#! /usr/bin/python2.2

import catacomb as C
import gdbm, struct
from sys import argv, exit, stdin, stdout, stderr
from getopt import getopt, GetoptError
from os import environ
from fnmatch import fnmatch

file = '%s/.pwsafe' % environ['HOME']

class DecryptError (Exception):
  pass

class Crypto (object):
  def __init__(me, c, h, m, ck, mk):
    me.c = c(ck)
    me.m = m(mk)
    me.h = h
  def encrypt(me, pt):
    if me.c.__class__.blksz:
      iv = C.rand.block(me.c.__class__.blksz)
      me.c.setiv(iv)
    else:
      iv = ''
    y = iv + me.c.encrypt(pt)
    t = me.m().hash(y).done()
    return t + y
  def decrypt(me, ct):
    t = ct[:me.m.__class__.tagsz]
    y = ct[me.m.__class__.tagsz:]
    if t != me.m().hash(y).done():
      raise DecryptError
    iv = y[:me.c.__class__.blksz]
    if me.c.__class__.blksz: me.c.setiv(iv)
    return me.c.decrypt(y[me.c.__class__.blksz:])
  
class PPK (Crypto):
  def __init__(me, pp, c, h, m, salt = None):
    if not salt: salt = C.rand.block(h.hashsz)
    tag = '%s\0%s' % (pp, salt)
    Crypto.__init__(me, c, h, m,
                  h().hash('cipher:' + tag).done(),
                  h().hash('mac:' + tag).done())
    me.salt = salt

class Buffer (object):
  def __init__(me, s):
    me.str = s
    me.i = 0
  def get(me, n):
    i = me.i
    if n + i > len(me.str):
      raise IndexError, 'buffer underflow'
    me.i += n
    return me.str[i:i + n]
  def getbyte(me):
    return ord(me.get(1))
  def unpack(me, fmt):
    return struct.unpack(fmt, me.get(struct.calcsize(fmt)))
  def getstring(me):
    return me.get(me.unpack('>H')[0])
  def checkend(me):
    if me.i != len(me.str):
      raise ValueError, 'junk at end of buffer'

def wrapstr(s):
  return struct.pack('>H', len(s)) + s

class PWIter (object):
  def __init__(me, pw):
    me.pw = pw
    me.k = me.pw.db.firstkey()
  def next(me):
    k = me.k
    while True:
      if k is None:
        raise StopIteration
      if k[0] == '$':
        break
      k = me.pw.db.nextkey(k)
    me.k = me.pw.db.nextkey(k)
    return me.pw.unpack(me.pw.db[k])[0]
class PW (object):
  def __init__(me, file, mode = 'r'):
    me.db = gdbm.open(file, mode)
    c = C.gcciphers[me.db['cipher']]
    h = C.gchashes[me.db['hash']]
    m = C.gcmacs[me.db['mac']]
    tag = me.db['tag']
    ppk = PPK(C.ppread(tag), c, h, m, me.db['salt'])
    try:
      buf = Buffer(ppk.decrypt(me.db['key']))
    except DecryptError:
      C.ppcancel(tag)
      raise
    me.ck = buf.getstring()
    me.mk = buf.getstring()
    buf.checkend()
    me.k = Crypto(c, h, m, me.ck, me.mk)
    me.magic = me.k.decrypt(me.db['magic'])
  def keyxform(me, key):
    return '$' + me.k.h().hash(me.magic).hash(key).done()
  def changepp(me):
    tag = me.db['tag']
    C.ppcancel(tag)
    ppk = PPK(C.ppread(tag, C.PMODE_VERIFY),
              me.k.c.__class__, me.k.h, me.k.m.__class__)
    me.db['key'] = ppk.encrypt(wrapstr(me.ck) + wrapstr(me.mk))
    me.db['salt'] = ppk.salt
  def pack(me, key, value):
    w = wrapstr(key) + wrapstr(value)
    pl = (len(w) + 255) & ~255
    w += '\0' * (pl - len(w))
    return me.k.encrypt(w)
  def unpack(me, p):
    buf = Buffer(me.k.decrypt(p))
    key = buf.getstring()
    value = buf.getstring()
    return key, value
  def __getitem__(me, key):
    return me.unpack(me.db[me.keyxform(key)])[1]
  def __setitem__(me, key, value):
    me.db[me.keyxform(key)] = me.pack(key, value)
  def __delitem__(me, key):
    del me.db[me.keyxform(key)]
  def __iter__(me):
    return PWIter(me)

