# You should have received a copy of the GNU General Public License

# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""

kallithea.lib.feeds

~~~~~~~~~~~~~~~~~~~

Shared code for providing RSS and ATOM feeds.

"""

import datetime

import re

import mako.template

language = 'en-us'

ttl = "5"

# From ``django.utils.feedgenerator`` via webhelpers.feedgenerator

def rfc2822_date(date):

    # We do this ourselves to be timezone aware, email.Utils is not tz aware.

    if getattr(date, "tzinfo", False):

        time_str = date.strftime('%a, %d %b %Y %H:%M:%S ')

        offset = date.tzinfo.utcoffset(date)

        timezone = (offset.days * 24 * 60) + (offset.seconds / 60)

        hour, minute = divmod(timezone, 60)

        return time_str + "%+03d%02d" % (hour, minute)

    else:

        return date.strftime('%a, %d %b %Y %H:%M:%S -0000')

# From ``django.utils.feedgenerator`` via webhelpers.feedgenerator

def rfc3339_date(date):

    if getattr(date, "tzinfo", False):

        time_str = date.strftime('%Y-%m-%dT%H:%M:%S')

        offset = date.tzinfo.utcoffset(date)

        timezone = (offset.days * 24 * 60) + (offset.seconds / 60)

        hour, minute = divmod(timezone, 60)

        return time_str + "%+03d:%02d" % (hour, minute)

    else:

        return date.strftime('%Y-%m-%dT%H:%M:%SZ')

# From ``django.utils.feedgenerator`` via webhelpers.feedgenerator

def get_tag_uri(url, date):

    "Creates a TagURI. See http://diveintomark.org/archives/2004/05/28/howto-atom-id"

    tag = re.sub('^http://', '', url)

    if date is not None:

    tag = re.sub('#', '/', tag)

    return 'tag:' + tag

class Attributes(object):

    """Simple namespace for attribute dict access in mako and elsewhere"""

    def __init__(self, a_dict):

        self.__dict__ = a_dict

class _Feeder(object):

    content_type = None

    template = None  # subclass must provide a mako.template.Template

    @classmethod

    def render(cls, header, entries):

        try:

            latest_pubdate = max(

                pubdate for pubdate in (e.get('pubdate') for e in entries)

                if pubdate

            )

        except ValueError:  # max() arg is an empty sequence ... or worse

            latest_pubdate = datetime.datetime.now()

        return cls.template.render(

            language=language,

            ttl=ttl,  # rss only

            latest_pubdate=latest_pubdate,

            rfc2822_date=rfc2822_date,  # for RSS

            rfc3339_date=rfc3339_date,  # for Atom

            get_tag_uri=get_tag_uri,

            entries=[Attributes(e) for e in entries],

            **header

        )

class AtomFeed(_Feeder):

    content_type = 'application/atom+xml'

    template = mako.template.Template('''\

<?xml version="1.0" encoding="utf-8"?>

<feed xmlns="http://www.w3.org/2005/Atom" xml:lang="${language}">

  <title>${title}</title>

  <link href="${link}" rel="alternate"></link>

  <id>${link}</id>

  <updated>${rfc3339_date(latest_pubdate)}</updated>