at-container-registry/pkg/appview/handlers/diff.go

package handlers

import (
	"fmt"
	"log/slog"
	"net/http"
	"sort"
	"strings"
	"sync"

	"atcr.io/pkg/appview/db"
	"atcr.io/pkg/appview/holdclient"
	"atcr.io/pkg/atproto"
	"github.com/go-chi/chi/v5"
)

// LayerDiffEntry represents one row in the layer diff table.
type LayerDiffEntry struct {
	Status    string       // "shared", "rebuilt", "added", "removed"
	Layer     LayerDetail  // the "to" layer (or from-layer for "removed")
	PrevLayer *LayerDetail // set for "rebuilt" — the old layer
}

// VulnDiffEntry represents a vulnerability categorized by diff status.
type VulnDiffEntry struct {
	Status string // "fixed", "new", "unchanged"
	Vuln   vulnMatch
}

// SbomDiffEntry represents one package categorized by diff status.
type SbomDiffEntry struct {
	Status      string      // "added", "removed", "changed", "unchanged"
	Package     sbomPackage // the "to" package (or the "from" package for "removed")
	PrevVersion string      // set for "changed" — the old version
}

// DiffSummary is the top-line summary for the banner and diff page.
type DiffSummary struct {
	SizeDelta       int64 // bytes, positive = "to" is larger
	LayerCountFrom  int
	LayerCountTo    int
	VulnFixedCount  int
	VulnNewCount    int
	VulnFixedBySev  vulnSummary
	VulnNewBySev    vulnSummary
	HasVulnData     bool
	PkgAddedCount   int
	PkgRemovedCount int
	PkgChangedCount int
	HasSbomData     bool
}

// layerKey returns the matching key for a layer — digest for real layers, command for empty layers.
func layerKey(l LayerDetail) string {
	if l.Command != "" {
		return l.Command
	}
	return l.Digest
}

// computeLayerDiff compares two ordered LayerDetail slices using LCS on commands (git diff style).
// Handles insertions and deletions in the middle, not just prefix divergence.
func computeLayerDiff(fromLayers, toLayers []LayerDetail) []LayerDiffEntry {
	n := len(fromLayers)
	m := len(toLayers)

	// Build LCS table on layer keys (command or digest)
	dp := make([][]int, n+1)
	for i := range dp {
		dp[i] = make([]int, m+1)
	}
	for i := 1; i <= n; i++ {
		for j := 1; j <= m; j++ {
			if layerKey(fromLayers[i-1]) == layerKey(toLayers[j-1]) {
				dp[i][j] = dp[i-1][j-1] + 1
			} else if dp[i-1][j] >= dp[i][j-1] {
				dp[i][j] = dp[i-1][j]
			} else {
				dp[i][j] = dp[i][j-1]
			}
		}
	}

	// Backtrack to produce the diff
	var result []LayerDiffEntry
	i, j := n, m
	// Build in reverse, then flip
	var rev []LayerDiffEntry
	for i > 0 || j > 0 {
		if i > 0 && j > 0 && layerKey(fromLayers[i-1]) == layerKey(toLayers[j-1]) {
			fl := fromLayers[i-1]
			tl := toLayers[j-1]

			// Same key — check if digest also matches
			sameDigest := false
			if fl.EmptyLayer && tl.EmptyLayer {
				sameDigest = true // empty layers matched by command
			} else if !fl.EmptyLayer && !tl.EmptyLayer {
				sameDigest = fl.Digest == tl.Digest
			}

			if sameDigest {
				rev = append(rev, LayerDiffEntry{Status: "shared", Layer: tl})
			} else {
				prevLayer := fl
				rev = append(rev, LayerDiffEntry{Status: "rebuilt", Layer: tl, PrevLayer: &prevLayer})
			}
			i--
			j--
		} else if j > 0 && (i == 0 || dp[i][j-1] >= dp[i-1][j]) {
			rev = append(rev, LayerDiffEntry{Status: "added", Layer: toLayers[j-1]})
			j--
		} else {
			rev = append(rev, LayerDiffEntry{Status: "removed", Layer: fromLayers[i-1]})
			i--
		}
	}

