#!/bin/sh
# shellcheck disable=all
"exec" "${HOME}/.local/share/venv/statusbar/bin/python3" "-u" "$0" "$@"

import datetime
import json
import os
import signal
import sys
import time
import traceback

from collections.abc import Callable
from dataclasses import dataclass
from typing import Literal, Any, TypeVar
from urllib.parse import urlparse

import requests
from bs4 import BeautifulSoup, Tag

EMOJI_BY_STATUS = {
    0: '🟡',
    1: '🟢',
    2: '🔴',
}
TIMEOUT = 30
CONFIG_FILE = f"{os.environ['HOME']}/.my.itmo"
CACHE_FILE = f"{os.environ['HOME']}/.cache/my_itmo.cache"
SECRET_FILE = f"{os.environ['HOME']}/.secrets/my_itmo.secret"
PIPE_FILE = f"{os.environ['XDG_RUNTIME_DIR']}/my.itmo.pipe"

T = TypeVar('T')


def run_forever(fn: Callable, *args, **kwargs):
    while True:
        try:
            fn(*args, **kwargs)
        except Exception:
            print(traceback.format_exc())


def run_until_successful(fn: Callable[..., T], *args, **kwargs) -> T:
    while True:
        try:
            return fn(*args, **kwargs)
        except Exception:
            pass


def send_message(chat_id: int, text: str, token: str):
    requests.post(f"https://api.telegram.org/bot{token}/sendMessage", data={
        'chat_id': chat_id,
        'parse_mode': 'HTML',
        'text': text
    })


@dataclass
class StatusObject:
    id: int
    name: str
    notice: str
    status: Literal[0, 1, 2]
    status_name: str
    updated_at: datetime.datetime
    created_at: datetime.datetime

    @staticmethod
    def from_dict(data: dict[str, Any]):
        data['updated_at'] = datetime.datetime.strptime(data['updated_at'].replace("+03:00", ''), '%Y-%m-%dT%H:%M:%S')
        data['created_at'] = datetime.datetime.strptime(data['created_at'].replace("+03:00", ''), '%Y-%m-%dT%H:%M:%S')

        return StatusObject(**data)


class ApiException(Exception):
    status_code: int
    body: str

    def __init__(self, status_code: int, body: str):
        super().__init__(status_code, body)
        self.status_code = status_code
        self.body = body

    def __str__(self):
        return f'Status code: {self.status_code}\nBody: {self.body}'


class Api:
    _session: requests.Session
    _username: str
    _password: str
    _access_token: str
    _refresh_token: str
    _expires_in: int
    _refresh_expires_in: int

    def __init__(self, username: str, password: str, *, access_token: str | None = None,
                 refresh_token: str | None = None, expires_in: int | None = None,
                 refresh_expires_in: int | None = None, cookies: Any | None = None):
        self._session = requests.Session()
        self._username = username
        self._password = password
        self._refresh_token = refresh_token if refresh_token else ''
        self._expires_in = expires_in if expires_in else 0
        self._refresh_expires_in = refresh_expires_in if refresh_expires_in else 0
        if cookies: self._session.cookies.update(cookies)
        self._access_token = access_token if access_token else ''
        if access_token: self._session.headers.update({'Authorization': f'Bearer {access_token}'})
        self._ensure_authorized()


    def _first_auth(self):
        self._session.headers.clear()
        self._session.cookies.clear()
        code_request = run_until_successful(self._session.get, 'https://id.itmo.ru/auth/realms/itmo/protocol/openid-connect/auth', params={
            'protocol': 'oauth2',
            'response_type': 'code',
            'client_id': 'student-personal-cabinet',
            'redirect_uri': 'https://my.itmo.ru/login/callback',
            'scope': 'openid profile',
        }, timeout=2)
        soup = BeautifulSoup(code_request.text, features='html.parser')
        form = soup.find('form')
        if not isinstance(form, Tag):
            raise ApiException(code_request.status_code, code_request.text)

        url = form.get_attribute_list('action')[0]
        auth_request = run_until_successful(self._session.post, url, data={'username': self._username, 'password': self._password})
        if auth_request.status_code != 200:
            raise ApiException(auth_request.status_code, auth_request.text)

        parsed_url_params = {a.split('=')[0]: a.split('=')[1] for a in urlparse(auth_request.url).query.split('&')}

        self._get_and_save_tokens({
            'code' : parsed_url_params['code'],
            'client_id': 'student-personal-cabinet',
            'redirect_uri': 'https://my.itmo.ru/login/callback',
            'audience': '',
            'response_type': 'code',
            'grant_type': 'authorization_code',
            'code_verifier': ''
        })


    def _renew(self):
        self._session.headers.clear()
        self._session.cookies.clear()
        self._get_and_save_tokens({
            'refresh_token': self._refresh_token,
            'scopes': 'openid profile',
            'client_id': 'student-personal-cabinet',
            'grant_type': 'refresh_token'
        })


