TableBuilder: Extract custom action link methods to a new class

Move `#action_links`, `#action_link_method`, and
`#actions_after_policy_check` to a new class. They all depend on an
action and/or a model object, so it made sense to group these together.
Also, these should really be tested, and moved out of a private method
context. They now live in `TableBuilderHelper::CustomLinks`.

The advantage is that we now have these methods grouped together in a
separate module that can be tested separately.

Needed to change some things around now that they're in a class:

* `obj` and `action` are now instance variables
* In order to call Pundit's `policy` method, we have to call it directly
  on `Pundit`, since we're no longer in the context of a
  helper/controller/view.
* Create a `UserContext` that can be passed to Pundit based on the one
  created in `ApplicationController`.
* Rename some methods to make more sense in this new context.
* Move `actions_to_http_methods` to a class constant, so we're not
  redefining it in every call to `method_for_action`.
* Use `I18n.t` instead of `t` alone, otherwise getting the translation
  doesn't work.
* Move `TableBuilderHelper#polymorphic_url_parts` to a new class
  `TableBuilderHelper::URL`. This enables us to use it in both
  `CustomLinks` and the `TableBuilderHelper`. We can't use it from
  `CustomLinks` if it's a public method in `TableBuilderHelper`, and we
  can't use it in `TableBuilderHelper#tbody` if it's a class method in
  `TableBuilderHelper`.

There's a problem with the action symbols that aren't directly handled
in `actions_after_policy_check`. The `:show` action was passed by the
workbenches/show.html.slim template, but it doesn't appear in the
resulting output even though it should.

Refs #3479

3 files changed, 98 insertions, 79 deletions

diff --git a/app/helpers/table_builder_helper.rb b/app/helpers/table_builder_helper.rb
index d1afcddf7..98c170b85 100644
--- a/app/helpers/table_builder_helper.rb
+++ b/app/helpers/table_builder_helper.rb
@@ -1,3 +1,6 @@
+require 'table_builder_helper/custom_links'
+require 'table_builder_helper/url'
+
 # TODO: Add doc comment about neeeding to make a decorator for your collections
 # TODO: Document global variables this uses
 module TableBuilderHelper
@@ -100,7 +103,7 @@ module TableBuilderHelper
 
             if column_is_linkable?(column)
               # Build a link to the `item`
-              polymorph_url = polymorphic_url_parts(item)
+              polymorph_url = URL.polymorphic_url_parts(item)
               bcont << content_tag(:td, link_to(value, polymorph_url), title: 'Voir')
             else
               bcont << content_tag(:td, value)
@@ -122,12 +125,20 @@ module TableBuilderHelper
   end
 
   def build_links(item, links)
+    user_context = UserContext.new(
+      current_user,
+      referential: self.try(:current_referential)
+    )
+
     trigger = content_tag :div, class: 'btn dropdown-toggle', data: { toggle: 'dropdown' } do
       content_tag :span, '', class: 'fa fa-cog'
     end
 
