package utils

import (
	"fmt"
	"os/exec"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/Masterminds/semver"
)

// GetSshVer returns an SshVerInfo. If verStr is an empty string, get the version automatically.
func GetSshVer(verStr string) (ver SshVerInfo, err error) {

	var newVerStr string
	var sslVer OpenSslInfo
	var sslVerStr string
	var ptrn *regexp.Regexp
	var matches []string
	var verSlice [3]uint
	var n int
	var sver *semver.Version

	if verStr == "" {
		var out []byte
		cmd := exec.Command("ssh", "-V")
		if err = cmd.Run(); err != nil {
			return
		}
		if out, err = cmd.Output(); err != nil {
			return
		}
		verStr = string(out)
	}

	if ptrn, err = regexp.Compile(`^(?:Open|Sun_)SSH_(?P<sshver>[0-9.]+)(?:p?(?P<patchver>[0-9.]+))?,\s*(?P<sslverstr>.*)?$`); err != nil {
		return
	}

	matches = ptrn.FindStringSubmatch(verStr)

	// Reformat verStr to the combined version string.
	newVerStr = fmt.Sprintf(
		"%v.%v",
		matches[ptrn.SubexpIndex("sshver")],
		matches[ptrn.SubexpIndex("patchver")],
	)

	sslVerStr = matches[ptrn.SubexpIndex("sslverstr")]

	if sslVer, err = GetSslVer(sslVerStr); err != nil {
		return
	}

	for idx, s := range strings.Split(newVerStr, ".") {
		if n, err = strconv.Atoi(s); err != nil {
			return
		}
		verSlice[idx] = uint(n)
	}

	if sver, err = semver.NewVersion(newVerStr); err != nil {
		return
	}

	ver = SshVerInfo{
		Major:   verSlice[0],
		Minor:   verSlice[1],
		Patch:   verSlice[2],
		Raw:     verStr,
		SslInfo: sslVer,
		SemVer:  *sver,
	}

	return
}

// GetSslVer returns an OpenSslInfo. If verStr is an empty string, get the version automatically.
func GetSslVer(verStr string) (ver OpenSslInfo, err error) {

	var matches []string
	var verSlice [3]uint
	var newVerStr string
	var ptrn *regexp.Regexp
	var sver *semver.Version
	// TODO: confirm the day is zero-padded.
	var tfmt string = `02 Jan 2006`
	var n int
	var t time.Time

	if verStr == "" {
		var out []byte
		cmd := exec.Command("openssl", "version")
		if err = cmd.Run(); err != nil {
			return
		}
		if out, err = cmd.Output(); err != nil {
			return
		}
		verStr = string(out)
	}

	if ptrn, err = regexp.Compile(`^(?:Open|Sun_)SSL\s+(FIPS\s+)?(?P<sslver>[0-9.]+)(?P<sslrel>[A-Za-z]+)?\s+(?P<time>(?P<day>[0-9]{1,2})\s(?P<month>[A-Za-z]+)\s(?P<year>[0-9]{4}))$`); err != nil {
		return
	}

	matches = ptrn.FindStringSubmatch(verStr)

	for idx, s := range strings.Split(matches[ptrn.SubexpIndex("sslver")], ".") {
		if n, err = strconv.Atoi(s); err != nil {
			return
		}
		verSlice[idx] = uint(n)
	}

	if t, err = time.Parse(tfmt, matches[ptrn.SubexpIndex("time")]); err != nil {
		return
	}

	newVerStr = fmt.Sprintf(
		"%v-%v",
		matches[ptrn.SubexpIndex("sslver")],
		matches[ptrn.SubexpIndex("sslrel")],
	)

	if sver, err = semver.NewVersion(newVerStr); err != nil {
		return
	}

	ver = OpenSslInfo{
		Major:     verSlice[0],
		Minor:     verSlice[1],
		Patch:     verSlice[2],
		Revision:  matches[ptrn.SubexpIndex("sslrel")],
		BuildDate: t,
		Raw:       verStr,
		SemVer:    *sver,
	}

	return
}