package imagestore

import (
	"bytes"
	"context"
	"crypto/sha256"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"path"
	"path/filepath"
	"strings"
	"sync"
	"time"
	"unicode/utf8"

	"github.com/docker/distribution/registry/storage/driver"
	guuid "github.com/gofrs/uuid"
	godigest "github.com/opencontainers/go-digest"
	ispec "github.com/opencontainers/image-spec/specs-go/v1"
	artifactspec "github.com/oras-project/artifacts-spec/specs-go/v1"

	zerr "zotregistry.io/zot/errors"
	zcommon "zotregistry.io/zot/pkg/common"
	"zotregistry.io/zot/pkg/extensions/monitoring"
	syncConstants "zotregistry.io/zot/pkg/extensions/sync/constants"
	zlog "zotregistry.io/zot/pkg/log"
	zreg "zotregistry.io/zot/pkg/regexp"
	"zotregistry.io/zot/pkg/scheduler"
	"zotregistry.io/zot/pkg/storage/cache"
	common "zotregistry.io/zot/pkg/storage/common"
	storageConstants "zotregistry.io/zot/pkg/storage/constants"
	storageTypes "zotregistry.io/zot/pkg/storage/types"
	"zotregistry.io/zot/pkg/test/inject"
)

const (
	cosignSignatureTagSuffix = "sig"
	SBOMTagSuffix            = "sbom"
)

// ImageStore provides the image storage operations.
type ImageStore struct {
	rootDir     string
	storeDriver storageTypes.Driver
	lock        *sync.RWMutex
	log         zlog.Logger
	metrics     monitoring.MetricServer
	cache       cache.Cache
	dedupe      bool
	linter      common.Lint
	commit      bool
}

func (is *ImageStore) Name() string {
	return is.storeDriver.Name()
}

func (is *ImageStore) RootDir() string {
	return is.rootDir
}

func (is *ImageStore) DirExists(d string) bool {
	return is.storeDriver.DirExists(d)
}

// NewImageStore returns a new image store backed by cloud storages.
// see https://github.com/docker/docker.github.io/tree/master/registry/storage-drivers
// Use the last argument to properly set a cache database, or it will default to boltDB local storage.
func NewImageStore(rootDir string, cacheDir string, dedupe, commit bool, log zlog.Logger,
	metrics monitoring.MetricServer, linter common.Lint, storeDriver storageTypes.Driver, cacheDriver cache.Cache,
) storageTypes.ImageStore {
	if err := storeDriver.EnsureDir(rootDir); err != nil {
		log.Error().Err(err).Str("rootDir", rootDir).Msg("failed to create root dir")

		return nil
	}

	imgStore := &ImageStore{
		rootDir:     rootDir,
		storeDriver: storeDriver,
		lock:        &sync.RWMutex{},
		log:         log,
		metrics:     metrics,
		dedupe:      dedupe,
		linter:      linter,
		commit:      commit,
		cache:       cacheDriver,
	}

	return imgStore
}

// RLock read-lock.
func (is *ImageStore) RLock(lockStart *time.Time) {
	*lockStart = time.Now()

	is.lock.RLock()
}

// RUnlock read-unlock.
func (is *ImageStore) RUnlock(lockStart *time.Time) {
	is.lock.RUnlock()

	lockEnd := time.Now()
	// includes time spent in acquiring and holding a lock
	latency := lockEnd.Sub(*lockStart)
	monitoring.ObserveStorageLockLatency(is.metrics, latency, is.RootDir(), storageConstants.RLOCK) // histogram
}

// Lock write-lock.
func (is *ImageStore) Lock(lockStart *time.Time) {
	*lockStart = time.Now()

	is.lock.Lock()
}

// Unlock write-unlock.
func (is *ImageStore) Unlock(lockStart *time.Time) {
	is.lock.Unlock()

	lockEnd := time.Now()
	// includes time spent in acquiring and holding a lock
	latency := lockEnd.Sub(*lockStart)
	monitoring.ObserveStorageLockLatency(is.metrics, latency, is.RootDir(), storageConstants.RWLOCK) // histogram
}

func (is *ImageStore) initRepo(name string) error {
	repoDir := path.Join(is.rootDir, name)

	if !utf8.ValidString(name) {
		is.log.Error().Msg("invalid UTF-8 input")

		return zerr.ErrInvalidRepositoryName
	}

	if !zreg.FullNameRegexp.MatchString(name) {
		is.log.Error().Str("repository", name).Msg("invalid repository name")

		return zerr.ErrInvalidRepositoryName
	}

	// create "blobs" subdir
	err := is.storeDriver.EnsureDir(path.Join(repoDir, "blobs"))
	if err != nil {
		is.log.Error().Err(err).Str("repository", name).Str("dir", repoDir).Msg("failed to create blobs subdir")

		return err
	}
	// create BlobUploadDir subdir
	err = is.storeDriver.EnsureDir(path.Join(repoDir, storageConstants.BlobUploadDir))
	if err != nil {
		is.log.Error().Err(err).Msg("failed to create blob upload subdir")

		return err
	}

	// "oci-layout" file - create if it doesn't exist
	ilPath := path.Join(repoDir, ispec.ImageLayoutFile)
	if _, err := is.storeDriver.Stat(ilPath); err != nil {
		il := ispec.ImageLayout{Version: ispec.ImageLayoutVersion}

		buf, err := json.Marshal(il)
		if err != nil {
			is.log.Error().Err(err).Msg("failed to marshal JSON")

			return err
		}

		if _, err := is.storeDriver.WriteFile(ilPath, buf); err != nil {
			is.log.Error().Err(err).Str("file", ilPath).Msg("failed to write file")

			return err
		}
	}

	// "index.json" file - create if it doesn't exist
	indexPath := path.Join(repoDir, "index.json")
	if _, err := is.storeDriver.Stat(indexPath); err != nil {
		index := ispec.Index{}
		index.SchemaVersion = 2

		buf, err := json.Marshal(index)
		if err != nil {
			is.log.Error().Err(err).Msg("failed to marshal JSON")

			return err
		}

		if _, err := is.storeDriver.WriteFile(indexPath, buf); err != nil {
			is.log.Error().Err(err).Str("file", ilPath).Msg("failed to write file")

			return err
		}
	}

	return nil
}

// InitRepo creates an image repository under this store.
func (is *ImageStore) InitRepo(name string) error {
	var lockLatency time.Time

	is.Lock(&lockLatency)
	defer is.Unlock(&lockLatency)

	return is.initRepo(name)
}

// ValidateRepo validates that the repository layout is complaint with the OCI repo layout.
func (is *ImageStore) ValidateRepo(name string) (bool, error) {
	if !zreg.FullNameRegexp.MatchString(name) {
		return false, zerr.ErrInvalidRepositoryName
	}

