日: 2020年8月10日

// gsh - Go lang based Shell
// (c) 2020 ITS more Co., Ltd.
// 2020-0807 created by SatoxITS (sato@its-more.jp)
//
package main // gsh main
// Documents: https://golang.org/pkg/
import (
	"bufio"
	"strings"
	"strconv"
	"sort"
	"fmt"
	"os"
	"time"
	"syscall"
	"go/types"
	"go/token"
	"net"
)

var VERSION = "gsh/0.0.5 (2020-0810a)"
var LINESIZE = (8*1024)
var PATHSEP = ":" // should be ";" in Windows
var DIRSEP = "/" // canbe \ in Windows
var PROMPT = "> "
var GSH_HOME = ".gsh" // under home directory

type GCommandHistory struct {
	StartAt		time.Time
	EndAt		time.Time
	ResCode		int
	OutData		*os.File
	CmdLine		string
	ResCons		int // Resource consumption, CPU time or so
}
type GChdirHistory struct {
	Dir		string
	MovedAt		time.Time
}
type GshContext struct {
	StartDir	string	// the current directory at the start
	GetLine		string	// gsh-getline command as a input line editor
	ChdirHistory	[]GChdirHistory // the 1st entry is wd at the start
	gshPA		syscall.ProcAttr
	CommandHistory	[]GCommandHistory
	BackGround	bool
	BackGroundJobs	[]int
	LastRusage	syscall.Rusage
	GshHomeDir	string
	TerminalId	int
}

func isin(what string, list []string) bool {
	for _, v := range list  {
		if v == what {
			return true
		}
	}
	return false
}

func env(opts []string) {
	env := os.Environ()
	if isin("-s", opts){
		sort.Slice(env, func(i,j int) bool {
			return env[i] < env[j]
		})
	}
	for _, v := range env {
		fmt.Printf("%v\n",v)
	}
}

func strsubst(str string) string {
	rstr := ""
	inEsc := 0 // escape characer mode 
	for _, ch := range str {
		if inEsc == 0 {
			if ch == '\\' {
				inEsc = '\\'
				continue;
			}
		}
		if inEsc == '\\' {
			if ch == 's' { ch = ' ' }
			if ch == 'r' { ch = '\r' }
			if ch == 'n' { ch = '\n' }
			if ch == 't' { ch = '\t' }
			if ch == '\\' { ch = '\\' }
			inEsc = 0 
		}
		rstr = rstr + string(ch)
	}
	return rstr
}

func showFileInfo(path string, opts []string) {
	if isin("-ls",opts) {
		fi, _ := os.Stat(path)
		mod := fi.ModTime()
		date := mod.Format(time.Stamp)
		fmt.Printf("%v %8v %s ",fi.Mode(),fi.Size(),date)
	}
	fmt.Printf("%s",path)
	if ! isin("-n",opts) {
		fmt.Printf("\n")
	}
}

func toFullpath(path string) (fullpath string) {
	pathv := strings.Split(path,DIRSEP)
	if pathv[0] == "." {
		pathv[0], _ = os.Getwd()
	}else
	if pathv[0] == ".." {
		cwd, _ := os.Getwd()
		ppathv := strings.Split(cwd,DIRSEP)
		pathv[0] = strings.Join(ppathv,DIRSEP)
	}else
	if pathv[0] == "~" {
		pathv[0],_ = os.UserHomeDir()
	}
	return strings.Join(pathv,DIRSEP)
}

func which(list string, argv []string) (fullpathv []string, itis bool){
	if len(argv) <= 1 {
		fmt.Printf("Usage: which comand [-s] [-a] [-ls]\n")
		return []string{""}, false
	}
	path := argv[1]
	pathenv, efound := os.LookupEnv(list)
	if ! efound {
		fmt.Printf("which: no \"%s\" environment\n",list)
		return []string{""}, false
	}
	dirv := strings.Split(pathenv,PATHSEP)
	ffound := false
	ffullpath := path
	for _, dir := range dirv {
		fullpath := dir + DIRSEP + path
		fi, err := os.Stat(fullpath)
		if err != nil {
			fullpath = dir + DIRSEP + path + ".go"
			fi, err = os.Stat(fullpath)
		}
		if err == nil {
			fm := fi.Mode()
			if fm.IsRegular() {
				ffullpath = fullpath
				ffound = true
				if ! isin("-s", argv) {
					showFileInfo(fullpath,argv)
				}
				if ! isin("-a", argv) {
					break;
				}
			}
		}
	}
	return []string{ffullpath}, ffound
}

