/* Vuls - Vulnerability Scanner
Copyright (C) 2016  Future Corporation , 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 oval

import (
	"fmt"

	"github.com/future-architect/vuls/config"
	"github.com/future-architect/vuls/models"
	"github.com/future-architect/vuls/util"
	"github.com/kotakanbe/goval-dictionary/db"
	ovalmodels "github.com/kotakanbe/goval-dictionary/models"
)

// DebianBase is the base struct of Debian and Ubuntu
type DebianBase struct {
	Base
}

func (o DebianBase) update(r *models.ScanResult, defPacks defPacks) {
	ovalContent := *o.convertToModel(&defPacks.def)
	ovalContent.Type = models.NewCveContentType(o.family)
	vinfo, ok := r.ScannedCves[defPacks.def.Debian.CveID]
	if !ok {
		util.Log.Debugf("%s is newly detected by OVAL", defPacks.def.Debian.CveID)
		vinfo = models.VulnInfo{
			CveID:       defPacks.def.Debian.CveID,
			Confidences: []models.Confidence{models.OvalMatch},
			CveContents: models.NewCveContents(ovalContent),
		}
	} else {
		cveContents := vinfo.CveContents
		ctype := models.NewCveContentType(o.family)
		if _, ok := vinfo.CveContents[ctype]; ok {
			util.Log.Debugf("%s OVAL will be overwritten",
				defPacks.def.Debian.CveID)
		} else {
			util.Log.Debugf("%s is also detected by OVAL",
				defPacks.def.Debian.CveID)
			cveContents = models.CveContents{}
		}
		vinfo.Confidences.AppendIfMissing(models.OvalMatch)
		cveContents[ctype] = ovalContent
		vinfo.CveContents = cveContents
	}

	// uniq(vinfo.PackNames + defPacks.actuallyAffectedPackNames)
	for _, pack := range vinfo.AffectedPackages {
		defPacks.actuallyAffectedPackNames[pack.Name] = pack.NotFixedYet
	}

	// update notFixedYet of SrcPackage
	for binName := range defPacks.actuallyAffectedPackNames {
		if srcPack, ok := r.SrcPackages.FindByBinName(binName); ok {
			for _, p := range defPacks.def.AffectedPacks {
				if p.Name == srcPack.Name {
					defPacks.actuallyAffectedPackNames[binName] = p.NotFixedYet
				}
			}
		}
	}

	vinfo.AffectedPackages = defPacks.toPackStatuses()
	vinfo.AffectedPackages.Sort()
	r.ScannedCves[defPacks.def.Debian.CveID] = vinfo
}

func (o DebianBase) convertToModel(def *ovalmodels.Definition) *models.CveContent {
	var refs []models.Reference
	for _, r := range def.References {
		refs = append(refs, models.Reference{
			Link:   r.RefURL,
			Source: r.Source,
			RefID:  r.RefID,
		})
	}

	return &models.CveContent{
		CveID:         def.Debian.CveID,
		Title:         def.Title,
		Summary:       def.Description,
		Cvss2Severity: def.Advisory.Severity,
		References:    refs,
	}
}

// Debian is the interface for Debian OVAL
type Debian struct {
	DebianBase
}

// NewDebian creates OVAL client for Debian
func NewDebian() Debian {
	return Debian{
		DebianBase{
			Base{
				family: config.Debian,
			},
		},
	}
}

// FillWithOval returns scan result after updating CVE info by OVAL
func (o Debian) FillWithOval(driver db.DB, r *models.ScanResult) (nCVEs int, err error) {

	//Debian's uname gives both of kernel release(uname -r), version(kernel-image version)
	linuxImage := "linux-image-" + r.RunningKernel.Release

