"""Some utilities for the CubicWeb server.

:organization: Logilab

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

"""

__docformat__ = "restructuredtext en"

import sys

import string

from threading import Timer, Thread

from getpass import getpass

from random import choice

try:

    from crypt import crypt

except ImportError:

    # crypt is not available (eg windows)

    from cubicweb.md5crypt import crypt

def getsalt(chars=string.letters + string.digits):

    """generate a random 2-character 'salt'"""

    return choice(chars) + choice(chars)

def crypt_password(passwd, salt=None):

    """return the encrypted password using the given salt or a generated one

    """

    if passwd is None:

        return None

    if salt is None:

        salt = getsalt()

    return crypt(passwd, salt)

def cartesian_product(seqin):

    """returns a generator which returns the cartesian product of `seqin`

    for more details, see :

    http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302478

    """

    def rloop(seqin, comb):

        """recursive looping function"""

        if seqin:                   # any more sequences to process?

            for item in seqin[0]:

                newcomb = comb + [item]     # add next item to current combination

                # call rloop w/ remaining seqs, newcomb

                for item in rloop(seqin[1:], newcomb):   

                    yield item          # seqs and newcomb

        else:                           # processing last sequence

            yield comb                  # comb finished, add to list

    return rloop(seqin, [])

def cleanup_solutions(rqlst, solutions):

    for sol in solutions:

        for vname in sol.keys():

            if not (vname in rqlst.defined_vars or vname in rqlst.aliases):

                del sol[vname]

DEFAULT_MSG = 'we need a manager connection on the repository \

(the server doesn\'t have to run, even should better not)'

def manager_userpasswd(user=None, passwd=None, msg=DEFAULT_MSG, confirm=False):

    if not user:

        print msg

        while not user:

            user = raw_input('login: ')

        passwd = getpass('password: ')

        if confirm:

            while True:

                passwd2 = getpass('confirm password: ')

                if passwd == passwd2:

                    break

                print 'password doesn\'t match'

                passwd = getpass('password: ')

        user = unicode(user, sys.stdin.encoding)

    elif not passwd:

        assert not confirm

        passwd = getpass('password for %s: ' % user)

    # XXX decode password using stdin encoding then encode it using appl'encoding

    return user, passwd

class LoopTask(object):

    """threaded task restarting itself once executed"""

    def __init__(self, interval, func):

        self.interval = interval

        def auto_restart_func(self=self, func=func):

            try:

                func()

            finally:

                self.start()

        self.func = auto_restart_func

        self.name = func.__name__

    def start(self):

        self._t = Timer(self.interval, self.func)

        self._t.start()

    def cancel(self):

        self._t.cancel()

    def join(self):

        self._t.join()

class RepoThread(Thread):

    """subclass of thread so it auto remove itself from a given list once

    executed

    """

    def __init__(self, target, running_threads):

        def auto_remove_func(self=self, func=target):

            try:

                func()

            finally:

                self.running_threads.remove(self)

        Thread.__init__(self, target=target)

        self.running_threads = running_threads

        self._name = target.__name__

    def start(self):

        self.running_threads.append(self)

        Thread.start(self)

    @property

    def name(self):

        return '%s(%s)' % (self._name, Thread.getName(self))