func find(argv []string){
}

func eval(argv []string, nlend bool){
	var ai = 1
	pfmt := "%s"
	if argv[ai][0:1] == "%" {
		pfmt = argv[ai]
		ai = 2
	}
	if len(argv) <= ai {
		return
	}
	gocode := strings.Join(argv[ai:]," ");
	fset := token.NewFileSet()
	rval, _ := types.Eval(fset,nil,token.NoPos,gocode)
	fmt.Printf(pfmt,rval.Value)
	if nlend { fmt.Printf("\n") }
}

func getval(name string) (found bool, val int) {
	/* should expand the name here */
	if name == "gsh.pid" {
		return true, os.Getpid()
	}else
	if name == "gsh.ppid" {
		return true, os.Getppid()
	}
	return false, 0
}

func echo(argv []string, nlend bool){
	for ai := 1; ai < len(argv); ai++ {
		if 1 < ai {
			fmt.Printf(" ");
		}
		arg := argv[ai]
		found, val := getval(arg)
		if found {
			fmt.Printf("%d",val)
		}else{
			fmt.Printf("%s",arg)
		}
	}
	if nlend {
		fmt.Printf("\n");
	}
}

func resfile() string {
	return "gsh.tmp"
}
//var resF *File
func resmap() {
	//_ , err := os.OpenFile(resfile(), os.O_RDWR|os.O_CREATE, os.ModeAppend)
	// https://developpaper.com/solution-to-golang-bad-file-descriptor-problem/
	_ , err := os.OpenFile(resfile(), os.O_RDWR|os.O_CREATE, 0600)
	if err != nil {
		fmt.Printf("refF could not open: %s\n",err)
	}else{
		fmt.Printf("refF opened\n")
	}
}

func excommand(gshCtx GshContext, exec bool, argv []string) (GshContext, bool) {
	gshPA := gshCtx.gshPA
	fullpathv, itis := which("PATH",[]string{"which",argv[0],"-s"})
	if itis == false {
		return gshCtx, true
	}
	fullpath := fullpathv[0]
	if 0 < strings.Index(fullpath,".go") {
		nargv := argv // []string{}
		gofullpathv, itis := which("PATH",[]string{"which","go","-s"})
		if itis == false {
			fmt.Printf("--F-- Go not found\n")
			return gshCtx, true
		}
		gofullpath := gofullpathv[0]
		nargv = []string{ gofullpath, "run", fullpath }
		fmt.Printf("--I-- %s {%s %s %s}\n",gofullpath,
			nargv[0],nargv[1],nargv[2])
		if exec {
			syscall.Exec(gofullpath,nargv,os.Environ())
		}else{
			pid, _ := syscall.ForkExec(gofullpath,nargv,&gshPA)
			if gshCtx.BackGround {
				fmt.Printf("--I-- in Background [%d]\n",pid)
				gshCtx.BackGroundJobs = append(gshCtx.BackGroundJobs,pid)
			}else{
				rusage := syscall.Rusage {}
				syscall.Wait4(pid,nil,0,&rusage)
				gshCtx.LastRusage = rusage
			}
		}
	}else{
		if exec {
			syscall.Exec(fullpath,argv,os.Environ())
		}else{
			pid, _ := syscall.ForkExec(fullpath,argv,&gshPA)
			//fmt.Printf("[%d]\n",pid); // '&' to be background
			if gshCtx.BackGround {
				fmt.Printf("--I-- in Background [%d]\n",pid)
				gshCtx.BackGroundJobs = append(gshCtx.BackGroundJobs,pid)
			}else{
				rusage := syscall.Rusage {}
				syscall.Wait4(pid,nil,0,&rusage);
				gshCtx.LastRusage = rusage
			}
		}
	}
	return gshCtx, false
}
func sleep(gshCtx GshContext, gshPA syscall.ProcAttr, argv []string) {
	if len(argv) < 2 {
		fmt.Printf("Sleep 100ms, 100us, 100ns, ...\n")
		return
	}
	duration := argv[1];
	d, err := time.ParseDuration(duration)
	if err != nil {
		d, err = time.ParseDuration(duration+"s")
		if err != nil {
			fmt.Printf("duration ? %s (%s)\n",duration,err)
			return
		}
	}
	fmt.Printf("Sleep %v ns\n",duration)
	time.Sleep(d)
	if 0 < len(argv[2:]) {
		gshellv(gshCtx, gshPA, argv[2:])
	}
}
func repeat(gshCtx GshContext, gshPA syscall.ProcAttr, argv []string) {
	if len(argv) < 2 {
		return
	}
	start0 := time.Now()
	for ri,_ := strconv.Atoi(argv[1]); 0 < ri; ri-- {
		if 0 < len(argv[2:]) {
			//start := time.Now()
			gshellv(gshCtx, gshPA, argv[2:])
			end := time.Now()
			elps := end.Sub(start0);
			if( 1000000000 < elps ){
				fmt.Printf("(repeat#%d %v)\n",ri,elps);
			}
		}
	}
}

