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

# Haketilo proxy data and configuration (instantiatable HaketiloState subtype).
#
# 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 contains logic for keeping track of all settings, rules, mappings
and resources.
"""

# Enable using with Python 3.7.
from __future__ import annotations

import sqlite3
import typing as t
import dataclasses as dc

from pathlib import Path

from ...exceptions import HaketiloException
from ...translations import smart_gettext as _
from ... import url_patterns
from ... import item_infos
from .. import state as st
from .. import policies
from .. import simple_dependency_satisfying as sds
from . import base
from . import mappings
from . import repos
from . import _operations


here = Path(__file__).resolve().parent


@dc.dataclass(frozen=True, unsafe_hash=True)
class ConcreteRepoIterationRef(st.RepoIterationRef):
    pass


@dc.dataclass(frozen=True, unsafe_hash=True)
class ConcreteResourceRef(st.ResourceRef):
    pass


@dc.dataclass(frozen=True, unsafe_hash=True)
class ConcreteResourceVersionRef(st.ResourceVersionRef):
    pass

@dc.dataclass
class ConcreteHaketiloState(base.HaketiloStateWithFields):
    def __post_init__(self) -> None:
        sqlite3.enable_callback_tracebacks(True)

        self._prepare_database()

        self.rebuild_structures()

    def _prepare_database(self) -> None:
        """...."""
        cursor = self.connection.cursor()

        try:
            cursor.execute(
                '''
                SELECT
                        COUNT(name)
                FROM
                        sqlite_master
                WHERE
                        name = 'general' AND type = 'table';
                '''
            )

            (db_initialized,), = cursor.fetchall()

            if not db_initialized:
                cursor.executescript((here.parent / 'tables.sql').read_text())

            else:
                cursor.execute(
                    '''
                    SELECT
                            haketilo_version
                    FROM
                            general;
                    '''
                )

                (db_haketilo_version,) = cursor.fetchone()
                if db_haketilo_version != '3.0b1':
                    raise HaketiloException(_('err.proxy.unknown_db_schema'))

            cursor.execute('PRAGMA FOREIGN_KEYS;')
            if cursor.fetchall() == []:
                raise HaketiloException(_('err.proxy.no_sqlite_foreign_keys'))

            cursor.execute('PRAGMA FOREIGN_KEYS=ON;')
        finally:
            cursor.close()

    def import_packages(self, malcontent_path: Path) -> None:
        with self.cursor(transaction=True) as cursor:
            _operations._load_packages_no_state_update(
                cursor          = cursor,
                malcontent_path = malcontent_path,
                repo_id         = 1
            )

            self.rebuild_structures()

    def recompute_dependencies(
            self,
            extra_requirements: t.Iterable[sds.MappingRequirement] = []
    ) -> None:
        with self.cursor() as cursor:
            assert self.connection.in_transaction

            _operations._recompute_dependencies_no_state_update(
                cursor             = cursor,
                extra_requirements = extra_requirements
            )

            self.rebuild_structures()

    def repo_store(self) -> st.RepoStore:
        return repos.ConcreteRepoStore(self)

    def get_repo_iteration(self, repo_iteration_id: str) -> st.RepoIterationRef:
        return ConcreteRepoIterationRef(repo_iteration_id)

    def mapping_store(self) -> st.MappingStore:
        return mappings.ConcreteMappingStore(self)

    def mapping_version_store(self) -> st.MappingVersionStore:
        return mappings.ConcreteMappingVersionStore(self)

    def get_resource(self, resource_id: str) -> st.ResourceRef:
        return ConcreteResourceRef(resource_id)

    def get_resource_version(self, resource_version_id: str) \
        -> st.ResourceVersionRef:
        return ConcreteResourceVersionRef(resource_version_id)

    def get_payload(self, payload_id: str) -> st.PayloadRef:
        raise NotImplementedError()

    def get_settings(self) -> st.HaketiloGlobalSettings:
        return st.HaketiloGlobalSettings(
            mapping_use_mode       = st.MappingUseMode.AUTO,
            default_allow_scripts  = True,
            repo_refresh_seconds   = 0
        )

    def update_settings(
            self,
            *,
            mapping_use_mode:      t.Optional[st.MappingUseMode] = None,
            default_allow_scripts: t.Optional[bool]              = None,
            repo_refresh_seconds:  t.Optional[int]               = None
    ) -> None:
        raise NotImplementedError()

    def select_policy(self, url: url_patterns.ParsedUrl) -> policies.Policy:
        """...."""
        with self.lock:
            policy_tree = self.policy_tree

        try:
            best_priority: int                         = 0
            best_policy:   t.Optional[policies.Policy] = None

            for factories_set in policy_tree.search(url):
                for stored_factory in sorted(factories_set):
                    factory = stored_factory.item

                    policy = factory.make_policy(self)

                    if policy.priority > best_priority:
                        best_priority = policy.priority
                        best_policy   = policy
        except Exception as e:
            return policies.ErrorBlockPolicy(
                builtin = True,
                error   = e
            )

        if best_policy is not None:
            return best_policy

        if self.get_settings().default_allow_scripts:
            return policies.FallbackAllowPolicy()
        else:
            return policies.FallbackBlockPolicy()

    @staticmethod
    def make(store_dir: Path) -> 'ConcreteHaketiloState':
        connection = sqlite3.connect(
            str(store_dir / 'sqlite3.db'),
            isolation_level   = None,
            check_same_thread = False
        )
        return ConcreteHaketiloState(
            store_dir      = store_dir,
            connection     = connection
        )