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

"""

    rhodecode.lib.auth

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

    authentication and permission libraries

    :created_on: Apr 4, 2010

    :author: marcink

    :copyright: (C) 2010-2012 Marcin Kuzminski <marcin@python-works.com>

    :license: GPLv3, see COPYING for more details.

"""

# 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/>.

import random

import logging

import traceback

import hashlib

from tempfile import _RandomNameSequence

from decorator import decorator

from pylons import config, url, request

from pylons.controllers.util import abort, redirect

from pylons.i18n.translation import _

from rhodecode import __platform__, PLATFORM_WIN, PLATFORM_OTHERS

from rhodecode.model.meta import Session

if __platform__ in PLATFORM_WIN:

    from hashlib import sha256

if __platform__ in PLATFORM_OTHERS:

    import bcrypt

from rhodecode.lib import str2bool, safe_unicode

from rhodecode.lib.exceptions import LdapPasswordError, LdapUsernameError

from rhodecode.lib.utils import get_repo_slug, get_repos_group_slug

from rhodecode.lib.auth_ldap import AuthLdap

from rhodecode.model import meta

from rhodecode.model.user import UserModel

from rhodecode.model.db import Permission, RhodeCodeSetting, User

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

        print 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

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

        return self.passwd

class RhodeCodeCrypto(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 __platform__ in PLATFORM_WIN:

            return sha256(str_).hexdigest()

        elif __platform__ in PLATFORM_OTHERS:

            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 __platform__ in PLATFORM_WIN:

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

        elif __platform__ in PLATFORM_OTHERS:

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

        else:

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

                            % __platform__)

def get_crypt_password(password):

    return RhodeCodeCrypto.hash_string(password)

def check_password(password, hashed):

    return RhodeCodeCrypto.hash_check(password, hashed)

def generate_api_key(str_, salt=None):

    """

    Generates API KEY from given string

    :param str_:

    :param salt:

    """

    if salt is None:

        salt = _RandomNameSequence().next()

    return hashlib.sha1(str_ + salt).hexdigest()

def authfunc(environ, username, password):

    """

    Dummy authentication wrapper function used in Mercurial and Git for

    access control.

    :param environ: needed only for using in Basic auth

    """

    return authenticate(username, password)

def authenticate(username, password):

    """

    Authentication function used for access control,

    firstly checks for db authentication then if ldap is enabled for ldap

    authentication, also creates ldap user if not in database

    :param username: username

    :param password: password

    """

    user_model = UserModel()

    user = User.get_by_username(username)

    log.debug('Authenticating user using RhodeCode account')

    if user is not None and not user.ldap_dn:

        if user.active:

            if user.username == 'default' and user.active:

                log.info('user %s authenticated correctly as anonymous user',

                         username)

                return True

            elif user.username == username and check_password(password,

                                                              user.password):

                log.info('user %s authenticated correctly' % username)

                return True

        else:

            log.warning('user %s is disabled' % username)

    else:

        log.debug('Regular authentication failed')

        user_obj = User.get_by_username(username, case_insensitive=True)

        if user_obj is not None and not user_obj.ldap_dn:

            log.debug('this user already exists as non ldap')

            return False

        ldap_settings = RhodeCodeSetting.get_ldap_settings()

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

        # FALLBACK TO LDAP AUTH IF ENABLE

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

        if str2bool(ldap_settings.get('ldap_active')):

            log.debug("Authenticating user using ldap")

            kwargs = {

                  'server': ldap_settings.get('ldap_host', ''),

                  'base_dn': ldap_settings.get('ldap_base_dn', ''),

                  'port': ldap_settings.get('ldap_port'),

                  'bind_dn': ldap_settings.get('ldap_dn_user'),

                  'bind_pass': ldap_settings.get('ldap_dn_pass'),

                  'tls_kind': ldap_settings.get('ldap_tls_kind'),

                  'tls_reqcert': ldap_settings.get('ldap_tls_reqcert'),

                  'ldap_filter': ldap_settings.get('ldap_filter'),

                  'search_scope': ldap_settings.get('ldap_search_scope'),

                  'attr_login': ldap_settings.get('ldap_attr_login'),

                  'ldap_version': 3,

                  }

            log.debug('Checking for ldap authentication')

            try:

                aldap = AuthLdap(**kwargs)

                (user_dn, ldap_attrs) = aldap.authenticate_ldap(username,

                                                                password)

                log.debug('Got ldap DN response %s' % user_dn)

                get_ldap_attr = lambda k: ldap_attrs.get(ldap_settings\

                                                           .get(k), [''])[0]

                user_attrs = {

                 'name': safe_unicode(get_ldap_attr('ldap_attr_firstname')),

                 'lastname': safe_unicode(get_ldap_attr('ldap_attr_lastname')),

                 'email': get_ldap_attr('ldap_attr_email'),

                }

                # don't store LDAP password since we don't need it. Override 

                # with some random generated password

                _password = PasswordGenerator().gen_password(length=8)

                # create this user on the fly if it doesn't exist in rhodecode

                # database

                if user_model.create_ldap(username, _password, user_dn,

                                          user_attrs):

                    log.info('created new ldap user %s' % username)

                Session.commit()

                return True

            except (LdapUsernameError, LdapPasswordError,):

                pass

            except (Exception,):

                log.error(traceback.format_exc())

                pass

    return False

def login_container_auth(username):

    user = User.get_by_username(username)

    if user is None:

        user_attrs = {

            'name': username,

            'lastname': None,

            'email': None,

        }

        user = UserModel().create_for_container_auth(username, user_attrs)

        if not user:

            return None

        log.info('User %s was created by container authentication' % username)

    if not user.active:

        return None

    user.update_lastlogin()

    Session.commit()

    log.debug('User %s is now logged in by container authentication',

              user.username)

    return user

def get_container_username(environ, config):

    username = None

    if str2bool(config.get('container_auth_enabled', False)):

        from paste.httpheaders import REMOTE_USER