func gen(gshPA syscall.ProcAttr, argv []string) {
	if len(argv) < 2 {
		fmt.Printf("Usage: %s N\n",argv[0])
		return
	}
	// should br repeated by "repeat" command
	count, _ := strconv.Atoi(argv[1])
	fd := gshPA.Files[1] // Stdout
	file := os.NewFile(fd,"internalStdOut")
	fmt.Printf("--I-- Gen. Count=%d to [%d]\n",count,file.Fd())
	//buf := []byte{}
	outdata := "0123 5678 0123 5678 0123 5678 0123 5678\r"
	for gi := 0; gi < count; gi++ {
		file.WriteString(outdata)
	}
	//file.WriteString("\n")
	fmt.Printf("\n(%d B)\n",count*len(outdata));
	//file.Close()
}

// -s, -si, -so // bi-directional, source, sync (maybe socket)
func sconnect(gshCtx GshContext, gshPA syscall.ProcAttr, inTCP bool, argv []string) {
	if len(argv) < 2 {
		fmt.Printf("Usage: -s [host]:[port[.udp]]\n")
		return
	}
	remote := argv[1]
	if remote == ":" { remote = "0.0.0.0:9999" }

	if inTCP { // TCP
		dport, err := net.ResolveTCPAddr("tcp",remote);
		if err != nil {
			fmt.Printf("Address error: %s (%s)\n",remote,err)
			return
		}
		conn, err := net.DialTCP("tcp",nil,dport)
		if err != nil {
			fmt.Printf("Connection error: %s (%s)\n",remote,err)
			return
		}
		file, _ := conn.File();
		fd := file.Fd()
		fmt.Printf("Socket: connected to %s, socket[%d]\n",remote,fd)

		savfd := gshPA.Files[1]
		gshPA.Files[1] = fd;
		gshellv(gshCtx, gshPA, argv[2:])
		gshPA.Files[1] = savfd
		file.Close()
		conn.Close()
	}else{
		//dport, err := net.ResolveUDPAddr("udp4",remote);
		dport, err := net.ResolveUDPAddr("udp",remote);
		if err != nil {
			fmt.Printf("Address error: %s (%s)\n",remote,err)
			return
		}
		//conn, err := net.DialUDP("udp4",nil,dport)
		conn, err := net.DialUDP("udp",nil,dport)
		if err != nil {
			fmt.Printf("Connection error: %s (%s)\n",remote,err)
			return
		}
		file, _ := conn.File();
		fd := file.Fd()

		ar := conn.RemoteAddr()
		//al := conn.LocalAddr()
		fmt.Printf("Socket: connected to %s [%s], socket[%d]\n",
			remote,ar.String(),fd)

		savfd := gshPA.Files[1]
		gshPA.Files[1] = fd;
		gshellv(gshCtx, gshPA, argv[2:])
		gshPA.Files[1] = savfd
		file.Close()
		conn.Close()
	}
}
func saccept(gshCtx GshContext, gshPA syscall.ProcAttr, inTCP bool, argv []string) {
	if len(argv) < 2 {
		fmt.Printf("Usage: -ac [host]:[port[.udp]]\n")
		return
	}
	local := argv[1]
	if local == ":" { local = "0.0.0.0:9999" }
	if inTCP { // TCP
		port, err := net.ResolveTCPAddr("tcp",local);
		if err != nil {
			fmt.Printf("Address error: %s (%s)\n",local,err)
			return
		}
		//fmt.Printf("Listen at %s...\n",local);
		sconn, err := net.ListenTCP("tcp", port)
		if err != nil {
			fmt.Printf("Listen error: %s (%s)\n",local,err)
			return
		}
		//fmt.Printf("Accepting at %s...\n",local);
		aconn, err := sconn.AcceptTCP()
		if err != nil {
			fmt.Printf("Accept error: %s (%s)\n",local,err)
			return
		}
		file, _ := aconn.File()
		fd := file.Fd()
		fmt.Printf("Accepted TCP at %s [%d]\n",local,fd)

