# -*- 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.

"""

import hashlib

import itertools

import logging

import os

import ipaddr

from decorator import decorator

from sqlalchemy.orm import joinedload

from sqlalchemy.orm.exc import ObjectDeletedError

from tg import request

from tg.i18n import ugettext as _

from webob.exc import HTTPForbidden, HTTPFound

from kallithea import __platform__, is_unix, is_windows

from kallithea.config.routing import url

from kallithea.lib.caching_query import FromCache

from kallithea.lib.utils import conditional_cache, get_repo_group_slug, get_repo_slug, get_user_group_slug

from kallithea.lib.utils2 import safe_str, safe_unicode

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

from kallithea.model.db import (

    Permission, RepoGroup, Repository, User, UserApiKeys, UserGroup, UserGroupMember, UserGroupRepoGroupToPerm, UserGroupRepoToPerm, UserGroupToPerm, UserGroupUserGroupToPerm, UserIpMap, UserToPerm)

from kallithea.model.meta import Session

from kallithea.model.user import UserModel

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 gen_password(self, length, alphabet=ALPHABETS_FULL):

        assert len(alphabet) <= 256, alphabet

        l = []

        while len(l) < length:

            i = ord(os.urandom(1))

            if i < len(alphabet):

                l.append(alphabet[i])

        return ''.join(l)

def get_crypt_password(password):

    """

    Cryptographic function used for password hashing based on pybcrypt

    or Python's own OpenSSL wrapper on windows

    :param password: password to hash

    """

    if is_windows:

        return hashlib.sha256(password).hexdigest()

    elif is_unix:

        import bcrypt

        return bcrypt.hashpw(safe_str(password), bcrypt.gensalt(10))

    else:

        raise Exception('Unknown or unsupported platform %s'

                        % __platform__)

def check_password(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

    """

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

    elif is_unix:

        import bcrypt

        try:

            return bcrypt.checkpw(safe_str(password), safe_str(hashed))

        except ValueError as e:

            # bcrypt will throw ValueError 'Invalid hashed_password salt' on all password errors

            log.error('error from bcrypt checking password: %s', e)

            return False

    else:

        raise Exception('Unknown or unsupported platform %s'

                        % __platform__)

def _cached_perms_data(user_id, user_is_admin):

    RK = 'repositories'

    GK = 'repositories_groups'

    UK = 'user_groups'

    GLOBAL = 'global'

    PERM_WEIGHTS = Permission.PERM_WEIGHTS

    permissions = {RK: {}, GK: {}, UK: {}, GLOBAL: set()}

    def bump_permission(kind, key, new_perm):

        """Add a new permission for kind and key.

        Assuming the permissions are comparable, set the new permission if it

        has higher weight, else drop it and keep the old permission.

        """

        cur_perm = permissions[kind][key]

        new_perm_val = PERM_WEIGHTS[new_perm]

        cur_perm_val = PERM_WEIGHTS[cur_perm]

        if new_perm_val > cur_perm_val:

            permissions[kind][key] = new_perm

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

    # fetch default permissions

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

    default_user = User.get_by_username('default', cache=True)

    default_user_id = default_user.user_id

    default_repo_perms = Permission.get_default_perms(default_user_id)

    default_repo_groups_perms = Permission.get_default_group_perms(default_user_id)

    default_user_group_perms = Permission.get_default_user_group_perms(default_user_id)

    if user_is_admin:

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

        # admin users have all rights;

        # based on default permissions, just set everything to admin

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

        permissions[GLOBAL].add('hg.admin')

        permissions[GLOBAL].add('hg.create.write_on_repogroup.true')

        # repositories

        for perm in default_repo_perms:

            r_k = perm.UserRepoToPerm.repository.repo_name

            p = 'repository.admin'

            permissions[RK][r_k] = p

        # repository groups

        for perm in default_repo_groups_perms:

            rg_k = perm.UserRepoGroupToPerm.group.group_name

            p = 'group.admin'

            permissions[GK][rg_k] = p

        # user groups

        for perm in default_user_group_perms:

            u_k = perm.UserUserGroupToPerm.user_group.users_group_name

            p = 'usergroup.admin'

            permissions[UK][u_k] = p

        return permissions

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

    # SET DEFAULTS GLOBAL, REPOS, REPOSITORY GROUPS

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

    # default global permissions taken from the default user

    default_global_perms = UserToPerm.query() \

        .filter(UserToPerm.user_id == default_user_id) \

        .options(joinedload(UserToPerm.permission))

    for perm in default_global_perms:

        permissions[GLOBAL].add(perm.permission.permission_name)

