Any object can use a Asset

Remove coupling with AssetAssociation for Asset usage
functionality.

When a asset is updated (from Admin::AssetsController) the asset
touches its using objects.

app/controllers/admin/assets_controller.rb

@@ -95,6 +95,7 @@ def update_multiple
   def update
     @asset = Asset.find(params[:id])
     if @asset.update_attributes(params[:asset])
+      @asset.touch_usages
       flash[:notice] = "#{@asset.full_name} #{t(:saved, :scope => [:app, :admin_general])}"
     end
     respond_with @asset, :location => (params[:return_to] || edit_admin_asset_url(@asset))

app/models/asset.rb

@@ -88,25 +88,19 @@ def of_the_type(filetype)
   end
 
   def usages
-    @usages ||= _usages.map do |u|
-      u.except('container_id')
-    end.uniq.collect { |u| u['usage_type'].constantize.find(u['usage_id']) }
+    @usages ||= AssetUsages.new(self)
   end
 
-  def remove_usage(association)
-    usage = usage_from_association(association)
-    if _usages.include?(usage)
-      _usages.reject! { |u| u == usage }
-      save
-    end
+  def remove_usage object, context
+    usages.remove object, context
   end
 
-  def add_usage(association)
-    usage = usage_from_association(association)
-    unless _usages.include?(usage)
-      _usages << usage
-      save
-    end
+  def add_usage object, context
+    usages.add object, context
+  end
+
+  def touch_usages
+    usages.each &:touch
   end
 
   class << self
@@ -172,13 +166,4 @@ def store
   def cleanup
     Porthos.s3_storage.destroy(full_name)
   end
-
-  def usage_from_association(association)
-    {
-      'container_id' => association.id,
-      'usage_type' => association._root_document.class.model_name,
-      'usage_id' => association._root_document.id.to_s
-    }
-  end
-
 end

app/models/asset_usages.rb

@@ -0,0 +1,56 @@
+class AssetUsages
+  include Enumerable
+
+  attr_reader :asset
+
+  def initialize asset
+    @asset = asset
+  end
+
+  def each &block
+    using_objects.each &block
+  end
+
+  def add object, context = nil
+    usage = new_usage object, context
+
+    unless asset_usages.include?(usage)
+      asset_usages << usage
+      save_asset
+    end
+  end
+
+  def remove object, context = nil
+    usage = new_usage object, context
+    asset_usages.reject! { |u| u == usage }
+    save_asset
+  end
+
+  private
+
+  def asset_usages
+    asset._usages
+  end
+
+  def save_asset
+    asset.save
+  end
+
+  def using_objects
+    uniq_usages.collect do |usage|
+      usage["usage_type"].constantize.find usage["usage_id"]
+    end
+  end
+
+  def uniq_usages
+    asset_usages.uniq {|usage| [usage["usage_id"], usage["usage_type"]] }
+  end
+
+  def new_usage object, context
+    {
+      "container_id" => context.to_s,
+      "usage_type" => object.class.model_name,
+      "usage_id" => object.id.to_s
+    }
+  end
+end

app/models/data/asset_association.rb

@@ -87,14 +87,15 @@ def revert_to_asset_attributes
 
   def notify_asset
     if changes.include?(:asset_id)
-      unless asset_id_was.nil?
-        if old_asset = Asset.find(asset_id_was)
-          old_asset.remove_usage(self)
+      if old_asset = Asset.find(asset_id_was)
+        old_asset.remove_usage _root_document, self.id
+      end
+
+      if asset_id.present?
+        if new_asset = Asset.find(asset_id)
+          new_asset.add_usage _root_document, self.id
         end
       end
-      Asset.find(asset_id).tap do |new_asset|
-        new_asset.add_usage(self) if new_asset
-      end if asset_id.present?
     end
   end
 

app/views/admin/assets/edit.html.erb

@@ -90,7 +90,13 @@
         <h2>Används på:</h2>
         <ul>
         <% @asset.usages.each do |usage| %>
-          <li><%= link_to usage.title, admin_item_path(usage) %></li>
+          <li>
+            <% if usage.is_a?(Item) %>
+              <%= link_to usage.title, admin_item_path(usage) %>
+            <% else %>
+              <%= link_to usage.name, [:admin, usage] %>
+            <% end %>
+          </li>
         <% end %>
         </ul>
       </div>

test/support/integration_case.rb

@@ -39,4 +39,4 @@ def logout!
     visit admin_logout_path
   end
 
-end
+end

test/unit/asset_usages_test.rb

@@ -0,0 +1,51 @@
+require_relative "../test_helper"
+require "minitest/autorun"
+
+describe "AssetUsages" do
+  let(:item){ FactoryGirl.build :item, id: 123 }
+  let(:asset){ FactoryGirl.build :asset, created_by: FactoryGirl.build(:user) }
+  subject{ AssetUsages.new asset }
+
+  it "is initialized with a asset" do
+    subject.asset.must_equal asset
+  end
+
+  it "adds usages to asset" do
+    usage = {
+      "usage_type" => "Item",
+      "usage_id" => "123",
+      "container_id" => "a context",
+    }
+    subject.expects :save_asset
+
+    subject.add item, "a context"
+
+    asset._usages.must_equal [usage]
+  end
+
+  it "deletes usages from asset" do
+    asset.stubs _usages: [{
+      "usage_type" => "Item",
+      "usage_id" => "123",
+      "container_id" => "a context"
+    }]
+    subject.expects :save_asset
+
+    subject.remove item, "a context"
+
+    asset._usages.must_equal []
+  end
+
+  it "is enumerable" do
+    Item.stubs(:find).with("123").returns item
+    asset.stubs _usages: [{
+      "usage_type" => "Item",
+      "usage_id" => "123",
+      "container_id" => "a context"
+    }]
+    usages = []
+    subject.each {|using_object| usages << using_object }
+
+    usages.must_equal [item]
+  end
+end