		savfd := gshPA.Files[0]
		gshPA.Files[0] = fd;
		gshellv(gshCtx, gshPA, argv[2:])
		gshPA.Files[0] = savfd

		sconn.Close();
		aconn.Close();
		file.Close();
	}else{
		//port, err := net.ResolveUDPAddr("udp4",local);
		port, err := net.ResolveUDPAddr("udp",local);
		if err != nil {
			fmt.Printf("Address error: %s (%s)\n",local,err)
			return
		}
		fmt.Printf("Listen UDP at %s...\n",local);
		//uconn, err := net.ListenUDP("udp4", port)
		uconn, err := net.ListenUDP("udp", port)
		if err != nil {
			fmt.Printf("Listen error: %s (%s)\n",local,err)
			return
		}
		file, _ := uconn.File()
		fd := file.Fd()
		ar := uconn.RemoteAddr()
		remote := ""
		if ar != nil { remote = ar.String() }
		if remote == "" { remote = "?" }

		// not yet received
		//fmt.Printf("Accepted at %s [%d] <- %s\n",local,fd,"")

		savfd := gshPA.Files[0]
		gshPA.Files[0] = fd;
		savenv := gshPA.Env
		gshPA.Env = append(savenv, "REMOTE_HOST="+remote)
		gshellv(gshCtx, gshPA, argv[2:])
		gshPA.Env = savenv
		gshPA.Files[0] = savfd

		uconn.Close();
		file.Close();
	}
}

// empty line command
func pwd(gshPA syscall.ProcAttr){
	// execute context command, pwd + date
	// context notation, representation scheme, to be resumed at re-login
	cwd, _ := os.Getwd()
	t := time.Now()
	date := t.Format(time.UnixDate)
	exe, _ := os.Executable()
	host, _ := os.Hostname()
	fmt.Printf("{PWD=\"%s\"",cwd)
	fmt.Printf(" HOST=\"%s\"",host)
	fmt.Printf(" DATE=\"%s\"",date)
	fmt.Printf(" TIME=\"%s\"",t.String())
	fmt.Printf(" PID=\"%d\"",os.Getpid())
	fmt.Printf(" EXE=\"%s\"",exe)
	fmt.Printf("}\n")
}

// these should be browsed and edited by HTTP browser
// show the time of command with -t and direcotry with -ls
// openfile-history, sort by -a -m -c
// sort by elapsed time by -t -s
// search by "more" like interface
// edit history
// sort history, and wc or uniq
// CPU and other resource consumptions
// limit showing range (by time or so)
// export / import history
func xHistory(gshCtx GshContext, argv []string) (rgshCtx GshContext) {
	for i, v := range gshCtx.CommandHistory {
		fmt.Printf("!%d ",i)
		if isin("-v",argv){
			fmt.Println(v) // should be with it date
		}else{
			if isin("-l",argv){
				elps := v.EndAt.Sub(v.StartAt);
				start := v.StartAt.Format(time.Stamp)
				fmt.Printf("%s (%8v) ",start,elps)
			}
			fmt.Printf("%s",v.CmdLine)
			fmt.Printf("\n")
		}
	}
	return gshCtx
}
// !n - history index
func searchHistory(gshCtx GshContext, gline string) (string, bool, bool){
	if gline[0] == '!' {
		hix, err := strconv.Atoi(gline[1:])
		if err != nil {
			fmt.Printf("--E-- (%s : range)\n",hix)
			return "", false, true
		}
		if hix < 0 || len(gshCtx.CommandHistory) <= hix {
			fmt.Printf("--E-- (%d : out of range)\n",hix)
			return "", false, true
		}
		return gshCtx.CommandHistory[hix].CmdLine, false, false
	}
	// search
	//for i, v := range gshCtx.CommandHistory {
	//}
	return gline, false, false
}

