# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1509489934 -3600
# Node ID 8978b422905b3c3e7dd7f6d69373fde12a0ecce3
# Parent  418b856973df5d441044e878c018880908918ad1
Attempt to load existing recurrence instances when obtaining rescheduled period
objects, employing a new method to return objects for encoding into parts for
message generation.

diff -r 418b856973df -r 8978b422905b imiptools/client.py
--- a/imiptools/client.py	Mon Oct 30 23:15:51 2017 +0100
+++ b/imiptools/client.py	Tue Oct 31 23:45:34 2017 +0100
@@ -852,6 +852,49 @@
 
     # Specific message generation methods.
 
+    def get_rescheduled_objects(self, periods):
+
+        "Return objects describing rescheduled 'periods'."
+
+        objects = []
+
+        if periods:
+
+            # For new recurrences, duplicate the core of the object without any
+            # period information.
+
+            template = self.obj.copy()
+            template.remove_all(["RRULE", "RDATE", "DTSTART", "DTEND", "DURATION"])
+
+            # Process each period, attempting to update existing recurrences or
+            # creating new ones.
+
+            for p in periods:
+                if not p.origin:
+                    continue
+
+                # Attempt to find an existing recurrence.
+
+                obj = self.get_stored_object(self.uid, p.get_recurrenceid())
+                if not obj:
+                    obj = template.copy()
+
+                    # Acquire the original recurrence identifier associated with
+                    # this period. This may differ where the start of the period
+                    # has changed.
+
+                    dt, attr = p.get_recurrenceid_item()
+                    obj["RECURRENCE-ID"] = [(format_datetime(dt), attr)]
+
+                # Set specific recurrence information.
+
+                obj.set_datetime("DTSTART", p.get_start())
+                obj.set_datetime("DTEND", p.get_end())
+
+                objects.append(obj)
+
+        return objects
+
     def get_rescheduled_parts(self, periods, method):
 
         """
@@ -860,30 +903,8 @@
 
         rescheduled_parts = []
 
-        if periods:
-
-            # Duplicate the core of the object without any period information.
-
-            obj = self.obj.copy()
-            obj.remove_all(["RRULE", "RDATE", "DTSTART", "DTEND", "DURATION"])
-
-            for p in periods:
-                if not p.origin:
-                    continue
-
-                # Set specific recurrence information.
-
-                obj.set_datetime("DTSTART", p.get_start())
-                obj.set_datetime("DTEND", p.get_end())
-
-                # Acquire the original recurrence identifier associated with
-                # this period. This may differ where the start of the period has
-                # changed.
-
-                dt, attr = p.get_recurrenceid_item()
-                obj["RECURRENCE-ID"] = [(format_datetime(dt), attr)]
-
-                rescheduled_parts.append(self.object_to_part(method, obj))
+        for obj in self.get_rescheduled_objects(periods):
+            rescheduled_parts.append(self.object_to_part(method, obj))
 
         return rescheduled_parts