# 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 secrets
import threading
import typing as t
import dataclasses as dc

from pathlib import Path

from ..pattern_tree import PatternTree
from .. import url_patterns
from .. import versions
from .. import item_infos
from .simple_dependency_satisfying import ItemsCollection, ComputedPayload
from . import state as st
from . import policies


@dc.dataclass(frozen=True, unsafe_hash=True) # type: ignore[misc]
class ConcreteRepoRef(st.RepoRef):
    def remove(self, state: st.HaketiloState) -> None:
        raise NotImplementedError()

    def update(
            self,
            state: st.HaketiloState,
            *,
            name: t.Optional[str] = None,
            url:  t.Optional[str] = None
    ) -> ConcreteRepoRef:
        raise NotImplementedError()

    def refresh(self, state: st.HaketiloState) -> ConcreteRepoIterationRef:
        raise NotImplementedError()


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


@dc.dataclass(frozen=True, unsafe_hash=True)
class ConcreteMappingRef(st.MappingRef):
    def disable(self, state: st.HaketiloState) -> None:
        raise NotImplementedError()

    def forget_enabled(self, state: st.HaketiloState) -> None:
        raise NotImplementedError()


@dc.dataclass(frozen=True, unsafe_hash=True)
class ConcreteMappingVersionRef(st.MappingVersionRef):
    def enable(self, state: st.HaketiloState) -> None:
        raise NotImplementedError()


@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(frozen=True, unsafe_hash=True)
class ConcretePayloadRef(st.PayloadRef):
    computed_payload: ComputedPayload = dc.field(hash=False, compare=False)

    def get_data(self, state: st.HaketiloState) -> st.PayloadData:
        return t.cast(ConcreteHaketiloState, state).payloads_data[self.id]

    def get_mapping(self, state: st.HaketiloState) -> st.MappingVersionRef:
        return 'to implement'

    def get_script_paths(self, state: st.HaketiloState) \
        -> t.Iterator[t.Sequence[str]]:
        for resource_info in self.computed_payload.resources:
            for file_spec in resource_info.scripts:
                yield (resource_info.identifier, *file_spec.name.split('/'))

    def get_file_data(self, state: st.HaketiloState, path: t.Sequence[str]) \
        -> t.Optional[st.FileData]:
        if len(path) == 0:
            raise st.MissingItemError()

        resource_identifier, *file_name_segments = path

        file_name = '/'.join(file_name_segments)

        script_sha256 = ''

        matched_resource_info = False

        for resource_info in self.computed_payload.resources:
            if resource_info.identifier == resource_identifier:
                matched_resource_info = True

                for script_spec in resource_info.scripts:
                    if script_spec.name == file_name:
                        script_sha256 = script_spec.sha256

                break

        if not matched_resource_info:
            raise st.MissingItemError(resource_identifier)

        if script_sha256 == '':
            return None

        store_dir_path = t.cast(ConcreteHaketiloState, state).store_dir
        files_dir_path = store_dir_path / 'temporary_malcontent' / 'file'
        file_path = files_dir_path / 'sha256' / script_sha256

        return st.FileData(
            type     = 'application/javascript',
            name     = file_name,
            contents = file_path.read_bytes()
        )


# @dc.dataclass(frozen=True, unsafe_hash=True)
# class DummyPayloadRef(ConcretePayloadRef):
#     paths = {
#         ('someresource', 'somefolder', 'somescript.js'): st.FileData(
#             type     = 'application/javascript',
#             name     = 'somefolder/somescript.js',
#             contents = b'console.log("hello, mitmproxy")'
#         )
#     }

#     def get_data(self, state: st.HaketiloState) -> st.PayloadData:
#         parsed_pattern = next(url_patterns.parse_pattern('https://example.com'))

#         return st.PayloadData(
#             payload_ref         = self,
#             mapping_installed   = True,
#             explicitly_enabled  = True,
#             unique_token        = 'g54v45g456h4r',
#             pattern             = parsed_pattern,
#             eval_allowed        = True,
#             cors_bypass_allowed = True
#         )

#     def get_mapping(self, state: st.HaketiloState) -> st.MappingVersionRef:
#         return ConcreteMappingVersionRef('somemapping')

#     def get_file_paths(self, state: st.HaketiloState) \
#         -> t.Iterable[t.Sequence[str]]:
#         return tuple(self.paths.keys())