// temporary adding to PATH environment
// cd name -lib for LD_LIBRARY_PATH
// chdir with directory history (date + full-path)
// -s for sort option (by visit date or so)
func xChdirHistory(gshCtx GshContext, argv []string){
	for i, v := range gshCtx.ChdirHistory {
		fmt.Printf("!%d ",i)
		fmt.Printf("%v ",v.MovedAt.Format(time.Stamp))
		showFileInfo(v.Dir,argv)
	}
}
func xChdir(gshCtx GshContext, argv []string) (rgshCtx GshContext) {
	cdhist := gshCtx.ChdirHistory
	if isin("?",argv ) || isin("-t",argv) {
		xChdirHistory(gshCtx,argv)
		return gshCtx
	}
	pwd, _ := os.Getwd()
	dir := ""
	if len(argv) <= 1 {
		dir = toFullpath("~")
	}else{
		dir = argv[1]
	}
	if dir[0] == '!' {
		if dir == "!0" {
			dir = gshCtx.StartDir
		}else
		if dir == "!!" {
			index := len(cdhist) - 1
			if 0 < index { index -= 1 }
			dir = cdhist[index].Dir
		}else{
			index, err := strconv.Atoi(dir[1:])
			if err != nil {
				fmt.Printf("--E-- xChdir(%v)\n",err)
				dir = "?"
			}else
			if len(gshCtx.ChdirHistory) <= index {
				fmt.Printf("--E-- xChdir(history range error)\n")
				dir = "?"
			}else{
				dir = cdhist[index].Dir
			}
		}
	}
	if dir != "?" {
		err := os.Chdir(dir)
		if err != nil {
			fmt.Printf("--E-- xChdir(%s)(%v)\n",argv[1],err)
		}else{
			cwd, _ := os.Getwd()
			if cwd != pwd {
				hist1 := GChdirHistory { }
				hist1.Dir = cwd
				hist1.MovedAt = time.Now()
				gshCtx.ChdirHistory = append(cdhist,hist1)
			}
		}
	}
	return gshCtx
}
func showRusage(what string,argv []string, ru *syscall.Rusage){
	fmt.Printf("%s: ",what);
	fmt.Printf("Usr=%d.%06ds",ru.Utime.Sec,ru.Utime.Usec)
	fmt.Printf(" Sys=%d.%06ds",ru.Stime.Sec,ru.Stime.Usec)
	fmt.Printf(" Rss=%vB",ru.Maxrss)
	if isin("-l",argv) {
		fmt.Printf(" MinFlt=%v",ru.Minflt)
		fmt.Printf(" MajFlt=%v",ru.Majflt)
		fmt.Printf(" IxRSS=%vB",ru.Ixrss)
		fmt.Printf(" IdRSS=%vB",ru.Idrss)
		fmt.Printf(" Nswap=%vB",ru.Nswap)
	fmt.Printf(" Read=%v",ru.Inblock)
	fmt.Printf(" Write=%v",ru.Oublock)
	}
	fmt.Printf(" Snd=%v",ru.Msgsnd)
	fmt.Printf(" Rcv=%v",ru.Msgrcv)
	//if isin("-l",argv) {
		fmt.Printf(" Sig=%v",ru.Nsignals)
	//}
	fmt.Printf("\n");
}
func xTime(gshCtx GshContext, argv []string) (GshContext,bool) {
	if 2 <= len(argv){
		xgshCtx, fin := gshellv(gshCtx,gshCtx.gshPA,argv[1:])
		gshCtx = xgshCtx
		showRusage(argv[1],argv,&gshCtx.LastRusage)
		return gshCtx, fin
	}else{
		rusage:= syscall.Rusage {}
		syscall.Getrusage(syscall.RUSAGE_SELF,&rusage)
		showRusage("self",argv, &rusage)
		syscall.Getrusage(syscall.RUSAGE_CHILDREN,&rusage)
		showRusage("child",argv, &rusage)
		return gshCtx, false
	}
}
func xJobs(gshCtx GshContext, argv []string){
	fmt.Printf("%d Jobs\n",len(gshCtx.BackGroundJobs))
	for ji, pid := range gshCtx.BackGroundJobs {
		//wstat := syscall.WaitStatus {0}
		rusage := syscall.Rusage {}
		//wpid, err := syscall.Wait4(pid,&wstat,syscall.WNOHANG,&rusage);
		wpid, err := syscall.Wait4(pid,nil,syscall.WNOHANG,&rusage);
		if err != nil {
			fmt.Printf("--E-- %%%d [%d] (%v)\n",ji,pid,err)
		}else{
				fmt.Printf("%%%d[%d](%d)\n",ji,pid,wpid)
			showRusage("chld",argv,&rusage)
		}
	}
}

