[WIP] Add preliminary support for VTODOs

Quick PoC that converts VTODOs to VEVENTs before adding them to the
backend, this enables us to not treat tasks as something very special.

If this approach is interesting enough, it should be forbidden that
khal edits tasks as it is out of its scope.

This would fix pimutils#448

khal/icalendar.py

@@ -401,6 +401,47 @@ def sanitize(vevent, default_timezone, href='', calendar=''):
     return vevent
 
 
+def sanitize_vtodo(vtodo, default_timezone, href='', calendar=''):
+    """
+    cleanup vtodos so they look like vevents for khal
+
+    :param vtodo: the vtodo that needs to be cleaned
+    :type vtodo: icalendar.cal.Todo
+    :param default_timezone: timezone to apply to start and/or end dates which
+         were supposed to be localized but which timezone was not understood
+         by icalendar
+    :type timezone: pytz.timezone
+    :param href: used for logging to inform user which .ics files are
+        problematic
+    :type href: str
+    :param calendar: used for logging to inform user which .ics files are
+        problematic
+    :type calendar: str
+    :returns: clean vtodo as vevent
+    :rtype: icalendar.cal.Event
+    """
+    vdtstart = vtodo.pop('DTSTART', None)
+    vdue = vtodo.pop('DUE', None)
+
+    # it seems to be common for VTODOs to have DUE but no DTSTART
+    # so we default to that. E.g. NextCloud does something similar
+    if vdtstart is None and vdue is not None:
+        vdtstart = vdue
+
+    # Based loosely on new_event
+    event = icalendar.Event()
+    event.add('dtstart', vdtstart)
+    event.add('due', vdue)
+    # Copy common/necessary attributes
+    for attr in ['uid', 'summary', 'dtend', 'dtstamp', 'description',
+                 'location', 'categories', 'url']:
+        if attr in vtodo:
+            event.add(attr, vtodo.pop(attr))
+
+    # Chain with event sanitation
+    return sanitize(event, default_timezone, href=href, calendar=calendar)
+
+
 def sanitize_timerange(dtstart, dtend, duration=None):
     '''return sensible dtstart and end for events that have an invalid or
     missing DTEND, assuming the event just lasts one hour.'''

khal/khalendar/backend.py

@@ -35,7 +35,7 @@
 from dateutil import parser
 
 from .. import utils
-from ..icalendar import assert_only_one_uid, cal_from_ics
+from ..icalendar import assert_only_one_uid, cal_from_ics, sanitize_vtodo
 from ..icalendar import expand as expand_vevent
 from ..icalendar import sanitize as sanitize_vevent
 from ..icalendar import sort_key as sort_vevent_key
@@ -52,6 +52,11 @@
 
 PROTO = 'PROTO'
 
+SANITIZE_MAP = {
+    'VEVENT': sanitize_vevent,
+    'VTODO': sanitize_vtodo,
+}
+
 
 class EventType(IntEnum):
     DATE = 0
@@ -226,8 +231,8 @@ def update(self, vevent_str: str, href: str, etag: str='', calendar: str=None) -
                 "If you want to import it, please use `khal import FILE`."
             )
             raise NonUniqueUID
-        vevents = (sanitize_vevent(c, self.locale['default_timezone'], href, calendar) for
-                   c in ical.walk() if c.name == 'VEVENT')
+        vevents = (SANITIZE_MAP[c.name](c, self.locale['default_timezone'], href, calendar) for
+                   c in ical.walk() if c.name in SANITIZE_MAP.keys())
         # Need to delete the whole event in case we are updating a
         # recurring event with an event which is either not recurring any
         # more or has EXDATEs, as those would be left in the recursion

khal/khalendar/event.py

@@ -151,7 +151,7 @@ def fromVEvents(cls, events_list, ref=None, **kwargs):
     @classmethod
     def fromString(cls, event_str, ref=None, **kwargs):
         calendar_collection = cal_from_ics(event_str)
-        events = [item for item in calendar_collection.walk() if item.name == 'VEVENT']
+        events = [item for item in calendar_collection.walk() if item.name in ['VEVENT', 'VTODO']]
         return cls.fromVEvents(events, ref, **kwargs)
 
     def __lt__(self, other):
@@ -277,7 +277,8 @@ def symbol_strings(self):
                 'range': '\N{Left right arrow}',
                 'range_end': '\N{Rightwards arrow to bar}',
                 'range_start': '\N{Rightwards arrow from bar}',
-                'right_arrow': '\N{Rightwards arrow}'
+                'right_arrow': '\N{Rightwards arrow}',
+                'task': '\N{Pencil}',
             }
         else:
             return {
@@ -286,7 +287,8 @@ def symbol_strings(self):
                 'range': '<->',
                 'range_end': '->|',
                 'range_start': '|->',
-                'right_arrow': '->'
+                'right_arrow': '->',
+                'task': '(T)',
             }
 
