# encoding: utf-8

module Punchblock
  module Translator
    module InputComponent
      def setup
        @buffer = ""
        @initial_timeout = @component_node.initial_timeout || -1
        @inter_digit_timeout = @component_node.inter_digit_timeout || -1
      end

      def execute
        validate
        send_ref

        @grammar = prepare_grammar

        begin_initial_timer @initial_timeout/1000 unless @initial_timeout == -1

        @dtmf_handler_id = register_dtmf_event_handler
      rescue OptionError => e
        with_error 'option error', e.message
      end

      def process_dtmf(digit)
        @buffer << digit
        cancel_initial_timer
        case (match = @grammar.match @buffer.dup)
        when RubySpeech::GRXML::Match
          complete success_reason(match)
        when RubySpeech::GRXML::NoMatch
          complete Punchblock::Component::Input::Complete::NoMatch.new
        when RubySpeech::GRXML::PotentialMatch
          reset_inter_digit_timer
        end
      end

      def execute_command(command)
        case command
        when Punchblock::Component::Stop
          command.response = true
          complete Punchblock::Event::Complete::Stop.new
        else
          super
        end
      end

      private

      def validate
        raise OptionError, 'A grammar document is required.' unless @component_node.grammar
        raise OptionError, 'A mode value other than DTMF is unsupported.' unless @component_node.mode == :dtmf
        raise OptionError, 'An initial timeout value that is negative (and not -1) is invalid.' unless @initial_timeout >= -1
        raise OptionError, 'An inter-digit timeout value that is negative (and not -1) is invalid.' unless @inter_digit_timeout >= -1
      end

      def prepare_grammar
        @component_node.grammar.value.clone.tap do |grammar|
          grammar.inline!
          grammar.tokenize!
          grammar.normalize_whitespace
        end
      end

      def begin_initial_timer(timeout)
        @initial_timer = after timeout do
          complete Punchblock::Component::Input::Complete::NoInput.new
        end
      end

      def cancel_initial_timer
        return unless instance_variable_defined?(:@initial_timer) && @initial_timer
        @initial_timer.cancel
        @initial_timer = nil
      end

      def reset_inter_digit_timer
        return if @inter_digit_timeout == -1
        @inter_digit_timer ||= begin
          after @inter_digit_timeout/1000 do
            complete Punchblock::Component::Input::Complete::NoMatch.new
          end
        end
        @inter_digit_timer.reset
      end

      def cancel_inter_digit_timer
        return unless instance_variable_defined?(:@inter_digit_timer) && @inter_digit_timer
        @inter_digit_timer.cancel
        @inter_digit_timer = nil
      end

      def success_reason(match)
        Punchblock::Component::Input::Complete::Success.new :mode           => match.mode,
                                                            :confidence     => match.confidence,
                                                            :utterance      => match.utterance,
                                                            :interpretation => match.interpretation
      end

      def complete(reason)
        unregister_dtmf_event_handler
        cancel_initial_timer
        cancel_inter_digit_timer
        send_complete_event reason
      end
    end
  end
end