# -*- coding: utf-8 -*-

# This program is free software: you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation, either version 3 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""

kallithea.lib.auth

~~~~~~~~~~~~~~~~~~

authentication and permission libraries

This file was forked by the Kallithea project in July 2014.

Original author and date, and relevant copyright and licensing information is below:

:created_on: Apr 4, 2010

:author: marcink

:copyright: (c) 2013 RhodeCode GmbH, and others.

:license: GPLv3, see LICENSE.md for more details.

"""

from __future__ import with_statement

import time

import random

import logging

import traceback

import hashlib

import itertools

import collections

from tempfile import _RandomNameSequence

from decorator import decorator

from pylons import url, request

from pylons.controllers.util import abort, redirect

from pylons.i18n.translation import _

from sqlalchemy import or_

from sqlalchemy.orm.exc import ObjectDeletedError

from sqlalchemy.orm import joinedload

from kallithea import __platform__, is_windows, is_unix

from kallithea.lib.vcs.utils.lazy import LazyProperty

from kallithea.model import meta

from kallithea.model.meta import Session

from kallithea.model.user import UserModel

from kallithea.model.db import User, Repository, Permission, \

    UserToPerm, UserGroupRepoToPerm, UserGroupToPerm, UserGroupMember, \

    RepoGroup, UserGroupRepoGroupToPerm, UserIpMap, UserGroupUserGroupToPerm, \

    UserGroup, UserApiKeys

from kallithea.lib.utils2 import safe_unicode, aslist

from kallithea.lib.utils import get_repo_slug, get_repo_group_slug, \

    get_user_group_slug, conditional_cache

from kallithea.lib.caching_query import FromCache

log = logging.getLogger(__name__)

class PasswordGenerator(object):

    """

    This is a simple class for generating password from different sets of

    characters

    usage::

        passwd_gen = PasswordGenerator()

        #print 8-letter password containing only big and small letters

            of alphabet

        passwd_gen.gen_password(8, passwd_gen.ALPHABETS_BIG_SMALL)

    """

    ALPHABETS_NUM = r'''1234567890'''

    ALPHABETS_SMALL = r'''qwertyuiopasdfghjklzxcvbnm'''

    ALPHABETS_BIG = r'''QWERTYUIOPASDFGHJKLZXCVBNM'''

    ALPHABETS_SPECIAL = r'''`-=[]\;',./~!@#$%^&*()_+{}|:"<>?'''

    ALPHABETS_FULL = ALPHABETS_BIG + ALPHABETS_SMALL \

        + ALPHABETS_NUM + ALPHABETS_SPECIAL

    ALPHABETS_ALPHANUM = ALPHABETS_BIG + ALPHABETS_SMALL + ALPHABETS_NUM

    ALPHABETS_BIG_SMALL = ALPHABETS_BIG + ALPHABETS_SMALL

    ALPHABETS_ALPHANUM_BIG = ALPHABETS_BIG + ALPHABETS_NUM

    ALPHABETS_ALPHANUM_SMALL = ALPHABETS_SMALL + ALPHABETS_NUM

    def __init__(self, passwd=''):

        self.passwd = passwd

    def gen_password(self, length, type_=None):

        if type_ is None:

            type_ = self.ALPHABETS_FULL

        self.passwd = ''.join([random.choice(type_) for _ in xrange(length)])

        return self.passwd

class KallitheaCrypto(object):

    @classmethod

    def hash_string(cls, str_):

        """

        Cryptographic function used for password hashing based on pybcrypt

        or pycrypto in windows

        :param password: password to hash

        """

        if is_windows:

            from hashlib import sha256

            return sha256(str_).hexdigest()

        elif is_unix:

            import bcrypt

            return bcrypt.hashpw(str_, bcrypt.gensalt(10))

        else:

            raise Exception('Unknown or unsupported platform %s' \

                            % __platform__)

    @classmethod

    def hash_check(cls, password, hashed):

        """

        Checks matching password with it's hashed value, runs different

        implementation based on platform it runs on

        :param password: password

        :param hashed: password in hashed form

        """

        if is_windows:

            from hashlib import sha256

            return sha256(password).hexdigest() == hashed

        elif is_unix:

            import bcrypt

            return bcrypt.hashpw(password, hashed) == hashed

        else:

            raise Exception('Unknown or unsupported platform %s' \

                            % __platform__)

            if cache:

                default_ips = default_ips.options(FromCache("sql_cache_short",

                                                  "get_user_ips_default"))

            # populate from default user

            for ip in default_ips:

                try:

                    _set.add(ip.ip_addr)

                except ObjectDeletedError:

                    # since we use heavy caching sometimes it happens that we get

                    # deleted objects here, we just skip them

                    pass

        user_ips = UserIpMap.query().filter(UserIpMap.user_id == user_id)

        if cache:

            user_ips = user_ips.options(FromCache("sql_cache_short",

                                                  "get_user_ips_%s" % user_id))

        for ip in user_ips:

            try:

                _set.add(ip.ip_addr)

            except ObjectDeletedError:

                # since we use heavy caching sometimes it happens that we get

                # deleted objects here, we just skip them

                pass

        return _set or set(['0.0.0.0/0', '::/0'])

def set_available_permissions(config):

    """

    This function will propagate pylons globals with all available defined

    permission given in db. We don't want to check each time from db for new

    permissions since adding a new permission also requires application restart

