#!/usr/bin/python3

"""generate word compound passwords 

usage: pwgen -c [number_of_phrases default=1]
or     pwgen [-s | -S | -n | -p | -/] [-L len default=20] [number_of_phrases default=1]  


"""

import random, sys
from enum import Enum

class Padding(Enum):
  spaces = 0
  dots = 1
  punct = 2
  numbers = 3
  camel = 4
  snake = 5

class Config:
  def __init__(self):
    self.padding = Padding.spaces
    self.first_punct  = False
    self.last_punct   = False
    self.first_number = False
    self.last_number  = False
    self.capitalize   = False
    self.use_conjunctions = False
    self.target_len = 20    # default pw len
    self.number    = 1
  def __repr__(self):
    return(str(list((repr(self.padding),
      self.first_punct, self.last_punct,
      self.first_number, self.last_number,
      self.capitalize,
      self.target_len, self.number,
      self.use_conjunctions))))
 
SPACE        = " "
DOTS         = ".,"
PUNCTS       = """ !@#$%^&*()-_=+[{]}\\|;:/?.>,<~"""
NUMBERS      = "0123456789"
CONJUNCTIONS =  ["and", "and a", "and the","or", "or the", "or a", 
    "with a", "with", "with the", "by a", "by the", 
    "on a", "on the","on", "in a", "in the", "in", 
    "for", "for a", "for the"]

# delete these
number = 1
targetLen = 20

useConjunction = False
add_punc       = False
add_number     = False

def toInt(s, chkRange, errStr = "sorry, that's not a number", rangeStr = "sorry, I can't do that number"):
  try:
    t = int(s)
  except:
    print (errStr)
    sys.exit()
  if t<chkRange[0] or t>chkRange[1]:
    print (rangeStr)
    sys.exit()
  return t

def get_args(conf):
  narg = 1
  nargs = len(sys.argv)
  while narg<nargs:
    a = sys.argv[narg]
    if a=="-h" or a=="--help" or a=="--version":
      print ("pwgen.py  v1.3  generate passphrase; inspired by xkcd/936 and SteveGibson\n")
      print ("""Usage: pwgen.py [-sSpPkKnNcCaMX] [-L length] [num_phrases] 
         pwgen.py -h | --help | --version

       -s           pad with only spaces (default; for smartphone)
       -S           pad with period and comma (for smartphone)
       -p           pad with special characters
       -P           pad with numbers
       -k           connect the words as CamelCase
       -K           connect the words as snake_case
       -n           add a number at the beginning
       -N           add a number at the end
       -c           add a special character at the begnning
       -C           add a special character at the end
       -M           capitalize the words
       -a           connect the words with a conjuction filler
       -X           same as -MNCS (capital, periods & commas, extra number & char)
       -L <n>       make pass phrases at least this long; default=20
       num_phrases  make multiple pass phrases, one per line; default=1\n""")
      sys.exit()
    elif a[0]=='-':
      for b in a[1:]:
        match b:
          case 'c':
            conf.first_punt = True
          case 'C':
            conf.last_punct = True
          case 'n':
            conf.first_number = True
          case 'N':  # add number
            conf.last_number = True
          case 's':
            conf.padding = Padding.spaces
          case 'S':
            conf.padding = Padding.dots
          case 'p':
            conf.padding = Padding.punct
          case 'P':
            conf.padding = Padding.numbers
          case 'k':
            conf.padding = Padding.camel
          case 'K':
            conf.padding = Padding.snake
          case 'M': 
            conf.capitalize = True  
          case 'X':
            conf.capitalize = True
            conf.last_punct = True
            conf.last_number = True
            conf.padding = Padding.dots
          case 'a':
            conf.use_conjunctions = True;
          case 'L':
            narg = narg + 1
            if narg < nargs:
              conf.target_len = toInt(sys.argv[narg],[12,66],rangeStr = "Sorry, I can't build phrases that long")
          case _:
            print(f">>> unexpected command option '{b}'")      
    else:
      if narg < nargs:
        conf.number = toInt(sys.argv[narg],[0,40],rangeStr = "Sorry, I can't print that many; try a smaller number")  # pick off the number of phrases