    # defaults for repositories, taken from default user

    for perm in default_repo_perms:

        r_k = perm.UserRepoToPerm.repository.repo_name

        if perm.Repository.owner_id == user_id:

            p = 'repository.admin'

        elif perm.Repository.private:

            p = 'repository.none'

        else:

            p = perm.Permission.permission_name

        permissions[RK][r_k] = p

    # defaults for repository groups taken from default user permission

    # on given group

    for perm in default_repo_groups_perms:

        rg_k = perm.UserRepoGroupToPerm.group.group_name

        p = perm.Permission.permission_name

        permissions[GK][rg_k] = p

    # defaults for user groups taken from default user permission

    # on given user group

    for perm in default_user_group_perms:

        u_k = perm.UserUserGroupToPerm.user_group.users_group_name

        p = perm.Permission.permission_name

        permissions[UK][u_k] = p

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

    # !! Augment GLOBALS with user permissions if any found !!

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

    # USER GROUPS comes first

    # user group global permissions

    user_perms_from_users_groups = Session().query(UserGroupToPerm) \

        .options(joinedload(UserGroupToPerm.permission)) \

        .join((UserGroupMember, UserGroupToPerm.users_group_id ==

               UserGroupMember.users_group_id)) \

        .filter(UserGroupMember.user_id == user_id) \

        .join((UserGroup, UserGroupMember.users_group_id ==

               UserGroup.users_group_id)) \

        .filter(UserGroup.users_group_active == True) \

        .order_by(UserGroupToPerm.users_group_id) \

        .all()

    # need to group here by groups since user can be in more than

    # one group

    _grouped = [[x, list(y)] for x, y in

                itertools.groupby(user_perms_from_users_groups,

                                  lambda x:x.users_group)]

    for gr, perms in _grouped:

        for perm in perms:

            permissions[GLOBAL].add(perm.permission.permission_name)

    # user specific global permissions

    user_perms = Session().query(UserToPerm) \

            .options(joinedload(UserToPerm.permission)) \

            .filter(UserToPerm.user_id == user_id).all()

    for perm in user_perms:

        permissions[GLOBAL].add(perm.permission.permission_name)

    # for each kind of global permissions, only keep the one with heighest weight

    kind_max_perm = {}

    for perm in sorted(permissions[GLOBAL], key=lambda n: PERM_WEIGHTS[n]):

        kind = perm.rsplit('.', 1)[0]

        kind_max_perm[kind] = perm

    permissions[GLOBAL] = set(kind_max_perm.values())

    ## END GLOBAL PERMISSIONS

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

    # !! PERMISSIONS FOR REPOSITORIES !!

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

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

    # check if user is part of user groups for this repository and

    # fill in his permission from it.

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

    # user group for repositories permissions

    user_repo_perms_from_users_groups = \

     Session().query(UserGroupRepoToPerm, Permission, Repository,) \

        .join((Repository, UserGroupRepoToPerm.repository_id ==

               Repository.repo_id)) \

        .join((Permission, UserGroupRepoToPerm.permission_id ==

               Permission.permission_id)) \

        .join((UserGroup, UserGroupRepoToPerm.users_group_id ==

               UserGroup.users_group_id)) \

        .filter(UserGroup.users_group_active == True) \

        .join((UserGroupMember, UserGroupRepoToPerm.users_group_id ==

               UserGroupMember.users_group_id)) \

        .filter(UserGroupMember.user_id == user_id) \

        .all()

    for perm in user_repo_perms_from_users_groups:

        bump_permission(RK,

            perm.UserGroupRepoToPerm.repository.repo_name,

            perm.Permission.permission_name)

