Extract Height as a value class

Author: nilbus

app/models/height.rb

@@ -0,0 +1,28 @@
+class Height
+  def initialize(observation)
+    return unless observation.present?
+    @height   = observation.value
+    @imperial = (observation.units == 'in')
+  end
+
+  def feet
+    if @imperial
+      (@height / 12).floor
+    else
+      (@height / 30).floor
+    end
+  end
+
+  def inches
+    if @imperial
+      @height % 12
+    else
+      (@height / 30 / 2.54).round
+    end
+  end
+
+  def to_s
+    return 'N/A' unless @height.present?
+    "#{feet} ft. #{inches} in."
+  end
+end

app/models/patient.rb

@@ -46,21 +46,8 @@ def age
   end
 
   def height
-    if observations.map(&:code_display).include?("Body Height")
-      height_observation = [observations.select{|observation| observation.code_display == "Body Height"}].flatten.sort_by(&:date).last
-      height_number = height_observation.value
-      if height_observation.units == "in"
-        height_feet = (height_number / 12).floor
-        height_inches = height_number % 12
-      else
-        height_feet = (height_number / 30).floor
-        height_inches = (height_number / 30 / 2.54).round
-      end
-      height = "#{height_feet} ft. #{height_inches} in."
-    else
-      height = "N/A"
-    end
-    height
+    height_observation = observations.select { |observation| observation.code_display == "Body Height" }
+    Height.new(height_observation).to_s
   end
 
   def observations