	// https://github.com/opencontainers/image-spec/blob/master/image-layout.md#content
	// at least, expect at least 3 entries - ["blobs", "oci-layout", "index.json"]
	// and an additional/optional BlobUploadDir in each image store
	// for s3 we can not create empty dirs, so we check only against index.json and oci-layout
	dir := path.Join(is.rootDir, name)
	if fi, err := is.storeDriver.Stat(dir); err != nil || !fi.IsDir() {
		return false, zerr.ErrRepoNotFound
	}

	files, err := is.storeDriver.List(dir)
	if err != nil {
		is.log.Error().Err(err).Str("dir", dir).Msg("failed to read directory")

		return false, zerr.ErrRepoNotFound
	}

	//nolint:gomnd
	if len(files) < 2 {
		return false, zerr.ErrRepoBadVersion
	}

	found := map[string]bool{
		ispec.ImageLayoutFile: false,
		"index.json":          false,
	}

	for _, file := range files {
		fileInfo, err := is.storeDriver.Stat(file)
		if err != nil {
			return false, err
		}

		filename, err := filepath.Rel(dir, file)
		if err != nil {
			return false, err
		}

		if filename == "blobs" && !fileInfo.IsDir() {
			return false, nil
		}

		found[filename] = true
	}

	// check blobs dir exists only for filesystem, in s3 we can't have empty dirs
	if is.storeDriver.Name() == storageConstants.LocalStorageDriverName {
		if !is.storeDriver.DirExists(path.Join(dir, "blobs")) {
			return false, nil
		}
	}

	for k, v := range found {
		if !v && k != storageConstants.BlobUploadDir {
			return false, nil
		}
	}

	buf, err := is.storeDriver.ReadFile(path.Join(dir, ispec.ImageLayoutFile))
	if err != nil {
		return false, err
	}

	var il ispec.ImageLayout
	if err := json.Unmarshal(buf, &il); err != nil {
		return false, err
	}

	if il.Version != ispec.ImageLayoutVersion {
		return false, zerr.ErrRepoBadVersion
	}

	return true, nil
}

// GetRepositories returns a list of all the repositories under this store.
func (is *ImageStore) GetRepositories() ([]string, error) {
	var lockLatency time.Time

	dir := is.rootDir

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	stores := make([]string, 0)

	err := is.storeDriver.Walk(dir, func(fileInfo driver.FileInfo) error {
		if !fileInfo.IsDir() {
			return nil
		}

		// skip .sync and .uploads dirs no need to try to validate them
		if strings.HasSuffix(fileInfo.Path(), syncConstants.SyncBlobUploadDir) ||
			strings.HasSuffix(fileInfo.Path(), storageConstants.BlobUploadDir) {
			return driver.ErrSkipDir
		}

		rel, err := filepath.Rel(is.rootDir, fileInfo.Path())
		if err != nil {
			return nil //nolint:nilerr // ignore paths that are not under root dir
		}

		if ok, err := is.ValidateRepo(rel); !ok || err != nil {
			return nil //nolint:nilerr // ignore invalid repos
		}

		stores = append(stores, rel)

		return nil
	})

	// if the root directory is not yet created then return an empty slice of repositories
	var perr driver.PathNotFoundError
	if errors.As(err, &perr) {
		return stores, nil
	}

	return stores, err
}

// GetNextRepository returns next repository under this store.
func (is *ImageStore) GetNextRepository(repo string) (string, error) {
	var lockLatency time.Time

	dir := is.rootDir

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	_, err := is.storeDriver.List(dir)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			is.log.Debug().Msg("empty rootDir")

			return "", nil
		}

		is.log.Error().Err(err).Str("root-dir", dir).Msg("failed to walk storage root-dir")

		return "", err
	}

	found := false
	store := ""
	err = is.storeDriver.Walk(dir, func(fileInfo driver.FileInfo) error {
		if !fileInfo.IsDir() {
			return nil
		}

		rel, err := filepath.Rel(is.rootDir, fileInfo.Path())
		if err != nil {
			return nil //nolint:nilerr // ignore paths not relative to root dir
		}

		ok, err := is.ValidateRepo(rel)
		if !ok || err != nil {
			return nil //nolint:nilerr // ignore invalid repos
		}

		if repo == "" && ok && err == nil {
			store = rel

			return io.EOF
		}

		if found {
			store = rel

			return io.EOF
		}

		if rel == repo {
			found = true
		}

		return nil
	})

	driverErr := &driver.Error{}

	// some s3 implementations (eg, digitalocean spaces) will return pathnotfounderror for walk but not list
	// therefore, we must also catch that error here.
	if errors.As(err, &driver.PathNotFoundError{}) {
		is.log.Debug().Msg("empty rootDir")

		return "", nil
	}

	if errors.Is(err, io.EOF) ||
		(errors.As(err, driverErr) && errors.Is(driverErr.Enclosed, io.EOF)) {
		return store, nil
	}

	return store, err
}

// GetImageTags returns a list of image tags available in the specified repository.
func (is *ImageStore) GetImageTags(repo string) ([]string, error) {
	var lockLatency time.Time

	dir := path.Join(is.rootDir, repo)
	if fi, err := is.storeDriver.Stat(dir); err != nil || !fi.IsDir() {
		return nil, zerr.ErrRepoNotFound
	}

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	index, err := common.GetIndex(is, repo, is.log)
	if err != nil {
		return nil, err
	}

	return common.GetTagsByIndex(index), nil
}

// GetImageManifest returns the image manifest of an image in the specific repository.
func (is *ImageStore) GetImageManifest(repo, reference string) ([]byte, godigest.Digest, string, error) {
	dir := path.Join(is.rootDir, repo)
	if fi, err := is.storeDriver.Stat(dir); err != nil || !fi.IsDir() {
		return nil, "", "", zerr.ErrRepoNotFound
	}

	var lockLatency time.Time

	var err error

	is.RLock(&lockLatency)
	defer func() {
		is.RUnlock(&lockLatency)

		if err == nil {
			monitoring.IncDownloadCounter(is.metrics, repo)
		}
	}()

	index, err := common.GetIndex(is, repo, is.log)
	if err != nil {
		return nil, "", "", err
	}

	manifestDesc, found := common.GetManifestDescByReference(index, reference)
	if !found {
		return nil, "", "", zerr.ErrManifestNotFound
	}

	buf, err := is.GetBlobContent(repo, manifestDesc.Digest)
	if err != nil {
		if errors.Is(err, zerr.ErrBlobNotFound) {
			return nil, "", "", zerr.ErrManifestNotFound
		}

		return nil, "", "", err
	}

	var manifest ispec.Manifest
	if err := json.Unmarshal(buf, &manifest); err != nil {
		is.log.Error().Err(err).Str("dir", dir).Msg("invalid JSON")

		return nil, "", "", err
	}

	return buf, manifestDesc.Digest, manifestDesc.MediaType, nil
}

// PutImageManifest adds an image manifest to the repository.
func (is *ImageStore) PutImageManifest(repo, reference, mediaType string, //nolint: gocyclo
	body []byte,
) (godigest.Digest, godigest.Digest, error) {
	if err := is.InitRepo(repo); err != nil {
		is.log.Debug().Err(err).Msg("init repo")

		return "", "", err
	}

	var lockLatency time.Time

	var err error

	is.Lock(&lockLatency)
	defer func() {
		is.Unlock(&lockLatency)

		if err == nil {
			if is.storeDriver.Name() == storageConstants.LocalStorageDriverName {
				monitoring.SetStorageUsage(is.metrics, is.rootDir, repo)
			}

			monitoring.IncUploadCounter(is.metrics, repo)
		}
	}()

	refIsDigest := true

	mDigest, err := common.GetAndValidateRequestDigest(body, reference, is.log)
	if err != nil {
		if errors.Is(err, zerr.ErrBadManifest) {
			return mDigest, "", err
		}

		refIsDigest = false
	}

	dig, err := common.ValidateManifest(is, repo, reference, mediaType, body, is.log)
	if err != nil {
		return dig, "", err
	}

	index, err := common.GetIndex(is, repo, is.log)
	if err != nil {
		return "", "", err
	}

