# -*- coding: utf-8 -*-

"""

events plugin for Pelican

=========================

This plugin looks for and parses an "events" directory and generates

blog posts with a user-defined event date. (typically in the future)

It also generates an ICalendar v2.0 calendar file.

https://en.wikipedia.org/wiki/ICalendar

Author: Federico Ceratto <[email protected]>

Released under AGPLv3+ license, see LICENSE

"""

from datetime import datetime, timedelta

from icalendar import vDatetime

from pelican import signals, utils

from collections import namedtuple, defaultdict

import icalendar

import logging

import os.path

import pytz

log = logging.getLogger(__name__)

TIME_MULTIPLIERS = {

'w': 'weeks',

'd': 'days',

'h': 'hours',

'm': 'minutes',

's': 'seconds'

}

events = []

localized_events = defaultdict(list)

Event = namedtuple("Event", "dtstart dtend metadata")

def parse_tstamp(ev, field_name):

"""Parse a timestamp string in format "YYYY-MM-DD HH:MM"

:returns: datetime

"""

try:

return datetime.strptime(ev[field_name], '%Y-%m-%d %H:%M')

except Exception as e:

log.error("Unable to parse the '%s' field in the event named '%s': %s" % (field_name, ev['title'], e))

raise

def parse_timedelta(ev):

"""Parse a timedelta string in format [<num><multiplier> ]*

e.g. 2h 30m

:returns: timedelta

"""

chunks = ev['duration'].split()

tdargs = {}

for c in chunks:

try:

m = TIME_MULTIPLIERS[c[-1]]

val = int(c[:-1])

tdargs[m] = val

except KeyError:

log.error("""Unknown time multiplier '%s' value in the \

'duration' field in the '%s' event. Supported multipliers \

are: '%s'.""" % (c, ev['title'], ' '.join(TIME_MULTIPLIERS)))

raise RuntimeError("Unknown time multiplier '%s'" % c)

except ValueError:

log.error("""Unable to parse '%s' value in the 'duration' \

field in the '%s' event.""" % (c, ev['title']))

raise ValueError("Unable to parse '%s'" % c)

return timedelta(**tdargs)

def generate_ical_file(generator, **_):

"""Generate an iCalendar file

"""

ics_fname = generator.settings['PLUGIN_EVENTS']['ics_fname']

if not ics_fname:

return

ics_fname = os.path.join(generator.settings['OUTPUT_PATH'], ics_fname)

log.debug("Generating calendar at %s with %d events" % (ics_fname, len(events)))

tz = generator.settings.get('TIMEZONE', 'UTC')

tz = pytz.timezone(tz)

siteurl = "%s/{}" % generator.settings['SITEURL']

ical = icalendar.Calendar()

ical.add('prodid', generator.settings['SITENAME'])

ical.add('version', '2.0')

for article in generator.articles:

if 'start' not in article.metadata:

continue

dtstart = tz.localize(parse_tstamp(article.metadata, 'start')).astimezone(pytz.UTC)

dtdelta = parse_timedelta(article.metadata)

dtend = dtstart + dtdelta

ie = icalendar.Event(

summary=article.title,

dtstart=vDatetime(dtstart),

dtend=vDatetime(dtend),

priority=5,

uid=article.url,

url=siteurl.format(article.url),

location=article.metadata['location'],

)

ie.add('description', article.content, {'altrep': siteurl.format(article.url)})

ie.add('x-alt-desc', article.content, {'fmttype': 'text/html'})

ical.add_component(ie)

with open(ics_fname, 'wb') as f:

f.write(ical.to_ical())

def register():

signals.article_writer_finalized.connect(generate_ical_file)