from . import data
from .web import Difftable


from ll.xist import xsc, parse
from ll.xist.ns import xml, rss20


def rss():
    versions = data.Version.raw('''\
SELECT * 
FROM version v
WHERE EXISTS (SELECT 1 
              FROM version v2
              WHERE v2.id != v.id 
                AND v2.item_id == v.item_id
                AND v2.created_date < v.created_date)
ORDER BY v.created_date DESC
LIMIT 30''')

    items = []
    for to_version in versions:
        from_version = data.Version.select() \
            .where((data.Version.id != to_version.id) &
                   (data.Version.item == to_version.item) &
                   (data.Version.created_date < to_version.created_date)) \
            .order_by(data.Version.created_date.desc()) \
            .first()

        difftable = Difftable(to_version, from_version,
                              inline_style=True).string('utf-8')
        items.append(rss20.item(
            rss20.title(
                '{} - {}'.format(to_version.item.feed.title, to_version.title)),
            rss20.author(to_version.authors),
            rss20.pubDate(to_version.created_date.strftime(
                '%a, %d %b %Y %T %z')),
            rss20.guid('from={},to={}'.format(from_version.id, to_version.id)),
            rss20.link(to_version.url),
            rss20.description(
                xsc.Text(difftable)
            )
        ))
    return xsc.Frag(xml.XML(), rss20.rss(
        rss20.channel(
            rss20.title('Watchnews change report'),
            *items
        )
    )
    ).string('utf-8')