--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcalendar/calendar.py	Sat May 05 17:10:48 2012 -0500
@@ -0,0 +1,148 @@
+"""
+This file contains the calendar class wich abstracts the Google gdata API for working with
+Google Calendars.
+
+"""
+import datetime
+import pytz
+
+from django.utils.tzinfo import FixedOffset
+from gdata.calendar.client import CalendarClient
+from gdata.calendar.data import (CalendarEventEntry, CalendarEventFeed,
+        CalendarWhere, When, EventWho)
+import atom.data
+
+from gcalendar.models import Event
+
+
+class CalendarError(Exception):
+    def __init__(self, msg):
+        self.msg = msg
+
+    def __str__(self):
+        return repr(self.msg)
+
+
+class Calendar(object):
+    DATE_FMT = '%Y-%m-%d'
+    DATE_TIME_FMT = DATE_FMT + 'T%H:%M:%S'
+    DATE_TIME_TZ_FMT = DATE_TIME_FMT + '.000Z'
+
+    def __init__(self, source=None, calendar_id='default', access_token=None):
+        self.client = CalendarClient(source=source, auth_token=access_token)
+
+        self.insert_feed = ('https://www.google.com/calendar/feeds/'
+            '%s/private/full' % calendar_id)
+        self.batch_feed = '%s/batch' % self.insert_feed
+
+    def sync_events(self, qs):
+        request_feed = CalendarEventFeed()
+        for model in qs:
+            if model.status == Event.NEW_APRV:
+                event = CalendarEventEntry()
+                request_feed.AddInsert(entry=self._populate_event(model, event))
+            elif model.status == Event.EDIT_APRV:
+                event = self._retrieve_event(model)
+                request_feed.AddUpdate(entry=self._populate_event(model, event))
+            elif model.status == Event.DEL_APRV:
+                event = self._retrieve_event(model)
+                request_feed.AddDelete(entry=event)
+            else:
+                assert False, 'unexpected status in sync_events'
+
+        try:
+            response_feed = self.client.ExecuteBatch(request_feed, self.batch_feed)
+        except Exception, e:
+            raise CalendarError('ExecuteBatch exception: %s' % e)
+
+        err_msgs = []
+        for entry in response_feed.entry:
+            i = int(entry.batch_id.text)
+            code = int(entry.batch_status.code)
+
+            error = False
+            if qs[i].status == Event.NEW_APRV:
+                if code == 201:
+                    qs[i].status = Event.ON_CAL
+                    qs[i].google_id = entry.GetEditLink().href
+                    qs[i].google_url = entry.GetHtmlLink().href
+                    qs[i].save()
+                    qs[i].notify_on_calendar()
+                else:
+                    error = True
+
+            elif qs[i].status == Event.EDIT_APRV:
+                if code == 200:
+                    qs[i].status = Event.ON_CAL
+                    qs[i].save()
+                else:
+                    error = True
+
+            elif qs[i].status == Event.DEL_APRV:
+                if code == 200:
+                    qs[i].delete()
+                else:
+                    error = True
+
+            if error:
+                err_msgs.append('%s - (%d) %s' % (
+                    qs[i].what, code, entry.batch_status.reason))
+
+        if len(err_msgs) > 0:
+            raise CalendarError(', '.join(err_msgs))
+
+    def _retrieve_event(self, model):
+        try:
+            event = self.client.GetEventEntry(model.google_id)
+        except Exception, e:
+            raise CalendarError('Could not retrieve event from Google: %s, %s' \
+                    % (model.what, e))
+        return event
+
+    def _populate_event(self, model, event):
+        """Populates a gdata event from an Event model object."""
+        event.title = atom.data.Title(text=model.what)
+        event.content = atom.data.Content(text=model.html)
+        event.where = [CalendarWhere(value=model.where)]
+        event.who = [EventWho(email=model.user.email)]
+
+        if model.all_day:
+            start_time = self._make_time(model.start_date)
+            if model.start_date == model.end_date:
+                end_time = None
+            else:
+                end_time = self._make_time(model.end_date)
+        else:
+            start_time = self._make_time(model.start_date, model.start_time, model.time_zone)
+            end_time = self._make_time(model.end_date, model.end_time, model.time_zone)
+
+        event.when = [When(start=start_time, end=end_time)]
+        return event
+
+    def _make_time(self, date, time=None, tz_name=None):
+        """
+        Returns the gdata formatted date/time string given a date, optional time,
+        and optional time zone name (e.g. 'US/Pacific'). If the time zone name is None,
+        no time zone info will be added to the string.
+        """
+
+        if time is not None:
+            d = datetime.datetime.combine(date, time)
+        else:
+            d = datetime.datetime(date.year, date.month, date.day)
+
+        if time is None:
+            s = d.strftime(self.DATE_FMT)
+        elif tz_name is None:
+            s = d.strftime(self.DATE_TIME_FMT)
+        else:
+            try:
+                tz = pytz.timezone(tz_name)
+            except pytz.UnknownTimeZoneError:
+                raise CalendarError('Invalid time zone: %s' (tz_name,))
+            local = tz.localize(d)
+            zulu = local.astimezone(FixedOffset(0))
+            s = zulu.strftime(self.DATE_TIME_TZ_FMT)
+
+        return s
+