module PipeRpc
  class Hub
    def initialize(args)
      @channel = args[:input]
      @socket = Socket.new(self, args)
      @requester = Requester.new(self)
      @responder = Responder.new(self)
      @clients = {}
      self.loop_iteration = nil
    end

    attr_reader :channel
    attr_accessor :logger

    def log(msg)
      if logger == :reflect
        notify(server: :reflect_logger, method: :log, arguments: [msg])
      elsif logger.respond_to? :debug
        logger.debug msg
      elsif logger
        logger.call msg
      end
    end

    def add_server(servers)
      @responder.add_server(servers)
    end

    def rmv_server(server_name)
      @responder.rmv_server(server_name)
    end

    def on_incoming_request(&on_request)
      @responder.on_request(&on_request)
    end

    def client_for(server_name)
      @clients[server_name] ||= Client.new(self, server: server_name)
    end

    def loop_iteration=(proc)
      @loop_iteration = proc
    end

    def on_sent(&on_sent)
      @socket.on_write(&on_sent)
    end

    def on_received(&on_received)
      @socket.on_read(&on_received)
    end

    def notify(signature)
      @socket.write @requester.notification(signature)
    end

    def request(signature, &on_result)
      result = nil
      result_ready = false

      request = @requester.request(signature) do |*response|
        result = on_result.call(*response)
        result_ready = true
      end
      @socket.write request

      loop do
        return result if result_ready
        @loop_iteration ? @loop_iteration.call : handle_message
      end
    end

    def send_error(error = {})
      @socket.write ErrorResponse.new(id: error.delete(:id), error: error)
    end

    def handle_message
      message = next_message # blocks

      return unless message

      if message.notification?
        @responder.handle_notification(message.handler)
      elsif message.request?
        @responder.handle_request(message.handler) { |response| @socket.write response }
      elsif message.response?
        @requester.handle_response(message.handler)
      elsif message.error?
        raise message.handler.native_error
      else
        send_error(id: nil, code: -32600, data: { message: 'no request, result or error' })
      end
    end

    private

    def next_message
      Message.new(self, @socket.read) # blocks
    rescue => e
      send_error(id: nil, code: -32700, data: { message: e.message })
      nil
    end
  end
end