# -*- 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 string

import bcrypt

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

import kallithea

from kallithea.config.routing import url

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

from kallithea.lib.utils2 import ascii_bytes, ascii_str, safe_bytes

from kallithea.model.db import (Permission, 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 bcrypt password hashing.

    :param password: password to hash

    """

    return ascii_str(bcrypt.hashpw(safe_bytes(password), bcrypt.gensalt(10)))

def check_password(password, hashed):

    """

    Checks password match the hashed value using bcrypt.

    Remains backwards compatible and accept plain sha256 hashes which used to

    be used on Windows.

    :param password: password

    :param hashed: password in hashed form

    """

    # sha256 hashes will always be 64 hex chars

    # bcrypt hashes will always contain $ (and be shorter)

    if len(hashed) == 64 and all(x in string.hexdigits for x in hashed):

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

    try:

        return bcrypt.checkpw(safe_bytes(password), ascii_bytes(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

    log.error('check_password failed - no method found for hash length %s', len(hashed))

    return False

def get_user_permissions(user_id, user_is_admin):

    PERM_WEIGHTS = Permission.PERM_WEIGHTS

    repository_permissions = {}

    repository_group_permissions = {}

    user_group_permissions = {}

    global_permissions = set()

    def bump_permission(permissions, key, new_perm):

        """Add a new permission for key to permissions.

        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[key]

        new_perm_val = PERM_WEIGHTS[new_perm]

        cur_perm_val = PERM_WEIGHTS[cur_perm]

        if new_perm_val > cur_perm_val:

            permissions[key] = new_perm

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

    # fetch default permissions

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

    default_repo_perms = Permission.get_default_perms(kallithea.DEFAULT_USER_ID)

    for perm in user_user_groups_perms:

        bump_permission(user_group_permissions,

            perm.user_group.users_group_name,

            perm.permission.permission_name)

    return (repository_permissions, repository_group_permissions, user_group_permissions, global_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)

        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 below if the requested user is

        # found or anonymous access (using the default user) is 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().items():

                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)

        log.debug('Getting PERMISSION tree for %s', self)

        (self.repository_permissions, self.repository_group_permissions, self.user_group_permissions, self.global_permissions,

        )= get_user_permissions(self.user_id, self.is_admin)

            'global': self.global_permissions,

            'repositories': self.repository_permissions,

            'repositories_groups': self.repository_group_permissions,

            'user_groups': self.user_group_permissions,

    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.repository_permissions.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.repository_group_permissions.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.user_group_permissions.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_api_keys(self):

        api_keys = [self.api_key]

        for api_key in UserApiKeys.query() \

                .filter_by(user_id=self.user_id, is_expired=False):

            api_keys.append(api_key.api_key)

        return api_keys

    @property

    def is_admin(self):

        return self.admin

    @property

    def repositories_admin(self):

        """

        Returns list of repositories you're an admin of

        """

        return [x[0] for x in self.repository_permissions.items()

                if x[1] == 'repository.admin']

    @property

    def repository_groups_admin(self):

        """

        Returns list of repository groups you're an admin of

        """

        return [x[0] for x in self.repository_group_permissions.items()

                if x[1] == 'group.admin']

    @property

    def user_groups_admin(self):

        """

        Returns list of user groups you're an admin of

        """

        return [x[0] for x in self.user_group_permissions.items()

                if x[1] == 'usergroup.admin']

    def __repr__(self):

        return "<%s %s: %r>" % (self.__class__.__name__, self.user_id, self.username)

    def to_cookie(self):

        """ Serializes this login session to a cookie `dict`. """

        return {

            'user_id': self.user_id,

            'is_external_auth': self.is_external_auth,

        }

    @staticmethod

    def from_cookie(cookie, ip_addr):

        """

        Deserializes an `AuthUser` from a cookie `dict` ... or return None.

        """

        return AuthUser.make(

            dbuser=UserModel().get(cookie.get('user_id')),

            is_external_auth=cookie.get('is_external_auth', False),

            ip_addr=ip_addr,