// Copyright 2020 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package dutio

import (
	"bytes"
	"fmt"
	"golang.org/x/crypto/ssh"
	"log"
	"strconv"
)

// This is the TCP Port number on which an ssh server listens (in the test image).
const sshServerPortNumber = 22

// This key is not considered secret.  It's used for authenticating with ChromeOS devices
// running test images.
const testKey = ("\x2d\x2d\x2d\x2d\x2d\x42\x45\x47\x49\x4e\x20\x52\x53\x41\x20\x50\x52\x49\x56\x41\x54\x45\x20\x4b" +
	"\x45\x59\x2d\x2d\x2d\x2d\x2d\x0a\x4d\x49\x49\x45\x6f\x41\x49\x42\x41\x41\x4b\x43\x41\x51" +
	"\x45\x41\x76\x73\x4e\x70\x46\x64\x4b\x35\x6c\x62\x30\x47\x66\x4b\x78\x2b\x46\x67\x73\x72" +
	"\x73\x4d\x2f\x32\x2b\x61\x5a\x56\x46\x59\x58\x48\x4d\x50\x64\x76\x47\x74\x54\x7a\x36\x33" +
	"\x63\x69\x52\x68\x71\x30\x0a\x4a\x6e\x77\x37\x6e\x6c\x6e\x31\x53\x4f\x63\x48\x72\x61\x53" +
	"\x7a\x33\x2f\x69\x6d\x45\x43\x42\x67\x38\x4e\x48\x49\x4b\x56\x36\x72\x41\x2b\x42\x39\x7a" +
	"\x62\x66\x37\x70\x5a\x58\x45\x76\x32\x30\x78\x35\x55\x6c\x30\x76\x72\x63\x50\x71\x59\x57" +
	"\x43\x34\x34\x50\x54\x0a\x74\x67\x73\x67\x76\x69\x38\x73\x30\x4b\x5a\x55\x5a\x4e\x39\x33" +
	"\x59\x6c\x63\x6a\x5a\x2b\x51\x37\x42\x6a\x51\x2f\x74\x75\x77\x47\x53\x61\x4c\x57\x4c\x71" +
	"\x4a\x37\x68\x6e\x48\x41\x4c\x4d\x4a\x33\x64\x62\x45\x4d\x39\x66\x4b\x42\x48\x51\x42\x43" +
	"\x72\x47\x35\x48\x0a\x4f\x61\x57\x44\x32\x67\x74\x58\x6a\x37\x6a\x70\x30\x34\x4d\x2f\x57" +
	"\x55\x6e\x44\x44\x64\x65\x6d\x71\x2f\x4b\x4d\x67\x36\x45\x39\x6a\x63\x72\x4a\x4f\x69\x51" +
	"\x33\x39\x49\x75\x54\x70\x61\x73\x34\x68\x4c\x51\x7a\x56\x6b\x4b\x41\x4b\x53\x72\x70\x6c" +
	"\x36\x4d\x59\x0a\x32\x65\x74\x48\x79\x6f\x4e\x61\x72\x6c\x57\x68\x63\x4f\x77\x69\x74\x41" +
	"\x72\x45\x44\x77\x66\x33\x57\x67\x6e\x63\x74\x77\x4b\x73\x74\x49\x2f\x4d\x54\x4b\x42\x35" +
	"\x42\x54\x70\x4f\x32\x57\x58\x55\x4e\x55\x76\x34\x6b\x58\x7a\x41\x2b\x67\x38\x2f\x6c\x31" +
	"\x61\x6c\x0a\x6a\x49\x47\x31\x33\x76\x74\x64\x39\x41\x2f\x49\x56\x33\x4b\x46\x56\x78\x2f" +
	"\x73\x4c\x6b\x6b\x6a\x75\x5a\x37\x7a\x32\x72\x51\x58\x79\x4e\x4b\x75\x4a\x77\x49\x42\x49" +
	"\x77\x4b\x43\x41\x51\x41\x37\x39\x45\x57\x5a\x4a\x50\x68\x2f\x68\x49\x30\x43\x6e\x4a\x79" +
	"\x6e\x0a\x31\x36\x41\x45\x58\x70\x34\x54\x38\x6e\x4b\x44\x47\x32\x70\x39\x47\x70\x43\x69" +
	"\x43\x47\x6e\x71\x36\x75\x32\x44\x76\x7a\x2f\x75\x31\x70\x5a\x6b\x39\x37\x4e\x39\x54\x2b" +
	"\x78\x34\x5a\x76\x61\x30\x47\x76\x4a\x63\x31\x76\x6e\x6c\x53\x54\x37\x6f\x62\x6a\x57\x2f" +
