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# Copyright 2012 OpenStack LLC
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

from keystone.common import dependency
from keystone.common import sql
from keystone.common.sql import migration
from keystone.common import utils
from keystone import exception
from keystone import identity


class User(sql.ModelBase, sql.DictBase):
    __tablename__ = 'user'
    attributes = ['id', 'name', 'domain_id', 'password', 'enabled']
    id = sql.Column(sql.String(64), primary_key=True)
    name = sql.Column(sql.String(64), nullable=False)
    domain_id = sql.Column(sql.String(64), sql.ForeignKey('domain.id'),
                           nullable=False)
    password = sql.Column(sql.String(128))
    enabled = sql.Column(sql.Boolean)
    extra = sql.Column(sql.JsonBlob())
    # Unique constraint across two columns to create the separation
    # rather than just only 'name' being unique
    __table_args__ = (sql.UniqueConstraint('domain_id', 'name'), {})


class Group(sql.ModelBase, sql.DictBase):
    __tablename__ = 'group'
    attributes = ['id', 'name', 'domain_id', 'description']
    id = sql.Column(sql.String(64), primary_key=True)
    name = sql.Column(sql.String(64), nullable=False)
    domain_id = sql.Column(sql.String(64), sql.ForeignKey('domain.id'),
                           nullable=False)
    description = sql.Column(sql.Text())
    extra = sql.Column(sql.JsonBlob())
    # Unique constraint across two columns to create the separation
    # rather than just only 'name' being unique
    __table_args__ = (sql.UniqueConstraint('domain_id', 'name'), {})


class UserGroupMembership(sql.ModelBase, sql.DictBase):
    """Group membership join table."""
    __tablename__ = 'user_group_membership'
    user_id = sql.Column(sql.String(64),
                         sql.ForeignKey('user.id'),
                         primary_key=True)
    group_id = sql.Column(sql.String(64),
                          sql.ForeignKey('group.id'),
                          primary_key=True)


@dependency.requires('assignment_api')
class Identity(sql.Base, identity.Driver):
    def default_assignment_driver(self):
        return "keystone.assignment.backends.sql.Assignment"

    # Internal interface to manage the database
    def db_sync(self, version=None):
        migration.db_sync(version=version)

    def _check_password(self, password, user_ref):
        """Check the specified password against the data store.

        This is modeled on ldap/core.py.  The idea is to make it easier to
        subclass Identity so that you can still use it to store all the data,
        but use some other means to check the password.
        Note that we'll pass in the entire user_ref in case the subclass
        needs things like user_ref.get('name')
        For further justification, please see the follow up suggestion at
        https://blueprints.launchpad.net/keystone/+spec/sql-identiy-pam

        """
        return utils.check_password(password, user_ref.password)

    # Identity interface
    def authenticate(self, user_id, password):
        session = self.get_session()
        user_ref = None
        try:
            user_ref = self._get_user(session, user_id)
        except exception.UserNotFound:
            raise AssertionError('Invalid user / password')
        if not self._check_password(password, user_ref):
            raise AssertionError('Invalid user / password')
        return identity.filter_user(user_ref.to_dict())

    # user crud

    @sql.handle_conflicts(type='user')
    def create_user(self, user_id, user):
        user = utils.hash_user_password(user)
        session = self.get_session()
        with session.begin():
            user_ref = User.from_dict(user)
            session.add(user_ref)
            session.flush()
        return identity.filter_user(user_ref.to_dict())

    def list_users(self):
        session = self.get_session()
        user_refs = session.query(User)
        return [identity.filter_user(x.to_dict()) for x in user_refs]

    def _get_user(self, session, user_id):
        user_ref = session.query(User).get(user_id)
        if not user_ref:
            raise exception.UserNotFound(user_id=user_id)
        return user_ref

    def get_user(self, user_id):
        session = self.get_session()
        return identity.filter_user(self._get_user(session, user_id).to_dict())

    def get_user_by_name(self, user_name, domain_id):
        session = self.get_session()
        query = session.query(User)
        query = query.filter_by(name=user_name)
        query = query.filter_by(domain_id=domain_id)
        try:
            user_ref = query.one()
        except sql.NotFound:
            raise exception.UserNotFound(user_id=user_name)
        return identity.filter_user(user_ref.to_dict())