	// create a new descriptor
	desc := ispec.Descriptor{
		MediaType: mediaType, Size: int64(len(body)), Digest: mDigest,
	}

	if !refIsDigest {
		desc.Annotations = map[string]string{ispec.AnnotationRefName: reference}
	}

	var subjectDigest godigest.Digest

	artifactType := ""

	if mediaType == ispec.MediaTypeImageManifest {
		var manifest ispec.Manifest

		err := json.Unmarshal(body, &manifest)
		if err != nil {
			return "", "", err
		}

		if manifest.Subject != nil {
			subjectDigest = manifest.Subject.Digest
		}

		artifactType = zcommon.GetManifestArtifactType(manifest)
	} else if mediaType == ispec.MediaTypeImageIndex {
		var index ispec.Index

		err := json.Unmarshal(body, &index)
		if err != nil {
			return "", "", err
		}

		if index.Subject != nil {
			subjectDigest = index.Subject.Digest
		}

		artifactType = zcommon.GetIndexArtifactType(index)
	}

	updateIndex, oldDgst, err := common.CheckIfIndexNeedsUpdate(&index, &desc, is.log)
	if err != nil {
		return "", "", err
	}

	if !updateIndex {
		return desc.Digest, subjectDigest, nil
	}

	// write manifest to "blobs"
	dir := path.Join(is.rootDir, repo, "blobs", mDigest.Algorithm().String())
	manifestPath := path.Join(dir, mDigest.Encoded())

	if _, err = is.storeDriver.WriteFile(manifestPath, body); err != nil {
		is.log.Error().Err(err).Str("file", manifestPath).Msg("failed to write")

		return "", "", err
	}

	err = common.UpdateIndexWithPrunedImageManifests(is, &index, repo, desc, oldDgst, is.log)
	if err != nil {
		return "", "", err
	}

	// now update "index.json"
	index.Manifests = append(index.Manifests, desc)

	// update the descriptors artifact type in order to check for signatures when applying the linter
	desc.ArtifactType = artifactType

	// apply linter only on images, not signatures
	pass, err := common.ApplyLinter(is, is.linter, repo, desc)
	if !pass {
		is.log.Error().Err(err).Str("repository", repo).Str("reference", reference).
			Msg("linter didn't pass")

		return "", "", err
	}

	if err := is.PutIndexContent(repo, index); err != nil {
		return "", "", err
	}

	return desc.Digest, subjectDigest, nil
}

// DeleteImageManifest deletes the image manifest from the repository.
func (is *ImageStore) DeleteImageManifest(repo, reference string, detectCollisions bool) error {
	dir := path.Join(is.rootDir, repo)
	if fi, err := is.storeDriver.Stat(dir); err != nil || !fi.IsDir() {
		return zerr.ErrRepoNotFound
	}

	var lockLatency time.Time

	is.Lock(&lockLatency)
	defer is.Unlock(&lockLatency)

	err := is.deleteImageManifest(repo, reference, detectCollisions)
	if err != nil {
		return err
	}

	return nil
}

func (is *ImageStore) deleteImageManifest(repo, reference string, detectCollisions bool) error {
	defer func() {
		if is.storeDriver.Name() == storageConstants.LocalStorageDriverName {
			monitoring.SetStorageUsage(is.metrics, is.rootDir, repo)
		}
	}()

	index, err := common.GetIndex(is, repo, is.log)
	if err != nil {
		return err
	}

	manifestDesc, err := common.RemoveManifestDescByReference(&index, reference, detectCollisions)
	if err != nil {
		return err
	}

	/* check if manifest is referenced in image indexes, do not allow index images manipulations
	(ie. remove manifest being part of an image index)	*/
	if manifestDesc.MediaType == ispec.MediaTypeImageManifest {
		for _, mDesc := range index.Manifests {
			if mDesc.MediaType == ispec.MediaTypeImageIndex {
				if ok, _ := common.IsBlobReferencedInImageIndex(is, repo, manifestDesc.Digest, ispec.Index{
					Manifests: []ispec.Descriptor{mDesc},
				}, is.log); ok {
					return zerr.ErrManifestReferenced
				}
			}
		}
	}

	err = common.UpdateIndexWithPrunedImageManifests(is, &index, repo, manifestDesc, manifestDesc.Digest, is.log)
	if err != nil {
		return err
	}

	// now update "index.json"
	dir := path.Join(is.rootDir, repo)
	file := path.Join(dir, "index.json")

	buf, err := json.Marshal(index)
	if err != nil {
		return err
	}

	if _, err := is.storeDriver.WriteFile(file, buf); err != nil {
		is.log.Debug().Str("reference", reference).Str("repository", repo).Msg("failed to update index.json")

		return err
	}

	// Delete blob only when blob digest not present in manifest entry.
	// e.g. 1.0.1 & 1.0.2 have same blob digest so if we delete 1.0.1, blob should not be removed.
	toDelete := true

	for _, manifest := range index.Manifests {
		if manifestDesc.Digest.String() == manifest.Digest.String() {
			toDelete = false

			break
		}
	}

	if toDelete {
		p := path.Join(dir, "blobs", manifestDesc.Digest.Algorithm().String(), manifestDesc.Digest.Encoded())

		err = is.storeDriver.Delete(p)
		if err != nil {
			return err
		}
	}

	return nil
}

// BlobUploadPath returns the upload path for a blob in this store.
func (is *ImageStore) BlobUploadPath(repo, uuid string) string {
	dir := path.Join(is.rootDir, repo)
	blobUploadPath := path.Join(dir, storageConstants.BlobUploadDir, uuid)

	return blobUploadPath
}

// NewBlobUpload returns the unique ID for an upload in progress.
func (is *ImageStore) NewBlobUpload(repo string) (string, error) {
	if err := is.InitRepo(repo); err != nil {
		is.log.Error().Err(err).Msg("failed to initialize repo")

		return "", err
	}

	uuid, err := guuid.NewV4()
	if err != nil {
		return "", err
	}

	uid := uuid.String()

	blobUploadPath := is.BlobUploadPath(repo, uid)

	// create multipart upload (append false)
	writer, err := is.storeDriver.Writer(blobUploadPath, false)
	if err != nil {
		is.log.Debug().Err(err).Str("blob", blobUploadPath).Msg("failed to start multipart writer")

		return "", zerr.ErrRepoNotFound
	}

	defer writer.Close()

	return uid, nil
}

// GetBlobUpload returns the current size of a blob upload.
func (is *ImageStore) GetBlobUpload(repo, uuid string) (int64, error) {
	blobUploadPath := is.BlobUploadPath(repo, uuid)

	if !utf8.ValidString(blobUploadPath) {
		is.log.Error().Msg("invalid UTF-8 input")

		return -1, zerr.ErrInvalidRepositoryName
	}

	writer, err := is.storeDriver.Writer(blobUploadPath, true)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			return -1, zerr.ErrUploadNotFound
		}

		return -1, err
	}

	defer writer.Close()

	return writer.Size(), nil
}

// PutBlobChunkStreamed appends another chunk of data to the specified blob. It returns
// the number of actual bytes to the blob.
func (is *ImageStore) PutBlobChunkStreamed(repo, uuid string, body io.Reader) (int64, error) {
	if err := is.InitRepo(repo); err != nil {
		return -1, err
	}

	blobUploadPath := is.BlobUploadPath(repo, uuid)

	file, err := is.storeDriver.Writer(blobUploadPath, true)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			return -1, zerr.ErrUploadNotFound
		}

		is.log.Error().Err(err).Msg("failed to continue multipart upload")

		return -1, err
	}

	var n int64 //nolint: varnamelen

	defer func() {
		err = file.Close()
	}()

	n, err = io.Copy(file, body)