	"\x0a\x59\x38\x2f\x45\x54\x38\x51\x65\x47\x53\x43\x54\x37\x78\x35\x50\x59\x44\x71\x69\x56" +
	"\x73\x70\x6f\x65\x6d\x72\x33\x44\x43\x79\x59\x54\x4b\x50\x6b\x41\x44\x4b\x6e\x2b\x63\x4c" +
	"\x41\x6e\x67\x44\x7a\x42\x58\x47\x48\x44\x54\x63\x66\x4e\x50\x34\x55\x36\x78\x66\x72\x0a" +
	"\x51\x63\x35\x4a\x4b\x38\x42\x73\x46\x52\x38\x6b\x41\x70\x71\x53\x73\x2f\x7a\x43\x55\x34" +
	"\x65\x71\x42\x74\x70\x32\x46\x56\x76\x50\x62\x67\x55\x4f\x76\x33\x75\x55\x72\x46\x6e\x6a" +
	"\x45\x75\x47\x73\x39\x72\x62\x31\x51\x5a\x30\x4b\x36\x6f\x30\x38\x4c\x34\x43\x71\x0a\x4e" +
	"\x2b\x65\x32\x6e\x54\x79\x73\x6a\x70\x37\x38\x62\x6c\x61\x6b\x5a\x66\x71\x6c\x75\x72\x71" +
	"\x54\x59\x36\x69\x4a\x62\x30\x49\x6d\x55\x32\x57\x33\x54\x38\x73\x56\x36\x77\x35\x47\x50" +
	"\x31\x4e\x54\x37\x65\x69\x63\x58\x4c\x4f\x33\x57\x64\x49\x52\x42\x31\x35\x61\x0a\x65\x76" +
	"\x6f\x67\x50\x65\x71\x74\x4d\x6f\x38\x47\x63\x4f\x36\x32\x77\x55\x2f\x44\x34\x55\x43\x76" +
	"\x71\x34\x47\x4e\x45\x6a\x76\x59\x4f\x76\x46\x6d\x50\x7a\x58\x48\x76\x68\x54\x78\x73\x69" +
	"\x57\x76\x35\x4b\x45\x41\x43\x74\x6c\x65\x42\x49\x45\x59\x6d\x57\x48\x41\x0a\x50\x4f\x77" +
	"\x72\x41\x6f\x47\x42\x41\x4f\x4b\x67\x4e\x52\x67\x78\x48\x4c\x37\x72\x34\x62\x4f\x6d\x70" +
	"\x4c\x51\x63\x59\x4b\x37\x78\x67\x41\x34\x39\x4f\x70\x69\x6b\x6d\x72\x65\x62\x58\x43\x51" +
	"\x6e\x5a\x2f\x6b\x5a\x33\x51\x73\x4c\x56\x76\x31\x51\x64\x4e\x4d\x48\x0a\x52\x78\x2f\x65" +
	"\x78\x37\x37\x32\x31\x67\x38\x52\x30\x6f\x57\x73\x6c\x4d\x31\x34\x6f\x74\x5a\x53\x4d\x49" +
	"\x54\x43\x44\x43\x4d\x57\x54\x59\x56\x42\x4e\x4d\x31\x62\x71\x59\x6e\x55\x65\x45\x75\x35" +
	"\x48\x61\x67\x46\x77\x78\x6a\x51\x32\x74\x4c\x75\x53\x73\x38\x45\x0a\x53\x42\x7a\x45\x72" +
	"\x39\x36\x4a\x4c\x66\x68\x77\x75\x42\x68\x44\x48\x31\x30\x73\x51\x71\x6e\x2b\x4f\x51\x47" +
	"\x31\x79\x6a\x35\x61\x63\x73\x34\x50\x74\x33\x4c\x34\x77\x6c\x59\x77\x4d\x78\x30\x76\x73" +
	"\x31\x42\x78\x41\x6f\x47\x42\x41\x4e\x64\x39\x4f\x77\x72\x6f\x0a\x35\x4f\x4e\x69\x4a\x58" +
	"\x66\x4b\x4e\x61\x4e\x59\x2f\x63\x4a\x59\x75\x4c\x52\x2b\x62\x7a\x47\x65\x79\x70\x38\x6f" +
	"\x78\x54\x6f\x78\x67\x6d\x4d\x34\x55\x75\x41\x34\x68\x68\x44\x55\x37\x70\x65\x67\x34\x73" +
	"\x64\x6f\x4b\x4a\x34\x58\x6a\x42\x39\x63\x4b\x4d\x43\x7a\x0a\x5a\x47\x55\x35\x4b\x48\x4b" +
	"\x4b\x78\x4e\x66\x39\x35\x2f\x5a\x37\x61\x79\x77\x69\x49\x4a\x45\x55\x45\x2f\x78\x50\x52" +
	"\x47\x4e\x50\x36\x74\x6e\x67\x52\x75\x6e\x65\x76\x70\x32\x51\x79\x76\x5a\x66\x34\x70\x67" +
	"\x76\x41\x43\x76\x6b\x31\x74\x6c\x39\x42\x33\x48\x48\x0a\x37\x4a\x35\x74\x59\x2f\x47\x52" +
