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

# Haketilo addon for Mitmproxy.
#
# 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 the definition of a mitmproxy addon that gets instantiated
from addon script.
"""

# Enable using with Python 3.7.
from __future__ import annotations

import os.path
import typing as t
import dataclasses as dc

from threading import Lock
from pathlib import Path
from contextlib import contextmanager

from mitmproxy import http, addonmanager, ctx
from mitmproxy.script import concurrent

from .flow_handlers import make_flow_handler, FlowHandler
from .state import HaketiloState
from ..translations import smart_gettext as _

FlowHandlers = dict[int, FlowHandler]

StateUpdater = t.Callable[[HaketiloState], None]

HTTPHandlerFun = t.Callable[
    ['HaketiloAddon', http.HTTPFlow],
    t.Optional[StateUpdater]
]

def http_event_handler(handler_fun: HTTPHandlerFun):
    """....decorator"""
    def wrapped_handler(self: 'HaketiloAddon', flow: http.HTTPFlow):
        """...."""
        with self.configured_lock:
            assert self.configured

        assert self.state is not None

        state_updater = handler_fun(self, flow)

        if state_updater is not None:
                state_updater(self.state)

    return wrapped_handler

@dc.dataclass
class HaketiloAddon:
    """
    .......
    """
    configured:      bool                      = False
    configured_lock: Lock                      = dc.field(default_factory=Lock)

    state:           t.Optional[HaketiloState] = None

    flow_handlers:   FlowHandlers              = dc.field(default_factory=dict)
    handlers_lock:   Lock                      = dc.field(default_factory=Lock)

    def load(self, loader: addonmanager.Loader) -> None:
        """...."""
        loader.add_option(
            name     = 'haketilo_dir',
            typespec = str,
            default  = '~/.haketilo/',
            help     = "Point to a Haketilo data directory to use",
        )

    def configure(self, updated: set[str]) -> None:
        """...."""
        if 'haketilo_dir' not in updated:
            return

        with self.configured_lock:
            if self.configured:
                ctx.log.warn(_('haketilo_dir_already_configured'))
                return

            haketilo_dir = Path(ctx.options.haketilo_dir)
            self.state = HaketiloState(haketilo_dir / 'store')

    def assign_handler(self, flow: http.HTTPFlow, flow_handler: FlowHandler) \
        -> None:
        """...."""
        with self.handlers_lock:
            self.flow_handlers[id(flow)] = flow_handler

    def lookup_handler(self, flow: http.HTTPFlow) -> FlowHandler:
        """...."""
        with self.handlers_lock:
            return self.flow_handlers[id(flow)]

    def forget_handler(self, flow: http.HTTPFlow) -> None:
        """...."""
        with self.handlers_lock:
            self.flow_handlers.pop(id(flow), None)

    @concurrent
    @http_event_handler
    def requestheaders(self, flow: http.HTTPFlow) -> t.Optional[StateUpdater]:
        """
        .....
        """
        assert self.state is not None

        policy = self.state.select_policy(flow.request.url)

        flow_handler = make_flow_handler(flow, policy)

        self.assign_handler(flow, flow_handler)

        return flow_handler.on_requestheaders()

    @concurrent
    @http_event_handler
    def request(self, flow: http.HTTPFlow) -> t.Optional[StateUpdater]:
        """
        ....
        """
        return self.lookup_handler(flow).on_request()

    @concurrent
    @http_event_handler
    def responseheaders(self, flow: http.HTTPFlow) -> t.Optional[StateUpdater]:
        """
        ......
        """
        return self.lookup_handler(flow).on_responseheaders()

    @concurrent
    @http_event_handler
    def response(self, flow: http.HTTPFlow) -> t.Optional[StateUpdater]:
        """
        ......
        """
        updater = self.lookup_handler(flow).on_response()

        self.forget_handler(flow)

        return updater

    @http_event_handler
    def error(self, flow: http.HTTPFlow) -> None:
        """...."""
        self.forget_handler(flow)

addons = [
    HaketiloAddon()
]