import datetime
import urllib.parse
import hashlib
import lxml.builder
import lxml.etree

import aiohttp.web


SEARCH_URL = "https://www.conseil-etat.fr/xsearch"
DOWNLOAD_URL = "https://www.conseil-etat.fr/plugin?plugin=Service.downloadFilePagePlugin&Index=Ariane_Web"


def url_add_params(url, params):
    parts = urllib.parse.urlsplit(url)
    qs = {**dict(urllib.parse.parse_qsl(parts.query)), **params}
    parts = parts._replace(query=urllib.parse.urlencode(qs))
    return urllib.parse.urlunsplit(parts)


def make_atom_entry(document):
    maker = lxml.builder.ElementMaker()
    hash_id = hashlib.sha256(document["Id"].encode("ascii"))
    date = datetime.datetime.fromisoformat(document["Version"])
    return maker.entry(
        maker.title("{}: {}".format(document["SourceStr3"], document["SourceStr5"])),
        maker.id("urn:hash::sha256:{}".format(hash_id.hexdigest())),
        maker.link(href=url_add_params(DOWNLOAD_URL, {"Id": document["Id"]})),
        maker.update(date.isoformat()),
        maker.author(document["SourceStr3"]),
        maker.content(document["HtmlSummary"]),
    )


def latest_date(documents):
    return max(
        (datetime.datetime.fromisoformat(d["Version"]) for d in documents),
        default=datetime.datetime.min,
    )


def make_atom(content):
    feed = lxml.etree.Element("feed")
    documents = content["Documents"]
    updated = lxml.etree.SubElement(feed, "updated")
    updated.text = latest_date(documents).isoformat()
    feed.extend(make_atom_entry(d) for d in documents)
    return feed


async def view(request):
    text = request.rel_url.query["text"]
    data = {
        "advanced": "1",
        "type": "json",
        "SourceStr4": [
            "AW_DCE",
            "AW_AJCE",
            "AW_CRP",
            "AW_DTC",
            "AW_AJTC",
            "AW_DCA",
            "AW_AJCA",
        ],
        "text.add": text,
        "synonyms": "true",
        "scmode": "smart",
        "SkipCount": "50",
        "SkipMode": "0",
        "sort": "SourceDateTime1.desc,SourceStr5.desc",
    }

    async with request.app["client_session"].post(SEARCH_URL, data=data) as resp:
        content = await resp.json()
        feed = make_atom(content)
        return aiohttp.web.Response(
            body=lxml.etree.tostring(feed, pretty_print=True),
            content_type="application/atom+xml",
        )


async def client_session_ctx(app):
    app["client_session"] = aiohttp.ClientSession()
    yield
    await app["client_session"].close()


def main():

    app = aiohttp.web.Application()
    app.cleanup_ctx.append(client_session_ctx)
    app.add_routes((aiohttp.web.get("/", view),))

    aiohttp.web.run_app(app)


if __name__ == "__main__":
    main()