	// Reverse
	result = make([]LayerDiffEntry, len(rev))
	for k, v := range rev {
		result[len(rev)-1-k] = v
	}

	return result
}

// computeVulnDiff compares two vulnerability match slices by CVE ID.
func computeVulnDiff(fromMatches, toMatches []vulnMatch) []VulnDiffEntry {
	fromSet := make(map[string]vulnMatch, len(fromMatches))
	for _, m := range fromMatches {
		fromSet[m.CVEID] = m
	}

	toSet := make(map[string]vulnMatch, len(toMatches))
	for _, m := range toMatches {
		toSet[m.CVEID] = m
	}

	var result []VulnDiffEntry

	// Fixed: in from but not to
	for id, m := range fromSet {
		if _, ok := toSet[id]; !ok {
			result = append(result, VulnDiffEntry{Status: "fixed", Vuln: m})
		}
	}

	// New: in to but not from
	for id, m := range toSet {
		if _, ok := fromSet[id]; !ok {
			result = append(result, VulnDiffEntry{Status: "new", Vuln: m})
		}
	}

	// Unchanged: in both
	for id, m := range toSet {
		if _, ok := fromSet[id]; ok {
			result = append(result, VulnDiffEntry{Status: "unchanged", Vuln: m})
		}
	}

	return result
}

// computeSbomDiff compares two package lists. Identical entries
// (name+type+version) match first as "unchanged"; leftovers pair by
// name+type as "changed" (version bump); the rest are "added"/"removed".
// Multiset counting keeps duplicate identical entries on one side from all
// matching a single entry on the other, and the name+type grouping keeps a
// deb package from pairing against a binary of the same name.
func computeSbomDiff(fromPkgs, toPkgs []sbomPackage) []SbomDiffEntry {
	exactKey := func(p sbomPackage) string {
		return p.Name + "\x00" + p.Type + "\x00" + p.Version
	}
	nameKey := func(p sbomPackage) string {
		return p.Name + "\x00" + p.Type
	}

	// Exact pass: count from-side entries, consume per to-side match.
	fromCounts := make(map[string]int, len(fromPkgs))
	for _, p := range fromPkgs {
		fromCounts[exactKey(p)]++
	}

	var result []SbomDiffEntry
	var toLeft []sbomPackage
	for _, p := range toPkgs {
		if k := exactKey(p); fromCounts[k] > 0 {
			fromCounts[k]--
			result = append(result, SbomDiffEntry{Status: "unchanged", Package: p})
		} else {
			toLeft = append(toLeft, p)
		}
	}
	fromGroups := make(map[string][]sbomPackage)
	for _, p := range fromPkgs {
		if k := exactKey(p); fromCounts[k] > 0 {
			fromCounts[k]--
			fromGroups[nameKey(p)] = append(fromGroups[nameKey(p)], p)
		}
	}

	// Version-change pass: pair leftovers that share name+type. Versions are
	// sorted lexically per group — determinism matters more than semver
	// correctness for pairing multiple installed versions.
	toGroups := make(map[string][]sbomPackage)
	for _, p := range toLeft {
		toGroups[nameKey(p)] = append(toGroups[nameKey(p)], p)
	}
	byVersion := func(pkgs []sbomPackage) {
		sort.Slice(pkgs, func(i, j int) bool { return pkgs[i].Version < pkgs[j].Version })
	}
	for k, toGroup := range toGroups {
		fromGroup := fromGroups[k]
		byVersion(fromGroup)
		byVersion(toGroup)
		paired := min(len(fromGroup), len(toGroup))
		for i := range paired {
			result = append(result, SbomDiffEntry{Status: "changed", Package: toGroup[i], PrevVersion: fromGroup[i].Version})
		}
		for _, p := range toGroup[paired:] {
			result = append(result, SbomDiffEntry{Status: "added", Package: p})
		}
		for _, p := range fromGroup[paired:] {
			result = append(result, SbomDiffEntry{Status: "removed", Package: p})
		}
		delete(fromGroups, k)
	}
	for _, fromGroup := range fromGroups {
		for _, p := range fromGroup {
			result = append(result, SbomDiffEntry{Status: "removed", Package: p})
		}
	}

	// Map iteration above is unordered — sort for stable rendering.
	sort.Slice(result, func(i, j int) bool {
		a, b := result[i].Package, result[j].Package
		if a.Name != b.Name {
			return a.Name < b.Name
		}
		if a.Type != b.Type {
			return a.Type < b.Type
		}
		if a.Version != b.Version {
			return a.Version < b.Version
		}
		return result[i].Status < result[j].Status
	})
	return result
}