     menu = content_tag :ul, class: 'dropdown-menu' do
-      (action_links(links, item) + item.action_links).map do |link|
+      (
+        CustomLinks.new(item, user_context, links).links +
+        item.action_links
+      ).map do |link|
         content_tag :li, link_to(
           link.name,
           link.href,
@@ -248,81 +259,4 @@ module TableBuilderHelper
   def column_is_linkable?(column)
     column.attribute == 'name' || column.attribute == 'comment'
   end
-
-  def polymorphic_url_parts(item)
-    polymorph_url = []
-
-    unless item.is_a?(Calendar) || item.is_a?(Referential)
-      if current_referential
-        polymorph_url << current_referential
-        polymorph_url << item.line if item.respond_to? :line
-        polymorph_url << item.route.line if item.is_a?(Chouette::RoutingConstraintZone)
-        polymorph_url << item if item.respond_to? :line_referential
-        polymorph_url << item.stop_area if item.respond_to? :stop_area
-        polymorph_url << item if item.respond_to? :stop_points || item.is_a?(Chouette::TimeTable)
-      elsif item.respond_to? :referential
-        polymorph_url << item.referential
-      end
-    else
-      polymorph_url << item
-    end
-
-    polymorph_url
-  end
-
-  # TODO: rename
-  def action_links(actions, obj)
-    actions_after_policy_check(actions, obj).map do |action|
-      # TODO: Move that s to another method
-      polymorph_url = []
-
-      unless [:show, :delete].include? action
-        polymorph_url << action
-      end
-
-      polymorph_url += polymorphic_url_parts(obj)
-
-      Link.new(
-        name: t("actions.#{action}"),
-        href: polymorph_url,
-        method: action_link_method(action)
-      )
-    end
-  end
-
-  def action_link_method(action)
-    actions_to_http_methods = {
-      delete: :delete,
-      archive: :put,
-      unarchive: :put
-    }
-
-    actions_to_http_methods[action] || :get
-  end
-
-  def actions_after_policy_check(actions, obj)
-    actions.select do |action|
-    #   if action == :delete
-    #     if policy(item).present? && policy(item).destroy?
-    #       action
-    #     end
-    #   elsif action == :edit
-    #     if policy(item).present? && policy(item).update?
-    #       action
-    #     end
-    #   elsif action == :edit
-    #     
-    #   end
-      # if (action == :delete && policy(item).present? && policy(item).destroy?) ||
-      (action == :delete && policy(obj).present? && policy(obj).destroy?) ||
-        (action == :delete && !policy(obj).present?) ||
-        (action == :edit && policy(obj).present? && policy(obj).update?) ||
-        (action == :edit && !policy(obj).present?) ||
-        (action == :archive && !obj.archived?) ||
-        (action == :unarchive && obj.archived?) ||
-        ([:delete, :edit, :archive, :unarchive].include?(action))
-      #   action
-      # end
-    end
-  end
 end
diff --git a/app/helpers/table_builder_helper/custom_links.rb b/app/helpers/table_builder_helper/custom_links.rb
new file mode 100644
index 000000000..9703940d6
--- /dev/null
+++ b/app/helpers/table_builder_helper/custom_links.rb
@@ -0,0 +1,61 @@
+require 'table_builder_helper/url'
+
+module TableBuilderHelper
+  class CustomLinks
+    ACTIONS_TO_HTTP_METHODS = {
+      delete: :delete,
+      archive: :put,
+      unarchive: :put
+    }
+
+    def initialize(obj, user_context, actions)
+      @obj = obj
+      @user_context = user_context
+      @actions = actions
+    end
+
+    def links
+      actions_after_policy_check.map do |action|
+        Link.new(
+          name: I18n.t("actions.#{action}"),
+          href: polymorphic_url(action),
+          method: method_for_action(action)
+        )
+      end
+    end
+
+    def polymorphic_url(action)
+      polymorph_url = []
+
+      unless [:show, :delete].include?(action)
+        polymorph_url << action
+      end
+
+      polymorph_url += URL.polymorphic_url_parts(@obj)
+    end
+
+    def method_for_action(action)
+      ACTIONS_TO_HTTP_METHODS[action] || :get
+    end
+
+    def actions_after_policy_check
+      @actions.select do |action|
+        (action == :delete &&
+            Pundit.policy(@user_context, @obj).present? &&
+            Pundit.policy(@user_context, @obj).destroy?) ||
+          (action == :delete &&
+            !Pundit.policy(@user_context, @obj).present?) ||
+          (action == :edit &&
+            Pundit.policy(@user_context, @obj).present? &&
+            Pundit.policy(@user_context, @obj).update?) ||
+          (action == :edit &&
+            !Pundit.policy(@user_context, @obj).present?) ||
+          (action == :archive && !@obj.archived?) ||
+          (action == :unarchive && @obj.archived?) ||
+
+          # TODO: Something wrong here for actions not handled
+          ([:delete, :edit, :archive, :unarchive].include?(action))
+      end
+    end
+  end
+end
diff --git a/app/helpers/table_builder_helper/url.rb b/app/helpers/table_builder_helper/url.rb
new file mode 100644
index 000000000..59099ee99
--- /dev/null
+++ b/app/helpers/table_builder_helper/url.rb
@@ -0,0 +1,24 @@
+module TableBuilderHelper
+  class URL
+    def self.polymorphic_url_parts(item)
+      polymorph_url = []
+
+      unless item.is_a?(Calendar) || item.is_a?(Referential)
+        if current_referential
+          polymorph_url << current_referential
+          polymorph_url << item.line if item.respond_to? :line
+          polymorph_url << item.route.line if item.is_a?(Chouette::RoutingConstraintZone)
+          polymorph_url << item if item.respond_to? :line_referential
+          polymorph_url << item.stop_area if item.respond_to? :stop_area
+          polymorph_url << item if item.respond_to? :stop_points || item.is_a?(Chouette::TimeTable)
+        elsif item.respond_to? :referential
+          polymorph_url << item.referential
+        end
+      else
+        polymorph_url << item
+      end
+
+      polymorph_url
+    end
+  end
+end