	"\x6b\x54\x34\x73\x51\x75\x5a\x59\x70\x78\x33\x59\x6e\x62\x64\x50\x35\x59\x36\x4b\x78\x33" +
	"\x33\x42\x46\x37\x51\x58\x41\x6f\x47\x41\x56\x43\x7a\x67\x68\x56\x51\x52\x2f\x63\x56\x54" +
	"\x31\x51\x4e\x68\x76\x7a\x32\x39\x67\x73\x36\x36\x0a\x69\x50\x49\x72\x74\x51\x6e\x77\x55" +
	"\x74\x4e\x4f\x48\x41\x36\x69\x39\x68\x2b\x4d\x6e\x62\x50\x42\x4f\x59\x52\x49\x70\x69\x64" +
	"\x47\x54\x61\x71\x45\x74\x4b\x54\x54\x4b\x69\x73\x77\x37\x39\x4a\x6a\x4a\x37\x38\x58\x36" +
	"\x54\x52\x34\x61\x39\x4d\x4c\x30\x6f\x53\x67\x0a\x63\x31\x4b\x37\x31\x7a\x39\x4e\x6d\x5a" +
	"\x67\x50\x62\x4a\x55\x32\x35\x71\x4d\x4e\x38\x30\x5a\x43\x70\x68\x33\x2b\x68\x32\x66\x39" +
	"\x68\x77\x63\x36\x41\x6a\x4c\x7a\x30\x55\x35\x77\x51\x34\x61\x6c\x50\x39\x30\x39\x56\x52" +
	"\x56\x49\x58\x37\x69\x4d\x38\x70\x61\x66\x0a\x71\x35\x39\x77\x42\x69\x48\x68\x79\x44\x33" +
	"\x4a\x31\x36\x51\x41\x78\x68\x73\x43\x67\x59\x42\x75\x30\x72\x43\x6d\x68\x6d\x63\x56\x32" +
	"\x72\x51\x75\x2b\x6b\x64\x34\x6c\x43\x71\x37\x75\x4a\x6d\x42\x5a\x5a\x68\x46\x5a\x35\x74" +
	"\x6e\x79\x39\x4d\x6c\x50\x67\x69\x4b\x0a\x7a\x49\x4a\x6b\x72\x31\x72\x6b\x46\x62\x79\x49" +
	"\x66\x71\x43\x44\x7a\x79\x72\x55\x39\x69\x72\x4f\x54\x4b\x63\x2b\x69\x43\x55\x41\x32\x35" +
	"\x45\x6b\x39\x75\x6a\x6b\x48\x43\x34\x6d\x2f\x61\x54\x55\x33\x6c\x6e\x6b\x4e\x6a\x59\x70" +
	"\x2f\x4f\x46\x58\x70\x58\x46\x33\x0a\x58\x57\x5a\x4d\x59\x2b\x30\x41\x6b\x35\x75\x55\x70" +
	"\x6c\x64\x47\x38\x35\x6d\x77\x4c\x49\x76\x41\x54\x75\x33\x69\x76\x70\x62\x79\x5a\x43\x54" +
	"\x46\x59\x4d\x35\x61\x66\x53\x6d\x34\x53\x74\x6d\x61\x55\x69\x55\x35\x74\x41\x2b\x6f\x5a" +
	"\x4b\x45\x63\x47\x69\x6c\x79\x0a\x6a\x77\x4b\x42\x67\x42\x64\x46\x4c\x67\x2b\x6b\x54\x6d" +
	"\x38\x37\x37\x6c\x63\x79\x62\x51\x30\x34\x47\x31\x6b\x49\x52\x4d\x66\x35\x76\x41\x58\x63" +
	"\x43\x6f\x6e\x7a\x42\x74\x38\x72\x79\x39\x4a\x2b\x32\x69\x58\x31\x64\x64\x6c\x75\x32\x4b" +
	"\x32\x76\x4d\x72\x6f\x44\x0a\x31\x63\x50\x2f\x55\x2f\x45\x6d\x76\x6f\x43\x58\x53\x4f\x47" +
	"\x75\x65\x74\x61\x49\x34\x55\x4e\x51\x77\x45\x2f\x72\x47\x43\x74\x6b\x70\x76\x4e\x6a\x35" +
	"\x79\x34\x74\x77\x56\x4c\x68\x35\x51\x75\x66\x53\x4f\x6c\x34\x39\x56\x30\x55\x74\x30\x6d" +
	"\x77\x6a\x50\x58\x77\x0a\x48\x66\x4e\x2f\x32\x4d\x6f\x4f\x30\x37\x76\x51\x72\x6a\x67\x73" +
	"\x46\x79\x6c\x76\x72\x77\x39\x41\x37\x39\x78\x49\x74\x41\x42\x61\x71\x4b\x6e\x64\x6c\x6d" +
	"\x71\x6c\x77\x4d\x5a\x57\x63\x39\x4e\x65\x0a\x2d\x2d\x2d\x2d\x2d\x45\x4e\x44\x20\x52\x53" +
	"\x41\x20\x50\x52\x49\x56\x41\x54\x45\x20\x4b\x45\x59\x2d\x2d\x2d\x2d\x2d\x0a")

