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

# Haketilo proxy data and configuration (definition of fields of a class that
# will implement HaketiloState).
#
# 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.

"""
This module defines fields that will later be part of a concrete HaketiloState
subtype.
"""

# Enable using with Python 3.7.
from __future__ import annotations

import sqlite3
import threading
import dataclasses as dc
import typing as t

from pathlib import Path
from contextlib import contextmanager

import sqlite3

from immutables import Map

from ... import pattern_tree
from .. import state
from .. import policies


PolicyTree = pattern_tree.PatternTree[policies.PolicyFactory]
PayloadsData = t.Mapping[state.PayloadRef, state.PayloadData]

# mypy needs to be corrected:
# https://stackoverflow.com/questions/70999513/conflict-between-mix-ins-for-abstract-dataclasses/70999704#70999704
@dc.dataclass # type: ignore[misc]
class HaketiloStateWithFields(state.HaketiloState):
    """...."""
    store_dir:      Path
    connection:     sqlite3.Connection
    current_cursor: t.Optional[sqlite3.Cursor] = None
    #settings:       state.HaketiloGlobalSettings

    policy_tree:   PolicyTree   = PolicyTree()
    payloads_data: PayloadsData = dc.field(default_factory=dict)

    lock: threading.RLock = dc.field(default_factory=threading.RLock)

    @contextmanager
    def cursor(self, transaction: bool = False) \
        -> t.Iterator[sqlite3.Cursor]:
        """...."""
        start_transaction = transaction and not self.connection.in_transaction

        with self.lock:
            if self.current_cursor is not None:
                yield self.current_cursor
                return

            try:
                self.current_cursor = self.connection.cursor()

                if start_transaction:
                    self.current_cursor.execute('BEGIN TRANSACTION;')

                try:
                    yield self.current_cursor

                    if start_transaction:
                        assert self.connection.in_transaction
                        self.current_cursor.execute('COMMIT TRANSACTION;')
                except:
                    if start_transaction:
                        self.current_cursor.execute('ROLLBACK TRANSACTION;')
                    raise
            finally:
                self.current_cursor = None

    def recompute_payloads(self, cursor: sqlite3.Cursor) -> None:
        """...."""
        ...