// computeDiffSummary derives the top-line summary from layer and vuln diffs.
func computeDiffSummary(fromLayers, toLayers []LayerDetail, vulnDiff []VulnDiffEntry, hasVulnData bool, sbomDiff []SbomDiffEntry, hasSbomData bool) DiffSummary {
	var fromSize, toSize int64
	for _, l := range fromLayers {
		fromSize += l.Size
	}
	for _, l := range toLayers {
		toSize += l.Size
	}

	summary := DiffSummary{
		SizeDelta:      toSize - fromSize,
		LayerCountFrom: len(fromLayers),
		LayerCountTo:   len(toLayers),
		HasVulnData:    hasVulnData,
		HasSbomData:    hasSbomData,
	}

	for _, entry := range vulnDiff {
		switch entry.Status {
		case "fixed":
			summary.VulnFixedCount++
			addToSevCount(&summary.VulnFixedBySev, entry.Vuln.Severity)
		case "new":
			summary.VulnNewCount++
			addToSevCount(&summary.VulnNewBySev, entry.Vuln.Severity)
		}
	}

	for _, entry := range sbomDiff {
		switch entry.Status {
		case "added":
			summary.PkgAddedCount++
		case "removed":
			summary.PkgRemovedCount++
		case "changed":
			summary.PkgChangedCount++
		}
	}

	return summary
}

func addToSevCount(s *vulnSummary, severity string) {
	// Normalize to canonical casing so "CRITICAL", "critical", "Crit" all land
	// in the same bucket. Unknown severities count toward the total but don't
	// bump any bucket — the template renders them as "Unknown" via the
	// severityLabel helper.
	switch strings.ToLower(strings.TrimSpace(severity)) {
	case "critical", "crit", "c":
		s.Critical++
	case "high", "h":
		s.High++
	case "medium", "med", "m":
		s.Medium++
	case "low", "l":
		s.Low++
	}
	s.Total++
}

// sbomDiffStatus maps one side's SBOM fetch result to a status the template
// can branch on: "ok", "no-data" (no scan record or SBOM blob),
// "not-applicable" (scanner skipped this artifact type), or
// "hold-unreachable" (couldn't resolve or reach the hold).
func sbomDiffStatus(d *sbomDetailsData) string {
	switch {
	case d == nil:
		return "hold-unreachable"
	case d.Status == atproto.ScanStatusSkipped:
		return "not-applicable"
	case d.Error != "":
		return "no-data"
	default:
		return "ok"
	}
}

// ManifestDiffHandler renders the full diff page comparing two manifests.
type ManifestDiffHandler struct {
	BaseUIHandler
}

func (h *ManifestDiffHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	identifier := chi.URLParam(r, "handle")
	// Route: /diff/{handle}/* — wildcard captures the repo name
	repo := strings.TrimPrefix(chi.URLParam(r, "*"), "/")
	if repo == "" {
		RenderNotFound(w, r, &h.BaseUIHandler)
		return
	}

	fromParam := r.URL.Query().Get("from")
	toParam := r.URL.Query().Get("to")
	if fromParam == "" || toParam == "" {
		RenderNotFound(w, r, &h.BaseUIHandler)
		return
	}

	// Resolve identity
	did, resolvedHandle, _, err := atproto.ResolveIdentity(r.Context(), identifier)
	if err != nil {
		RenderNotFound(w, r, &h.BaseUIHandler)
		return
	}

	owner, err := db.GetUserByDID(h.ReadOnlyDB, did)
	if err != nil || owner == nil {
		RenderNotFound(w, r, &h.BaseUIHandler)
		return
	}
	if owner.Handle != resolvedHandle {
		_ = db.UpdateUserHandle(h.DB, did, resolvedHandle)
		owner.Handle = resolvedHandle
	}

	// Resolve from/to params — accept either digests (sha256:...) or tag names
	fromDigest := fromParam
	toDigest := toParam
	if !strings.HasPrefix(fromDigest, "sha256:") {
		tag, err := db.GetTagByName(h.ReadOnlyDB, owner.DID, repo, fromParam)
		if err != nil || tag == nil {
			RenderNotFound(w, r, &h.BaseUIHandler)
			return
		}
		fromDigest = tag.Digest
	}
	if !strings.HasPrefix(toDigest, "sha256:") {
		tag, err := db.GetTagByName(h.ReadOnlyDB, owner.DID, repo, toParam)
		if err != nil || tag == nil {
			RenderNotFound(w, r, &h.BaseUIHandler)
			return
		}
		toDigest = tag.Digest
	}

