hoshinotsuyoshi/acts_as_shellscript_executable

require 'tempfile'

module ActiveRecord
  module Acts
    module ShellscriptExecutable
      def self.included(base)
        base.extend(ClassMethods)
      end

      module ClassMethods
        def __define_execute_method(method, type)
          class_eval <<-EOV
            def #{method}(&block)
              script = @@__executable_methods__[:#{method}][:script]
              command  = @@__executable_methods__[:#{method}][:command]
              answer = ''
              __execute__(script, :#{type}, answer, command, block)
              block_given? ? nil : answer
            end
          EOV
        end

        def __configs_set(command, script, method)
          configurations = begin
                             class_variable_get(:@@__executable_methods__)
                           rescue NameError
                             {}
                           end
          configurations[method] = { command: command, script: script }
          class_variable_set(:@@__executable_methods__, configurations)
        end

        def acts_as_shellscript_executable(opt)
          __add_method(:shell, opt)
        end

        def acts_as_rubyscript_executable(opt)
          __add_method(:ruby, opt)
        end

        def __add_method(type, method: nil, script: :script, command: nil)
          method ||= (type == :ruby ? :ruby_execute! : :execute!)
          command ||= (type == :ruby ? 'ruby' : '/bin/sh')
          __define_execute_method method, type
          __configs_set command, script, method
          include ::ActiveRecord::Acts::ShellscriptExecutable::InstanceMethods
        end
      end

      module InstanceMethods
        private

        def __execute__(script, type, answer, command, block = nil)
          script = send script if script.is_a? Symbol
          path = __temp_script_path(script, type)

          retval = []
          IO.popen([*command, path], err: [:child, :out]).each do |io|
            block ? block.call(io) : retval << io
          end
          answer.replace retval.join
        end

        def __temp_script_path(script, type)
          Tempfile.open('') do |temp|
            temp.puts 'STDOUT.sync = true' if type == :ruby
            temp.puts script
            temp.path
          end
        end
      end
    end
  end
end