    # user permissions for repositories

    user_repo_perms = Permission.get_default_perms(user_id)

    for perm in user_repo_perms:

        bump_permission(RK,

            perm.UserRepoToPerm.repository.repo_name,

            perm.Permission.permission_name)

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

    # !! PERMISSIONS FOR REPOSITORY GROUPS !!

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

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

    # check if user is part of user groups for this repository groups and

    # fill in his permission from it.

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

    # user group for repo groups permissions

    user_repo_group_perms_from_users_groups = \

     Session().query(UserGroupRepoGroupToPerm, Permission, RepoGroup) \

     .join((RepoGroup, UserGroupRepoGroupToPerm.group_id == RepoGroup.group_id)) \

     .join((Permission, UserGroupRepoGroupToPerm.permission_id

            == Permission.permission_id)) \

     .join((UserGroup, UserGroupRepoGroupToPerm.users_group_id ==

            UserGroup.users_group_id)) \

     .filter(UserGroup.users_group_active == True) \

     .join((UserGroupMember, UserGroupRepoGroupToPerm.users_group_id

            == UserGroupMember.users_group_id)) \

     .filter(UserGroupMember.user_id == user_id) \

     .all()

    for perm in user_repo_group_perms_from_users_groups:

        bump_permission(GK,

            perm.UserGroupRepoGroupToPerm.group.group_name,

            perm.Permission.permission_name)

    # user explicit permissions for repository groups

    user_repo_groups_perms = Permission.get_default_group_perms(user_id)

    for perm in user_repo_groups_perms:

        bump_permission(GK,

            perm.UserRepoGroupToPerm.group.group_name,

            perm.Permission.permission_name)

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

    # !! PERMISSIONS FOR USER GROUPS !!

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

    # user group for user group permissions

    user_group_user_groups_perms = \

     Session().query(UserGroupUserGroupToPerm, Permission, UserGroup) \

     .join((UserGroup, UserGroupUserGroupToPerm.target_user_group_id

            == UserGroup.users_group_id)) \

     .join((Permission, UserGroupUserGroupToPerm.permission_id

            == Permission.permission_id)) \

     .join((UserGroupMember, UserGroupUserGroupToPerm.user_group_id

            == UserGroupMember.users_group_id)) \

     .filter(UserGroupMember.user_id == user_id) \

     .join((UserGroup, UserGroupMember.users_group_id ==

            UserGroup.users_group_id), aliased=True, from_joinpoint=True) \

     .filter(UserGroup.users_group_active == True) \

     .all()

    for perm in user_group_user_groups_perms:

        bump_permission(UK,

            perm.UserGroupUserGroupToPerm.target_user_group.users_group_name,

            perm.Permission.permission_name)

    # user explicit permission for user groups

    user_user_groups_perms = Permission.get_default_user_group_perms(user_id)

    for perm in user_user_groups_perms:

        bump_permission(UK,

            perm.UserUserGroupToPerm.user_group.users_group_name,

            perm.Permission.permission_name)

    return permissions

class AuthUser(object):

    """

    Represents a Kallithea user, including various authentication and

    authorization information. Typically used to store the current user,

    but is also used as a generic user information data structure in

    parts of the code, e.g. user management.

    Constructed from a database `User` object, a user ID or cookie dict,

    it looks up the user (if needed) and copies all attributes to itself,

    adding various non-persistent data. If lookup fails but anonymous

    access to Kallithea is enabled, the default user is loaded instead.

    `AuthUser` does not by itself authenticate users. It's up to other parts of

    the code to check e.g. if a supplied password is correct, and if so, trust

    the AuthUser object as an authenticated user.

    However, `AuthUser` does refuse to load a user that is not `active`.

    Note that Kallithea distinguishes between the default user (an actual

    user in the database with username "default") and "no user" (no actual

    User object, AuthUser filled with blank values and username "None").

    If the default user is active, that will always be used instead of

    "no user". On the other hand, if the default user is disabled (and

    there is no login information), we instead get "no user"; this should

    only happen on the login page (as all other requests are redirected).

    `is_default_user` specifically checks if the AuthUser is the user named

    "default". Use `is_anonymous` to check for both "default" and "no user".

