package main

import (
	"fmt"
	"github.com/chzyer/readline"
	"reflect"
	"strings"
	"sync"
	"time"
)

type serverStr struct {
	userInteractionMutex sync.Mutex // all user interactions (controlserver or web access) must be serialized:
}

func isClosed(hdl interface{}) bool {
	v := reflect.ValueOf(hdl)
	if v.Kind() != reflect.Ptr {
		return false
	}
	v = v.Elem()
	if v.Kind() != reflect.Struct {
		return false
	}
	v = v.FieldByName("target").Elem()
	if v.Kind() != reflect.Ptr {
		return false
	}
	v = v.Elem()
	if v.Kind() != reflect.Struct {
		return false
	}
	v = v.FieldByName("closed")
	if v.Kind() != reflect.Int32 {
		return false
	}
	closed := v.Int()
	return closed == 1
}

func (srv *serverStr) StartCLIServer() {
	go func() {
		port := 1234

		prompt := "tst "

		cfg := &readline.Config{
			Prompt:      prompt + " > ",
			HistoryFile: "readlineHist",
		}

		handleFunc := func(rl *readline.Instance) {
			for {
				if func() bool { // so we can "defer srv.userInteractionMutex.Unlock()" on the level of each line. "true" means to break the for loop, "false" means to continue.
					line, err := rl.Readline()
					print(line)
					if err != nil {
						return true
					}
					//fmt.Fprintln(rl.Stdout(), "receive:"+line)
					line = strings.TrimSpace(line)
					srv.userInteractionMutex.Lock()
					defer srv.userInteractionMutex.Unlock()

					if line == "pause" {
						time.Sleep(time.Second * 10)
						print("paused")
					}
					if line == "close" {
						return true
					}

					stdout := rl.Stdout()
					if isClosed(stdout) {
						return true
					}

					n, err := fmt.Fprintln(stdout, "done: "+line)
					print(n)
					return false
				}() {
					break
				}
			}
		}
		err := readline.ListenRemote("tcp", fmt.Sprintf(":%d", port), cfg, handleFunc)
		if err != nil {
			println(err.Error())
		}
	}()
}

func main() {
	var s serverStr
	s.StartCLIServer()
	for {
		time.Sleep(time.Second)
	}
}