From 9cc3d59910a9ba980c2099065768e12064e65cf5 Mon Sep 17 00:00:00 2001
From: John Hutchinson <johnhutch@gmail.com>
Date: Tue, 13 Jun 2017 22:09:32 -0400
Subject: [PATCH] Issue #112 - restructured add/sub functions in grocery list,
 moving to ingredient model, avoids checking compatibility for non-united
 ingredients.

---
 app/models/grocery_list.rb | 27 ++++++------------------
 app/models/ingredient.rb   | 43 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 22 deletions(-)

diff --git a/app/models/grocery_list.rb b/app/models/grocery_list.rb
index 727987c..481fca5 100644
--- a/app/models/grocery_list.rb
+++ b/app/models/grocery_list.rb
@@ -11,16 +11,8 @@ def add_ingredient(add_i)
 
     self.ingredients.each do |list_i|
       if list_i.matched?(add_i)
-        if list_i.unitless? || add_i.unitless?
-          if list_i.unitless? && add_i.unitless?
-            list_i.amount = sum_i(list_i, add_i)
-            return list_i.save
-          end
-        else
-          if list_i.unitized_amount.compatible?(add_i.unitized_amount)
-            list_i.amount = Unit.new( list_i.unitized_amount + add_i.unitized_amount ).scalar
-            return list_i.save
-          end
+        if list_i.sum(add_i)
+          return true
         end
       end
     end
@@ -29,23 +21,16 @@ def add_ingredient(add_i)
 
   def subtract_ingredient(sub_i)
     # search for the ingredient by name, then subtract the recipe's amount from the grocery list
-    # if amount = 0, remove entirely
+    # if resultant amount would be <= 0, remove entirely
 
     self.ingredients.each do |list_i|
       if list_i.matched?(sub_i)
-        if (list_i.unitized_amount > sub_i.unitized_amount) && list_i.unitized_amount.compatible?(sub_i.unitized_amount)
-          list_i.amount = Unit.new( list_i.unitized_amount - sub_i.unitized_amount ).scalar
-          return list_i.save
-        else
-          return self.ingredients.delete(list_i)
+        if list_i.sub(sub_i)
+          return true
         end
       end
+      return self.ingredients.delete(list_i)
     end
   end
 
-  private
-
-  def sum_i(list_i, add_i)
-    Unit.new( list_i.unitized_amount + add_i.unitized_amount ).scalar
-  end
 end
diff --git a/app/models/ingredient.rb b/app/models/ingredient.rb
index 6d0308c..18dd8f5 100644
--- a/app/models/ingredient.rb
+++ b/app/models/ingredient.rb
@@ -46,10 +46,51 @@ def matched?(ing)
       return self.name.singularize == ing.name.singularize
   end
 
+  def sum(ing)
+    # verify that ingredients are compatibly unit'd (or not unit'd)
+    # could probably be combined with sub(ing) with the math operator sent as a 
+    # param but I don't know how to do that.
+
+    if self.unitless? || ing.unitless?
+      if self.unitless? && ing.unitless?
+        self.amount = Unit.new( self.unitized_amount + ing.unitized_amount ).scalar
+        return self.save
+      end
+    else
+      if self.unitized_amount.compatible?(ing.unitized_amount)
+        self.amount = Unit.new( self.unitized_amount + ing.unitized_amount ).scalar
+        return self.save
+      end
+    end
+    return false
+  end
+
+  def sub(ing)
+    # verify that ingredients are compatibly unit'd (or not unit'd) and then subtract
+    # could probably be combined with sum(ing) with the math operator sent as a param
+    # but I don't know how to do that.
+
+    if self.unitless? || ing.unitless?
+      if self.unitless? && ing.unitless?
+        if (self.amount > ing.amount)
+          self.amount = Unit.new( self.unitized_amount - ing.unitized_amount ).scalar
+          return self.save
+        end
+      end
+    else
+      if self.unitized_amount.compatible?(ing.unitized_amount)
+        if (self.unitized_amount > ing.unitized_amount)
+          self.amount = Unit.new( self.unitized_amount - ing.unitized_amount ).scalar
+          return self.save
+        end
+      end
+    end
+  end
+
   def ingreedy_parse(ing_string)
     begin
       parsed_ing = Ingreedy.parse(ing_string)
-    rescue 
+    rescue
       # ingreedy chokes if you give it an ingredient string that doesn't contain a 
       # quantity. so let's handle that so our app doesn't crash
       parsed_ing = false