from collections import namedtuple

from pylons import url

from spline.model import meta

from splinext.forum import model as forum_model
from splinext.frontpage.sources import Source

def frontpage_hook(limit, max_age, forum_id):
    """Hook to return recent news for the front page."""

FrontPageThread = namedtuple('FrontPageThread', ['source', 'time', 'post'])
class ForumSource(Source):
    """Represents a forum whose threads are put on the front page.

    ``link``, ``title``, and ``icon`` are all optional; the link and title
    default to the forum's thread list and name, and the icon defaults to a
    newspaper.

    Extra properties:

    ``forum_id``
        id of the forum to check for new threads.
    """

    template = '/forum/front_page.mako'

    def __init__(self, forum_id, **kwargs):
        forum = meta.Session.query(forum_model.Forum).get(forum_id)

        # Link is tricky.  Needs url(), which doesn't exist when this class is
        # loaded.  Lazy-load it in poll() below, instead
        kwargs.setdefault('link', None)
        kwargs.setdefault('title', forum.name)
        kwargs.setdefault('icon', 'newspapers')
        super(ForumSource, self).__init__(**kwargs)

        self.forum_id = forum_id

    def _poll(self, limit, max_age):
        if not self.link:
            self.link = url(
                controller='forum', action='threads', forum_id=self.forum_id)

        thread_q = meta.Session.query(forum_model.Thread) \
            .filter_by(forum_id=self.forum_id) \
            .join(forum_model.Thread.first_post)

        if max_age:
            thread_q = thread_q.filter(forum_model.Post.posted_time >= max_age)

        threads = thread_q \
            .order_by(forum_model.Post.posted_time.desc()) \
            [:limit]

        updates = []
        for thread in threads:
            update = FrontPageThread(
                source = self,
                time = thread.first_post.posted_time,
                post = thread.first_post,
            )
            updates.append(update)

        return updates