Add function to compare local and engelsystem assignments

app/models/conference.rb

@@ -67,4 +67,33 @@ class Conference < ApplicationRecord
       return nil
     end
   end
+
+  def compare_engelsystem_shifts(additional_conferences = [])
+    return unless translation_angel_id = fetch_translation_angel_id
+    return unless data = fetch_engelsystem("angeltypes/#{translation_angel_id}/shifts")
+    engelsystem_shifts = data.each_with_object({}) do |shift, hash|
+      hash[shift['id']] = shift
+        &.dig("needed_angel_types")
+        &.find{ |t| t["angel_type"]["id"] == translation_angel_id }
+        &.dig("entries")
+        &.map{ |t| t["user"]["name"] }
+    end
+    Session.where(conference: [self]+additional_conferences).includes(:assignments).each do |session|
+      next if session.engelsystem_id.blank?
+      engelsystem_assigned = engelsystem_shifts[session.engelsystem_id]
+      local_assigned = session.assignments.includes(:user).map{|a|a.user.name}
+
+      only_engelsystem = engelsystem_assigned - local_assigned
+      only_local = local_assigned - engelsystem_assigned
+
+      unless only_engelsystem.blank? and only_local.blank?
+        puts "============================="
+        puts "Session: #{session.title} (#{session.engelsystem_id})"
+        puts "============================="
+        puts "Not signed up in engelsystem: #{only_local.join(", ")}" unless only_local.blank?
+        puts "Missing in local assignments: #{only_engelsystem.join(", ")}" unless only_engelsystem.blank?
+        puts
+      end
+    end
+  end
 end