"""Some utilities for the CubicWeb server.

"""

__docformat__ = "restructuredtext en"

import sys

import string

from threading import Timer, Thread

from getpass import getpass

from random import choice

from logilab.common.configuration import Configuration

from cubicweb.server import SOURCE_TYPES

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]

def eschema_eid(session, eschema):

    """get eid of the CWEType entity for the given yams type. You should use

    this because when schema has been loaded from the file-system, not from the

    database, (e.g. during tests), eschema.eid is not set.

    """

    if eschema.eid is None:

        eschema.eid = session.execute(

            'Any X WHERE X is CWEType, X name %(name)s',

            {'name': str(eschema)})[0][0]

    return eschema.eid

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, msg=DEFAULT_MSG, confirm=False,

                       passwdmsg='password'):

    if not user:

        if msg:

            print msg

        while not user:

            user = raw_input('login: ')

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

    passwd = getpass('%s: ' % passwdmsg)

    if confirm:

        while True:

            passwd2 = getpass('confirm password: ')

            if passwd == passwd2:

                break

            print 'password doesn\'t match'

            passwd = getpass('password: ')

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

    return user, passwd

def ask_source_config(sourcetype, inputlevel=0):

    sconfig = Configuration(options=SOURCE_TYPES[sourcetype].options)

    sconfig.adapter = sourcetype

    sconfig.input_config(inputlevel=inputlevel)

    return sconfig

class LoopTask(object):

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

    def __init__(self, interval, func, args):

        self.interval = interval

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

            try:

                func(*args)

            finally:

                self.start()

        self.func = auto_restart_func

        self.name = func.__name__

    def __str__(self):

        return '%s (%s seconds)' % (self.name, self.interval)

    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=auto_remove_func)

        self.running_threads = running_threads

        self._name = target.__name__

    def start(self):

        self.running_threads.append(self)

        self.daemon = True

        Thread.start(self)

    def getName(self):

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