// SendSSHCommand ssh's to a host, executes a command, and returns the output.
func SendSSHCommand(hostname string, remoteCmd string) (out string, reterr error) {
	testKeyParsed, err := ssh.ParsePrivateKey([]byte(testKey))
	if err != nil {
		return "", fmt.Errorf("unable to parse testing ssh key: %v", err)
	}

	config := &ssh.ClientConfig{
		User: "root",
		Auth: []ssh.AuthMethod{
			ssh.PublicKeys(testKeyParsed),
		},
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
	}

	// TODO(kmshelton): Avoid creating a connection and session for each command.
	conn, err := ssh.Dial("tcp", hostname+":"+strconv.Itoa(sshServerPortNumber), config)
	if err != nil {
		return "", fmt.Errorf("failed to dial: %v", err)
	}
	defer conn.Close()

	session, err := conn.NewSession()
	if err != nil {
		return "", fmt.Errorf("failed to create session: %v", err)
	}
	defer session.Close()

	var stdout bytes.Buffer
	var stderr bytes.Buffer
	session.Stdout = &stdout
	session.Stderr = &stderr
	if err := session.Run(remoteCmd); err != nil {
		// TODO(kmshelton): create a new Error type
		log.Printf("Encountered an error when trying to run a remote command: %v", err)
		log.Printf("Failed to run \"%s\" on host: %s.\nStdout was: %s\nStderr was: %s", remoteCmd, hostname, stdout.String(), stderr.String())
		return "", err
	}
	return stdout.String(), nil
}