* VRFS-2606 get offset time into MM:SS:MLS format

admin/app/views/admin/jam_tracks/_jam_track_tap_in_fields.html.slim

@@ -1,7 +1,7 @@
 = f.inputs name: 'Tap In fields' do
 
   ol.nested-fields
-    = f.input :offset_time,  :required=>true
+    = f.input :offset_time_raw, :label => 'Offset Time', :hint => 'MM:SS:MLS', :required => true, :as => :string
 
     - if f.object.new_record?
       p style='margin-left:10px'

ruby/lib/jam_ruby/models/jam_track_tap_in.rb

@@ -1,11 +1,38 @@
 module JamRuby
   class JamTrackTapIn < ActiveRecord::Base
 
-    attr_accessible :jam_track_id, :offset_time, as: :admin
+    attr_accessible :jam_track_id, :offset_time, :offset_time_raw, as: :admin
 
     validates :offset_time,  presence: true, numericality: {only_integer: true}, length: {in: 1..1000}
     validates :jam_track,  presence: true
 
     belongs_to :jam_track, class_name: "JamRuby::JamTrack"
+
+    # this is used by active admin/jam-admin
+    def offset_time_raw
+      if self.offset_time.nil? || self.offset_time.nil?
+        '00:00:000'
+      else
+        seconds = self.offset_time.to_f/1000
+        time = Time.at(seconds)
+        time.strftime("%M:%S:#{(self.offset_time % 1000).to_s.rjust(3, '0')}")
+      end
+    end
+
+    # this is used by active admin/jam-admin
+    def offset_time_raw=(new_value)
+      if new_value && new_value.kind_of?(String) && new_value.include?(':')
+        bits = new_value.split(':')
+        if bits.length != 3
+          raise "format of offset time must be MM:SS:MLS"
+        end
+
+        self.offset_time = (bits[0].to_i * 60000) + (bits[1].to_i * 1000) + (bits[2].to_i)
+
+      else
+        raise "format of offset time must be MM:SS:MLS"
+      end
+
+    end
   end
 end