    @sql.handle_conflicts(type='user')
    def update_user(self, user_id, user):
        session = self.get_session()
        if 'id' in user and user_id != user['id']:
            raise exception.ValidationError('Cannot change user ID')

        with session.begin():
            user_ref = self._get_user(session, user_id)
            old_user_dict = user_ref.to_dict()
            user = utils.hash_user_password(user)
            for k in user:
                old_user_dict[k] = user[k]
            new_user = User.from_dict(old_user_dict)
            for attr in User.attributes:
                if attr != 'id':
                    setattr(user_ref, attr, getattr(new_user, attr))
            user_ref.extra = new_user.extra
            session.flush()
        return identity.filter_user(user_ref.to_dict(include_extra_dict=True))

    def add_user_to_group(self, user_id, group_id):
        session = self.get_session()
        self.get_group(group_id)
        self.get_user(user_id)
        query = session.query(UserGroupMembership)
        query = query.filter_by(user_id=user_id)
        query = query.filter_by(group_id=group_id)
        rv = query.first()
        if rv:
            return

        with session.begin():
            session.add(UserGroupMembership(user_id=user_id,
                                            group_id=group_id))
            session.flush()

    def check_user_in_group(self, user_id, group_id):
        session = self.get_session()
        self.get_group(group_id)
        self.get_user(user_id)
        query = session.query(UserGroupMembership)
        query = query.filter_by(user_id=user_id)
        query = query.filter_by(group_id=group_id)
        if not query.first():
            raise exception.NotFound('User not found in group')

    def remove_user_from_group(self, user_id, group_id):
        session = self.get_session()
        # We don't check if user or group are still valid and let the remove
        # be tried anyway - in case this is some kind of clean-up operation
        query = session.query(UserGroupMembership)
        query = query.filter_by(user_id=user_id)
        query = query.filter_by(group_id=group_id)
        membership_ref = query.first()
        if membership_ref is None:
            raise exception.NotFound('User not found in group')
        with session.begin():
            session.delete(membership_ref)
            session.flush()

    def list_groups_for_user(self, user_id):
        session = self.get_session()
        self.get_user(user_id)
        query = session.query(UserGroupMembership)
        query = query.filter_by(user_id=user_id)
        membership_refs = query.all()
        return [self.get_group(x.group_id) for x in membership_refs]

    def list_users_in_group(self, group_id):
        session = self.get_session()
        self.get_group(group_id)
        query = session.query(UserGroupMembership)
        query = query.filter_by(group_id=group_id)
        membership_refs = query.all()
        return [self.get_user(x.user_id) for x in membership_refs]

    def delete_user(self, user_id):
        session = self.get_session()

        with session.begin():
            ref = self._get_user(session, user_id)

            q = session.query(UserGroupMembership)
            q = q.filter_by(user_id=user_id)
            q.delete(False)

            session.delete(ref)
            session.flush()
        self.assignment_api.delete_user(user_id)

    # group crud

    @sql.handle_conflicts(type='group')
    def create_group(self, group_id, group):
        session = self.get_session()
        with session.begin():
            ref = Group.from_dict(group)
            session.add(ref)
            session.flush()
        return ref.to_dict()

    def list_groups(self):
        session = self.get_session()
        refs = session.query(Group).all()
        return [ref.to_dict() for ref in refs]

    def _get_group(self, session, group_id):
        ref = session.query(Group).get(group_id)
        if not ref:
            raise exception.GroupNotFound(group_id=group_id)
        return ref

    def get_group(self, group_id):
        session = self.get_session()
        return self._get_group(session, group_id).to_dict()

    @sql.handle_conflicts(type='group')
    def update_group(self, group_id, group):
        session = self.get_session()

        with session.begin():
            ref = self._get_group(session, group_id)
            old_dict = ref.to_dict()
            for k in group:
                old_dict[k] = group[k]
            new_group = Group.from_dict(old_dict)
            for attr in Group.attributes:
                if attr != 'id':
                    setattr(ref, attr, getattr(new_group, attr))
            ref.extra = new_group.extra
            session.flush()
        return ref.to_dict()

    def delete_group(self, group_id):
        session = self.get_session()

        with session.begin():
            ref = self._get_group(session, group_id)

            q = session.query(UserGroupMembership)
            q = q.filter_by(group_id=group_id)
            q.delete(False)

            session.delete(ref)
            session.flush()
        self.assignment_api.delete_group(group_id)