def cmd_create(av):
  cipher = 'blowfish-cbc'
  hash = 'rmd160'
  mac = None
  try:
    opts, args = getopt(av, 'c:h:m:', ['cipher=', 'mac=', 'hash='])
  except GetoptError:
    return 1
  for o, a in opts:
    if o in ('-c', '--cipher'):
      cipher = a
    elif o in ('-m', '--mac'):
      mac = a
    elif o in ('-h', '--hash'):
      hash = a
    else:
      raise 'Barf!'
  if len(args) > 2:
    return 1
  if len(args) >= 1:
    tag = args[0]
  else:
    tag = 'pwsafe'
  db = gdbm.open(file, 'n', 0600)
  pp = C.ppread(tag, C.PMODE_VERIFY)
  if not mac: mac = hash + '-hmac'
  c = C.gcciphers[cipher]
  h = C.gchashes[hash]
  m = C.gcmacs[mac]
  ppk = PPK(pp, c, h, m)
  ck = C.rand.block(c.keysz.default)
  mk = C.rand.block(m.keysz.default)
  k = Crypto(c, h, m, ck, mk)
  db['tag'] = tag
  db['salt'] = ppk.salt
  db['cipher'] = cipher
  db['hash'] = hash
  db['mac'] = mac
  db['key'] = ppk.encrypt(wrapstr(ck) + wrapstr(mk))
  db['magic'] = k.encrypt(C.rand.block(h.hashsz))

def cmd_changepp(av):
  if len(av) != 0:
    return 1
  pw = PW(file, 'w')
  pw.changepp()

def cmd_find(av):
  if len(av) != 1:
    return 1
  pw = PW(file)
  print pw[av[0]]

def cmd_store(av):
  if len(av) < 1 or len(av) > 2:
    return 1
  tag = av[0]
  if len(av) < 2:
    pp = C.getpass("Enter passphrase `%s': " % tag)
    vpp = C.getpass("Confirm passphrase `%s': " % tag)
    if pp != vpp:
      raise ValueError, "passphrases don't match"
  elif av[1] == '-':
    pp = stdin.readline()
  else:
    pp = av[1]
  pw = PW(file, 'w')
  pw[av[0]] = pp

def cmd_copy(av):
  if len(av) < 1 or len(av) > 2:
    return 1
  pw_in = PW(file)
  pw_out = PW(av[0], 'w')
  if len(av) >= 3:
    pat = av[1]
  else:
    pat = None
  for k in pw_in:
    if pat is None or fnmatch(k, pat):
      pw_out[k] = pw_in[k]

def cmd_list(av):
  if len(av) > 1:
    return 1
  pw = PW(file)
  if len(av) >= 1:
    pat = av[0]
  else:
    pat = None
  for k in pw:
    if pat is None or fnmatch(k, pat):
      print k

def cmd_topixie(av):
  if len(av) < 1 or len(av) > 2:
    return 1
  pw = PW(file)
  tag = av[0]
  if len(av) >= 2:
    pptag = av[1]
  else:
    pptag = av[0]
  C.Pixie().set(pptag, pw[tag])

def asciip(s):
  for ch in s:
    if ch < ' ' or ch > '~': return False
  return True
def present(s):
  if asciip(s): return s
  return C.ByteString(s)
def cmd_dump(av):
  db = gdbm.open(file, 'r')
  k = db.firstkey()
  while True:
    if k is None: break
    print '%r: %r' % (present(k), present(db[k]))
    k = db.nextkey(k)

commands = { 'create': [cmd_create,
                        '[-c CIPHER] [-h HASH] [-m MAC] [PP-TAG]'],
             'find' : [cmd_find, 'LABEL'],
             'store' : [cmd_store, 'LABEL [VALUE]'],
             'list' : [cmd_list, '[GLOB-PATTERN]'],
             'changepp' : [cmd_changepp, ''],
             'copy' : [cmd_copy, 'DEST-FILE [GLOB-PATTERN]'],
             'to-pixie' : [cmd_topixie, 'TAG [PIXIE-TAG]'],
             'dump' : [cmd_dump, '']}

def version():
  print 'pwsafe 1.0.0'
def usage(fp):
  print >>fp, 'Usage: pwsafe COMMAND [ARGS...]'
def help():
  version()
  print
  usage(stdout)  
  print '''
Maintains passwords or other short secrets securely.

Options:

-h, --help		Show this help text.
-v, --version		Show program version number.
-u, --usage		Show short usage message.

Commands provided:
'''
  for c in commands:
    print '%s %s' % (c, commands[c][1])

try:
  opts, argv = getopt(argv[1:],
                      'hvuf:',
                      ['help', 'version', 'usage', 'file='])
except GetoptError:
  usage(stderr)
  exit(1)
for o, a in opts:
  if o in ('-h', '--help'):
    help()
    exit(0)
  elif o in ('-v', '--version'):
    version()
    exit(0)
  elif o in ('-u', '--usage'):
    usage(stdout)
    exit(0)
  elif o in ('-f', '--file'):
    file = a
  else:
    raise 'Barf!'
if len(argv) < 1:
  usage(stderr)
  exit(1)

if argv[0] in commands:
  c = argv[0]
  argv = argv[1:]
else:
  c = 'find'
if commands[c][0](argv):
  print >>stderr, 'Usage: pwsafe %s %s' % (c, commands[c][1])
  exit(1)