	return n, err
}

// PutBlobChunk writes another chunk of data to the specified blob. It returns
// the number of actual bytes to the blob.
func (is *ImageStore) PutBlobChunk(repo, uuid string, from, to int64,
	body io.Reader,
) (int64, error) {
	if err := is.InitRepo(repo); err != nil {
		return -1, err
	}

	blobUploadPath := is.BlobUploadPath(repo, uuid)

	file, err := is.storeDriver.Writer(blobUploadPath, true)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			return -1, zerr.ErrUploadNotFound
		}

		is.log.Error().Err(err).Msg("failed to continue multipart upload")

		return -1, err
	}

	defer file.Close()

	if from != file.Size() {
		is.log.Error().Int64("expected", from).Int64("actual", file.Size()).
			Msg("invalid range start for blob upload")

		return -1, zerr.ErrBadUploadRange
	}

	n, err := io.Copy(file, body)

	return n, err
}

// BlobUploadInfo returns the current blob size in bytes.
func (is *ImageStore) BlobUploadInfo(repo, uuid string) (int64, error) {
	blobUploadPath := is.BlobUploadPath(repo, uuid)

	writer, err := is.storeDriver.Writer(blobUploadPath, true)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			return -1, zerr.ErrUploadNotFound
		}

		return -1, err
	}

	defer writer.Close()

	return writer.Size(), nil
}

// FinishBlobUpload finalizes the blob upload and moves blob the repository.
func (is *ImageStore) FinishBlobUpload(repo, uuid string, body io.Reader, dstDigest godigest.Digest) error {
	if err := dstDigest.Validate(); err != nil {
		return err
	}

	src := is.BlobUploadPath(repo, uuid)

	// complete multiUploadPart
	fileWriter, err := is.storeDriver.Writer(src, true)
	if err != nil {
		is.log.Error().Err(err).Str("blob", src).Msg("failed to open blob")

		return zerr.ErrUploadNotFound
	}

	if err := fileWriter.Commit(); err != nil {
		is.log.Error().Err(err).Msg("failed to commit file")

		return err
	}

	if err := fileWriter.Close(); err != nil {
		is.log.Error().Err(err).Msg("failed to close file")

		return err
	}

	srcDigest, err := getBlobDigest(is, src)
	if err != nil {
		is.log.Error().Err(err).Str("blob", src).Msg("failed to open blob")

		return err
	}

	if srcDigest != dstDigest {
		is.log.Error().Str("srcDigest", srcDigest.String()).
			Str("dstDigest", dstDigest.String()).Msg("actual digest not equal to expected digest")

		return zerr.ErrBadBlobDigest
	}

	dir := path.Join(is.rootDir, repo, "blobs", dstDigest.Algorithm().String())

	err = is.storeDriver.EnsureDir(dir)
	if err != nil {
		is.log.Error().Err(err).Str("dir", dir).Msg("failed to create dir")

		return err
	}

	dst := is.BlobPath(repo, dstDigest)

	var lockLatency time.Time

	is.Lock(&lockLatency)
	defer is.Unlock(&lockLatency)

	if is.dedupe && fmt.Sprintf("%v", is.cache) != fmt.Sprintf("%v", nil) {
		err = is.DedupeBlob(src, dstDigest, repo, dst)
		if err := inject.Error(err); err != nil {
			is.log.Error().Err(err).Str("src", src).Str("dstDigest", dstDigest.String()).
				Str("dst", dst).Msg("failed to dedupe blob")

			return err
		}
	} else {
		if err := is.storeDriver.Move(src, dst); err != nil {
			is.log.Error().Err(err).Str("src", src).Str("dstDigest", dstDigest.String()).
				Str("dst", dst).Msg("failed to finish blob")

			return err
		}
	}

	return nil
}

// FullBlobUpload handles a full blob upload, and no partial session is created.
func (is *ImageStore) FullBlobUpload(repo string, body io.Reader, dstDigest godigest.Digest) (string, int64, error) {
	if err := dstDigest.Validate(); err != nil {
		return "", -1, err
	}

	if err := is.InitRepo(repo); err != nil {
		return "", -1, err
	}

	u, err := guuid.NewV4()
	if err != nil {
		return "", -1, err
	}

	uuid := u.String()
	src := is.BlobUploadPath(repo, uuid)
	digester := sha256.New()
	buf := new(bytes.Buffer)

	_, err = buf.ReadFrom(body)
	if err != nil {
		is.log.Error().Err(err).Msg("failed to read blob")

		return "", -1, err
	}

	nbytes, err := is.storeDriver.WriteFile(src, buf.Bytes())
	if err != nil {
		is.log.Error().Err(err).Msg("failed to write blob")

		return "", -1, err
	}

	_, err = digester.Write(buf.Bytes())
	if err != nil {
		is.log.Error().Err(err).Str("component", "digester").Msg("failed to write")

		return "", -1, err
	}

	srcDigest := godigest.NewDigestFromEncoded(godigest.SHA256, fmt.Sprintf("%x", digester.Sum(nil)))
	if srcDigest != dstDigest {
		is.log.Error().Str("srcDigest", srcDigest.String()).
			Str("dstDigest", dstDigest.String()).Msg("actual digest not equal to expected digest")

		return "", -1, zerr.ErrBadBlobDigest
	}

	dir := path.Join(is.rootDir, repo, "blobs", dstDigest.Algorithm().String())
	_ = is.storeDriver.EnsureDir(dir)

	var lockLatency time.Time

	is.Lock(&lockLatency)
	defer is.Unlock(&lockLatency)

	dst := is.BlobPath(repo, dstDigest)

	if is.dedupe && fmt.Sprintf("%v", is.cache) != fmt.Sprintf("%v", nil) {
		if err := is.DedupeBlob(src, dstDigest, repo, dst); err != nil {
			is.log.Error().Err(err).Str("src", src).Str("dstDigest", dstDigest.String()).
				Str("dst", dst).Msg("failed to dedupe blob")

			return "", -1, err
		}
	} else {
		if err := is.storeDriver.Move(src, dst); err != nil {
			is.log.Error().Err(err).Str("src", src).Str("dstDigest", dstDigest.String()).
				Str("dst", dst).Msg("failed to finish blob")

			return "", -1, err
		}
	}

	return uuid, int64(nbytes), nil
}

func (is *ImageStore) DedupeBlob(src string, dstDigest godigest.Digest, dstRepo string, dst string) error {
retry:
	is.log.Debug().Str("src", src).Str("dstDigest", dstDigest.String()).Str("dst", dst).Msg("dedupe begin")

	dstRecord, err := is.cache.GetBlob(dstDigest)
	if err := inject.Error(err); err != nil && !errors.Is(err, zerr.ErrCacheMiss) {
		is.log.Error().Err(err).Str("blobPath", dst).Str("component", "dedupe").Msg("failed to lookup blob record")

		return err
	}

	if dstRecord == "" {
		// cache record doesn't exist, so first disk and cache entry for this digest
		if err := is.cache.PutBlob(dstDigest, dst); err != nil {
			is.log.Error().Err(err).Str("blobPath", dst).Str("component", "dedupe").
				Msg("failed to insert blob record")

			return err
		}

		// move the blob from uploads to final dest
		if err := is.storeDriver.Move(src, dst); err != nil {
			is.log.Error().Err(err).Str("src", src).Str("dst", dst).Str("component", "dedupe").
				Msg("failed to rename blob")

			return err
		}

		is.log.Debug().Str("src", src).Str("dst", dst).Str("component", "dedupe").Msg("rename")
	} else {
		// cache record exists, but due to GC and upgrades from older versions,
		// disk content and cache records may go out of sync
		if is.cache.UsesRelativePaths() {
			dstRecord = path.Join(is.rootDir, dstRecord)
		}