	// Add linux and set the version of running kernel to search OVAL.
	if r.Container.ContainerID == "" {
		newVer := ""
		if p, ok := r.Packages[linuxImage]; ok {
			newVer = p.NewVersion
		}
		r.Packages["linux"] = models.Package{
			Name:       "linux",
			Version:    r.RunningKernel.Version,
			NewVersion: newVer,
		}
	}

	var relatedDefs ovalResult
	if config.Conf.OvalDict.IsFetchViaHTTP() {
		if relatedDefs, err = getDefsByPackNameViaHTTP(r); err != nil {
			return 0, err
		}
	} else {
		if relatedDefs, err = getDefsByPackNameFromOvalDB(driver, r); err != nil {
			return 0, err
		}
	}

	delete(r.Packages, "linux")

	for _, defPacks := range relatedDefs.entries {
		// Remove "linux" added above for oval search
		// linux is not a real package name (key of affected packages in OVAL)
		if notFixedYet, ok := defPacks.actuallyAffectedPackNames["linux"]; ok {
			defPacks.actuallyAffectedPackNames[linuxImage] = notFixedYet
			delete(defPacks.actuallyAffectedPackNames, "linux")
			for i, p := range defPacks.def.AffectedPacks {
				if p.Name == "linux" {
					p.Name = linuxImage
					defPacks.def.AffectedPacks[i] = p
				}
			}
		}

		o.update(r, defPacks)
	}

	for _, vuln := range r.ScannedCves {
		if cont, ok := vuln.CveContents[models.Debian]; ok {
			cont.SourceLink = "https://security-tracker.debian.org/tracker/" + cont.CveID
			vuln.CveContents[models.Debian] = cont
		}
	}
	return len(relatedDefs.entries), nil
}

// Ubuntu is the interface for Debian OVAL
type Ubuntu struct {
	DebianBase
}

// NewUbuntu creates OVAL client for Debian
func NewUbuntu() Ubuntu {
	return Ubuntu{
		DebianBase{
			Base{
				family: config.Ubuntu,
			},
		},
	}
}

// FillWithOval returns scan result after updating CVE info by OVAL
func (o Ubuntu) FillWithOval(driver db.DB, r *models.ScanResult) (nCVEs int, err error) {
	switch major(r.Release) {
	case "14", "16":
		return o.ubuntu1416(driver, r)
	case "18":
		return o.ubuntu18(driver, r)
	}
	return 0, fmt.Errorf("Ubuntu %s is not support for now", r.Release)
}

func (o Ubuntu) ubuntu1416(driver db.DB, r *models.ScanResult) (nCVEs int, err error) {
	ovalKernelImageNames := []string{
		"linux-aws",
		"linux-azure",
		"linux-flo",
		"linux-gcp",
		"linux-gke",
		"linux-goldfish",
		"linux-hwe",
		"linux-hwe-edge",
		"linux-kvm",
		"linux-mako",
		"linux-raspi2",
		"linux-snapdragon",
	}
	linuxImage := "linux-image-" + r.RunningKernel.Release

	found := false
	if r.Container.ContainerID == "" {
		for _, n := range ovalKernelImageNames {
			if _, ok := r.Packages[n]; ok {
				v, ok := r.Packages[linuxImage]
				if ok {
					// Set running kernel version
					p := r.Packages[n]
					p.Version = v.Version
					p.NewVersion = v.NewVersion
					r.Packages[n] = p
				} else {
					util.Log.Warnf("Running kernel image %s is not found: %s",
						linuxImage, r.RunningKernel.Version)
				}
				found = true
				break
			}
		}

		if !found {
			// linux-generic is described as "linux" in Ubuntu's oval.
			// Add "linux" and set the version of running kernel to search OVAL.
			v, ok := r.Packages[linuxImage]
			if ok {
				r.Packages["linux"] = models.Package{
					Name:       "linux",
					Version:    v.Version,
					NewVersion: v.NewVersion,
				}
			} else {
				util.Log.Warnf("%s is not found. Running: %s",
					linuxImage, r.RunningKernel.Release)
			}
		}
	}

	var relatedDefs ovalResult
	if config.Conf.OvalDict.IsFetchViaHTTP() {
		if relatedDefs, err = getDefsByPackNameViaHTTP(r); err != nil {
			return 0, err
		}
	} else {
		if relatedDefs, err = getDefsByPackNameFromOvalDB(driver, r); err != nil {
			return 0, err
		}
	}