    def _get_and_save_tokens(self, data: Any):
        tokens_request = run_until_successful(self._session.post, 'https://id.itmo.ru/auth/realms/itmo/protocol/openid-connect/token', data=data, timeout=2)
        if tokens_request.status_code != 200:
            raise ApiException(tokens_request.status_code, tokens_request.text)
        tokens = tokens_request.json()
        self._access_token = tokens['access_token']
        self._expires_in = int(time.time()) + tokens['expires_in'] - 10
        self._refresh_expires_in = int(time.time()) + tokens['refresh_expires_in'] - 10
        self._refresh_token = tokens['refresh_token']
        self._session.headers.update({"Authorization": f"Bearer {tokens_request.json()['access_token']}"})


    def _ensure_authorized(self):
        current_time = int(time.time())

        if self._access_token and self._expires_in > current_time:
            return
        elif self._refresh_token and self._refresh_expires_in > current_time:
            self._renew()
        else:
            self._first_auth()


    def _make_request(self, method: Literal["GET", "POST"], endpoint: str):
        self._ensure_authorized()
        r = run_until_successful(self._session.request, method, f'https://my.itmo.ru/api/{endpoint}', timeout=2)

        if r.status_code == 403:
            self._first_auth() # do full reauth if 403 after self._ensure_authorized()
            r = run_until_successful(self._session.request, method, f'https://my.itmo.ru/api/{endpoint}', timeout=2)

        if r.status_code != 200 or r.json()['error_code'] != 0:
            raise ApiException(r.status_code, r.text)

        return r.json()


    def get_status_list(self):
        return [StatusObject.from_dict(obj) for obj in self._make_request('GET', 'requests/my')['result']]


    def to_dict(self) -> Any:
        return {
            'username': self._username,
            'password': self._password,
            'access_token': self._access_token,
            'refresh_token': self._refresh_token,
            'expires_in': self._expires_in,
            'refresh_expires_in': self._refresh_expires_in,
            'cookies': self._session.cookies.get_dict()
        }


    @staticmethod
    def from_dict(data: Any):
        return Api(
            data['username'],
            data['password'],
            access_token = data['access_token'],
            refresh_token = data['refresh_token'],
            expires_in = data['expires_in'],
            refresh_expires_in = data['refresh_expires_in'],
            cookies = data['cookies'],
        )


def listen_for_messages(api: Api, timeout=TIMEOUT, filter_func: Callable[[StatusObject], bool] | None = None):
    prev_msg = None
    while True:
        msg = list(filter(filter_func, api.get_status_list()))

        if not msg or msg == prev_msg:
            time.sleep(timeout)
            continue

        prev_msg = msg
        yield msg
        time.sleep(timeout)


format_status = lambda status: f"{EMOJI_BY_STATUS[status.status]} {status.notice.split('.')[0].strip()}"
format_message = lambda status: f"{EMOJI_BY_STATUS[status.status]} <b>{status.name}</b>\n\n{status.notice}"


class IDsFilter:
    _ids: list[str]
    _update_time: float

    def __init__(self):
        self._ids = []
        self._update_dict()


    def __call__(self, status: StatusObject) -> bool:
        if self._update_time + TIMEOUT < time.time():
            self._update_dict()

        return str(status.id) in self._ids

    def _update_dict(self):
        self._update_time = time.time()
        try:
            with open(CONFIG_FILE) as file:
                self._ids = file.read().strip().replace(' ', '').split(',')
        except Exception:
            self._ids = []


class LastUpdateFilter:
    _update_time: datetime.datetime

    def __init__(self, ignore_now = False) -> None:
        self._update_time = datetime.datetime.fromtimestamp(0) if not ignore_now else datetime.datetime.now()

    def __call__(self, status: StatusObject):
        return status.updated_at >= self._update_time

    def update(self):
        self._update_time = datetime.datetime.now()


def main():
    api = None

    if os.path.isfile(CACHE_FILE):
        with open(CACHE_FILE) as file:
            api = Api.from_dict(json.load(file))

    if os.path.isfile(SECRET_FILE):
        with open(SECRET_FILE) as secret_file:
            data = json.load(secret_file)

        owner_id = data['owner_id']
        bot_token = data['bot_token']

        if not api:
            api = Api(data['username'], data['password'])
    else:
        print("Missing secret file!", file=sys.stderr)
        exit(1)

    def die(*_):
        with open(CACHE_FILE, 'w') as file:
            json.dump(api.to_dict(), file)
        if os.path.isfile(PIPE_FILE):
            os.remove(PIPE_FILE)
        exit(0)

    signal.signal(signal.SIGTERM, die)
    signal.signal(signal.SIGINT, die)

    for message in listen_for_messages(api, filter_func=IDsFilter()):
        with open(PIPE_FILE, 'w') as file:
            print('\n'.join(map(format_status, message)))
            file.write(' '.join(map(format_status, message)))

    update_filter = LastUpdateFilter(ignore_now=True)
    for message in listen_for_messages(api, filter_func=update_filter):
        formatted_messages = list(map(format_message, message))
        print('\n---\n'.join(formatted_messages))
        for message in formatted_messages:
            send_message(owner_id, message, bot_token)
        update_filter.update()


if __name__ == "__main__":
    run_forever(main)

# vim: ft=python