# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443389998 -7200
# Node ID 71ff0157387ba678e3dcfd811a37f0db66b6bb23
# Parent  57c3866a301d641f083509f5842fe4554efe1841
Fixed the generation of time selection controls so that contiguous periods can
be selected even when time instants are present.

diff -r 57c3866a301d -r 71ff0157387b imipweb/calendar.py
--- a/imipweb/calendar.py	Sun Sep 27 23:38:51 2015 +0200
+++ b/imipweb/calendar.py	Sun Sep 27 23:39:58 2015 +0200
@@ -470,8 +470,43 @@
         # Generate controls to select time periods.
 
         slots = self.env.get_args().get("slot", [])
+        last = None
+
+        # Produce controls for the intervals/slots. Where instants in time are
+        # encountered, they are merged with the following slots, permitting the
+        # selection of contiguous time periods. However, the identifiers
+        # employed by controls corresponding to merged periods will encode the
+        # instant so that labels may reference them conveniently.
+
+        intervals = list(intervals)
+        intervals.sort()
+
         for point, endpoint in intervals:
-            value, identifier = self._slot_value_and_identifier(point, endpoint)
+
+            # Merge any previous slot with this one, producing a control.
+
+            if last:
+                _value, identifier = self._slot_value_and_identifier(last, last)
+                value, _identifier = self._slot_value_and_identifier(last, endpoint)
+                self._slot_selector(value, identifier, slots)
+
+            # If representing an instant, hold the slot for merging.
+
+            if endpoint and point.point == endpoint.point:
+                last = point
+
+            # If not representing an instant, produce a control.
+
+            else:
+                value, identifier = self._slot_value_and_identifier(point, endpoint)
+                self._slot_selector(value, identifier, slots)
+                last = None
+
+        # Produce a control for any unmerged slot.
+
+        if last:
+            _value, identifier = self._slot_value_and_identifier(last, last)
+            value, _identifier = self._slot_value_and_identifier(last, endpoint)
             self._slot_selector(value, identifier, slots)
 
     def show_calendar_participant_headings(self, group_types, group_sources, group_columns):
@@ -622,13 +657,16 @@
                 ])
 
             page.tr(class_=css)
+
+            # Produce a time interval heading, spanning two rows if this point
+            # represents an instant.
+
             if point.indicator == Point.PRINCIPAL:
                 timestr, timeid = self._slot_value_and_identifier(point, endpoint)
-                page.th(class_="timeslot", id="region-%s" % timeid)
+                page.th(class_="timeslot", id="region-%s" % timeid,
+                    rowspan=(endpoint and point.point == endpoint.point and 2 or 1))
                 self._time_point(point, endpoint)
-            else:
-                page.th()
-            page.th.close()
+                page.th.close()
 
             # Obtain slots for the time point from each group.