Add Event#location.

app/models/event.rb

@@ -32,6 +32,38 @@ class Event < ActiveRecord::Base
     where.not(lat: nil).where.not(lng: nil)
   }
 
+  def location
+    @location ||= {
+      # lat and lng are BigDecimal, so convert them to Float
+      lat: (lat.to_f if lat),
+      lng: (lng.to_f if lng),
+      radius:
+        begin
+          h = payload[:horizontal_accuracy].presence
+          v = payload[:vertical_accuracy].presence
+          if h && v
+            (h.to_f + v.to_f) / 2
+          else
+            (h || v || payload[:accuracy]).to_f
+          end
+        end,
+      course:
+        begin
+          if (v = payload[:course].presence) &&
+             (v = v.to_f) >= 0
+            v
+          end
+        end,
+      speed:
+        begin
+          if (v = payload[:speed].presence) &&
+             (v = v.to_f) >= 0
+            v
+          end
+        end,
+    }
+  end
+
   # Emit this event again, as a new Event.
   def reemit!
     agent.create_event :payload => payload, :lat => lat, :lng => lng

spec/models/event_spec.rb

@@ -15,6 +15,56 @@ describe Event do
     end
   end
 
+  describe "#location" do
+    it "returns a default hash when an event does not have a location" do
+      event = events(:bob_website_agent_event)
+      event.location.should == {
+        lat: nil,
+        lng: nil,
+        radius: 0.0,
+        speed: nil,
+        course: nil,
+      }
+    end
+
+    it "returns a hash containing location information" do
+      event = events(:bob_website_agent_event)
+      event.lat = 2
+      event.lng = 3
+      event.payload = {
+        radius: 300,
+        speed: 0.5,
+        course: 90.0,
+      }
+      event.save!
+      event.location.should == {
+        lat: 2.0,
+        lng: 3.0,
+        radius: 0.0,
+        speed: 0.5,
+        course: 90.0,
+      }
+    end
+
+    it "ignores invalid speed and course" do
+      event = events(:bob_website_agent_event)
+      event.lat = 2
+      event.lng = 3
+      event.payload = {
+        speed: -1,
+        course: -1,
+      }
+      event.save!
+      event.location.should == {
+        lat: 2.0,
+        lng: 3.0,
+        radius: 0.0,
+        speed: nil,
+        course: nil,
+      }
+    end
+  end
+
   describe "#reemit" do
     it "creates a new event identical to itself" do
       events(:bob_website_agent_event).lat = 2