	// Fetch both manifests
	type manifestData struct {
		manifest *db.ManifestWithMetadata
		layers   []LayerDetail
		vulnData *vulnDetailsData
		sbomData *sbomDetailsData
		err      error
	}

	// fetchManifest fetches layers and vulns for a digest.
	// For manifest lists, it uses the provided platform child digest instead.
	fetchManifest := func(digest, platformDigest string) manifestData {
		m, err := db.GetManifestDetail(h.ReadOnlyDB, owner.DID, repo, digest)
		if err != nil {
			return manifestData{err: err}
		}

		// For multi-arch, resolve to the platform child
		layerManifest := m
		layerDigest := digest
		holdEndpoint := m.HoldEndpoint

		if m.IsManifestList && platformDigest != "" {
			child, err := db.GetManifestDetail(h.ReadOnlyDB, owner.DID, repo, platformDigest)
			if err == nil {
				layerManifest = child
				layerDigest = platformDigest
				if child.HoldEndpoint != "" {
					holdEndpoint = child.HoldEndpoint
				}
			}
		}

		dbLayers, _ := db.GetLayersForManifest(h.ReadOnlyDB, layerManifest.ID)

		var layers []LayerDetail
		var vulnData *vulnDetailsData
		var sbomData *sbomDetailsData

		hold, holdErr := ResolveHold(r.Context(), h.ReadOnlyDB, holdEndpoint)
		if holdErr == nil {
			// Parallelize the three hold fetches. They're independent and
			// each takes a network round-trip; serial runs add up on slow links.
			var fwg sync.WaitGroup
			fwg.Add(3)
			go func() {
				defer fwg.Done()
				config, err := holdclient.FetchImageConfig(r.Context(), hold.URL, layerDigest)
				if err == nil {
					layers = buildLayerDetails(config.History, dbLayers)
				} else {
					layers = buildLayerDetails(nil, dbLayers)
				}
			}()
			go func() {
				defer fwg.Done()
				vd := FetchVulnDetails(r.Context(), hold.DID, layerDigest)
				vulnData = &vd
			}()
			go func() {
				defer fwg.Done()
				sd := FetchSbomDetails(r.Context(), hold.DID, layerDigest)
				sbomData = &sd
			}()
			fwg.Wait()
		} else {
			layers = buildLayerDetails(nil, dbLayers)
		}

		return manifestData{manifest: m, layers: layers, vulnData: vulnData, sbomData: sbomData}
	}

	// First fetch both top-level manifests to check for multi-arch
	fromManifest, err := db.GetManifestDetail(h.ReadOnlyDB, owner.DID, repo, fromDigest)
	if err != nil {
		RenderNotFound(w, r, &h.BaseUIHandler)
		return
	}
	toManifest, err := db.GetManifestDetail(h.ReadOnlyDB, owner.DID, repo, toDigest)
	if err != nil {
		RenderNotFound(w, r, &h.BaseUIHandler)
		return
	}

	// Find common platforms for multi-arch
	var commonPlatforms []db.PlatformInfo
	var selectedPlatform string
	isMultiArch := fromManifest.IsManifestList && toManifest.IsManifestList

	fromPlatformDigest := ""
	toPlatformDigest := ""

	// platKey returns "os/arch[/variant]" for a platform.
	platKey := func(os, arch, variant string) string {
		k := os + "/" + arch
		if variant != "" {
			k += "/" + variant
		}
		return k
	}

	// pickPlatformChild returns the child digest from a manifest list whose
	// platform matches the given key. Returns "" if no match.
	pickPlatformChild := func(m *db.ManifestWithMetadata, key string) string {
		for _, p := range m.Platforms {
			if platKey(p.OS, p.Architecture, p.Variant) == key {
				return p.Digest
			}
		}
		return ""
	}

	if isMultiArch {
		// Build intersection of platforms
		for _, fp := range fromManifest.Platforms {
			for _, tp := range toManifest.Platforms {
				if fp.OS == tp.OS && fp.Architecture == tp.Architecture && fp.Variant == tp.Variant {
					commonPlatforms = append(commonPlatforms, tp)
					break
				}
			}
		}

