/* Vuls - Vulnerability Scanner
Copyright (C) 2016  Future Architect, Inc. Japan.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package commands

import (
	"context"
	"flag"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"

	c "github.com/future-architect/vuls/config"
	"github.com/future-architect/vuls/scan"
	"github.com/future-architect/vuls/util"
	"github.com/google/subcommands"
	"github.com/k0kubun/pp"
)

// ScanCmd is Subcommand of host discovery mode
type ScanCmd struct {
	debug          bool
	configPath     string
	resultsDir     string
	logDir         string
	cacheDBPath    string
	httpProxy      string
	askKeyPassword bool
	containersOnly bool
	fast           bool
	offline        bool
	deep           bool
	skipBroken     bool
	sshNative      bool
	pipe           bool
	vvv            bool
	timeoutSec     int
	scanTimeoutSec int
}

// Name return subcommand name
func (*ScanCmd) Name() string { return "scan" }

// Synopsis return synopsis
func (*ScanCmd) Synopsis() string { return "Scan vulnerabilities" }

// Usage return usage
func (*ScanCmd) Usage() string {
	return `scan:
	scan
		[-fast]
		[-offline]
		[-deep]
		[-config=/path/to/config.toml]
		[-results-dir=/path/to/results]
		[-log-dir=/path/to/log]
		[-cachedb-path=/path/to/cache.db]
		[-ssh-native-insecure]
		[-containers-only]
		[-skip-broken]
		[-http-proxy=http://192.168.0.1:8080]
		[-ask-key-password]
		[-timeout=300]
		[-timeout-scan=7200]
		[-debug]
		[-pipe]
		[-vvv]

		[SERVER]...
`
}

// SetFlags set flag
func (p *ScanCmd) SetFlags(f *flag.FlagSet) {
	f.BoolVar(&p.debug, "debug", false, "debug mode")

	wd, _ := os.Getwd()

	defaultConfPath := filepath.Join(wd, "config.toml")
	f.StringVar(&p.configPath, "config", defaultConfPath, "/path/to/toml")

	defaultResultsDir := filepath.Join(wd, "results")
	f.StringVar(&p.resultsDir, "results-dir", defaultResultsDir, "/path/to/results")

	defaultLogDir := util.GetDefaultLogDir()
	f.StringVar(&p.logDir, "log-dir", defaultLogDir, "/path/to/log")

	defaultCacheDBPath := filepath.Join(wd, "cache.db")
	f.StringVar(
		&p.cacheDBPath,
		"cachedb-path",
		defaultCacheDBPath,
		"/path/to/cache.db (local cache of changelog for Ubuntu/Debian)")

	f.BoolVar(
		&p.sshNative,
		"ssh-native-insecure",
		false,
		"Use Native Go implementation of SSH. Default: Use the external command")

	f.BoolVar(
		&p.containersOnly,
		"containers-only",
		false,
		"Scan containers only. Default: Scan both of hosts and containers")

	f.BoolVar(
		&p.skipBroken,
		"skip-broken",
		false,
		"[For CentOS] yum update changelog with --skip-broken option")

	f.StringVar(
		&p.httpProxy,
		"http-proxy",
		"",
		"http://proxy-url:port (default: empty)",
	)

	f.BoolVar(
		&p.askKeyPassword,
		"ask-key-password",
		false,
		"Ask ssh privatekey password before scanning",
	)

	f.BoolVar(
		&p.fast,
		"fast",
		false,
		"Online fast scan mode.")

	f.BoolVar(
		&p.offline,
		"offline",
		false,
		"Offline scan mode. Unable to get updatable packages information.")