     @property
@@ -304,6 +306,24 @@ def start(self):
         """this should return the start date(time) as saved in the event"""
         return self._start
 
+    @property
+    def task(self):
+        """this should return whether or not we are representing a task"""
+        return self._vevents[self.ref].name == 'VTODO'
+
+    @property
+    def task_status(self):
+        """nice representation of a task status"""
+        vstatus = self._vevents[self.ref].get('STATUS', 'NEEDS-ACTION')
+        status = ' '
+        if vstatus == 'COMPLETED':
+            status = 'X'
+        elif vstatus == 'IN-PROGRESS':
+            status = '/'
+        elif vstatus == 'CANCELLED':
+            status = '-'
+        return status
+
     @property
     def end(self):
         """this should return the end date(time) as saved in the event or
@@ -427,7 +447,10 @@ def summary(self):
                 name=name, number=number, suffix=suffix, desc=description, leap=leap,
             )
         else:
-            return self._vevents[self.ref].get('SUMMARY', '')
+            summary = self._vevents[self.ref].get('SUMMARY', '')
+            if self.task:
+                summary = '[{state}] {summary}'.format(state=self.task_status, summary=summary)
+            return summary
 
     def update_summary(self, summary):
         self._vevents[self.ref]['SUMMARY'] = summary
@@ -516,6 +539,14 @@ def _alarm_str(self):
             alarmstr = ''
         return alarmstr
 
+    @property
+    def _task_str(self):
+        if self.task:
+            taskstr = ' ' + self.symbol_strings['task']
+        else:
+            taskstr = ''
+        return taskstr
+
     def format(self, format_string, relative_to, env=None, colors=True):
         """
         :param colors: determines if colors codes should be printed or not
@@ -642,6 +673,7 @@ def format(self, format_string, relative_to, env=None, colors=True):
         attributes["repeat-symbol"] = self._recur_str
         attributes["repeat-pattern"] = self.recurpattern
         attributes["alarm-symbol"] = self._alarm_str
+        attributes["task-symbol"] = self._task_str
         attributes["title"] = self.summary
         attributes["organizer"] = self.organizer.strip()
         attributes["description"] = self.description.strip()

khal/settings/khal.spec

@@ -273,7 +273,7 @@ bold_for_light_color = boolean(default=True)
 # ignored in `ikhal`, where events will always be shown in the color of the
 # calendar they belong to.
 # The syntax is the same as for :option:`--format`.
-agenda_event_format = string(default='{calendar-color}{cancelled}{start-end-time-style} {title}{repeat-symbol}{alarm-symbol}{description-separator}{description}{reset}')
+agenda_event_format = string(default='{calendar-color}{cancelled}{start-end-time-style} {title}{repeat-symbol}{alarm-symbol}{task-symbol}{description-separator}{description}{reset}')
 
 # Specifies how each *day header* is formatted.
 agenda_day_format = string(default='{bold}{name}, {date-long}{reset}')
@@ -288,7 +288,7 @@ monthdisplay = monthdisplay(default='firstday')
 # but :command:`list` and :command:`calendar`. It is therefore probably a
 # sensible choice to include the start- and end-date.
 # The syntax is the same as for :option:`--format`.
-event_format = string(default='{calendar-color}{cancelled}{start}-{end} {title}{repeat-symbol}{alarm-symbol}{description-separator}{description}{reset}')
+event_format = string(default='{calendar-color}{cancelled}{start}-{end} {title}{repeat-symbol}{alarm-symbol}{task-symbol}{description-separator}{description}{reset}')
 
 # When highlight_event_days is enabled, this section specifies how
 # the highlighting/coloring of days is handled.