//go:build !scanner
// +build !scanner

package gost

import (
	"encoding/json"
	"fmt"
	"strconv"
	"strings"

	debver "github.com/knqyf263/go-deb-version"
	"golang.org/x/exp/maps"
	"golang.org/x/xerrors"

	"github.com/future-architect/vuls/logging"
	"github.com/future-architect/vuls/models"
	"github.com/future-architect/vuls/util"
	gostmodels "github.com/vulsio/gost/models"
)

// Ubuntu is Gost client for Ubuntu
type Ubuntu struct {
	Base
}

func (ubu Ubuntu) supported(version string) bool {
	_, ok := map[string]string{
		"606":  "dapper",
		"610":  "edgy",
		"704":  "feisty",
		"710":  "gutsy",
		"804":  "hardy",
		"810":  "intrepid",
		"904":  "jaunty",
		"910":  "karmic",
		"1004": "lucid",
		"1010": "maverick",
		"1104": "natty",
		"1110": "oneiric",
		"1204": "precise",
		"1210": "quantal",
		"1304": "raring",
		"1310": "saucy",
		"1404": "trusty",
		"1410": "utopic",
		"1504": "vivid",
		"1510": "wily",
		"1604": "xenial",
		"1610": "yakkety",
		"1704": "zesty",
		"1710": "artful",
		"1804": "bionic",
		"1810": "cosmic",
		"1904": "disco",
		"1910": "eoan",
		"2004": "focal",
		"2010": "groovy",
		"2104": "hirsute",
		"2110": "impish",
		"2204": "jammy",
		"2210": "kinetic",
		"2304": "lunar",
	}[version]
	return ok
}

type cveContent struct {
	cveContent  models.CveContent
	fixStatuses models.PackageFixStatuses
}

// DetectCVEs fills cve information that has in Gost
func (ubu Ubuntu) DetectCVEs(r *models.ScanResult, _ bool) (nCVEs int, err error) {
	if !ubu.supported(strings.Replace(r.Release, ".", "", 1)) {
		logging.Log.Warnf("Ubuntu %s is not supported yet", r.Release)
		return 0, nil
	}

	if r.Container.ContainerID == "" {
		if r.RunningKernel.Release == "" {
			logging.Log.Warnf("Since the exact kernel release is not available, the vulnerability in the kernel package is not detected.")
		}
	}

	fixedCVEs, err := ubu.detectCVEsWithFixState(r, true)
	if err != nil {
		return 0, xerrors.Errorf("Failed to detect fixed CVEs. err: %w", err)
	}

	unfixedCVEs, err := ubu.detectCVEsWithFixState(r, false)
	if err != nil {
		return 0, xerrors.Errorf("Failed to detect unfixed CVEs. err: %w", err)
	}

	return len(unique(append(fixedCVEs, unfixedCVEs...))), nil
}

func (ubu Ubuntu) detectCVEsWithFixState(r *models.ScanResult, fixed bool) ([]string, error) {
	detects := map[string]cveContent{}
	if ubu.driver == nil {
		urlPrefix, err := util.URLPathJoin(ubu.baseURL, "ubuntu", strings.Replace(r.Release, ".", "", 1), "pkgs")
		if err != nil {
			return nil, xerrors.Errorf("Failed to join URLPath. err: %w", err)
		}
		s := "fixed-cves"
		if !fixed {
			s = "unfixed-cves"
		}
		responses, err := getCvesWithFixStateViaHTTP(r, urlPrefix, s)
		if err != nil {
			return nil, xerrors.Errorf("Failed to get fixed CVEs via HTTP. err: %w", err)
		}

		for _, res := range responses {
			if !res.request.isSrcPack {
				continue
			}

			n := strings.NewReplacer("linux-signed", "linux", "linux-meta", "linux").Replace(res.request.packName)

			if ubu.isKernelSourcePackage(n) {
				isRunning := false
				for _, bn := range r.SrcPackages[res.request.packName].BinaryNames {
					if bn == fmt.Sprintf("linux-image-%s", r.RunningKernel.Release) {
						isRunning = true
						break
					}
				}
				// To detect vulnerabilities in running kernels only, skip if the kernel is not running.
				if !isRunning {
					continue
				}
			}

			cs := map[string]gostmodels.UbuntuCVE{}
			if err := json.Unmarshal([]byte(res.json), &cs); err != nil {
				return nil, xerrors.Errorf("Failed to unmarshal json. err: %w", err)
			}
			for _, content := range ubu.detect(cs, fixed, models.SrcPackage{Name: res.request.packName, Version: r.SrcPackages[res.request.packName].Version, BinaryNames: r.SrcPackages[res.request.packName].BinaryNames}, fmt.Sprintf("linux-image-%s", r.RunningKernel.Release)) {
				c, ok := detects[content.cveContent.CveID]
				if ok {
					content.fixStatuses = append(content.fixStatuses, c.fixStatuses...)
				}
				detects[content.cveContent.CveID] = content
			}
		}
	} else {
		for _, p := range r.SrcPackages {
			n := strings.NewReplacer("linux-signed", "linux", "linux-meta", "linux").Replace(p.Name)