    """

    @classmethod

    def make(cls, dbuser=None, is_external_auth=False, ip_addr=None):

        """Create an AuthUser to be authenticated ... or return None if user for some reason can't be authenticated.

        Checks that a non-None dbuser is provided, is active, and that the IP address is ok.

        """

        assert ip_addr is not None

        if dbuser is None:

            log.info('No db user for authentication')

            return None

        if not dbuser.active:

            log.info('Db user %s not active', dbuser.username)

            return None

        allowed_ips = AuthUser.get_allowed_ips(dbuser.user_id, cache=True)

        if not check_ip_access(source_ip=ip_addr, allowed_ips=allowed_ips):

            log.info('Access for %s from %s forbidden - not in %s', dbuser.username, ip_addr, allowed_ips)

            return None

        return cls(dbuser=dbuser, is_external_auth=is_external_auth)

    def __init__(self, user_id=None, dbuser=None, is_external_auth=False):

        self.is_external_auth = is_external_auth # container auth - don't show logout option

        # These attributes will be overridden by fill_data, below, unless the

        # requested user cannot be found and the default anonymous user is

        # not enabled.

        self.user_id = None

        self.username = None

        self.api_key = None

        self.name = ''

        self.lastname = ''

        self.email = ''

        self.admin = False

        # Look up database user, if necessary.

        if user_id is not None:

            assert dbuser is None

            log.debug('Auth User lookup by USER ID %s', user_id)

            dbuser = UserModel().get(user_id)

            assert dbuser is not None

        else:

            assert dbuser is not None

            log.debug('Auth User lookup by database user %s', dbuser)

        log.debug('filling %s data', dbuser)

        self.is_anonymous = dbuser.is_default_user

        if dbuser.is_default_user and not dbuser.active:

            self.username = 'None'

            self.is_default_user = False

        else:

            # copy non-confidential database fields from a `db.User` to this `AuthUser`.

            for k, v in dbuser.get_dict().iteritems():

                assert k not in ['api_keys', 'permissions']

                setattr(self, k, v)

            self.is_default_user = dbuser.is_default_user

        log.debug('Auth User is now %s', self)

    @LazyProperty

    def permissions(self):

        return self.__get_perms(user=self, cache=False)

    def has_repository_permission_level(self, repo_name, level, purpose=None):

        required_perms = {

            'read': ['repository.read', 'repository.write', 'repository.admin'],

            'write': ['repository.write', 'repository.admin'],

            'admin': ['repository.admin'],

        }[level]

        actual_perm = self.permissions['repositories'].get(repo_name)

        ok = actual_perm in required_perms

        log.debug('Checking if user %r can %r repo %r (%s): %s (has %r)',

            self.username, level, repo_name, purpose, ok, actual_perm)

        return ok

    def has_repository_group_permission_level(self, repo_group_name, level, purpose=None):

        required_perms = {

            'read': ['group.read', 'group.write', 'group.admin'],

            'write': ['group.write', 'group.admin'],

            'admin': ['group.admin'],

        }[level]

        actual_perm = self.permissions['repositories_groups'].get(repo_group_name)

        ok = actual_perm in required_perms

        log.debug('Checking if user %r can %r repo group %r (%s): %s (has %r)',

            self.username, level, repo_group_name, purpose, ok, actual_perm)

        return ok

    def has_user_group_permission_level(self, user_group_name, level, purpose=None):

        required_perms = {

            'read': ['usergroup.read', 'usergroup.write', 'usergroup.admin'],

            'write': ['usergroup.write', 'usergroup.admin'],

            'admin': ['usergroup.admin'],

        }[level]

        actual_perm = self.permissions['user_groups'].get(user_group_name)

        ok = actual_perm in required_perms

        log.debug('Checking if user %r can %r user group %r (%s): %s (has %r)',

            self.username, level, user_group_name, purpose, ok, actual_perm)

        return ok

    @property

    def api_keys(self):

        return self._get_api_keys()

    def __get_perms(self, user, cache=False):

        """

        Fills user permission attribute with permissions taken from database

        works for permissions given for repositories, and for permissions that

        are granted to groups