#!/usr/bin/env python
# RSS feed mirror on Misskey
# Copyright (C) 2021  Nguyễn Gia Phong
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

from configparser import ConfigParser
from contextlib import AsyncExitStack
from functools import partial
from re import split, sub

from dateutil.parser import parse as parse_time
from feedparser import parse as parse_feed
from httpx import AsyncClient
from loca import Loca
from markdownify import markdownify as md
from trio import open_nursery, run


async def create(client, **note):
    """Create the given note and return its ID."""
    response = await client.post('notes/create', json=note)
    return response.json()['createdNote']['id']


async def post(job, client, link, title, summary):
    """Post the given entry to Misskey.

    In case the link was already posted, the entry shall be skipped.
    """
    search = await client.post('notes/search', json={'query': link,
                                                     'userId': job['user']})
    if search.json(): return

    note = partial(create, client, i=job['token'], visibility='home', cw=title)
    original = f'Original: {link}'
    rest = '\n\n'.join((*map(partial(sub, r'\s+', ' '),
                             split(r'\s*\n{2,}\s*', md(summary).strip())),
                        original))
    limit = int(job['limit'])
    parent = None

    while len(rest) > limit:
        index = rest.rfind('\n\n', 0, limit+2)  # split paragraphs
        if index < 0:
            index = rest.rfind('. ', 0, limit+1)  # split sentences
            if index < 0:
                parent = await note(text=original, replyId=parent)
                return
            first, rest = rest[:index+1], rest[index+2:]
        else:
            first, rest = rest[:index], rest[index+2:]
        parent = await note(text=first, replyId=parent)
    parent = await note(text=rest, replyId=parent)


async def mirror(nursery, job, client):
    """Perform the given mirror job."""
    feed = await client.get(job['source'])
    for entry in parse_feed(feed.text)['entries']:
        nursery.start_soon(post, job, client, entry['link'],
                           entry['title'], entry['summary'])


async def main():
    """Parse and run jobs."""
    config = ConfigParser()
    config.read(Loca().user.config()/'rsskey'/'jobs.conf')
    async with AsyncExitStack() as stack, open_nursery() as nursery:
        for section in config:
            if section == 'DEFAULT': continue
            job = config[section]
            client = AsyncClient(base_url=job['dest'])
            await stack.enter_async_context(client)
            nursery.start_soon(mirror, nursery, job, client)


if __name__ == '__main__': run(main)