	if !found {
		delete(r.Packages, "linux")
	}

	for _, defPacks := range relatedDefs.entries {
		// Remove "linux" added above to search for oval
		// "linux" is not a real package name (key of affected packages in OVAL)
		if _, ok := defPacks.actuallyAffectedPackNames["linux"]; !found && ok {
			defPacks.actuallyAffectedPackNames[linuxImage] = true
			delete(defPacks.actuallyAffectedPackNames, "linux")
			for i, p := range defPacks.def.AffectedPacks {
				if p.Name == "linux" {
					p.Name = linuxImage
					defPacks.def.AffectedPacks[i] = p
				}
			}
		}

		o.update(r, defPacks)
	}

	for _, vuln := range r.ScannedCves {
		if cont, ok := vuln.CveContents[models.Ubuntu]; ok {
			cont.SourceLink = "http://people.ubuntu.com/~ubuntu-security/cve/" + cont.CveID
			vuln.CveContents[models.Ubuntu] = cont
		}
	}
	return len(relatedDefs.entries), nil
}

func (o Ubuntu) ubuntu18(driver db.DB, r *models.ScanResult) (nCVEs int, err error) {
	// kernel names in OVAL except for linux-image-generic
	ovalKernelImageNames := []string{
		"linux-image-aws",
		"linux-image-azure",
		"linux-image-extra-virtual",
		"linux-image-gcp",
		"linux-image-generic-lpae",
		"linux-image-kvm",
		"linux-image-lowlatency",
		"linux-image-oem",
		"linux-image-oracle",
		"linux-image-raspi2",
		"linux-image-snapdragon",
		"linux-image-virtual",
	}
	linuxImage := "linux-image-" + r.RunningKernel.Release

	const linuxImageGeneric = "linux-image-generic"
	unusedKernels := []models.Package{}
	found := false
	if r.Container.ContainerID == "" {
		if v, ok := r.Packages[linuxImage]; ok {
			r.Packages[linuxImageGeneric] = models.Package{
				Name:       linuxImageGeneric,
				Version:    v.Version,
				NewVersion: v.NewVersion,
			}
			// remove unused kernels from packages
			for _, n := range ovalKernelImageNames {
				if v, ok := r.Packages[n]; ok {
					unusedKernels = append(unusedKernels, v)
					delete(r.Packages, n)
				}
			}
			found = true
		} else {
			util.Log.Warnf("Running kernel image %s is not found in installed Packages. So all vulns for installed kernel wll be detected",
				r.RunningKernel.Version)
		}
	}

	var relatedDefs ovalResult
	if config.Conf.OvalDict.IsFetchViaHTTP() {
		if relatedDefs, err = getDefsByPackNameViaHTTP(r); err != nil {
			return 0, err
		}
	} else {
		if relatedDefs, err = getDefsByPackNameFromOvalDB(driver, r); err != nil {
			return 0, err
		}
	}

	if found {
		delete(r.Packages, linuxImageGeneric)
		for _, p := range unusedKernels {
			r.Packages[p.Name] = p
		}
	}

	for _, defPacks := range relatedDefs.entries {
		// Remove "linux" added above to search for oval
		// "linux" is not a real package name (key of affected packages in OVAL)
		if _, ok := defPacks.actuallyAffectedPackNames[linuxImageGeneric]; !found && ok {
			defPacks.actuallyAffectedPackNames[linuxImage] = true
			delete(defPacks.actuallyAffectedPackNames, linuxImageGeneric)
			for i, p := range defPacks.def.AffectedPacks {
				if p.Name == linuxImageGeneric {
					p.Name = linuxImage
					defPacks.def.AffectedPacks[i] = p
				}
			}
		}
		o.update(r, defPacks)
	}

	for _, vuln := range r.ScannedCves {
		if cont, ok := vuln.CveContents[models.Ubuntu]; ok {
			cont.SourceLink = "http://people.ubuntu.com/~ubuntu-security/cve/" + cont.CveID
			vuln.CveContents[models.Ubuntu] = cont
		}
	}
	return len(relatedDefs.entries), nil
}