#!/usr/bin/env python3

import datetime
import json
import urllib.request

from base64 import b64decode
from subprocess import run

import cherrypy

from icalendar import Calendar, Todo

GITEA_REPO_URL="https://git.bitmessage.org/api/v1"

combined = {}

def retrieve(token, kind):
    if kind not in ("review_requested", "assigned"):
        raise cherrypy.HTTPError(401, 'Unauthorized')
    req = urllib.request.Request(GITEA_REPO_URL
                + f"/repos/issues/search?state=open&{kind}=true")
    req.add_header("Accept", "application/json")
    req.add_header("Authorization", "token " + token)

    retval = {}

    with urllib.request.urlopen(req) as response:
        issues = json.load(response)
        for issue in issues:
            _id = issue['id']
            retval[_id] = issue
            retval[_id]['categories'] = [kind]
    return retval

def process(retrieved):
    cal = Calendar()
    for _id, issue in retrieved.items():
        todo = Todo()
        todo['uid'] = _id
        todo['dtstamp'] = issue['created_at']
        if issue['due_date']:
            todo['due'] = issue['due_date']
        todo['summary'] = issue['title']
        todo['description'] = issue['body']
        todo['categories'] = issue['categories']
        cal.add_component(todo)
    return cal.to_ical()

def get_token(input_token):
    token = input_token.removeprefix("Basic ")
    token = b64decode(token).decode('utf8', 'ignore')
    with cherrypy.HTTPError.handle(ValueError, 401):
        _, token = token.split(":", 2)
    return token

class Root:
    def _authenticate(self, kind):
        cherrypy.response.headers['WWW-Authenticate'] = \
                'Basic realm="ICS access"'
        cherrypy.response.headers['Content-Type'] = \
                'text/calendar'
        cherrypy.response.headers['Content-Disposition'] = \
                f'attachment; filename="Gitea {kind}.ics"'
        authorization = cherrypy.request.headers.get('Authorization', ':')
        if not authorization:
            raise cherrypy.HTTPError(401, 'Unauthorized')
        token = get_token(authorization)
        if not token:
            raise cherrypy.HTTPError(401, 'Unauthorized')
        return token

    @cherrypy.expose
    def assigned(self):
        token = self._authenticate("assigned")
        retrieved = retrieve(token, "assigned")
        if not retrieved:
            raise cherrypy.HTTPError(401, 'Unauthorized')
        return(process(retrieved))

    @cherrypy.expose
    def review_requested(self):
        token = self._authenticate("review_requested")
        retrieved = retrieve(token, "review_requested")
        if not retrieved:
            raise cherrypy.HTTPError(401, 'Unauthorized')
        return(process(retrieved))

if __name__ == '__main__':
    cherrypy.config.update({'server.socket_host': '0.0.0.0',
                        'server.socket_port': 8080,
                       })
    cherrypy.quickstart(Root(), '/')