func gshellv(gshCtx GshContext, gshPA syscall.ProcAttr, argv []string) (xx GshContext, fin bool) {
	//fmt.Printf("--I-- gshellv((%d))\n",len(argv))
	if len(argv) <= 0 {
		return gshCtx, false
	}
	for ai := 0; ai < len(argv); ai++ {
		argv[ai] = strsubst(argv[ai])
	}
	if false {
		for ai := 0; ai < len(argv); ai++ {
			fmt.Printf("[%d] %s [%d]%T\n",
				ai,argv[ai],len(argv[ai]),argv[ai])
		}
	}
	cmd := argv[0]
	if cmd == "-ot" {
		sconnect(gshCtx, gshPA, true, argv)
		return gshCtx, false
	}
	if cmd == "-ou" {
		sconnect(gshCtx, gshPA, false, argv)
		return gshCtx, false
	}
	if cmd == "-it" {
		saccept(gshCtx, gshPA, true , argv)
		return gshCtx, false
	}
	if cmd == "-iu" {
		saccept(gshCtx, gshPA, false, argv)
		return gshCtx, false
	}
	if cmd == "-i" || cmd == "-o" || cmd == "-a" || cmd == "-s" {
		if len(argv) < 2 {
			return gshCtx, false
		}
		fdix := 0;
		mode := os.O_RDONLY;
		if cmd == "-i" {
		}
		if cmd == "-o" {
			fdix = 1;
			mode = os.O_RDWR | os.O_CREATE;
		}
		if cmd == "-a" {
			fdix = 1;
			mode = os.O_RDWR | os.O_CREATE | os.O_APPEND;
		}
		f, err := os.OpenFile(argv[1], mode, 0600)
		if err != nil {
			fmt.Printf("%s\n",err)
			return gshCtx, false
		}
		savfd := gshPA.Files[fdix]
		gshPA.Files[fdix] = f.Fd()
		fmt.Printf("--I-- Opened [%d] %s\n",f.Fd(),argv[1])
		gshCtx, _ = gshellv(gshCtx, gshPA, argv[2:])
		gshPA.Files[fdix] = savfd
		return gshCtx, false
	}
	if cmd == "-bg" {
		xfin := false
		// set background option
		gshCtx.BackGround = true
		gshCtx, xfin = gshellv(gshCtx,gshPA,argv[1:])
		gshCtx.BackGround = false
		return gshCtx, xfin
	}
	if cmd == "call" {
		gshCtx, _ = excommand(gshCtx, false,argv[1:])
		return gshCtx, false
	}
	if cmd == "cd" || cmd == "chdir" {
		gshCtx = xChdir(gshCtx,argv);
		return gshCtx, false
	}
	if cmd == "#define" {
	}
	if cmd == "echo" {
		echo(argv,true)
		return gshCtx, false
	}
	if cmd == "env" {
		env(argv)
		return gshCtx, false
	}
	if cmd == "eval" {
		eval(argv,true)
		return gshCtx, false
	}
	if cmd == "exec" {
		gshCtx, _ = excommand(gshCtx, true,argv[1:])
		// should not return here
		return gshCtx, false
	}
	if cmd == "exit" || cmd == "quit" {
		// write Result code EXIT to 3>
		return gshCtx, true
	}
	if cmd == "-find" {
		find(argv)
		return gshCtx, false
	}
	if cmd == "fork" {
		// mainly for a server
		return gshCtx, false
	}
	if cmd == "-gen" {
		gen(gshPA, argv)
		return gshCtx, false
	}
	if cmd == "history" || cmd == "hi" { // hi should be alias
		gshCtx = xHistory(gshCtx, argv)
		return gshCtx, false
	}
	if cmd == "jobs" {
		xJobs(gshCtx,argv)
		return gshCtx, false
	}
	if cmd == "nop" {
		return gshCtx, false
	}
	if cmd == "pstitle" {
		// to be gsh.title
	}
	if cmd == "repeat" || cmd == "rep" { // repeat cond command
		repeat(gshCtx,gshPA,argv)
		return gshCtx, false
	}
	if cmd == "set" { // set name ...
		return gshCtx, false
	}
	if cmd == "time" {
		gshCtx, fin = xTime(gshCtx,argv)
		return gshCtx, fin
	}
	if cmd == "sleep" {
		sleep(gshCtx,gshPA,argv)
		return gshCtx, false
	}
	if cmd == "-ver" {
		fmt.Printf("%s\n",VERSION);
		return gshCtx, false
	}
	if cmd == "pwh" {
		pwd(gshPA);
		return gshCtx, false
	}
	if cmd == "where" {
		// data file or so?
	}
	if cmd == "which" {
		which("PATH",argv);
		return gshCtx, false
	}
	gshCtx, _ = excommand(gshCtx, false,argv)
	return gshCtx, false
}
func gshelll(gshCtx GshContext, gshPA syscall.ProcAttr, gline string) (gx GshContext, rfin bool) {
	argv := strings.Split(string(gline)," ")
	gshCtx, fin := gshellv(gshCtx,gshPA,argv)
	return gshCtx, fin
}
func tgshelll(gshCtx GshContext, gshPA syscall.ProcAttr, gline string) (gx GshContext, xfin bool) {
	start := time.Now()
	gshCtx, fin := gshelll(gshCtx,gshPA,gline)
	end := time.Now()
	elps := end.Sub(start);
	fmt.Printf("--I-- (%d.%09ds)\n",elps/1000000000,elps%1000000000)
	return gshCtx, fin
}
func Ttyid() (int) {
	fi, err := os.Stdin.Stat()
	if err != nil {
		return 0;
	}
	//fmt.Printf("Stdin: %v Dev=%d\n",
	//	fi.Mode(),fi.Mode()&os.ModeDevice)
	if (fi.Mode() & os.ModeDevice) != 0 {
		stat := syscall.Stat_t{};
		err := syscall.Fstat(0,&stat)
		if err != nil {
			//fmt.Printf("--I-- Stdin: (%v)\n",err)
		}else{
			//fmt.Printf("--I-- Stdin: rdev=%d %d\n",
			//	stat.Rdev&0xFF,stat.Rdev);
			//fmt.Printf("--I-- Stdin: tty%d\n",stat.Rdev&0xFF);
			return int(stat.Rdev & 0xFF)
		}
	}
	return 0
}
func ttyfile(gshCtx GshContext) string {
	//fmt.Printf("--I-- GSH_HOME=%s\n",gshCtx.GshHomeDir)
	ttyfile := gshCtx.GshHomeDir + "/" + "gsh-tty" +
		 strconv.Itoa(gshCtx.TerminalId)
	//fmt.Printf("--I-- ttyfile=%s\n",ttyfile)
	return ttyfile
}
func ttyline(gshCtx GshContext) (*os.File){
	file, err := os.OpenFile(ttyfile(gshCtx),
		os.O_RDWR|os.O_CREATE|os.O_TRUNC,0600)
	if err != nil {
		fmt.Printf("--F-- cannot open %s (%s)\n",ttyfile(gshCtx),err)
		return file;
	}
	return file
}
func getline(gshCtx GshContext, hix int, skipping, with_exgetline bool, gsh_getlinev[]string, prevline string) (string) {
	if( skipping ){
		reader := bufio.NewReaderSize(os.Stdin,LINESIZE)
		line, _, _ := reader.ReadLine()
		return string(line)
	}else
	if( with_exgetline && gshCtx.GetLine != "" ){
		//var xhix int64 = int64(hix); // cast
		newenv := os.Environ()
		newenv = append(newenv, "GSH_LINENO="+strconv.FormatInt(int64(hix),10) )