#     def get_file_data(self, state: st.HaketiloState, path: t.Sequence[str]) \
#         -> t.Optional[st.FileData]:
#         return self.paths[tuple(path)]


PolicyTree = PatternTree[policies.PolicyFactory]

def register_payload(
        policy_tree: PolicyTree,
        payload_key: st.PayloadKey,
        token:       str
) -> PolicyTree:
    """...."""
    payload_policy_factory = policies.PayloadPolicyFactory(
        builtin     = False,
        payload_key = payload_key
    )

    policy_tree = policy_tree.register(
        payload_key.pattern,
        payload_policy_factory
    )

    resource_policy_factory = policies.PayloadResourcePolicyFactory(
        builtin     = False,
        payload_key = payload_key
    )

    policy_tree = policy_tree.register(
        payload_key.pattern.path_append(token, '***'),
        resource_policy_factory
    )

    return policy_tree

DataById = t.Mapping[str, st.PayloadData]

AnyInfo = t.TypeVar('AnyInfo', item_infos.ResourceInfo, item_infos.MappingInfo)

@dc.dataclass
class ConcreteHaketiloState(st.HaketiloState):
    store_dir:     Path
    #    settings:       state.HaketiloGlobalSettings
    policy_tree:   PolicyTree = PatternTree()
    payloads_data: DataById   = dc.field(default_factory=dict)

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

    def __post_init__(self) -> None:
        def newest_item_path(item_dir: Path) -> t.Optional[Path]:
            available_versions = tuple(
                versions.parse_normalize_version(ver_path.name)
                for ver_path in item_dir.iterdir()
                if ver_path.is_file()
            )

            if available_versions == ():
                return None

            newest_version = max(available_versions)

            version_path = item_dir / versions.version_string(newest_version)

            assert version_path.is_file()

            return version_path

        def read_items(dir_path: Path, item_class: t.Type[AnyInfo]) \
            -> t.Mapping[str, AnyInfo]:
            items: dict[str, AnyInfo] = {}

            for resource_dir in dir_path.iterdir():
                if not resource_dir.is_dir():
                    continue

                item_path = newest_item_path(resource_dir)
                if item_path is None:
                    continue

                item = item_class.load(item_path)

                assert versions.version_string(item.version) == item_path.name
                assert item.identifier == resource_dir.name

                items[item.identifier] = item

            return items

        malcontent_dir = self.store_dir / 'temporary_malcontent'

        items_collection = ItemsCollection(
            read_items(malcontent_dir / 'resource', item_infos.ResourceInfo),
            read_items(malcontent_dir / 'mapping',  item_infos.MappingInfo)
        )
        computed_payloads = items_collection.compute_payloads()

        payloads_data = {}

        for mapping_info, by_pattern in computed_payloads.items():
            for num, (pattern, payload) in enumerate(by_pattern.items()):
                payload_id = f'{num}@{mapping_info.identifier}'

                ref = ConcretePayloadRef(payload_id, payload)

                data = st.PayloadData(
                    payload_ref         = ref,
                    mapping_installed   = True,
                    explicitly_enabled  = True,
                    unique_token        = secrets.token_urlsafe(16),
                    pattern             = pattern,
                    eval_allowed        = payload.allows_eval,
                    cors_bypass_allowed = payload.allows_cors_bypass
                )

                payloads_data[payload_id] = data

                key = st.PayloadKey(
                    payload_ref        = ref,
                    mapping_identifier = mapping_info.identifier,
                    pattern            = pattern
                )

                self.policy_tree = register_payload(
                    self.policy_tree,
                    key,
                    data.unique_token
                )

        self.payloads_data = payloads_data

    def get_repo(self, repo_id: str) -> st.RepoRef:
        return ConcreteRepoRef(repo_id)

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

    def get_mapping(self, mapping_id: str) -> st.MappingRef:
        return ConcreteMappingRef(mapping_id)

    def get_mapping_version(self, mapping_version_id: str) \
        -> st.MappingVersionRef:
        return ConcreteMappingVersionRef(mapping_version_id)

    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:
        return 'not implemented'

    def add_repo(self, name: t.Optional[str], url:  t.Optional[str]) \
        -> st.RepoRef:
        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':
        return ConcreteHaketiloState(store_dir=store_dir)