    ie. to decorate new views with the newly created permission

    :param config: current pylons config instance

    """

    log.info('getting information about all available permissions')

    try:

        sa = meta.Session

        all_perms = sa.query(Permission).all()

        config['available_permissions'] = [x.permission_name for x in all_perms]

    finally:

        meta.Session.remove()

#==============================================================================

# CHECK DECORATORS

#==============================================================================

class LoginRequired(object):

    """

    Must be logged in to execute this function else

    redirect to login page

    :param api_access: if enabled this checks only for valid auth token

        and grants access based on valid token

    """

    def __init__(self, api_access=False):

        self.api_access = api_access

    def __call__(self, func):

        return decorator(self.__wrapper, func)

    def __wrapper(self, func, *fargs, **fkwargs):

        cls = fargs[0]

        user = cls.authuser

        loc = "%s:%s" % (cls.__class__.__name__, func.__name__)

        # check if our IP is allowed

        ip_access_valid = True

        if not user.ip_allowed:

            from kallithea.lib import helpers as h

            h.flash(h.literal(_('IP %s not allowed' % (user.ip_addr))),

                    category='warning')

            ip_access_valid = False

        # check if we used an APIKEY and it's a valid one

        # defined whitelist of controllers which API access will be enabled

        _api_key = request.GET.get('api_key', '')

        api_access_valid = allowed_api_access(loc, api_key=_api_key)

        # explicit controller is enabled or API is in our whitelist

        if self.api_access or api_access_valid:

            log.debug('Checking API KEY access for %s' % cls)

            if _api_key and _api_key in user.api_keys:

                api_access_valid = True

                log.debug('API KEY ****%s is VALID' % _api_key[-4:])

            else:

                api_access_valid = False

                if not _api_key:

                    log.debug("API KEY *NOT* present in request")

                else:

                    log.warning("API KEY ****%s *NOT* valid" % _api_key[-4:])

        log.debug('Checking if %s is authenticated @ %s' % (user.username, loc))

        reason = 'RegularAuth' if user.is_authenticated else 'APIAuth'

        if ip_access_valid and (user.is_authenticated or api_access_valid):

            log.info('user %s authenticating with:%s IS authenticated on func %s '

                     % (user, reason, loc)

            )

            return func(*fargs, **fkwargs)

        else:

            log.warning('user %s authenticating with:%s NOT authenticated on func: %s: '

                     'IP_ACCESS:%s API_ACCESS:%s'

                     % (user, reason, loc, ip_access_valid, api_access_valid)

            )

            p = url.current()

            log.debug('redirecting to login page with %s' % p)

            return redirect(url('login_home', came_from=p))

class NotAnonymous(object):

    """

    Must be logged in to execute this function else

    redirect to login page"""

    def __call__(self, func):

        return decorator(self.__wrapper, func)

    def __wrapper(self, func, *fargs, **fkwargs):

        cls = fargs[0]

        self.user = cls.authuser

        log.debug('Checking if user is not anonymous @%s' % cls)

        anonymous = self.user.username == User.DEFAULT_USER

        if anonymous:

            p = url.current()

            import kallithea.lib.helpers as h

            h.flash(_('You need to be a registered user to '

                      'perform this action'),

                    category='warning')

            return redirect(url('login_home', came_from=p))

        else:

            return func(*fargs, **fkwargs)

class PermsDecorator(object):

    """Base class for controller decorators"""

    def __init__(self, *required_perms):

        self.required_perms = set(required_perms)

        self.user_perms = None

    def __call__(self, func):

        return decorator(self.__wrapper, func)

    def __wrapper(self, func, *fargs, **fkwargs):

        cls = fargs[0]

        self.user = cls.authuser

        self.user_perms = self.user.permissions

        log.debug('checking %s permissions %s for %s %s',

           self.__class__.__name__, self.required_perms, cls, self.user)

        if self.check_permissions():

            log.debug('Permission granted for %s %s' % (cls, self.user))

            return func(*fargs, **fkwargs)

        else:

            log.debug('Permission denied for %s %s' % (cls, self.user))

            anonymous = self.user.username == User.DEFAULT_USER

            if anonymous:

                p = url.current()

                import kallithea.lib.helpers as h

                h.flash(_('You need to be signed in to '

                          'view this page'),

                        category='warning')

                return redirect(url('login_home', came_from=p))

            else:

                # redirect with forbidden ret code

                return abort(403)

    def check_permissions(self):

        """Dummy function for overriding"""

        raise Exception('You have to write this function in child class')

class HasPermissionAllDecorator(PermsDecorator):

    """

    Checks for access permission for all given predicates. All of them

    have to be meet in order to fulfill the request

    """