#!/usr/bin/python

"""generate word compound passwords 

usage: pwgen -c [number_of_phrases default=1]
or     pwgen [len default=20] [number_of_phrases default=1]    // no conjunctions
	-c   use conjunction
"""
import random, sys

targetLen = 20		# default pw len
useConjunction = False
number = 1
punc = " !@#$%^&*()-_=+[{]}\|;:/?.>,<`~"
number_punc = "0123456789"

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

narg = 1
if len(sys.argv)>1:
	if sys.argv[1]=="-h" or sys.argv[1]=="--help":
		print "pwgen.py  v1.3  generate passphrase; inspired by xkcd/936 and SteveGibson\n"
		print "Usage: pwgen.py [-p | -P | -n | -N] [length [num_phrases]] "
		print "       pwgen.py -c [num_phrases]"
		print "       pwgen.py -h | --help \n"
		print "     -p           pad with only spaces (for smartphone)"
		print "     -P           pad with spaces, period and comma (for smartphone)"
		print "     -n           pad with numbers"
		print "     -N           pad with numbers, spaces, period, comma like -P -n"
		print "     length       make pass phrases padded with punctuation filler; default=20"
		print "     -c           make 2 word pass phrases with a conjuction filler"
		print "     num_phrases  make multiple pass phrases, one per line; default=1\n"
		sys.exit()
	elif sys.argv[1]=="-c":	# conjunction mode
		useConjunction = True
		narg = narg + 1
	elif sys.argv[1]=='-n': # number fill mode
		punc = number_punc
		narg = narg + 1
	elif sys.argv[1]=='-N':
		punc = number_punc + " ,."
		narg = narg + 1
	elif sys.argv[1]=="-p": # use only space
		punc = " "
		narg = narg + 1
	elif sys.argv[1]=="-P":
		punc = " .,"
		narg = narg + 1
	if not useConjunction:
		if len(sys.argv)>narg:
			targetLen = toInt(sys.argv[narg],[12,36],rangeStr = "Sorry, I can't build phrases that long")
			narg = narg + 1
	if len(sys.argv)>narg:
		number = toInt(sys.argv[narg],[0,40])  # pick off the number of phrases
 
f = open("/usr/share/dict/words")
#f = open("/usr/share/dict/corncob_lowercase.txt")
d = f.read().splitlines()
f.close()

numWords = len(d)	

for i in range(number):

	w=['','','']
	for i in range(3):
		w[i] = d[random.randint(0,numWords-1)]
		while (len(w[i]) > 10) or (w[i].endswith("'s")):
			w[i] = d[random.randint(0,numWords-1)]
			
	whole = len(w[0])+len(w[1])

	thisPunct = punc[int(random.random() * len(punc))] 

	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"]

	if useConjunction == False:
		if whole + 6 >= targetLen:	# if 2 words is enough
			r = max(1,targetLen - whole)
			pw = w[0] + thisPunct*r + w[1]
		else:		# otherwise use 3
			whole = whole + len(w[2])
			r = targetLen - whole
			if r<2:
				r = 2
			pw = w[0] + thisPunct*(r/2) + w[1] + thisPunct*(r-r/2) + w[2]
	else:
		conj = conjunctions[random.randint(0,len(conjunctions)-1)]
		if w[1][0].lower() in ['a','A','e','E','i','I','o','O','u','U']:
			if conj[-2:]==" a":
				conj = conj+'n'
		pw = w[0] + ' ' + conj + ' ' + w[1]

	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
"""