		blobInfo, err := is.storeDriver.Stat(dstRecord)
		if err != nil {
			is.log.Error().Err(err).Str("blobPath", dstRecord).Str("component", "dedupe").Msg("failed to stat")
			// the actual blob on disk may have been removed by GC, so sync the cache
			err := is.cache.DeleteBlob(dstDigest, dstRecord)
			if err = inject.Error(err); err != nil {
				//nolint:lll
				is.log.Error().Err(err).Str("dstDigest", dstDigest.String()).Str("dst", dst).
					Str("component", "dedupe").Msg("failed to delete blob record")

				return err
			}

			goto retry
		}

		// prevent overwrite original blob
		if !is.storeDriver.SameFile(dst, dstRecord) {
			if err := is.storeDriver.Link(dstRecord, dst); err != nil {
				is.log.Error().Err(err).Str("blobPath", dstRecord).Str("component", "dedupe").
					Msg("failed to link blobs")

				return err
			}

			if err := is.cache.PutBlob(dstDigest, dst); err != nil {
				is.log.Error().Err(err).Str("blobPath", dst).Str("component", "dedupe").
					Msg("failed to insert blob record")

				return err
			}
		} else {
			// if it's same file then it was already uploaded, check if blob is corrupted
			if desc, err := common.GetBlobDescriptorFromRepo(is, dstRepo, dstDigest, is.log); err == nil {
				// blob corrupted, replace content
				if desc.Size != blobInfo.Size() {
					if err := is.storeDriver.Move(src, dst); err != nil {
						is.log.Error().Err(err).Str("src", src).Str("dst", dst).Str("component", "dedupe").
							Msg("failed to rename blob")

						return err
					}

					is.log.Debug().Str("src", src).Str("component", "dedupe").Msg("remove")

					return nil
				}
			}
		}

		// remove temp blobupload
		if err := is.storeDriver.Delete(src); err != nil {
			is.log.Error().Err(err).Str("src", src).Str("component", "dedupe").
				Msg("failed to remove blob")

			return err
		}

		is.log.Debug().Str("src", src).Str("component", "dedupe").Msg("remove")
	}

	return nil
}

// DeleteBlobUpload deletes an existing blob upload that is currently in progress.
func (is *ImageStore) DeleteBlobUpload(repo, uuid string) error {
	blobUploadPath := is.BlobUploadPath(repo, uuid)

	writer, err := is.storeDriver.Writer(blobUploadPath, true)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			return zerr.ErrUploadNotFound
		}

		return err
	}

	defer writer.Close()

	if err := writer.Cancel(); err != nil {
		is.log.Error().Err(err).Str("blobUploadPath", blobUploadPath).Msg("failed to delete blob upload")

		return err
	}

	return nil
}

// BlobPath returns the repository path of a blob.
func (is *ImageStore) BlobPath(repo string, digest godigest.Digest) string {
	return path.Join(is.rootDir, repo, "blobs", digest.Algorithm().String(), digest.Encoded())
}

/*
	CheckBlob verifies a blob and returns true if the blob is correct

If the blob is not found but it's found in cache then it will be copied over.
*/
func (is *ImageStore) CheckBlob(repo string, digest godigest.Digest) (bool, int64, error) {
	var lockLatency time.Time

	if err := digest.Validate(); err != nil {
		return false, -1, err
	}

	blobPath := is.BlobPath(repo, digest)

	if is.dedupe && fmt.Sprintf("%v", is.cache) != fmt.Sprintf("%v", nil) {
		is.Lock(&lockLatency)
		defer is.Unlock(&lockLatency)
	} else {
		is.RLock(&lockLatency)
		defer is.RUnlock(&lockLatency)
	}

	binfo, err := is.storeDriver.Stat(blobPath)
	if err == nil && binfo.Size() > 0 {
		// try to find blob size in blob descriptors, if blob can not be found
		desc, err := common.GetBlobDescriptorFromRepo(is, repo, digest, is.log)
		if err != nil || desc.Size == binfo.Size() {
			// blob not found in descriptors, can not compare, just return
			is.log.Debug().Str("blob path", blobPath).Msg("blob path found")

			return true, binfo.Size(), nil //nolint: nilerr
		}

		if desc.Size != binfo.Size() {
			is.log.Debug().Str("blob path", blobPath).Msg("blob path found, but it's corrupted")

			return false, -1, zerr.ErrBlobNotFound
		}
	}
	// otherwise is a 'deduped' blob (empty file)

	// Check blobs in cache
	dstRecord, err := is.checkCacheBlob(digest)
	if err != nil {
		is.log.Warn().Err(err).Str("digest", digest.String()).Msg("not found in cache")

		return false, -1, zerr.ErrBlobNotFound
	}

	blobSize, err := is.copyBlob(repo, blobPath, dstRecord)
	if err != nil {
		return false, -1, zerr.ErrBlobNotFound
	}

	// put deduped blob in cache
	if err := is.cache.PutBlob(digest, blobPath); err != nil {
		is.log.Error().Err(err).Str("blobPath", blobPath).Str("component", "dedupe").Msg("failed to insert blob record")

		return false, -1, err
	}

	return true, blobSize, nil
}

// StatBlob verifies if a blob is present inside a repository. The caller function MUST lock from outside.
func (is *ImageStore) StatBlob(repo string, digest godigest.Digest) (bool, int64, time.Time, error) {
	if err := digest.Validate(); err != nil {
		return false, -1, time.Time{}, err
	}

	blobPath := is.BlobPath(repo, digest)

	binfo, err := is.storeDriver.Stat(blobPath)
	if err == nil && binfo.Size() > 0 {
		is.log.Debug().Str("blob path", blobPath).Msg("blob path found")

		return true, binfo.Size(), binfo.ModTime(), nil
	}

	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

		return false, -1, time.Time{}, zerr.ErrBlobNotFound
	}

	// then it's a 'deduped' blob

	// Check blobs in cache
	dstRecord, err := is.checkCacheBlob(digest)
	if err != nil {
		is.log.Warn().Err(err).Str("digest", digest.String()).Msg("not found in cache")

		return false, -1, time.Time{}, zerr.ErrBlobNotFound
	}

	binfo, err = is.storeDriver.Stat(dstRecord)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

		return false, -1, time.Time{}, zerr.ErrBlobNotFound
	}

	return true, binfo.Size(), binfo.ModTime(), nil
}

func (is *ImageStore) checkCacheBlob(digest godigest.Digest) (string, error) {
	if err := digest.Validate(); err != nil {
		return "", err
	}

	if fmt.Sprintf("%v", is.cache) == fmt.Sprintf("%v", nil) {
		return "", zerr.ErrBlobNotFound
	}

	dstRecord, err := is.cache.GetBlob(digest)
	if err != nil {
		return "", err
	}

	if is.cache.UsesRelativePaths() {
		dstRecord = path.Join(is.rootDir, dstRecord)
	}

	if _, err := is.storeDriver.Stat(dstRecord); err != nil {
		is.log.Error().Err(err).Str("blob", dstRecord).Msg("failed to stat blob")

