USDA density calculations now more powerful; added ability to parse cubic values

app/models/ingredient.rb

@@ -49,25 +49,7 @@ class Ingredient < ActiveRecord::Base
     self.kcal = food.kcal
     self.fiber = food.fiber
     self.sugar = food.sugar
-    self.density = calculate_density(food.gram_weight_1, food.gram_weight_desc_1) || calculate_density(food.gram_weight_2, food.gram_weight_desc_2)
-  end
-
-  def calculate_density(grams, description)
-    return nil if grams.blank? || description.blank?
-
-    begin
-      value_unit = UnitConversion.parse(description)
-      if value_unit.volume?
-        density_value = grams.to_d / value_unit.raw_value
-        density_units = "g/#{value_unit.unit.unit}"
-        density = UnitConversion.parse(density_value, density_units)
-        return density.convert('oz/cup').to_s
-      else
-        return nil
-      end
-    rescue UnitConversion::UnparseableUnitError
-      return nil
-    end
+    self.density = food.density_best_guess
   end
 
 end

app/models/usda_food.rb

@@ -14,9 +14,8 @@ class UsdaFood < ActiveRecord::Base
   end
 
   def density_best_guess
-    usda_food_weights.each do |w|
-
-    end
+    density = usda_food_weights.map { |w| w.calculate_density }.compact.first
+    density.nil? ? nil : density.to_s
   end
 
 end

lib/unit_conversion/constants.rb

@@ -15,11 +15,12 @@ module UnitConversion
       '[qt_us]': %w(quart quarts qt),
       '[gal_us]': %w(gallon gallons ga),
       '[foz_us]': %w(foz floz),
+      '[in_i]': %w(inch inches in)
   }
 
   METRIC_UNIT_ALIASES = {
       g: %w(gram grams),
-      kg: %w(kilograms kilogram),
+      kg: %w(kilogram kilograms),
 
       ml: %w(milliliter milliliters),
       cl: %w(centiliter centiliters),

lib/unit_conversion/parsed_unit.rb

@@ -56,6 +56,9 @@ module UnitConversion
       # fluid ounce is the only known unit with a space; fix it up before the following replacement
       unit_description = unit_description.gsub(/fl oz/i, 'floz')
 
+      # if a cubic unit is found, map it to unit3 (ex 'cubic inches' is converted to 'inches3')
+      unit_description = unit_description.gsub(/cubic\s+(\w+)/i, '\13')
+
       unit_description.downcase.gsub(/[a-z_\[\]]+/) do |match|
         UNIT_ALIAS_MAP[match] || match
       end

spec/lib/unit_conversion/parsed_unit_spec.rb

@@ -12,7 +12,10 @@ RSpec.describe UnitConversion::ParsedUnit do
         'Grams' => 'g',
         'Tbsp' => '[tbs_us]',
         '[tbs_us]' => '[tbs_us]',
-        '[oz_av]' => '[oz_av]'
+        '[oz_av]' => '[oz_av]',
+        'cubic inch' => '[in_i]3',
+        'in3' => '[in_i]3'
+
     }
 
     data.each do |input, output|

spec/lib/unit_conversion/value_unit_spec.rb

@@ -44,6 +44,14 @@ RSpec.describe UnitConversion::ValueUnit do
     it 'Converts parsed objects' do
       check_vu(UnitConversion::ValueUnit.for(UnitConversion::ParsedNumber.new('5'), UnitConversion::ParsedUnit.new('cups')), 5, 'cup')
     end
+
+    it 'converts multi word units' do
+      check_vu(UnitConversion::ValueUnit.for('2 cubic inches'), 2, 'inch3')
+    end
+
+    it 'understands cubic inches to be volume' do
+      expect(UnitConversion::ValueUnit.for('2 cubic inches').volume?).to be_truthy
+    end
   end
 
 end