package main

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"os/signal"
	"syscall"

	"golang.org/x/crypto/ssh"
	"golang.org/x/crypto/ssh/terminal"
)

func main() {
	host := "target.host.local"
	port := "22"
	user := "user"
	pass := "password"

	// Create sshClientConfig
	sshConfig := &ssh.ClientConfig{
		User: user,
		Auth: []ssh.AuthMethod{
			ssh.Password(pass),
		},
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
	}

	// SSH connect.
	client, err := ssh.Dial("tcp", host+":"+port, sshConfig)

	// Create Session
	session, err := client.NewSession()
	defer session.Close()

	// キー入力を接続先が認識できる形式に変換する(ここがキモ)
	fd := int(os.Stdin.Fd())
	state, err := terminal.MakeRaw(fd)
	if err != nil {
		fmt.Println(err)
	}
	defer terminal.Restore(fd, state)

	// ターミナルサイズの取得
	w, h, err := terminal.GetSize(fd)
	if err != nil {
		fmt.Println(err)
	}

	modes := ssh.TerminalModes{
		ssh.ECHO:          1,
		ssh.TTY_OP_ISPEED: 14400,
		ssh.TTY_OP_OSPEED: 14400,
	}

	err = session.RequestPty("xterm", h, w, modes)
	if err != nil {
		fmt.Println(err)
	}

	log := new(bytes.Buffer)
	logFile, _ := os.OpenFile("./ssh_term_with_log.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0600)

	session.Stdout = io.MultiWriter(os.Stdout, logFile)
	session.Stderr = io.MultiWriter(os.Stderr, logFile)
	session.Stdin = os.Stdin

	err = session.Shell()
	if err != nil {
		fmt.Println(err)
	}

	// ターミナルサイズの変更検知・処理
	signal_chan := make(chan os.Signal, 1)
	signal.Notify(signal_chan, syscall.SIGWINCH)
	go func() {
		for {
			s := <-signal_chan
			switch s {
			case syscall.SIGWINCH:
				fd := int(os.Stdout.Fd())
				w, h, _ = terminal.GetSize(fd)
				session.WindowChange(h, w)
			}
		}
	}()

	err = session.Wait()
	if err != nil {
		fmt.Println(err)
	}
}