		// the actual blob on disk may have been removed by GC, so sync the cache
		if err := is.cache.DeleteBlob(digest, dstRecord); err != nil {
			is.log.Error().Err(err).Str("digest", digest.String()).Str("blobPath", dstRecord).
				Msg("failed to remove blob path from cache")

			return "", err
		}

		return "", zerr.ErrBlobNotFound
	}

	is.log.Debug().Str("digest", digest.String()).Str("dstRecord", dstRecord).Str("component", "cache").
		Msg("found dedupe record")

	return dstRecord, nil
}

func (is *ImageStore) copyBlob(repo string, blobPath, dstRecord string) (int64, error) {
	if err := is.initRepo(repo); err != nil {
		is.log.Error().Err(err).Str("repository", repo).Msg("failed to initialize an empty repo")

		return -1, err
	}

	_ = is.storeDriver.EnsureDir(filepath.Dir(blobPath))

	if err := is.storeDriver.Link(dstRecord, blobPath); err != nil {
		is.log.Error().Err(err).Str("blobPath", blobPath).Str("link", dstRecord).Str("component", "dedupe").
			Msg("failed to hard link")

		return -1, zerr.ErrBlobNotFound
	}

	// return original blob with content instead of the deduped one (blobPath)
	binfo, err := is.storeDriver.Stat(dstRecord)
	if err == nil {
		return binfo.Size(), nil
	}

	return -1, zerr.ErrBlobNotFound
}

// GetBlobPartial returns a partial stream to read the blob.
// blob selector instead of directly downloading the blob.
func (is *ImageStore) GetBlobPartial(repo string, digest godigest.Digest, mediaType string, from, to int64,
) (io.ReadCloser, int64, int64, error) {
	var lockLatency time.Time

	if err := digest.Validate(); err != nil {
		return nil, -1, -1, err
	}

	blobPath := is.BlobPath(repo, digest)

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	binfo, err := is.storeDriver.Stat(blobPath)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

		return nil, -1, -1, zerr.ErrBlobNotFound
	}

	// is a deduped blob
	if binfo.Size() == 0 {
		// Check blobs in cache
		blobPath, err = is.checkCacheBlob(digest)
		if err != nil {
			is.log.Debug().Err(err).Str("digest", digest.String()).Msg("not found in cache")

			return nil, -1, -1, zerr.ErrBlobNotFound
		}

		binfo, err = is.storeDriver.Stat(blobPath)
		if err != nil {
			is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

			return nil, -1, -1, zerr.ErrBlobNotFound
		}
	}

	end := to

	if to < 0 || to >= binfo.Size() {
		end = binfo.Size() - 1
	}

	blobHandle, err := is.storeDriver.Reader(blobPath, from)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to open blob")

		return nil, -1, -1, err
	}

	blobReadCloser, err := newBlobStream(blobHandle, from, end)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to open blob stream")

		return nil, -1, -1, err
	}

	// The caller function is responsible for calling Close()
	return blobReadCloser, end - from + 1, binfo.Size(), nil
}

// GetBlob returns a stream to read the blob.
// blob selector instead of directly downloading the blob.
func (is *ImageStore) GetBlob(repo string, digest godigest.Digest, mediaType string) (io.ReadCloser, int64, error) {
	var lockLatency time.Time

	if err := digest.Validate(); err != nil {
		return nil, -1, err
	}

	blobPath := is.BlobPath(repo, digest)

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	binfo, err := is.storeDriver.Stat(blobPath)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

		return nil, -1, zerr.ErrBlobNotFound
	}

	blobReadCloser, err := is.storeDriver.Reader(blobPath, 0)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to open blob")

		return nil, -1, err
	}

	// is a 'deduped' blob?
	if binfo.Size() == 0 {
		// Check blobs in cache
		dstRecord, err := is.checkCacheBlob(digest)
		if err != nil {
			is.log.Debug().Err(err).Str("digest", digest.String()).Msg("not found in cache")

			return nil, -1, zerr.ErrBlobNotFound
		}

		binfo, err := is.storeDriver.Stat(dstRecord)
		if err != nil {
			is.log.Error().Err(err).Str("blob", dstRecord).Msg("failed to stat blob")

			return nil, -1, zerr.ErrBlobNotFound
		}

		blobReadCloser, err := is.storeDriver.Reader(dstRecord, 0)
		if err != nil {
			is.log.Error().Err(err).Str("blob", dstRecord).Msg("failed to open blob")

			return nil, -1, err
		}

		return blobReadCloser, binfo.Size(), nil
	}

	// The caller function is responsible for calling Close()
	return blobReadCloser, binfo.Size(), nil
}

// GetBlobContent returns blob contents, the caller function MUST lock from outside.
func (is *ImageStore) GetBlobContent(repo string, digest godigest.Digest) ([]byte, error) {
	if err := digest.Validate(); err != nil {
		return []byte{}, err
	}

	blobPath := is.BlobPath(repo, digest)

	binfo, err := is.storeDriver.Stat(blobPath)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

		return []byte{}, zerr.ErrBlobNotFound
	}

	blobBuf, err := is.storeDriver.ReadFile(blobPath)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to open blob")

		return nil, err
	}

	// is a 'deduped' blob?
	if binfo.Size() == 0 {
		// Check blobs in cache
		dstRecord, err := is.checkCacheBlob(digest)
		if err != nil {
			is.log.Debug().Err(err).Str("digest", digest.String()).Msg("not found in cache")

			return nil, zerr.ErrBlobNotFound
		}

		blobBuf, err := is.storeDriver.ReadFile(dstRecord)
		if err != nil {
			is.log.Error().Err(err).Str("blob", dstRecord).Msg("failed to open blob")

			return nil, err
		}

		return blobBuf, nil
	}

	return blobBuf, nil
}

func (is *ImageStore) GetReferrers(repo string, gdigest godigest.Digest, artifactTypes []string,
) (ispec.Index, error) {
	var lockLatency time.Time

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	return common.GetReferrers(is, repo, gdigest, artifactTypes, is.log)
}

func (is *ImageStore) GetOrasReferrers(repo string, gdigest godigest.Digest, artifactType string,
) ([]artifactspec.Descriptor, error) {
	var lockLatency time.Time

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	return common.GetOrasReferrers(is, repo, gdigest, artifactType, is.log)
}

// GetIndexContent returns index.json contents, the caller function MUST lock from outside.
func (is *ImageStore) GetIndexContent(repo string) ([]byte, error) {
	dir := path.Join(is.rootDir, repo)

	buf, err := is.storeDriver.ReadFile(path.Join(dir, "index.json"))
	if err != nil {
		if errors.Is(err, driver.PathNotFoundError{}) {
			is.log.Error().Err(err).Str("dir", dir).Msg("failed to read index.json")

			return []byte{}, zerr.ErrRepoNotFound
		}

		is.log.Error().Err(err).Str("dir", dir).Msg("failed to read index.json")

		return []byte{}, err
	}

	return buf, nil
}

func (is *ImageStore) StatIndex(repo string) (bool, int64, time.Time, error) {
	repoIndexPath := path.Join(is.rootDir, repo, "index.json")

	fileInfo, err := is.storeDriver.Stat(repoIndexPath)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			is.log.Error().Err(err).Str("indexFile", repoIndexPath).Msg("failed to stat index.json")

			return false, 0, time.Time{}, zerr.ErrRepoNotFound
		}

		is.log.Error().Err(err).Str("indexFile", repoIndexPath).Msg("failed to read index.json")

		return false, 0, time.Time{}, err
	}

	return true, fileInfo.Size(), fileInfo.ModTime(), nil
}

func (is *ImageStore) PutIndexContent(repo string, index ispec.Index) error {
	dir := path.Join(is.rootDir, repo)

	indexPath := path.Join(dir, "index.json")

	buf, err := json.Marshal(index)
	if err != nil {
		is.log.Error().Err(err).Str("file", indexPath).Msg("failed to marshal JSON")

