# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1505161895 -7200
# Node ID ea2b740d77457ed980488af1bd180e7704326381
# Parent  c0ee74128fca71ac67efc0b26a849fc38b6b8468
Handled null datetimes in form periods, also serialising nulls as empty strings.
Added a function that exposes the field inputs used to provide datetime details.

diff -r c0ee74128fca -r ea2b740d7745 imipweb/data.py
--- a/imipweb/data.py	Mon Sep 11 16:39:20 2017 +0200
+++ b/imipweb/data.py	Mon Sep 11 22:31:35 2017 +0200
@@ -35,7 +35,8 @@
     intended to represent information obtained from an iCalendar resource.
     """
 
-    def __init__(self, start, end, tzid=None, origin=None, start_attr=None, end_attr=None, form_start=None, form_end=None, replaced=False):
+    def __init__(self, start, end, tzid=None, origin=None, start_attr=None,
+                 end_attr=None, form_start=None, form_end=None, replaced=False):
 
         """
         Initialise a period with the given 'start' and 'end' datetimes, together
@@ -50,7 +51,8 @@
         self.replaced = replaced
 
     def as_tuple(self):
-        return self.start, self.end, self.tzid, self.origin, self.start_attr, self.end_attr, self.form_start, self.form_end, self.replaced
+        return self.start, self.end, self.tzid, self.origin, self.start_attr, \
+               self.end_attr, self.form_start, self.form_end, self.replaced
 
     def __repr__(self):
         return "EventPeriod%r" % (self.as_tuple(),)
@@ -101,7 +103,8 @@
 
     "A period whose information originates from a form."
 
-    def __init__(self, start, end, end_enabled=True, times_enabled=True, tzid=None, origin=None, replaced=False):
+    def __init__(self, start, end, end_enabled=True, times_enabled=True,
+                 tzid=None, origin=None, replaced=False):
         self.start = start
         self.end = end
         self.end_enabled = end_enabled
@@ -138,12 +141,14 @@
                 index is not None and ("dtend", index) or "dtend"
                 ])
 
-        return EventPeriod(dtstart, end_date_to_calendar(dtend), self.tzid, self.origin, dtstart_attr, dtend_attr, self.start, self.end, self.replaced)
+        return EventPeriod(dtstart, end_date_to_calendar(dtend), self.tzid,
+                           self.origin, dtstart_attr, dtend_attr,
+                           self.start, self.end, self.replaced)
 
     # Period data methods.
 
     def get_start(self):
-        return self.start.as_datetime(self.times_enabled)
+        return self.start and self.start.as_datetime(self.times_enabled) or None
 
     def get_end(self):
 
@@ -178,10 +183,10 @@
         return dtend
 
     def get_start_attr(self):
-        return self.start.get_attributes(self.times_enabled)
+        return self.start and self.start.get_attributes(self.times_enabled) or {}
 
     def get_end_attr(self):
-        return self.end.get_attributes(self.times_enabled)
+        return self.end and self.end.get_attributes(self.times_enabled) or {}
 
     # Form data methods.
 
@@ -323,8 +328,26 @@
     else:
         return event_period_from_period(period).as_form_period()
 
+
+
 # Form field extraction and serialisation.
 
+def get_date_control_inputs(args, name, tzid_name=None):
+
+    """
+    Return a tuple of date control inputs taken from 'args' for field names
+    starting with 'name'.
+
+    If 'tzid_name' is specified, the time zone information will be acquired
+    from fields starting with 'tzid_name' instead of 'name'.
+    """
+
+    return args.get("%s-date" % name, []), \
+           args.get("%s-hour" % name, []), \
+           args.get("%s-minute" % name, []), \
+           args.get("%s-second" % name, []), \
+           args.get("%s-tzid" % (tzid_name or name), [])
+
 def get_date_control_values(args, name, multiple=False, tzid_name=None, tzid=None):
 
     """
@@ -341,11 +364,7 @@
     time zone information is indicated in the field data.
     """
 
-    dates = args.get("%s-date" % name, [])
-    hours = args.get("%s-hour" % name, [])
-    minutes = args.get("%s-minute" % name, [])
-    seconds = args.get("%s-second" % name, [])
-    tzids = args.get("%s-tzid" % (tzid_name or name), [])
+    dates, hours, minutes, seconds, tzids = get_date_control_inputs(args, name, tzid_name)
 
     # Handle absent values by employing None values.
 
@@ -384,11 +403,11 @@
     args["%s-tzid" % (tzid_name or name)] = []
 
     for d in formdates:
-        args["%s-date" % name].append(d.date)
-        args["%s-hour" % name].append(d.hour)
-        args["%s-minute" % name].append(d.minute)
-        args["%s-second" % name].append(d.second)
-        args["%s-tzid" % (tzid_name or name)].append(d.tzid)
+        args["%s-date" % name].append(d and d.date or "")
+        args["%s-hour" % name].append(d and d.hour or "")
+        args["%s-minute" % name].append(d and d.minute or "")
+        args["%s-second" % name].append(d and d.second or "")
+        args["%s-tzid" % (tzid_name or name)].append(d and d.tzid or "")
 
 def get_period_control_values(args, start_name, end_name,
                               end_enabled_name, times_enabled_name,