# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1427155828 -3600
# Node ID c28146a67ca280447afd2a4f5082281e396822c1
# Parent  21f7421c806afae71fa3195c4fd34f4917f54d14
Changed the get_periods function to convert date periods and plain dates to
datetime periods, partly to avoid problems sorting the periods before
potentially excluding some of them.
Renamed get_date to to_date and added a to_datetime function in the dates
module. Added various convenience functions related to iCalendar item
generation.

diff -r 21f7421c806a -r c28146a67ca2 imiptools/data.py
--- a/imiptools/data.py	Mon Mar 23 00:39:26 2015 +0100
+++ b/imiptools/data.py	Tue Mar 24 01:10:28 2015 +0100
@@ -23,8 +23,8 @@
 from datetime import datetime, timedelta
 from email.mime.text import MIMEText
 from imiptools.dates import format_datetime, get_datetime, get_duration, \
-                            get_freebusy_period, get_period, to_timezone, \
-                            to_utc_datetime
+                            get_freebusy_period, get_period, to_datetime, \
+                            to_timezone, to_utc_datetime
 from imiptools.period import period_overlaps
 from pytz import timezone
 from vCalendar import iterwrite, parse, ParseError, to_dict, to_node
@@ -426,8 +426,12 @@
         origin_value = origin and ("RDATE",) or ()
         for rdate in rdates:
             if isinstance(rdate, tuple):
-                periods.add(rdate + origin_value)
+                start, end = rdate
+                start = to_datetime(start, tzid)
+                end = to_datetime(end, tzid)
+                periods.add((start, end) + origin_value)
             else:
+                rdate = to_datetime(rdate, tzid)
                 periods.add((rdate, rdate + duration) + origin_value)
 
     # Return a sorted list of the periods.
@@ -442,8 +446,12 @@
     if exdates:
         for exdate in exdates:
             if isinstance(exdate, tuple):
-                period = exdate
+                start, end = exdate
+                start = to_datetime(start, tzid)
+                end = to_datetime(end, tzid)
+                period = start, end
             else:
+                exdate = to_datetime(exdate, tzid)
                 period = (exdate, exdate + duration)
             i = bisect_left(periods, period)
             while i < len(periods) and periods[i][:2] == period:
diff -r 21f7421c806a -r c28146a67ca2 imiptools/dates.py
--- a/imiptools/dates.py	Mon Mar 23 00:39:26 2015 +0100
+++ b/imiptools/dates.py	Tue Mar 24 01:10:28 2015 +0100
@@ -137,20 +137,61 @@
     else:
         return None
 
+def get_datetime_attributes(dt, tzid=None):
+
+    "Return attributes for 'dt' and 'tzid'."
+
+    if isinstance(dt, datetime):
+        attr = {"VALUE" : "DATE-TIME"}
+        if tzid:
+            attr["TZID"] = tzid
+        return attr
+    else:
+        return {"VALUE" : "DATE"}
+
+    return {}
+
+def get_period_attributes(tzid=None):
+
+    "Return attributes for 'tzid'."
+
+    attr = {"VALUE" : "PERIOD"}
+    if tzid:
+        attr["TZID"] = tzid
+    return attr
+
 def get_datetime_item(dt, tzid=None):
 
     "Return an iCalendar-compatible string and attributes for 'dt' and 'tzid'."
 
     if not dt:
         return None, None
+    dt = to_timezone(dt, tzid)
     value = format_datetime(dt)
-    if isinstance(dt, datetime):
-        attr = {"VALUE" : "DATE-TIME"}
-        if tzid:
-            attr["TZID"] = tzid
+    attr = get_datetime_attributes(dt, tzid)
+    return value, attr
+
+def get_period_item(start, end, tzid=None):
+
+    """
+    Return an iCalendar-compatible string and attributes for 'start', 'end' and
+    'tzid'.
+    """
+
+    start = start and to_timezone(start, tzid)
+    end = end and to_timezone(end, tzid)
+
+    start_value = start and format_datetime(start) or None
+    end_value = end and format_datetime(end) or None
+
+    if start and end:
+        attr = get_period_attributes(tzid)
+        return "%s/%s" % (start_value, end_value), attr
+    elif start:
+        attr = get_datetime_attributes(start, tzid)
+        return start_value, attr
     else:
-        attr = {"VALUE" : "DATE"}
-    return value, attr
+        return None, None
 
 def get_datetime(value, attr=None):
 
@@ -243,12 +284,24 @@
     else:
         return None
 
-def get_date(dt):
+def to_date(dt):
 
     "Return the date of 'dt'."
 
     return date(dt.year, dt.month, dt.day)
 
+def to_datetime(dt, tzid):
+
+    """
+    Return a datetime for 'dt', using the start of day for dates, and using the
+    'tzid' for the conversion.
+    """
+
+    if isinstance(dt, datetime):
+        return dt
+    else:
+        return get_start_of_day(dt, tzid)
+
 def get_start_of_day(dt, tzid):
 
     """