Rotator

#!/usr/bin/python3

import sys, getopt

spanish_alphabet_lower_case = "abcdefghijklmnñopqrstuvwxyz"
english_alphabet_lower_case = "abcdefghijklmnopqrstuvwxyz"

verbose = False

help = "\t-h\t\t\tshow this help.\n\t-v\t\t\tverbose mode.\n\t-i <text>\t\tinput text to rotate.\n\t-I, --ifile <file>\tinput file to rotate.\n\t-o, --ofile <file>\toutput file.\n\t-r, --rotate <number>\tpositions to rotate.\n\t-d\t\t\tdecode text.\n\t-a, --alphabet <text>\tset the alphabet (spanish or english)"
usage = "usage: python3 rotator.py -i <input string> -r <position> -a <alphabet>"
help_options = "Option not recognised. Use -h to see help."
help_arguments = "Bad arguments. Use -h to see help."

def rotateChar(character, position, alphabet, decode=False):
    if decode == True:
        alphabet = alphabet[::-1]

    if not character in ("\n", "\r", "\0", "\t"):
        #check if character is uppercase, then convert it to lower.
        isUpperCase = character.isupper()
        if isUpperCase:
            character = character.lower()

        initial_pos = alphabet.find(character)
        if initial_pos != -1:
            alphabet += alphabet
            final_pos = initial_pos + int(position)
            character = alphabet[final_pos]
            if verbose:
                print ("initial pos = " + str(initial_pos))
                print ("final pos = " + str(final_pos))
                print(character + "->" + alphabet[final_pos])
                print("is upper case: " + str(isUpperCase))
            #if the character was uppercase convert it to upper again
            if isUpperCase:
                character = character.upper()
    return character

def main(argv):
    global verbose

    input = ""
    inputfile = ""
    outputfile = ""
    alphabet = ""
    rotate = 0
    decode = False

    try:
      opts, args = getopt.getopt(argv,"hi:I:o:a:r:dv",["ifile=","ofile=", "alphabet=","rotate=","decode="])
    except getopt.GetoptError:
        print(help_options)
        sys.exit(2)

    for opt, arg in opts:
        if opt == '-h':
            print (usage)
            print(help)
            sys.exit()
        elif opt in ("-i"):
            input = arg
        elif opt in ("-I", "--ifile"):
            inputfile = arg
        elif opt in ("-o", "--ofile"):
            outputfile = arg
        elif opt in ("-a", "--alphabet"):
            if arg == 'english':
                alphabet = english_alphabet_lower_case
            elif arg == 'spanish':
                alphabet = spanish_alphabet_lower_case
        elif opt in ("-r", "--rotate"):
            rotate = arg
        elif opt in ("-d", "--decode"):
            decode = True
        elif opt in ("-v"):
            verbose = True

    if rotate == 0 or len(input) != 0 and len(inputfile) != 0:
        print(help_arguments)
        sys.exit(1)

    if len(input) != 0:    
        string_to_rotate = input
    else:
        string_to_rotate = open(inputfile, 'r').read()
    
    if len(alphabet) == 0 or len(string_to_rotate) == 0:
        print(help_arguments)
        sys.exit(1)    
    
    rotate_string = ""
    for character in string_to_rotate:
        rotate_string += rotateChar(character, rotate, alphabet, decode)

    if len(outputfile) == 0:
        print (rotate_string)
    else:
        try:
            f = open(outputfile, 'w')
            f.write(rotate_string)
            f.close()
        except Exception as e:
            print(e)

if __name__ == '__main__':
    main(sys.argv[1:])