		return err
	}

	if _, err = is.storeDriver.WriteFile(indexPath, buf); err != nil {
		is.log.Error().Err(err).Str("file", indexPath).Msg("failed to write")

		return err
	}

	return nil
}

// DeleteBlob removes the blob from the repository.
func (is *ImageStore) DeleteBlob(repo string, digest godigest.Digest) error {
	var lockLatency time.Time

	if err := digest.Validate(); err != nil {
		return err
	}

	is.Lock(&lockLatency)
	defer is.Unlock(&lockLatency)

	return is.deleteBlob(repo, digest)
}

/*
CleanupRepo removes blobs from the repository and removes repo if flag is true and all blobs were removed
the caller function MUST lock from outside.
*/
func (is *ImageStore) CleanupRepo(repo string, blobs []godigest.Digest, removeRepo bool) (int, error) {
	count := 0

	for _, digest := range blobs {
		is.log.Debug().Str("repository", repo).
			Str("digest", digest.String()).Msg("perform GC on blob")

		if err := is.deleteBlob(repo, digest); err != nil {
			if errors.Is(err, zerr.ErrBlobReferenced) {
				if err := is.deleteImageManifest(repo, digest.String(), true); err != nil {
					if errors.Is(err, zerr.ErrManifestConflict) || errors.Is(err, zerr.ErrManifestReferenced) {
						continue
					}

					is.log.Error().Err(err).Str("repository", repo).Str("digest", digest.String()).Msg("failed to delete manifest")

					return count, err
				}

				count++
			} else {
				is.log.Error().Err(err).Str("repository", repo).Str("digest", digest.String()).Msg("failed to delete blob")

				return count, err
			}
		} else {
			count++
		}
	}

	blobUploads, err := is.storeDriver.List(path.Join(is.RootDir(), repo, storageConstants.BlobUploadDir))
	if err != nil {
		is.log.Debug().Str("repository", repo).Msg("failed to list .uploads/ dir")
	}

	// if removeRepo flag is true and we cleanup all blobs and there are no blobs currently being uploaded.
	if removeRepo && count == len(blobs) && count > 0 && len(blobUploads) == 0 {
		is.log.Info().Str("repository", repo).Msg("removed all blobs, removing repo")

		if err := is.storeDriver.Delete(path.Join(is.rootDir, repo)); err != nil {
			is.log.Error().Err(err).Str("repository", repo).Msg("failed to remove repo")

			return count, err
		}
	}

	return count, nil
}

func (is *ImageStore) deleteBlob(repo string, digest godigest.Digest) error {
	blobPath := is.BlobPath(repo, digest)

	_, err := is.storeDriver.Stat(blobPath)
	if err != nil {
		is.log.Error().Err(err).Str("blob", blobPath).Msg("failed to stat blob")

		return zerr.ErrBlobNotFound
	}

	// first check if this blob is not currently in use
	if ok, _ := common.IsBlobReferenced(is, repo, digest, is.log); ok {
		return zerr.ErrBlobReferenced
	}

	if fmt.Sprintf("%v", is.cache) != fmt.Sprintf("%v", nil) {
		dstRecord, err := is.cache.GetBlob(digest)
		if err != nil && !errors.Is(err, zerr.ErrCacheMiss) {
			is.log.Error().Err(err).Str("blobPath", dstRecord).Str("component", "dedupe").
				Msg("failed to lookup blob record")

			return err
		}

		// remove cache entry and move blob contents to the next candidate if there is any
		if ok := is.cache.HasBlob(digest, blobPath); ok {
			if err := is.cache.DeleteBlob(digest, blobPath); err != nil {
				is.log.Error().Err(err).Str("digest", digest.String()).Str("blobPath", blobPath).
					Msg("failed to remove blob path from cache")

				return err
			}
		}

		// if the deleted blob is one with content
		if dstRecord == blobPath {
			// get next candidate
			dstRecord, err := is.cache.GetBlob(digest)
			if err != nil && !errors.Is(err, zerr.ErrCacheMiss) {
				is.log.Error().Err(err).Str("blobPath", dstRecord).Str("component", "dedupe").
					Msg("failed to lookup blob record")

				return err
			}

			// if we have a new candidate move the blob content to it
			if dstRecord != "" {
				/* check to see if we need to move the content from original blob to duplicate one
				(in case of filesystem, this should not be needed */
				binfo, err := is.storeDriver.Stat(dstRecord)
				if err != nil {
					is.log.Error().Err(err).Str("path", blobPath).Str("component", "dedupe").
						Msg("failed to stat blob")

					return err
				}

				if binfo.Size() == 0 {
					if err := is.storeDriver.Move(blobPath, dstRecord); err != nil {
						is.log.Error().Err(err).Str("blobPath", blobPath).Str("component", "dedupe").
							Msg("failed to remove blob path")

						return err
					}
				}

				return nil
			}
		}
	}

	if err := is.storeDriver.Delete(blobPath); err != nil {
		is.log.Error().Err(err).Str("blobPath", blobPath).Msg("failed to remove blob path")

		return err
	}

	return nil
}

func getBlobDigest(imgStore *ImageStore, path string) (godigest.Digest, error) {
	fileReader, err := imgStore.storeDriver.Reader(path, 0)
	if err != nil {
		return "", zerr.ErrUploadNotFound
	}

	defer fileReader.Close()

	digest, err := godigest.FromReader(fileReader)
	if err != nil {
		return "", zerr.ErrBadBlobDigest
	}

	return digest, nil
}

func (is *ImageStore) GetAllBlobs(repo string) ([]string, error) {
	dir := path.Join(is.rootDir, repo, "blobs", "sha256")

	files, err := is.storeDriver.List(dir)
	if err != nil {
		if errors.As(err, &driver.PathNotFoundError{}) {
			is.log.Debug().Msg("empty rootDir")

			return []string{}, nil
		}

		return []string{}, err
	}

	ret := []string{}

	for _, file := range files {
		ret = append(ret, filepath.Base(file))
	}

	return ret, nil
}

func (is *ImageStore) GetNextDigestWithBlobPaths(repos []string, lastDigests []godigest.Digest,
) (godigest.Digest, []string, error) {
	var lockLatency time.Time

	dir := is.rootDir

	is.RLock(&lockLatency)
	defer is.RUnlock(&lockLatency)

	var duplicateBlobs []string

	var digest godigest.Digest

	err := is.storeDriver.Walk(dir, func(fileInfo driver.FileInfo) error {
		// skip blobs under .sync and .uploads
		if strings.HasSuffix(fileInfo.Path(), syncConstants.SyncBlobUploadDir) ||
			strings.HasSuffix(fileInfo.Path(), storageConstants.BlobUploadDir) {
			return driver.ErrSkipDir
		}

		if fileInfo.IsDir() {
			// skip repositories not found in repos
			repo := path.Base(fileInfo.Path())

			if !zcommon.Contains(repos, repo) && repo != "blobs" && repo != "sha256" {
				return driver.ErrSkipDir
			}
		}

		blobDigest := godigest.NewDigestFromEncoded("sha256", path.Base(fileInfo.Path()))
		if err := blobDigest.Validate(); err != nil { //nolint: nilerr
			return nil //nolint: nilerr // ignore files which are not blobs
		}

		if digest == "" && !zcommon.Contains(lastDigests, blobDigest) {
			digest = blobDigest
		}

		if blobDigest == digest {
			duplicateBlobs = append(duplicateBlobs, fileInfo.Path())
		}

		return nil
	})

