Replaced Quantity 'primary' attr with ColumnView model

app/models/column_view.rb

@@ -1,2 +1,17 @@
 class ColumnView < ActiveRecord::Base
+  enum domain: Quantity.domains
+
+  belongs_to :project, required: true
+  has_and_belongs_to_many :quantities
+
+  validates :name, presence: true, uniqueness: {scope: :domain}
+  validates :domain, inclusion: {in: domains.keys}
+
+  # TODO: enforce column_view - quantity 'domain' identity
+  def toggle_column!(q)
+    column = self.quantities.find(q.id)
+    self.quantites.destroy(column)
+  rescue ActiveRecord::RecordNotFound
+    self.quantities.create!(quantity: q)
+  end
 end

app/models/measurement.rb

@@ -28,6 +28,33 @@ class Measurement < ActiveRecord::Base
     end
   end
 
+  # Copy/rename ColumnView on Measurement rename
+  after_save do
+    old_column_view = self.project.column_views
+      .find_by(name: self.name_was, domain: :measurement)
+    return unless old_column_view
+
+    if self.project.measurements.exists?(name: self.name_was)
+      return unless old_column_view.quantities.exist?
+      self.column_view.quantities.create(old_column_view.quantities)
+      self.column_view.save!
+    else
+      old_column_view.name = self.name
+      old_column_view.save!
+    end
+  end, if: :name_changed?
+
+  # Destroy ColumnView after last Measurement destruction
+  after_destroy do
+    unless self.project.measurements.exists?(name: self.name)
+      self.column_view.destroy!
+    end
+  end
+
+  def column_view
+    self.project.column_views.find_or_create_by(name: self.name, domain: :measurement)
+  end
+
   def toggle_hidden!
     self.toggle!(:hidden)
   end

app/models/quantity.rb

@@ -15,6 +15,7 @@ class Quantity < ActiveRecord::Base
 
   acts_as_nested_set dependent: :destroy, scope: :project
   belongs_to :project, required: false
+  has_and_belongs_to_many :column_views
 
   validates :name, presence: true, uniqueness: {scope: :project_id}
   validates :domain, inclusion: {in: domains.keys}
@@ -26,7 +27,6 @@ class Quantity < ActiveRecord::Base
   after_initialize do
     if new_record?
       self.domain ||= :diet
-      self.primary = false if self.primary.nil?
     end
   end
 
@@ -46,10 +46,6 @@ class Quantity < ActiveRecord::Base
     end
   end
 
-  def toggle_primary!
-    self.toggle!(:primary)
-  end
-
   def formula_quantities
     Formula.new(self.project, self.formula).get_quantities
   end