convert(url, expression): # In the event a currency conversion is needed for a US webpage
    source = urlopen(url) # Retrieves website that maintains updated currency conversions, specific to US to AUD
    source = source.read().decode('UTF-8')
    conversion_rate = re.findall(expression, source)
    conversion_rate = float(conversion_rate[0])
    return conversion_rate

def extract_from_page(address, webpage_name, method, expression_list):
    global sites
    if method == 'live': # Determines whether to open from downloaded source or to pull from a live webpage
        source = urlopen(address).read().decode('UTF-8')
    else:
        source = open(address).read()
    source_items = re.findall(expression_list[0], source)
    if webpage_name in source_items:
        source_items.remove(webpage_name) # Item names are marked up with <title> in the source but so is the title of the webpage -
        # this removes it from the list
    source_prices = re.findall(expression_list[1], source)
    for price in range(len(source_prices)): # Fixes a bug where certain items' prices were marked up with <span class...>
        if 'class' in source_prices[price]:
            source_prices[price] = re.findall('>(.+?)<', source_prices[price])[0]
    source_images = re.findall(expression_list[2], source)
    source_combined = []
    if len(source_items) == len(source_prices) == len(source_images): # Ensures all lists have the same amount of items
        for product in range(len(source_items)):
            source_combined.append([source_items[product], source_prices[product], source_images[product]])
        sites.append(webpage_name)
    else:
        print('The expressions of "' + webpage_name + '" have matched an unequeal amount of items in each list.')
    return source_combined

# Page Backend Retrieval
sites = [] # Put this down here so the sites list doesn't reset everytime I call 'extract_from_page(...)'
conversion_rate = currency_convert('https://www.xe.com/currencyconverter/convert/?Amount=1&From=USD&To=AUD', 'data-amount="(\d\..+?)"')
photo_equipment = extract_from_page('http://www.photoequipmentstore.com.au/rss.php?type=rss', 'Photo Equipment Store Australia: New Products', 'live',
        ['<title><\!\[CDATA\[(.+?)\]', '<isc:price><\!\[CDATA\[(.+?)\]', '<isc:image><\!\[CDATA\[(.+[jpg|png])'])
kitchen_shelf = extract_from_page('http://www.thekitchenshelf.com.au/rss.php?type=rss', 'The Kitchen Shelf: New Products', 'live',
        ['<title><\!\[CDATA\[(.+?)\]', '<isc:price><\!\[CDATA\[(.+?)\]', '<isc:image><\!\[CDATA\[(.+jpg|png)'])
amazon_books = extract_from_page('static_pages/amazon_books.html', 'Amazon.com.au: Bestsellers in Books', 'static',
        ['<title>#\d+:\s(.+?)<', '"price">(.+?)<', 'src="(https://images-fe.+?)"'])
beaver_sportswear = extract_from_page('static_pages/beaver_sportswear.html', 'Beaver Sportswear (The Beaver Dam): New Products', 'static',
        ['<title><\!\[CDATA\[(.+?)\]', '<isc:price><\!\[CDATA\[(.+?)\]', '<isc:image><\!\[CDATA\[(.+jpg|png)'])


# UI Backend Functions
def radio_1():
    global active_site
    active_site = 1
    items_box.delete(0, END)
    for item in photo_equipment:
        items_box.insert(END, item[0] + ' |  AU' + item[1])

def radio_2():
    global active_site
    active_site = 2
    items_box.delete(0, END)
    for item in kitchen_shelf:
        items_box.insert(END, item[0] + ' | AU' + item[1])

def radio_3():
    global active_site
    active_site = 3
    items_box.delete(0, END)
    for item in amazon_books:
        items_box.insert(END, item[0] + ' | AU' + item[1])

def radio_4():
    global active_site
    active_site = 4
    items_box.delete(0, END)
    for item in beaver_sportswear:
        items_box.insert(END, item[0] + ' | AU' + item[1])

def add_to_cart():
    if items_box.curselection() != ():
        if active_site == 1:
            cart.append(photo_equipment[items_box.curselection()[0]])
        elif active_site == 2:
            cart.append(kitchen_shelf[items_box.curselection()[0]])
        elif active_site == 3:
            cart.append(amazon_books[items_box.curselection()[0]])
        else:
            cart.append(beaver_sportswear[items_box.curselection()[0]])

