Fix bug preventing the creation of CFPs

continues #14

app/controllers/admin/cfps_controller.rb

@@ -13,7 +13,7 @@ def new
     def edit; end
 
     def create
-      @cfp = @program.build_cfp(cfp_params)
+      @cfp = Cfp.new(cfp_params)
       send_mail_on_cfp_dates_updates = @cfp.notify_on_cfp_date_update?
 
       if @cfp.save
@@ -54,24 +54,14 @@ def destroy
     private
 
     def cfp_params
-      # Do a bit of param massaging.
-      # 1. For some reason fields_for @cfp.program in the view produces a slightly
-      # wrong parameter name that can't be used with assign/update_attributes.
-      # Fix this by renaming :program to :program_attributes.
-      # 2. Starting with a CFP model object such as
-      # @cfp = #<Cfp id: 1, ... , program_id: 1>
-      # running .update_attributes on that with {... "program_attributes"=>{"speaker_proposals_req_speaker_event_reg"=>"true"}}
-      # should simply update the program associated with that CFP. Unfortunately,
-      # it also sets @cfp.program_id to nil. Not clear why as update_attributes
-      # is supposed to merge rather than replace, but the workaround is to inject
-      # the @cfp's program_id into the incoming parameters so the link is not lost.
-
-    cfp = params.require(:cfp)
-      cfp[:program_attributes] = cfp.delete(:program) if cfp.has_key? :program
-      cfp[:program_attributes][:id] = @cfp.program.id
-
-      cfp.permit(:start_date, :end_date,
-                 program_attributes: [ :id, :speaker_proposals_req_speaker_event_reg, :speaker_proposals_req_bio, :speaker_proposals_req_subtitle, :speaker_proposals_req_commercial, :speaker_proposals_req_track, :speaker_proposals_req_difficulty_level])
+      params.require(:cfp).permit(:start_date, :end_date,
+                                  program_attributes: %i[id
+                                                         speaker_proposals_req_bio
+                                                         speaker_proposals_req_commercial
+                                                         speaker_proposals_req_difficulty_level
+                                                         speaker_proposals_req_speaker_event_reg
+                                                         speaker_proposals_req_subtitle
+                                                         speaker_proposals_req_track])
     end
   end
 end

app/models/cfp.rb

@@ -3,7 +3,7 @@
 class Cfp < ActiveRecord::Base
   has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
   belongs_to :program
-  accepts_nested_attributes_for :program
+  accepts_nested_attributes_for :program, update_only: true
 
   validates :program_id, presence: true
   validates :start_date, :end_date, presence: true
@@ -56,6 +56,13 @@ def remaining_days(date = Date.today)
     result > 0 ? result : 0
   end
 
+  # Workaround for https://stackoverflow.com/q/6346134
+  def program_attributes=(attributes)
+    self.program = Program.find(attributes[:id]) if attributes[:id].present?
+
+    assign_nested_attributes_for_one_to_one_association(:program, attributes) # super
+  end
+
   private
 
   def before_end_of_conference

app/views/admin/cfps/_form.html.haml

@@ -7,7 +7,7 @@
     = semantic_form_for(@cfp, url: admin_conference_program_cfp_path(@conference.short_title), html: {multipart: true}) do |f|
       = f.input :start_date, as: :string, input_html: { id: 'registration-period-start-datepicker', start_date: @conference.start_date, end_date: @conference.end_date, readonly: 'readonly' }
       = f.input :end_date, as: :string, input_html: { id: 'registration-period-end-datepicker', readonly: 'readonly' }
-      = f.fields_for @cfp.program do |p|
+      = f.fields_for :program do |p|
         = p.input :speaker_proposals_req_speaker_event_reg, as: :radio, label: 'Speakers todo: remind to register for event', input_html: { id: 'speaker_proposals_req_speaker_event_reg'}
         = p.input :speaker_proposals_req_bio, as: :radio, label: 'Speakers todo: remind to fill out bio', input_html: { id: 'speaker_proposals_req_bio'}
         = p.input :speaker_proposals_req_subtitle, as: :radio, label: 'Speakers todo: remind to add subtitle', input_html: { id: 'speaker_proposals_req_subtitle'}