#! /usr/bin/env python
# Newspipe - A web news aggregator.
# Copyright (C) 2010-2022 Cédric Bonhomme - https://www.cedricbonhomme.org
#
# For more information: https://sr.ht/~cedric/newspipe
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

__author__ = "Cedric Bonhomme"
__version__ = "$Revision: 0.4 $"
__date__ = "$Date: 2013/11/05 $"
__revision__ = "$Date: 2014/04/12 $"
__copyright__ = "Copyright (c) Cedric Bonhomme"
__license__ = "GPLv3"

from sqlalchemy.engine import reflection
from sqlalchemy.schema import (
    DropConstraint,
    DropTable,
    ForeignKeyConstraint,
    MetaData,
    Table,
)

from .article import Article
from .bookmark import Bookmark
from .category import Category
from .feed import Feed
from .icon import Icon
from .role import Role
from .tag import ArticleTag, BookmarkTag
from .user import User

__all__ = [
    "Feed",
    "Role",
    "User",
    "Article",
    "Icon",
    "Category",
    "Bookmark",
    "ArticleTag",
    "BookmarkTag",
]


def db_empty(db):
    "Will drop every datas stocked in db."
    # From http://www.sqlalchemy.org/trac/wiki/UsageRecipes/DropEverything
    conn = db.engine.connect()

    # the transaction only applies if the DB supports
    # transactional DDL, i.e. Postgresql, MS SQL Server
    trans = conn.begin()

    inspector = reflection.Inspector.from_engine(db.engine)

    # gather all data first before dropping anything.
    # some DBs lock after things have been dropped in
    # a transaction.
    metadata = MetaData()

    tbs = []
    all_fks = []

    for table_name in inspector.get_table_names():
        fks = []
        for fk in inspector.get_foreign_keys(table_name):
            if not fk["name"]:
                continue
            fks.append(ForeignKeyConstraint((), (), name=fk["name"]))
        t = Table(table_name, metadata, *fks)
        tbs.append(t)
        all_fks.extend(fks)

    for fkc in all_fks:
        conn.execute(DropConstraint(fkc))

    for table in tbs:
        conn.execute(DropTable(table))

    trans.commit()