		// Use query param or default to first common platform
		selectedPlatform = r.URL.Query().Get("platform")
		if len(commonPlatforms) > 0 {
			if selectedPlatform == "" {
				selectedPlatform = platKey(commonPlatforms[0].OS, commonPlatforms[0].Architecture, commonPlatforms[0].Variant)
			}
			fromPlatformDigest = pickPlatformChild(fromManifest, selectedPlatform)
			toPlatformDigest = pickPlatformChild(toManifest, selectedPlatform)
		}
	} else if fromManifest.IsManifestList != toManifest.IsManifestList {
		// Mixed: one side is a manifest list, the other is a platform child.
		// Match them by looking up the single-arch side's platform via its
		// parent manifest_references row and picking the matching child from
		// the manifest list side.
		var listSide *db.ManifestWithMetadata
		var childDigest string
		if fromManifest.IsManifestList {
			listSide = fromManifest
			childDigest = toDigest
		} else {
			listSide = toManifest
			childDigest = fromDigest
		}

		plat, _ := db.GetChildManifestPlatform(h.ReadOnlyDB, owner.DID, repo, childDigest)
		var listChildDigest string
		if plat != nil {
			listChildDigest = pickPlatformChild(listSide, platKey(plat.OS, plat.Architecture, plat.Variant))
		}
		// Fallback: if we couldn't determine the platform (or no match),
		// default to the first non-attestation child of the manifest list so
		// the diff at least shows real layers instead of an empty index.
		if listChildDigest == "" {
			for _, p := range listSide.Platforms {
				if p.Digest != "" {
					listChildDigest = p.Digest
					break
				}
			}
		}
		if fromManifest.IsManifestList {
			fromPlatformDigest = listChildDigest
		} else {
			toPlatformDigest = listChildDigest
		}
	}

	// Fetch layer/vuln data in parallel
	var fromData, toData manifestData
	var wg sync.WaitGroup
	wg.Add(2)
	go func() {
		defer wg.Done()
		fromData = fetchManifest(fromDigest, fromPlatformDigest)
	}()
	go func() {
		defer wg.Done()
		toData = fetchManifest(toDigest, toPlatformDigest)
	}()
	wg.Wait()

	// Track per-side fetch failures so we render the page with an inline
	// alert naming which tag failed, instead of a generic 404 that makes
	// users guess whether they typoed a tag or hit a transient outage.
	// fromData.manifest / toData.manifest is nil only when the re-fetch at
	// the top of fetchManifest hit a DB error (the tag resolution earlier
	// already ruled out typos).
	fromFailed := fromData.err != nil || fromData.manifest == nil
	toFailed := toData.err != nil || toData.manifest == nil

	// Fall back to the top-level manifest we already fetched so the page
	// still has something to render for tag labels and metadata.
	if fromFailed {
		fromData.manifest = fromManifest
	}
	if toFailed {
		toData.manifest = toManifest
	}

	// Compute diffs
	layerDiff := computeLayerDiff(fromData.layers, toData.layers)

	// ScanStatus distinguishes why vuln data may be missing: "ok" when both
	// sides returned clean scan results; "no-data" when a scan was never
	// recorded; "hold-unreachable" when we couldn't reach the hold to ask.
	// The template branches on these so users can tell "not scanned yet"
	// from "hold offline" at a glance.
	fromScanStatus := "ok"
	toScanStatus := "ok"
	if fromData.vulnData == nil {
		fromScanStatus = "hold-unreachable"
	} else if fromData.vulnData.Error != "" {
		fromScanStatus = "no-data"
	}
	if toData.vulnData == nil {
		toScanStatus = "hold-unreachable"
	} else if toData.vulnData.Error != "" {
		toScanStatus = "no-data"
	}

	var vulnDiff []VulnDiffEntry
	hasVulnData := fromScanStatus == "ok" && toScanStatus == "ok"
	if hasVulnData {
		vulnDiff = computeVulnDiff(fromData.vulnData.Matches, toData.vulnData.Matches)
	}

	// SBOM status mirrors the scan status, with one extra case: the scanner
	// records status="skipped" for artifact types it doesn't scan, which the
	// template surfaces as "not applicable" rather than "not scanned yet".
	fromSbomStatus := sbomDiffStatus(fromData.sbomData)
	toSbomStatus := sbomDiffStatus(toData.sbomData)

	var sbomDiff []SbomDiffEntry
	hasSbomData := fromSbomStatus == "ok" && toSbomStatus == "ok"
	if hasSbomData {
		sbomDiff = computeSbomDiff(fromData.sbomData.Packages, toData.sbomData.Packages)
	}

	summary := computeDiffSummary(fromData.layers, toData.layers, vulnDiff, hasVulnData, sbomDiff, hasSbomData)