		tty := ttyline(gshCtx)
		tty.WriteString(prevline)
		Pa := os.ProcAttr {
			"", // start dir
			newenv, //os.Environ(),
			[]*os.File{os.Stdin,os.Stdout,os.Stderr,tty},
			nil,
		}
//fmt.Printf("--I-- getline=%s // %s\n",gsh_getlinev[0],gshCtx.GetLine)
proc, err := os.StartProcess(gsh_getlinev[0],[]string{"getline","getline"},&Pa)
		if err != nil {
			fmt.Printf("Proc ERROR (%s)\n",nil)
			for ; ; {
			}
		}
		//stat, err := proc.Wait()
		proc.Wait()
		buff := make([]byte,LINESIZE)
		count, err := tty.Read(buff)
		//_, err = tty.Read(buff)
		//fmt.Printf("--D-- getline (%d)\n",count)
		if err != nil {
			if ! (count == 0) { // && err.String() == "EOF" ) {
				fmt.Printf("--E-- getline error (%s)\n",err)
			}
		}else{
			//fmt.Printf("--I-- getline OK \"%s\"\n",buff)
		}
		tty.Close()
		return string(buff[0:count])
	}else{
		// if isatty {
			fmt.Printf("!%d",hix)
			fmt.Print(PROMPT)
		// }
		reader := bufio.NewReaderSize(os.Stdin,LINESIZE)
		line, _, _ := reader.ReadLine()
		return string(line)
	}
}
//
// $USERHOME/.gsh/
//                gsh-history.txt
//                gsh-aliases.txt // should be conditional?
//
func gshSetup(gshCtx GshContext) (GshContext, bool) {
	homedir, err := os.UserHomeDir()
	if err != nil {
		fmt.Printf("--E-- You have no UserHomeDir (%v)\n",err)
		return gshCtx, true
	}
	gshhome := homedir + "/" + GSH_HOME
	_, err2 := os.Stat(gshhome)
	if err2 != nil {
		err3 := os.Mkdir(gshhome,0700)
		if err3 != nil {
			fmt.Printf("--E-- Could not Create %s (%s)\n",
				gshhome,err)
			return gshCtx, true
		}
		fmt.Printf("--I-- Created %s\n",gshhome)
	}
	gshCtx.GshHomeDir = gshhome
	return gshCtx, false
}
func script(gshCtx GshContext) (_ GshContext) {
	gshCtx, err0 := gshSetup(gshCtx)
	if err0 {
		return gshCtx
	}
	gshPA := syscall.ProcAttr {
		"", // the staring directory
		os.Environ(), // environ[]
		[]uintptr{os.Stdin.Fd(),os.Stdout.Fd(),os.Stderr.Fd()},
		nil, // OS specific
	}
	cwd, _ := os.Getwd()
	gshCtx = GshContext {
		cwd, // StartDir
		"", // GetLine
		[]GChdirHistory { {cwd,time.Now()} }, // ChdirHistory
		gshPA,
		[]GCommandHistory{ }, //something for invokation?
		false,
		[]int{},
		syscall.Rusage{},
		"", // GshHomeDir
		Ttyid(),
	}
	gshCtx, _ = gshSetup(gshCtx)
	fmt.Printf("--I-- GSH_HOME=%s\n",gshCtx.GshHomeDir)
	//resmap()
	gsh_getlinev, with_exgetline :=
		 which("PATH",[]string{"which","gsh-getline","-s"})
	if with_exgetline {
		gsh_getlinev[0] = toFullpath(gsh_getlinev[0])
		gshCtx.GetLine = toFullpath(gsh_getlinev[0])
	}else{
	fmt.Printf("--W-- No gsh-getline found. Using internal getline.\n");
	}

