#: ## Lab 7 ##
#: 
#: CS-2911 Network Protocols
#: Dr. Yoder 
#: Fall quarter 2016-2017
#: 
#: | Team members (username) |
#: |:------------------------|
#: | Grace Hopper (hopperg)  |
#: | Donald Knuth (knuthd)   |
#: 
#: Thanks to Trip Horbinski from the Fall 2015 class for providing the password-entering functionality.

# GUI library for password entry
import tkinter as tk

# Socket library
import socket

# SSL/TLS library
import ssl

# base-64 encode/decode
import base64

# Python date/time and timezone modules
import datetime
import time
import pytz
import tzlocal

# Module for reading password from console without echoing it
import getpass

# Modules for some file operations
import os
import mimetypes

# Host name for MSOE (hosted) SMTP server
SMTP_SERVER = 'smtp.office365.com'

# The default port for STARTTLS SMTP servers is 587
SMTP_PORT = 587

# SMTP domain name
SMTP_DOMAINNAME = 'msoe.edu'


def main():
    """Main test method to send an SMTP email message.

    Modify data as needed/desired to test your code,
    but keep the same interface for the smtp_send
    method.
    """
    (username, password) = login_gui()

    message_info = {}
    message_info['To'] = 'sebern@msoe.edu'
    message_info['From'] = username
    message_info['Subject'] = 'Yet another test message'
    message_info['Date'] = 'Thu, 9 Oct 2014 23:56:09 +0000'
    message_info['Date'] = get_formatted_date()

    print("message_info =", message_info)

    message_text = 'Test message_info number 6\r\n\r\nAnother line.'

    smtp_send(password, message_info, message_text)


def login_gui():
    """Creates a graphical user interface for secure user authorization.

    Returns:
        email_value -- The email address as a string.
        password_value -- The password as a string.

    Author: Tripp Horbinski
    """
    gui = tk.Tk()
    gui.title("MSOE Email Client")
    center_gui_on_screen(gui, 370, 120)

    tk.Label(gui, text="Please enter your MSOE credentials below:") \
        .grid(row=0, columnspan=2)
    tk.Label(gui, text="Email Address: ").grid(row=1)
    tk.Label(gui, text="Password:         ").grid(row=2)

    email = tk.StringVar()
    email_input = tk.Entry(gui, textvariable=email)
    email_input.grid(row=1, column=1)

    password = tk.StringVar()
    password_input = tk.Entry(gui, textvariable=password, show='*')
    password_input.grid(row=2, column=1)

    auth_button = tk.Button(gui, text="Authenticate", width=25, command=gui.destroy)
    auth_button.grid(row=3, column=1)

    gui.mainloop()

    email_value = email.get()
    password_value = password.get()

    return email_value, password_value


def center_gui_on_screen(gui, gui_width, gui_height):
    """Centers the graphical user interface on the screen.

    Args:
        gui: The graphical user interface to be centered.
        gui_width: The width of the graphical user interface.
        gui_height: The height of the graphical user interface.

    Returns:
        The graphical user interface coordinates for the center of the screen.

    Author: Tripp Horbinski
    """
    screen_width = gui.winfo_screenwidth()
    screen_height = gui.winfo_screenheight()
    x_coord = (screen_width / 2) - (gui_width / 2)
    y_coord = (screen_height / 2) - (gui_height / 2)

    return gui.geometry('%dx%d+%d+%d' % (gui_width, gui_height, x_coord, y_coord))

# *** Do not modify code above this line ***


def smtp_send(password, message_info, message_text):
    """Send a message via SMTP.

    Args:
        password: String containing user password.
        message_info: Dictionary with string values for the following keys:
                'To': Recipient address (only one recipient required)
                'From': Sender address
                'Date': Date string for current date/time in SMTP format
                'Subject': Email subject
            Other keys can be added to support other email headers, etc.
    """
    pass  # Replace this line with your code


# Your code and additional functions go here. (Replace this line, too.)

# ** Do not modify code below this line. **

# Utility functions
# You may use these functions to simplify your code.


def get_formatted_date():
    """Get the current date and time, in a format suitable for an email date header.

    The constant TIMEZONE_NAME should be one of the standard pytz timezone names.
    If you really want to see them all, call the print_all_timezones function.

    tzlocal suggested by http://stackoverflow.com/a/3168394/1048186

    See RFC 5322 for details about what the timezone should be
    https://tools.ietf.org/html/rfc5322

    Returns:
         Formatted current date/time value, as a string.
    """
    zone = tzlocal.get_localzone()
    print("zone =", zone)
    timestamp = datetime.datetime.now(zone)
    timestring = timestamp.strftime('%a, %d %b %Y %H:%M:%S %z')  # Sun, 06 Nov 1994 08:49:37 +0000
    return timestring


def print_all_timezones():
    """Print all pytz timezone strings.
    """
    for tz in pytz.all_timezones:
        print(tz)


# You probably won't need the following methods, unless you decide to
# try to handle email attachments or send multi-part messages.
# These advanced capabilities are not required for the lab assignment.

def get_mime_type(file_path):
    """Try to guess the MIME type of a file (resource), given its path (primarily its file extension)

    Args:
        file_path: String containing path to (resource) file, such as './abc.jpg'

    Returns:
        If successful in guessing the MIME type, a string representing the content
          type, such as 'image/jpeg'
        Otherwise, None
    """
    mime_type_and_encoding = mimetypes.guess_type(file_path)
    mime_type = mime_type_and_encoding[0]
    return mime_type


def get_file_size(file_path):
    """Try to get the size of a file (resource) in bytes, given its path

    Args:
        file_path -- String containing path to (resource) file, such as './abc.html'

    Returns:
        If file_path designates a normal file, an integer value representing the the file size in bytes
        Otherwise (no such file, or path is not a file), None
    """
    # Initially, assume file does not exist
    file_size = None
    if os.path.isfile(file_path):
        file_size = os.stat(file_path).st_size
    return file_size


main()