	// Determine tag labels
	fromTag := fromDigest
	if len(fromData.manifest.Tags) > 0 {
		fromTag = fromData.manifest.Tags[0]
	}
	toTag := toDigest
	if len(toData.manifest.Tags) > 0 {
		toTag = toData.manifest.Tags[0]
	}

	// Count vulns by status for template
	var fixedVulns, newVulns, unchangedVulns []vulnMatch
	for _, entry := range vulnDiff {
		switch entry.Status {
		case "fixed":
			fixedVulns = append(fixedVulns, entry.Vuln)
		case "new":
			newVulns = append(newVulns, entry.Vuln)
		case "unchanged":
			unchangedVulns = append(unchangedVulns, entry.Vuln)
		}
	}

	// Split packages by status for template
	var addedPackages, removedPackages, changedPackages, unchangedPackages []SbomDiffEntry
	for _, entry := range sbomDiff {
		switch entry.Status {
		case "added":
			addedPackages = append(addedPackages, entry)
		case "removed":
			removedPackages = append(removedPackages, entry)
		case "changed":
			changedPackages = append(changedPackages, entry)
		case "unchanged":
			unchangedPackages = append(unchangedPackages, entry)
		}
	}

	title := fmt.Sprintf("Diff: %s → %s - %s/%s - %s", fromTag, toTag, owner.Handle, repo, h.ClientShortName)
	description := fmt.Sprintf("Comparing %s to %s in %s/%s", fromTag, toTag, owner.Handle, repo)
	meta := NewPageMeta(title, description).
		WithCanonical(fmt.Sprintf("https://%s/diff/%s/%s?from=%s&to=%s", h.SiteURL, owner.Handle, repo, fromDigest, toDigest)).
		WithSiteName(h.ClientShortName)

	data := struct {
		PageData
		Meta              *PageMeta
		Owner             *db.User
		Repository        string
		FromManifest      *db.ManifestWithMetadata
		ToManifest        *db.ManifestWithMetadata
		FromTag           string
		ToTag             string
		Summary           DiffSummary
		LayerDiff         []LayerDiffEntry
		FixedVulns        []vulnMatch
		NewVulns          []vulnMatch
		UnchangedVulns    []vulnMatch
		HasVulnData       bool
		FromScanStatus    string
		ToScanStatus      string
		AddedPackages     []SbomDiffEntry
		RemovedPackages   []SbomDiffEntry
		ChangedPackages   []SbomDiffEntry
		UnchangedPackages []SbomDiffEntry
		HasSbomData       bool
		FromSbomStatus    string
		ToSbomStatus      string
		FromFailed        bool
		ToFailed          bool
		IsMultiArch       bool
		CommonPlatforms   []db.PlatformInfo
		SelectedPlatform  string
		FromDigest        string
		ToDigest          string
	}{
		PageData:          NewPageData(r, &h.BaseUIHandler),
		Meta:              meta,
		Owner:             owner,
		Repository:        repo,
		FromManifest:      fromData.manifest,
		ToManifest:        toData.manifest,
		FromTag:           fromTag,
		ToTag:             toTag,
		Summary:           summary,
		LayerDiff:         layerDiff,
		FixedVulns:        fixedVulns,
		NewVulns:          newVulns,
		UnchangedVulns:    unchangedVulns,
		HasVulnData:       hasVulnData,
		FromScanStatus:    fromScanStatus,
		ToScanStatus:      toScanStatus,
		AddedPackages:     addedPackages,
		RemovedPackages:   removedPackages,
		ChangedPackages:   changedPackages,
		UnchangedPackages: unchangedPackages,
		HasSbomData:       hasSbomData,
		FromSbomStatus:    fromSbomStatus,
		ToSbomStatus:      toSbomStatus,
		FromFailed:        fromFailed,
		ToFailed:          toFailed,
		IsMultiArch:       isMultiArch,
		CommonPlatforms:   commonPlatforms,
		SelectedPlatform:  selectedPlatform,
		FromDigest:        fromDigest,
		ToDigest:          toDigest,
	}

	if err := h.Templates.ExecuteTemplate(w, "diff", data); err != nil {
		slog.Warn("Failed to render diff page", "error", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}