Synvert::Rewriter.new "strong_parameters", "Use strong_parameters syntax" do
  within_files 'config/**/*.rb' do
    # remove config.active_record.whitelist_attributes = ...
    with_node type: 'send', receiver: {type: 'send', receiver: {type: 'send', message: 'config'}, message: 'active_record'}, message: 'whitelist_attributes=' do
      remove
    end

    # remove config.active_record.mass_assignment_sanitizer = ...
    with_node type: 'send', receiver: {type: 'send', receiver: {type: 'send', message: 'config'}, message: 'active_record'}, message: 'mass_assignment_sanitizer=' do
      remove
    end
  end

  parameters = {}
  within_files 'app/models/**/*.rb' do
    # assign and remove attr_accessible ...
    within_node type: 'class' do
      object_name = node.name.source(self).underscore
      with_node type: 'send', message: 'attr_accessible' do
        parameters[object_name] = node.arguments.map { |key| key.source(self) }.join(', ')
        remove
      end
    end
  end

  within_file 'app/controllers/**/*.rb' do
    within_node type: 'class' do
      object_name = node.name.source(self).sub('Controller', '').singularize.underscore
      if_exist_node type: 'send', receiver: 'params', message: '[]', arguments: [object_name.to_sym] do
        if parameters[object_name]
          # append def xxx_params; ...; end
          unless_exist_node type: 'def', name: "#{object_name}_params" do
            new_code =  "def #{object_name}_params\n"
            new_code << "  params.require(:#{object_name}).permit(#{parameters[object_name]})\n"
            new_code << "end"
            append new_code
          end

          # params[:xxx] => xxx_params
          with_node type: 'send', receiver: 'params', message: '[]' do
            object_name = eval(node.arguments.first.source(self)).to_s
            if parameters[object_name]
              replace_with "#{object_name}_params"
            end
          end
        end
      end
    end
  end
end