			if ubu.isKernelSourcePackage(n) {
				isRunning := false
				for _, bn := range p.BinaryNames {
					if bn == fmt.Sprintf("linux-image-%s", r.RunningKernel.Release) {
						isRunning = true
						break
					}
				}
				// To detect vulnerabilities in running kernels only, skip if the kernel is not running.
				if !isRunning {
					continue
				}
			}

			var f func(string, string) (map[string]gostmodels.UbuntuCVE, error) = ubu.driver.GetFixedCvesUbuntu
			if !fixed {
				f = ubu.driver.GetUnfixedCvesUbuntu
			}
			cs, err := f(strings.Replace(r.Release, ".", "", 1), n)
			if err != nil {
				return nil, xerrors.Errorf("Failed to get CVEs. release: %s, src package: %s, err: %w", major(r.Release), p.Name, err)
			}
			for _, content := range ubu.detect(cs, fixed, p, fmt.Sprintf("linux-image-%s", r.RunningKernel.Release)) {
				c, ok := detects[content.cveContent.CveID]
				if ok {
					content.fixStatuses = append(content.fixStatuses, c.fixStatuses...)
				}
				detects[content.cveContent.CveID] = content
			}
		}
	}

	for _, content := range detects {
		v, ok := r.ScannedCves[content.cveContent.CveID]
		if ok {
			if v.CveContents == nil {
				v.CveContents = models.NewCveContents(content.cveContent)
			} else {
				v.CveContents[models.UbuntuAPI] = []models.CveContent{content.cveContent}
			}
			v.Confidences.AppendIfMissing(models.UbuntuAPIMatch)
		} else {
			v = models.VulnInfo{
				CveID:       content.cveContent.CveID,
				CveContents: models.NewCveContents(content.cveContent),
				Confidences: models.Confidences{models.UbuntuAPIMatch},
			}
		}

		for _, s := range content.fixStatuses {
			v.AffectedPackages = v.AffectedPackages.Store(s)
		}
		r.ScannedCves[content.cveContent.CveID] = v
	}

	return maps.Keys(detects), nil
}

func (ubu Ubuntu) detect(cves map[string]gostmodels.UbuntuCVE, fixed bool, srcPkg models.SrcPackage, runningKernelBinaryPkgName string) []cveContent {
	n := strings.NewReplacer("linux-signed", "linux", "linux-meta", "linux").Replace(srcPkg.Name)

	var contents []cveContent
	for _, cve := range cves {
		c := cveContent{
			cveContent: *(Ubuntu{}).ConvertToModel(&cve),
		}

		if fixed {
			for _, p := range cve.Patches {
				for _, rp := range p.ReleasePatches {
					installedVersion := srcPkg.Version
					patchedVersion := rp.Note

					// https://git.launchpad.net/ubuntu-cve-tracker/tree/scripts/generate-oval#n384
					if ubu.isKernelSourcePackage(n) && strings.HasPrefix(srcPkg.Name, "linux-meta") {
						// 5.15.0.1026.30~20.04.16 -> 5.15.0.1026
						ss := strings.Split(installedVersion, ".")
						if len(ss) >= 4 {
							installedVersion = strings.Join(ss[:4], ".")
						}

						// 5.15.0-1026.30~20.04.16 -> 5.15.0.1026
						lhs, rhs, ok := strings.Cut(patchedVersion, "-")
						if ok {
							patchedVersion = fmt.Sprintf("%s.%s", lhs, strings.Split(rhs, ".")[0])
						}
					}

					affected, err := ubu.isGostDefAffected(installedVersion, patchedVersion)
					if err != nil {
						logging.Log.Debugf("Failed to parse versions: %s, Ver: %s, Gost: %s", err, installedVersion, patchedVersion)
						continue
					}

					if affected {
						for _, bn := range srcPkg.BinaryNames {
							if ubu.isKernelSourcePackage(n) && bn != runningKernelBinaryPkgName {
								continue
							}
							c.fixStatuses = append(c.fixStatuses, models.PackageFixStatus{
								Name:    bn,
								FixedIn: patchedVersion,
							})
						}
					}
				}
			}
		} else {
			for _, bn := range srcPkg.BinaryNames {
				if ubu.isKernelSourcePackage(n) && bn != runningKernelBinaryPkgName {
					continue
				}
				c.fixStatuses = append(c.fixStatuses, models.PackageFixStatus{
					Name:        bn,
					FixState:    "open",
					NotFixedYet: true,
				})
			}
		}

		if len(c.fixStatuses) > 0 {
			contents = append(contents, c)
		}
	}
	return contents
}

func (ubu Ubuntu) isGostDefAffected(versionRelease, gostVersion string) (affected bool, err error) {
	vera, err := debver.NewVersion(versionRelease)
	if err != nil {
		return false, xerrors.Errorf("Failed to parse version. version: %s, err: %w", versionRelease, err)
	}
	verb, err := debver.NewVersion(gostVersion)
	if err != nil {
		return false, xerrors.Errorf("Failed to parse version. version: %s, err: %w", gostVersion, err)
	}
	return vera.LessThan(verb), nil
}