	// if the root directory is not yet created
	var perr driver.PathNotFoundError

	if errors.As(err, &perr) {
		return digest, duplicateBlobs, nil
	}

	return digest, duplicateBlobs, err
}

func (is *ImageStore) getOriginalBlobFromDisk(duplicateBlobs []string) (string, error) {
	for _, blobPath := range duplicateBlobs {
		binfo, err := is.storeDriver.Stat(blobPath)
		if err != nil {
			is.log.Error().Err(err).Str("path", blobPath).Str("component", "storage").Msg("failed to stat blob")

			return "", zerr.ErrBlobNotFound
		}

		if binfo.Size() > 0 {
			return blobPath, nil
		}
	}

	return "", zerr.ErrBlobNotFound
}

func (is *ImageStore) getOriginalBlob(digest godigest.Digest, duplicateBlobs []string) (string, error) {
	var originalBlob string

	var err error

	originalBlob, err = is.checkCacheBlob(digest)
	if err != nil && !errors.Is(err, zerr.ErrBlobNotFound) && !errors.Is(err, zerr.ErrCacheMiss) {
		is.log.Error().Err(err).Str("component", "dedupe").Msg("failed to find blob in cache")

		return originalBlob, err
	}

	// if we still don't have, search it
	if originalBlob == "" {
		is.log.Warn().Str("component", "dedupe").Msg("failed to find blob in cache, searching it in storage...")
		// a rebuild dedupe was attempted in the past
		// get original blob, should be found otherwise exit with error

		originalBlob, err = is.getOriginalBlobFromDisk(duplicateBlobs)
		if err != nil {
			return originalBlob, err
		}
	}

	is.log.Info().Str("originalBlob", originalBlob).Str("component", "dedupe").Msg("found original blob")

	return originalBlob, nil
}

func (is *ImageStore) dedupeBlobs(ctx context.Context, digest godigest.Digest, duplicateBlobs []string) error {
	if fmt.Sprintf("%v", is.cache) == fmt.Sprintf("%v", nil) {
		is.log.Error().Err(zerr.ErrDedupeRebuild).Msg("failed to dedupe blobs, no cache driver found")

		return zerr.ErrDedupeRebuild
	}

	is.log.Info().Str("digest", digest.String()).Str("component", "dedupe").Msg("deduping blobs for digest")

	var originalBlob string

	// rebuild from dedupe false to true
	for _, blobPath := range duplicateBlobs {
		if zcommon.IsContextDone(ctx) {
			return ctx.Err()
		}

		binfo, err := is.storeDriver.Stat(blobPath)
		if err != nil {
			is.log.Error().Err(err).Str("path", blobPath).Str("component", "dedupe").Msg("failed to stat blob")

			return err
		}

		if binfo.Size() == 0 {
			is.log.Warn().Str("component", "dedupe").Msg("found file without content, trying to find the original blob")
			// a rebuild dedupe was attempted in the past
			// get original blob, should be found otherwise exit with error
			if originalBlob == "" {
				originalBlob, err = is.getOriginalBlob(digest, duplicateBlobs)
				if err != nil {
					is.log.Error().Err(err).Str("component", "dedupe").Msg("failed to find original blob")

					return zerr.ErrDedupeRebuild
				}

				// cache original blob
				if ok := is.cache.HasBlob(digest, originalBlob); !ok {
					if err := is.cache.PutBlob(digest, originalBlob); err != nil {
						return err
					}
				}
			}

			// cache dedupe blob
			if ok := is.cache.HasBlob(digest, blobPath); !ok {
				if err := is.cache.PutBlob(digest, blobPath); err != nil {
					return err
				}
			}
		} else {
			// if we have an original blob cached then we can safely dedupe the rest of them
			if originalBlob != "" {
				if err := is.storeDriver.Link(originalBlob, blobPath); err != nil {
					is.log.Error().Err(err).Str("path", blobPath).Str("component", "dedupe").Msg("failed to dedupe blob")

					return err
				}
			}

			// cache it
			if ok := is.cache.HasBlob(digest, blobPath); !ok {
				if err := is.cache.PutBlob(digest, blobPath); err != nil {
					return err
				}
			}

			// mark blob as preserved
			originalBlob = blobPath
		}
	}

	is.log.Info().Str("digest", digest.String()).Str("component", "dedupe").
		Msg("deduping blobs for digest finished successfully")

	return nil
}

func (is *ImageStore) restoreDedupedBlobs(ctx context.Context, digest godigest.Digest, duplicateBlobs []string) error {
	is.log.Info().Str("digest", digest.String()).Str("component", "dedupe").Msg("restoring deduped blobs for digest")

	// first we need to find the original blob, either in cache or by checking each blob size
	originalBlob, err := is.getOriginalBlob(digest, duplicateBlobs)
	if err != nil {
		is.log.Error().Err(err).Str("component", "dedupe").Msg("failed to find original blob")

		return zerr.ErrDedupeRebuild
	}

	for _, blobPath := range duplicateBlobs {
		if zcommon.IsContextDone(ctx) {
			return ctx.Err()
		}

		binfo, err := is.storeDriver.Stat(blobPath)
		if err != nil {
			is.log.Error().Err(err).Str("path", blobPath).Str("component", "dedupe").Msg("failed to stat blob")

			return err
		}

		// if we find a deduped blob, then copy original blob content to deduped one
		if binfo.Size() == 0 {
			// move content from original blob to deduped one
			buf, err := is.storeDriver.ReadFile(originalBlob)
			if err != nil {
				is.log.Error().Err(err).Str("path", originalBlob).Str("component", "dedupe").
					Msg("failed to get original blob content")

				return err
			}

			_, err = is.storeDriver.WriteFile(blobPath, buf)
			if err != nil {
				return err
			}
		}
	}

	is.log.Info().Str("digest", digest.String()).
		Str("component", "dedupe").Msg("restoring deduped blobs for digest finished successfully")

	return nil
}

func (is *ImageStore) RunDedupeForDigest(ctx context.Context, digest godigest.Digest, dedupe bool,
	duplicateBlobs []string,
) error {
	var lockLatency time.Time

	is.Lock(&lockLatency)
	defer is.Unlock(&lockLatency)

	if dedupe {
		return is.dedupeBlobs(ctx, digest, duplicateBlobs)
	}

	return is.restoreDedupedBlobs(ctx, digest, duplicateBlobs)
}

func (is *ImageStore) RunDedupeBlobs(interval time.Duration, sch *scheduler.Scheduler) {
	generator := &common.DedupeTaskGenerator{
		ImgStore: is,
		Dedupe:   is.dedupe,
		Log:      is.log,
	}

	sch.SubmitGenerator(generator, interval, scheduler.MediumPriority)
}

func (is *ImageStore) PopulateStorageMetrics(interval time.Duration, sch *scheduler.Scheduler) {
	generator := &common.StorageMetricsInitGenerator{
		ImgStore: is,
		Metrics:  is.metrics,
		Log:      is.log,
		MaxDelay: 15, //nolint:gomnd
	}

	sch.SubmitGenerator(generator, interval, scheduler.HighPriority)
}

type blobStream struct {
	reader io.Reader
	closer io.Closer
}

func newBlobStream(readCloser io.ReadCloser, from, to int64) (io.ReadCloser, error) {
	if from < 0 || to < from {
		return nil, zerr.ErrBadRange
	}

	return &blobStream{reader: io.LimitReader(readCloser, to-from+1), closer: readCloser}, nil
}

func (bs *blobStream) Read(buf []byte) (int, error) {
	return bs.reader.Read(buf)
}

func (bs *blobStream) Close() error {
	return bs.closer.Close()
}