def clear_cart():
    global cart
    cart = []

def print_to_database(cart, database_file):
    global cart_quantity
    global cart_total
    db_connection = connect(database = database_file)
    cart_db = db_connection.cursor()
    cart_db.execute("DELETE FROM ShoppingCart") # Clears Database
    for item in cart:
        try:
            # Had an issue with inserting a particular item that had an apostrophe in the name so I just remove any
            # occurences of apostrophes from item name strings to prevent SQL errors
            cart_db.execute("INSERT INTO ShoppingCart VALUES('" + item[0].replace("'", "") + "', '" + item[1][1:].replace(",", "") + "')")
        except:
            print('Error inserting data into table.')
    # Wrote some queries to replace the for loop method of calculating certain information from the cart list
    cart_db.execute("SELECT COUNT(Item) FROM ShoppingCart")
    cart_quantity = str(cart_db.fetchall()[0][0])
    cart_db.execute("SELECT SUM(Price) FROM ShoppingCart")
    cart_total = str(cart_db.fetchall()[0][0])
    db_connection.commit()
    db_connection.close()

# Name of the invoice file. To simplify marking, your program should
# generate its invoice using this file name.
invoice_file = 'invoice.html'
database_file = 'shopping_cart.db'
logo_image = 'logo.gif'
cart = []

def print_invoice():
    print_to_database(cart, database_file)
    invoice = open(invoice_file, 'w')
    invoice.write('''<!DOCTYPE html>
<html>
    <head>
        <title>Keeto's Store</title>
    </head>
    <body> \n''')
    invoice.write('        <h1>Keeto\'s Store Invoice!</h1> \n')
    invoice.write('     <img src="' + logo_image + '"> \n')
    if len(cart) > 0:
        invoice.write('        <h2>Your cart consists of ' + cart_quantity + ' item')
        if len(cart) > 1: # Ensures proper pluralisation
            invoice.write('s')
        invoice.write('. \n')
        invoice.write('        <h2>Your total cost is: <u>AU$' + cart_total + '</u></h2> \n')
        invoice.write('        <br> \n')
        for item in cart:
            invoice.write('        <h3>' + item[0] + '</h3> \n')
            invoice.write('        <img src="' + item[2] + '" alt="' + item[0] + '" width = 200 height = 200> \n')
            invoice.write('        <p>Item Price: AU' + item[1] + '</p> \n')
    else:
        invoice.write('        <h2>Your cart is empty.</h2> \n')
    invoice.write('        <br> \n')
    invoice.write('    </body> \n')
    invoice.write('    <footer> \n')
    invoice.write('        <p>Items retrieved from:</p> \n')
    invoice.write('        <ul> \n')
    for site in sites:
        invoice.write('            <li>' + site + '</li> \n')
    invoice.write('        </ul> \n')
    invoice.write('    </footer> \n')
    invoice.write('</html>')
    invoice.close()

# User Interface
root_window = Tk()
root_window.title('Keeto\'s Store')

# Widgets
window_title = Label(root_window, text = 'Keeto\'s Online Shop').pack()
logo = PhotoImage(file = logo_image)
image_label = Label(root_window, image = logo).pack()
live_label = Label(root_window, text="Live Sites").pack(anchor = W)
v = IntVar() # Necessary for radio buttons
site1_button = Radiobutton(root_window, text = sites[0], variable = v, value = 1, command = radio_1).pack(anchor = W)
site2_button = Radiobutton(root_window, text = sites[1], variable = v, value = 2, command = radio_2).pack(anchor = W)
static_label = Label(root_window, text = "Archived Sites").pack(anchor = W)
site3_button = Radiobutton(root_window, text = sites[2], variable = v, value = 3, command=radio_3).pack(anchor = W)
site4_button = Radiobutton(root_window, text = sites[3], variable = v, value = 4, command=radio_4).pack(anchor = W)
items_label = Label(root_window, text = "Items").pack(anchor = W)
items_box = Listbox(root_window, width = 100)
items_box.pack(anchor = W)
cart_button = Button(root_window, text = "Add to Cart", command = add_to_cart).pack()
invoice_button = Button(root_window, text = "Print Invoice", command = print_invoice).pack()
clear_button = Button(root_window, text = "Clear Cart", command = clear_cart).pack()

root_window.mainloop()