import telnetlib
import os.path
import subprocess
import time
import sys


def telnet(command):

    username = "admin01"
    password = "cisco12345"

    port = 23
    connection_timeout = 5
    reading_timeout = 5
    connection = telnetlib.Telnet(ip_address, port, connection_timeout)
    router_output = connection.read_until(b"Username:", reading_timeout)
    connection.write(username.encode('ascii') + b"\n")

    router_output = connection.read_until(b"Password:", reading_timeout)
    connection.write(password.encode('ascii') + b"\n")
    time.sleep(1)
    connection.write(b"terminal length 0\n")
    time.sleep(1)

    connection.write(b"\n")
    connection.write(command.encode('ascii') + b"\n")
    time.sleep(5)

    router_output = connection.read_very_eager()
    connection.close()

    return router_output

################## USER MENU #################
try:

    while True:
        print("\nPlease select your Task:\n1 - Compare Running-config with Startup-config\n2 - Exit program\n")

        user_option = input("Enter your choice: ")

        if user_option == "1":


            print("\nPlease wait while the config file is being compared...\n")

            output_run = telnet("show running-config")
            output_start = telnet("show startup-config")

            file_run = open("file_run.txt", "w")
            print(output_run.decode('ascii'), file=file_run)

            file_start = open("file_start.txt", "w")
            print(output_start.decode('ascii'), file=file_start)

            file_run.close()
            file_start.close()

            file_run = open("file_run.txt", "r")

            file_start = open("file_start.txt", "r")

            list_run = file_run.readlines()

            list_start = file_start.readlines()

            file_run.close()
            file_start.close()


            for index, element in enumerate(list_run):
                if "version " in element and "!\r\n" == list_run[list_run.index(element) - 1]:
                    list_run[0:list_run.index(element)] = []


            for index, element in enumerate(list_start):
                if "version " in element and "!\r\n" == list_start[list_start.index(element) - 1]:
                    list_start[0:list_start.index(element)] = []


            file_diff = open("file_diff.txt", "w")

            run_diff = [x for x in list_run if x not in list_start]

            for line in run_diff:

                print("+" + line, file=file_diff)


            start_diff = [x for x in list_start if x not in list_run]

            for line in start_diff:

                print("-" + line, file=file_diff)

            file_diff.close()

        else:
            print("Thanks for using the script\n\n")
            sys.exit()

except KeyboardInterrupt:
    print("\n\nProgram aborted by user. Exiting...\n")
    sys.exit()