Changed reusing initial events.

A previously created event is now only reused (touching updated_at) when
it is the last on the participants event queue.

1 files changed, 32 insertions, 9 deletions

diff --git a/app/models/event.rb b/app/models/event.rb
index b77ad9f..ad352d2 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -21,6 +21,10 @@ class Event < ActiveRecord::Base
   belongs_to  :participant
   belongs_to  :message
 
+  def ===(y)
+    participant_id == y.participant_id and message_id == y.message_id and ev_type_id == y.ev_type_id
+  end
+
 private
 
   # if count <0 then list all events otherwise maximal count events
@@ -28,7 +32,10 @@ private
     :conditions => { :participant_id => participant_id },
     :order => "id ASC",
     count<0 ? :readonly : :limit => count }}
-
+  named_scope :for_participant_and_message_desc_order, lambda { |participant_id,message_id| {
+    :conditions => { :participant_id => participant_id, :message_id => message_id },
+    :order => "id DESC",
+    :limit => 1 }}
 
   def self.make(options)
     options.assert_valid_keys(:event_type_name, :membership_message, :participant, :message)
@@ -46,25 +53,41 @@ private
         event.ev_type_id = EvType.find_by_name("updated").id
       else event.ev_type_id = 7777
     end
-    if unique?(event) and event.save
+    if unique_or_notlast?(event) and event.save
       event
     else
-      # There is already a pending event describing a change of the
-      # message. So don't create another one. Instead only touch the
+      # There is already a pending event (the last one) describing a change of
+      # the message. So don't create another one. Instead only touch the
       # "updated_at" attribute of the event.
-      iev= initial_event(event.participant_id, event.message_id, event.ev_type_id)
+      iev= Event.for_participant_and_message_desc_order(event.participant_id, event.message_id)[0]
       iev.updated_at= Time.now.to_s(:db)
       iev.save
       nil
     end
   end
 
-  def self.unique?(event)
-    initial_event(event.participant_id, event.message_id, event.ev_type_id).blank?
+  def self.unique_or_notlast?(event)
+    # Normally there should/could only be multiple update events more than
+    # once. The testing code would also handle all other events correctly.
+    mid= event.message_id
+    pid= event.participant_id
+    etid= event.ev_type_id
+    case initial_event(pid, mid, etid)
+    when nil
+      # its a unique event
+      return true
+    when Event.for_participant_and_message_desc_order(pid, mid)[0]
+      # there is already such an event for that message and its the last in the queue
+      # for case equality see also overridden === case operator
+      return false
+    else
+      # there is such an event but it's not the last in the queue so create a new one
+      return true
+    end
   end
 
-  def self.initial_event(participant_id, msg_id, event_type_id) 
-    Event.find_by_participant_id_and_message_id_and_ev_type_id(participant_id, msg_id, event_type_id)
+  def self.initial_event(pid, mid, etid)
+    Event.find_by_participant_id_and_message_id_and_ev_type_id(pid, mid, etid)
   end
 
 end