adder

var RootCmd = &cmds.Command{
	Subcommands: map[string]*cmds.Command{

		"simpleAdd": &cmds.Command{
			Arguments: []cmdkit.Argument{
				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
			},
			Run: func(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment) {
				sum := 0

				for i, str := range req.Arguments {
					num, err := strconv.Atoi(str)
					if err != nil {
						re.SetError(err, cmdkit.ErrNormal)
						return
					}

					sum += num
					re.Emit(fmt.Sprintf("intermediate result: %d; %d left", sum, len(req.Arguments)-i-1))
				}

				re.Emit(fmt.Sprintf("total: %d", sum))
			},
		},

		"encodeAdd": &cmds.Command{
			Arguments: []cmdkit.Argument{
				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
			},
			Run: func(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment) {
				sum := 0

				for i, str := range req.Arguments {
					num, err := strconv.Atoi(str)
					if err != nil {
						re.SetError(err, cmdkit.ErrNormal)
						return
					}

					sum += num
					re.Emit(&AddStatus{
						Current: sum,
						Left:    len(req.Arguments) - i - 1,
					})
					time.Sleep(200 * time.Millisecond)
				}
			},
			Type: &AddStatus{},
			Encoders: cmds.EncoderMap{

				cmds.Text: cmds.MakeEncoder(func(req *cmds.Request, w io.Writer, v interface{}) error {
					s, ok := v.(*AddStatus)
					if !ok {
						return fmt.Errorf("cast error, got type %T", v)
					}

					if s.Left == 0 {
						fmt.Fprintln(w, "total:", s.Current)
					} else {
						fmt.Fprintf(w, "intermediate result: %d; %d left\n", s.Current, s.Left)
					}

					return nil
				}),
			},
		},

		"postRunAdd": &cmds.Command{
			Arguments: []cmdkit.Argument{
				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
			},

			Run: func(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment) {
				sum := 0

				for i, str := range req.Arguments {
					num, err := strconv.Atoi(str)
					if err != nil {
						re.SetError(err, cmdkit.ErrNormal)
						return
					}

					sum += num
					re.Emit(&AddStatus{
						Current: sum,
						Left:    len(req.Arguments) - i - 1,
					})
					time.Sleep(200 * time.Millisecond)
				}
			},
			Type: &AddStatus{},
			PostRun: cmds.PostRunMap{
				cmds.CLI: func(req *cmds.Request, re cmds.ResponseEmitter) cmds.ResponseEmitter {
					reNext, res := cmds.NewChanResponsePair(req)

					go func() {
						defer re.Close()
						defer fmt.Println()

						// length of line at last iteration
						var lastLen int

						for {
							v, err := res.Next()
							if err == io.EOF {
								return
							}
							if err == cmds.ErrRcvdError {
								fmt.Println("\nreceived error:", res.Error())
								return
							}
							if err != nil {
								fmt.Println("\nerror:", err)
								return
							}

							fmt.Print("\r" + strings.Repeat(" ", lastLen))

							s := v.(*AddStatus)
							if s.Left > 0 {
								lastLen, _ = fmt.Printf("\rcalculation sum... current: %d; left: %d", s.Current, s.Left)
							} else {
								lastLen, _ = fmt.Printf("\rsum is %d.", s.Current)
							}
						}
					}()

					return reNext
				},
			},
		},

		"exitAdd": &cmds.Command{
			Arguments: []cmdkit.Argument{
				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
			},

			Run: func(req *cmds.Request, re cmds.ResponseEmitter, env cmds.Environment) {
				sum := 0

				for i, str := range req.Arguments {
					num, err := strconv.Atoi(str)
					if err != nil {
						re.SetError(err, cmdkit.ErrNormal)
						return
					}

					sum += num
					re.Emit(&AddStatus{
						Current: sum,
						Left:    len(req.Arguments) - i - 1,
					})
					time.Sleep(200 * time.Millisecond)
				}
			},
			Type: &AddStatus{},
			PostRun: cmds.PostRunMap{
				cmds.CLI: func(req *cmds.Request, re cmds.ResponseEmitter) cmds.ResponseEmitter {
					reNext, res := cmds.NewChanResponsePair(req)
					clire := re.(cli.ResponseEmitter)

					go func() {
						defer re.Close()
						defer fmt.Println()

						// length of line at last iteration
						var lastLen int

						var exit int
						defer func() {
							clire.Exit(exit)
						}()

						for {
							v, err := res.Next()
							if err == io.EOF {
								return
							}
							if err == cmds.ErrRcvdError {
								fmt.Println("\nreceived error:", res.Error())
								break
							}
							if err != nil {
								fmt.Println("\nerror:", err)
								break
							}

							fmt.Print("\r" + strings.Repeat(" ", lastLen))

							s := v.(*AddStatus)
							if s.Left > 0 {
								lastLen, _ = fmt.Printf("\rcalculation sum... current: %d; left: %d", s.Current, s.Left)
							} else {
								lastLen, _ = fmt.Printf("\rsum is %d.", s.Current)
								exit = s.Current
							}
						}

					}()

					return reNext
				},
			},
		},
	},
}