	f.BoolVar(
		&p.deep,
		"deep",
		false,
		"Deep scan mode. Scan accuracy improves and scanned information becomes richer. Since analysis of changelog, issue commands requiring sudo, but it may be slower and high load on the target server")

	f.BoolVar(
		&p.pipe,
		"pipe",
		false,
		"Use stdin via PIPE")

	f.BoolVar(&p.vvv, "vvv", false, "ssh -vvv")

	f.IntVar(
		&p.timeoutSec,
		"timeout",
		5*60,
		"Number of seconds for processing other than scan",
	)

	f.IntVar(
		&p.scanTimeoutSec,
		"timeout-scan",
		120*60,
		"Number of seconds for scanning vulnerabilities for all servers",
	)
}

// Execute execute
func (p *ScanCmd) Execute(_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
	// Setup Logger
	c.Conf.Debug = p.debug
	c.Conf.LogDir = p.logDir
	util.Log = util.NewCustomLogger(c.ServerInfo{})

	var keyPass string
	var err error
	if p.askKeyPassword {
		prompt := "SSH key password: "
		if keyPass, err = getPasswd(prompt); err != nil {
			util.Log.Error(err)
			return subcommands.ExitFailure
		}
	}

	err = c.Load(p.configPath, keyPass)
	if err != nil {
		util.Log.Errorf("Error loading %s, %s", p.configPath, err)
		util.Log.Errorf("If you update Vuls and get this error, there may be incompatible changes in config.toml")
		util.Log.Errorf("Please check README: https://github.com/future-architect/vuls#configuration")
		return subcommands.ExitUsageError
	}

	util.Log.Info("Start scanning")
	util.Log.Infof("config: %s", p.configPath)

	c.Conf.Pipe = p.pipe
	c.Conf.Vvv = p.vvv
	var servernames []string
	if 0 < len(f.Args()) {
		servernames = f.Args()
	} else if c.Conf.Pipe {
		bytes, err := ioutil.ReadAll(os.Stdin)
		if err != nil {
			util.Log.Errorf("Failed to read stdin: %s", err)
			return subcommands.ExitFailure
		}
		fields := strings.Fields(string(bytes))
		if 0 < len(fields) {
			servernames = fields
		}
	}

	target := make(map[string]c.ServerInfo)
	for _, arg := range servernames {
		found := false
		for servername, info := range c.Conf.Servers {
			if servername == arg {
				target[servername] = info
				found = true
				break
			}
		}
		if !found {
			util.Log.Errorf("%s is not in config", arg)
			return subcommands.ExitUsageError
		}
	}
	if 0 < len(servernames) {
		c.Conf.Servers = target
	}
	util.Log.Debugf("%s", pp.Sprintf("%v", target))

	c.Conf.ResultsDir = p.resultsDir
	c.Conf.CacheDBPath = p.cacheDBPath
	c.Conf.SSHNative = p.sshNative
	c.Conf.HTTPProxy = p.httpProxy
	c.Conf.ContainersOnly = p.containersOnly
	c.Conf.SkipBroken = p.skipBroken

	c.Conf.Fast = p.fast
	c.Conf.Offline = p.offline
	c.Conf.Deep = p.deep
	if !(c.Conf.Fast || c.Conf.Offline || c.Conf.Deep) {
		c.Conf.Fast = true
	}

	util.Log.Info("Validating config...")
	if !c.Conf.ValidateOnScan() {
		return subcommands.ExitUsageError
	}

	util.Log.Info("Detecting Server/Container OS... ")
	if err := scan.InitServers(p.timeoutSec); err != nil {
		util.Log.Errorf("Failed to init servers: %s", err)
		return subcommands.ExitFailure
	}

	util.Log.Info("Detecting Platforms... ")
	scan.DetectPlatforms(p.timeoutSec)

	util.Log.Info("Scanning vulnerabilities... ")
	if err := scan.Scan(p.scanTimeoutSec); err != nil {
		util.Log.Errorf("Failed to scan. err: %s", err)
		return subcommands.ExitFailure
	}
	fmt.Printf("\n\n\n")
	fmt.Println("To view the detail, vuls tui is useful.")
	fmt.Println("To send a report, run vuls report -h.")

	return subcommands.ExitSuccess
}