    narg = narg + 1


def load_words():
  f = open("/usr/share/dict/words")
  #f = open("/usr/share/dict/corncob_lowercase.txt")
  d = f.read().splitlines()
  f.close()
  d = list(filter(lambda x : len(x)<10 and not x.endswith("'s"), d))
  return d

def get_word(conf, data):
  m = data[random.randint(0,len(data)-1)]
  if conf.capitalize or conf.padding == Padding.camel:
    m = m.capitalize()
  return m

def pwgen(conf, data):
  w = [get_word(conf, data)]
  nExtraChars = conf.first_punct+conf.last_punct+conf.first_number+conf.last_number
  # TODO: we need a length estimator for this loop
  while sum(len(a) for a in w) + (len(w)-1 if not conf.padding==Padding.camel else 0) + nExtraChars < conf.target_len:
    if conf.use_conjunctions == True:
      c = CONJUNCTIONS[random.randint(0,len(CONJUNCTIONS)-1)]
      w.extend(c.split())
    w.append(get_word(conf, data))    
    if w[-2] == 'a' and w[-1][0] in "aeiouAEIOU":
      w[-2] = "an"
  # change so that two-word conjunctions are multiple list elements
  
  if conf.padding == Padding.camel:
    ret = "".join(w)
  elif conf.padding == Padding.spaces:
    ret = SPACE.join(w)
  elif conf.padding == Padding.dots:
    p = DOTS[random.randint(0,len(DOTS)-1)]
    ret = p.join(w)
  elif conf.padding == Padding.numbers:
    n = NUMBERS[random.randint(0,len(NUMBERS)-1)]
    ret = n.join(w)
  elif conf.padding == Padding.punct:
    p = PUNCTS[random.randint(0,len(PUNCTS)-1)]
    ret = p.join(w)
  elif conf.padding == Padding.snake:
    ret = '_'.join(w)  

  n = NUMBERS[random.randint(0,len(NUMBERS)-1)]
  if conf.first_number:
    ret = n + ret
  if conf.last_number:
    ret = ret + n    
  p = PUNCTS[random.randint(0,len(PUNCTS)-1)]
  if conf.first_punct:
    ret = p + ret
  if conf.last_punct:
    ret = ret + p    

  return ret

if __name__ == "__main__":

  conf = Config()
  get_args(conf)

  data = load_words()

  for i in range(conf.number):
    pw = pwgen(conf, data)
    print(pw)


""" 
although this

read n; i="1"; while [ $i -le $n ]; do cat /etc/dictionaries-common/words | shuf | head -1; i=$(( $i + 1 )); done

will do the job almost as well

NEW PLAN
  -s spaces (default)
  -S comma+period
  -p punctuation
  -P number 
  -k CamelCase 
  -K SnakeCase (only one of these 6 allowed)

  -c special char at beginning
  -C special char at end
  -n number at beginning
  -N number at end
  -M capitalize all words
  -a fill with conjunctions
  -X equivalent to -SCNM
  -L <n> length
  <n> number of samples
  -k -a not recommended

  -s    dog cat mouse
  -S    dog.cat.mouse
  -p    dog#cat#mouse
  -P    dog4cat4mouse
  -c    !dog cat mouse
  -C    dog cat mouse#
  -n    4dog cat mouse
  -N    dog cat mouse4
  -cnCN $4dog cat mouse4$
  -M    Dog Cat Mouse
  -k    DogCatMouse
  -kN   DogCatMouse2
  -K    dog_cat_mouse
  -KMN  Dog_Cat_Mouse3
  -a    dog and a cat with mouse
  -Sa   dog.and.a.cat.with.mouse
  -pa   dog#and#a#cat#with#mouse
  -paCN dog^and^a^cat^with^mouse5%
  -X    Dog.Cat.Mouse6&

leet encoder a->4A e->3 i->I o->0 s->5$ t->7 
"""