# SPDX-License-Identifier: GPL-3.0-or-later

# Haketilo proxy data and configuration (removal of packages that are not used).
#
# This file is part of Hydrilla&Haketilo.
#
# Copyright (C) 2022 Wojtek Kosior
#
# 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 <https://www.gnu.org/licenses/>.
#
#
# I, Wojtek Kosior, thereby promise not to sue for violation of this
# file's license. Although I request that you do not make use this code
# in a proprietary program, I am not going to enforce this in court.

"""
....
"""

# Enable using with Python 3.7.
from __future__ import annotations

import sqlite3

from pathlib import Path


_remove_mapping_versions_sqls = [
    '''
    CREATE TEMPORARY TABLE removed_mappings(
            item_version_id INTEGER PRIMARY KEY
    );
    ''', '''
    INSERT INTO
            removed_mappings
    SELECT
            iv.item_version_id
    FROM
                 item_versions     AS iv
            JOIN items             AS i  USING (item_id)
            JOIN mapping_statuses  AS ms USING (item_id)
            JOIN orphan_iterations AS oi USING (repo_iteration_id)
    WHERE
            NOT ms.required;
    ''', '''
    UPDATE
            mapping_statuses
    SET
            active_version_id = NULL
    WHERE
            active_version_id IN removed_mappings;
    ''', '''
    DELETE FROM
            item_versions
    WHERE
            item_version_id IN removed_mappings;
    ''', '''
    DROP TABLE removed_mappings;
    '''
]

_remove_resource_versions_sql = '''
WITH removed_resources AS (
        SELECT
                iv.item_version_id
        FROM
                          item_versions               AS iv
                JOIN      items                       AS i
                        USING (item_id)
                JOIN      orphan_iterations           AS oi
                        USING (repo_iteration_id)
                LEFT JOIN resolved_depended_resources AS rdr
                        ON rdr.resource_item_id = iv.item_version_id
        WHERE
                rdr.payload_id IS NULL
)
DELETE FROM
        item_versions
WHERE
        item_version_id IN removed_resources;
'''

_remove_items_sql = '''
WITH removed_items AS (
        SELECT
                i.item_id
        FROM
                          items            AS i
                LEFT JOIN item_versions    AS iv USING (item_id)
                LEFT JOIN mapping_statuses AS ms USING (item_id)
        WHERE
                 iv.item_version_id IS NULL AND
                 i.type = 'R' OR ms.enabled = 'N'
)
DELETE FROM
        items
WHERE
        item_id IN removed_items;
'''

_remove_files_sql = '''
WITH removed_files AS (
        SELECT
                f.file_id
        FROM
                          files     AS f
                LEFT JOIN file_uses AS fu USING (file_id)
        WHERE
                fu.file_use_id IS NULL
)
DELETE FROM
        files
WHERE
        file_id IN removed_files;
'''

_remove_repo_iterations_sql = '''
WITH removed_iterations AS (
        SELECT
                oi.repo_iteration_id
        FROM
                          orphan_iterations AS oi
                LEFT JOIN item_versions     AS iv USING (repo_iteration_id)
        WHERE
                iv.item_version_id IS NULL
)
DELETE FROM
        repo_iterations
WHERE
        repo_iteration_id IN removed_iterations;
'''

_remove_repos_sql = '''
WITH removed_repos AS (
        SELECT
                r.repo_id
        FROM
                          repos           AS r
                LEFT JOIN repo_iterations AS ri USING (repo_id)
        WHERE
                r.deleted AND ri.repo_iteration_id IS NULL AND r.repo_id != 1
)
DELETE FROM
        repos
WHERE
        repo_id IN removed_repos;
'''

def prune_packages(cursor: sqlite3.Cursor) -> None:
    assert cursor.connection.in_transaction

    for sql in _remove_mapping_versions_sqls:
        cursor.execute(sql)
    cursor.execute(_remove_resource_versions_sql)
    cursor.execute(_remove_items_sql)
    cursor.execute(_remove_files_sql)
    cursor.execute(_remove_repo_iterations_sql)
    cursor.execute(_remove_repos_sql)