	prevline := ""
	skipping := false
	for hix := 1; ; {
		gline := getline(gshCtx,hix,skipping,with_exgetline,gsh_getlinev,prevline)
		if skipping {
			if strings.Index(gline,"fi") == 0 {
				fmt.Printf("fi\n");
				skipping = false;
			}else{
				//fmt.Printf("%s\n",gline);
			}
			continue
		}
		if strings.Index(gline,"if") == 0 {
			//fmt.Printf("--D-- if start: %s\n",gline);
			skipping = true;
			continue
		}
		if 0 < len(gline) && gline[0] == '!' {
			xgline, set, err := searchHistory(gshCtx,gline)
			if err {
				continue
			}
			if set {
				// set the line in command line editor
			}
			gline = xgline
		}
		ghist := GCommandHistory { }
		ghist.StartAt = time.Now()
		xgshCtx, fin := tgshelll(gshCtx,gshPA,gline)
		gshCtx = xgshCtx
		ghist.EndAt = time.Now()
		ghist.CmdLine = gline
		gshCtx.CommandHistory = append(gshCtx.CommandHistory, ghist)
		if fin {
			break;
		}
		if len(gline) == 0 {
			pwd(gshPA);
			continue;
		}
		prevline = gline;
		hix++;
	}
	return gshCtx
}
func main() {
	gshPA := syscall.ProcAttr {
		"", // the staring directory
		os.Environ(), // environ[]
		[]uintptr{},
		nil, // OS specific
	}
	gshCtx := GshContext {
		"", // StartDir
		"", // GetLine
		[]GChdirHistory{ {"",time.Now()} },
		gshPA,
		[]GCommandHistory{ },
		false,
		[]int{},
		syscall.Rusage{},
		"", // GshHomeDir
		Ttyid(),
	}
	gshCtx = script(gshCtx)
	fmt.Printf("%s\n",gshCtx.StartDir)
}
// TODO:
// - inter gsh communication, possibly running in remote hosts -- to be remote shell
// - merged histories of multiple parallel gsh sessions
// - alias as a function
// - instant alias end environ export to the permanent > ~/.gsh/gsh-alias and gsh-environ
// - retrieval PATH of files by its type
// - gsh as an IME
// - all commands have its subucomand after "---" symbol
// - filename expansion by "-find" command
// - history of ext code and output of each commoand
//---END--- (^-^)/