package client

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"time"

	"git.loafle.net/commons/logging-go"
	cuej "git.loafle.net/commons/util-go/encoding/json"
	ocmsc "git.loafle.net/overflow/commons-go/model/sensorconfig"
	"golang.org/x/crypto/ssh"
)

type SSHConfig struct {
	User string
	Auth []ssh.AuthMethod
	Host string
	Port int
}

type SSHClient struct {
	conf *SSHConfig
}

func (cli *SSHClient) Session() (*ssh.Session, error) {
	sshConfig := &ssh.ClientConfig{
		User:            cli.conf.User,
		Auth:            cli.conf.Auth,
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
		Timeout:         time.Second * 10,
	}

	addr := fmt.Sprintf("%s:%d", cli.conf.Host, cli.conf.Port)

	connection, err := ssh.Dial("tcp", addr, sshConfig)
	if err != nil {
		return nil, err
	}
	session, err := connection.NewSession()
	if err != nil {
		return nil, err
	}

	modes := ssh.TerminalModes{
		ssh.ECHO:          0,     // disable echoing
		ssh.TTY_OP_ISPEED: 14400, // input speed = 14.4kbaud
		ssh.TTY_OP_OSPEED: 14400, // output speed = 14.4kbaud
	}

	if err := session.RequestPty("xterm", 80, 40, modes); err != nil {
		session.Close()
		return nil, err
	}

	return session, nil
}

func (cli *SSHClient) RunCommand(command string) ([]byte, error) {

	session, err := cli.Session()
	if nil != err {
		return nil, err
	}
	defer func() {
		session.Close()
	}()

	var b bytes.Buffer
	session.Stdout = &b

	logging.Logger().Debugf("%s \n", command)
	if err := session.Run(command); nil != err {
		return nil, err
	}

	return b.Bytes(), nil
}

func parsePrivateKey(keyPath, pw string) (ssh.Signer, error) {
	buff, err := ioutil.ReadFile(keyPath)
	if err != nil {
		return nil, err
	}
	if pw == "" {
		return ssh.ParsePrivateKey(buff)
	}
	return ssh.ParsePrivateKeyWithPassphrase(buff, []byte(pw))
}

func New(connection *ocmsc.SensorConfigConnection) (*SSHClient, error) {
	credentials := connection.Credentials

	ip := connection.IP
	port, _ := cuej.NumberToInt(connection.Port)
	user := credentials["id"]
	pw := credentials["pw"]
	keyFilePath, keyFilePathExist := credentials["keyFilePath"]

	sshAuth := make([]ssh.AuthMethod, 0)

	if keyFilePathExist {
		if "" != keyFilePath {
			key, err := parsePrivateKey(keyFilePath, pw)
			if err != nil {
				return nil, err
			}
			sshAuth = append(sshAuth, ssh.PublicKeys(key))
		}
	}
	sshAuth = append(sshAuth, ssh.Password(pw))

	sshConf := &SSHConfig{
		User: user,
		Auth: sshAuth,
		Host: ip,
		Port: port,
	}

	return &SSHClient{
		conf: sshConf,
	}, nil
}