// ConvertToModel converts gost model to vuls model
func (ubu Ubuntu) ConvertToModel(cve *gostmodels.UbuntuCVE) *models.CveContent {
	references := []models.Reference{}
	for _, r := range cve.References {
		if strings.Contains(r.Reference, "https://cve.mitre.org/cgi-bin/cvename.cgi?name=") {
			references = append(references, models.Reference{Source: "CVE", Link: r.Reference})
		} else {
			references = append(references, models.Reference{Link: r.Reference})
		}
	}

	for _, b := range cve.Bugs {
		references = append(references, models.Reference{Source: "Bug", Link: b.Bug})
	}

	for _, u := range cve.Upstreams {
		for _, upstreamLink := range u.UpstreamLinks {
			references = append(references, models.Reference{Source: "UPSTREAM", Link: upstreamLink.Link})
		}
	}

	return &models.CveContent{
		Type:          models.UbuntuAPI,
		CveID:         cve.Candidate,
		Summary:       cve.Description,
		Cvss2Severity: cve.Priority,
		Cvss3Severity: cve.Priority,
		SourceLink:    fmt.Sprintf("https://ubuntu.com/security/%s", cve.Candidate),
		References:    references,
		Published:     cve.PublicDate,
	}
}

// https://git.launchpad.net/ubuntu-cve-tracker/tree/scripts/cve_lib.py#n931
func (ubu Ubuntu) isKernelSourcePackage(pkgname string) bool {
	switch ss := strings.Split(pkgname, "-"); len(ss) {
	case 1:
		return pkgname == "linux"
	case 2:
		if ss[0] != "linux" {
			return false
		}
		switch ss[1] {
		case "armadaxp", "mako", "manta", "flo", "goldfish", "joule", "raspi", "raspi2", "snapdragon", "aws", "azure", "bluefield", "dell300x", "gcp", "gke", "gkeop", "ibm", "lowlatency", "kvm", "oem", "oracle", "euclid", "hwe", "riscv":
			return true
		default:
			_, err := strconv.ParseFloat(ss[1], 64)
			return err == nil
		}
	case 3:
		if ss[0] != "linux" {
			return false
		}
		switch ss[1] {
		case "ti":
			return ss[2] == "omap4"
		case "raspi", "raspi2", "gke", "gkeop", "ibm", "oracle", "riscv":
			_, err := strconv.ParseFloat(ss[2], 64)
			return err == nil
		case "aws":
			switch ss[2] {
			case "hwe", "edge":
				return true
			default:
				_, err := strconv.ParseFloat(ss[2], 64)
				return err == nil
			}
		case "azure":
			switch ss[2] {
			case "fde", "edge":
				return true
			default:
				_, err := strconv.ParseFloat(ss[2], 64)
				return err == nil
			}
		case "gcp":
			switch ss[2] {
			case "edge":
				return true
			default:
				_, err := strconv.ParseFloat(ss[2], 64)
				return err == nil
			}
		case "intel":
			switch ss[2] {
			case "iotg":
				return true
			default:
				_, err := strconv.ParseFloat(ss[2], 64)
				return err == nil
			}
		case "oem":
			switch ss[2] {
			case "osp1":
				return true
			default:
				_, err := strconv.ParseFloat(ss[2], 64)
				return err == nil
			}
		case "lts":
			return ss[2] == "xenial"
		case "hwe":
			switch ss[2] {
			case "edge":
				return true
			default:
				_, err := strconv.ParseFloat(ss[2], 64)
				return err == nil
			}
		default:
			return false
		}
	case 4:
		if ss[0] != "linux" {
			return false
		}
		switch ss[1] {
		case "azure":
			if ss[2] != "fde" {
				return false
			}
			_, err := strconv.ParseFloat(ss[3], 64)
			return err == nil
		case "intel":
			if ss[2] != "iotg" {
				return false
			}
			_, err := strconv.ParseFloat(ss[3], 64)
			return err == nil
		case "lowlatency":
			if ss[2] != "hwe" {
				return false
			}
			_, err := strconv.ParseFloat(ss[3], 64)
			return err == nil
		default:
			return false
		}
	default:
		return false
	}
}