module ApiMe
  module Generators
    class PolicyGenerator < ::Rails::Generators::NamedBase
      source_root File.expand_path('../templates', __FILE__)
      check_class_collision :suffix => "Policy"

      argument :attributes, :type => :array, :default => [], :banner => "field field"

      class_option :parent, :type => :string, :desc => "The parent class for the generated policy"

      def create_api_policy_file
        template 'policy.rb', File.join('app/policies', "#{singular_name}_policy.rb")
      end

      def policy_class_name
        "#{class_name}Policy"
      end

      def attributes_names
        attributes.select { |attr| !attr.reference? }.map { |a| a.name.to_sym }
      end

      def associations
        attributes.select { |attr| attr.reference? }
      end

      def nonpolymorphic_attribute_names
        associations.select { |attr| attr.type.in?([:belongs_to, :references]) }
                    .reject { |attr| attr.attr_options.fetch(:polymorphic, false) }
                    .map { |attr| "#{attr.name}_id".to_sym }
      end

      def polymorphic_attribute_names
        associations.select { |attr| attr.type.in?([:belongs_to, :references]) }
                    .select { |attr| attr.attr_options.fetch(:polymorphic, false) }
                    .map { |attr| ["#{attr.name}_id".to_sym, "#{attr.name}_type".to_sym] }.flatten
      end

      def association_attribute_names
        nonpolymorphic_attribute_names + (polymorphic_attribute_names)
      end

      def strong_parameters
        (attributes_names + association_attribute_names).map(&:inspect).join(", ")
      end

      def parent_class_name
        if options[:parent]
          options[:parent]
        else
          "ApplicationPolicy"
        end
      end

      hook_for :test_framework
    end
  end
end