1 files changed, 60 insertions, 0 deletions

diff --git a/app/models/occurrence.rb b/app/models/occurrence.rb
new file mode 100644
index 0000000..6205618
--- /dev/null
+++ b/app/models/occurrence.rb
@@ -0,0 +1,60 @@
+# TODO Make a gem out of the c wrapper
+require 'lib/chaos_calendar/ical_occurrences'
+
+class Occurrence < ActiveRecord::Base
+  
+  # Associations
+  
+  belongs_to :node
+  belongs_to :event
+  
+  # Class Methods
+  
+  def self.find_in_range start_time, end_time
+    find(
+      :all, :conditions => [
+        "start_time > ? AND end_time < ?", start_time, end_time 
+      ]
+    )
+  end
+  
+  # Deletes all Occurrences which belong to the given event. Afterwards a few
+  # variables are set to save repetitive queries. The occurrences of the given
+  # event are then calculated and created.
+  def self.generate event
+    self.delete_all(:event_id => event.id)
+    
+    node        = event.node
+    summary     = node.head.title
+    duration    = (event.end_time - event.start_time)
+    occurrences = self.generate_dates(event)
+    
+    occurrences.each do |occurrence|
+      self.create(
+        :summary    => summary,
+        :start_time => occurrence,
+        :end_time   => (occurrence + duration),
+        :node_id    => node.id,
+        :event_id   => event.id
+      )
+    end
+  end
+  
+  # Calculates the start_time of all occurrences for a given event if a proper
+  # RRule is provided. An ArgumentError is thrown from within the libical
+  # wrapper if the RRule is malformed. If the rrule attribute of an event is
+  # nil, it simply returns the event start_time as only occurrence.
+  # Return value is always an array of Time objects.
+  def self.generate_dates event
+    if event.rrule
+      Ical_occurrences::occurrences( 
+        event.start_time.utc.iso8601, 
+        (Time.now + 5.years).utc.iso8601, 
+        event.rrule
+      )
+    else
+      [event.start_time]
+    end
+      
+  end
+end