package digestinfo

import (
	"strings"

	ispec "github.com/opencontainers/image-spec/specs-go/v1"
	"zotregistry.io/zot/pkg/extensions/search/common"
	"zotregistry.io/zot/pkg/log"
	"zotregistry.io/zot/pkg/storage"
)

// DigestInfo implements searching by manifes/config/layer digest.
type DigestInfo struct {
	Log         log.Logger
	LayoutUtils *common.OciLayoutUtils
}

// NewDigestInfo initializes a new DigestInfo object.
func NewDigestInfo(storeController storage.StoreController, log log.Logger) *DigestInfo {
	layoutUtils := common.NewOciLayoutUtils(storeController, log)

	return &DigestInfo{Log: log, LayoutUtils: layoutUtils}
}

// FilterImagesByDigest returns a list of image tags in a repository matching a specific divest.
func (digestinfo DigestInfo) GetImageTagsByDigest(repo, digest string) ([]*string, error) {
	uniqueTags := []*string{}

	manifests, err := digestinfo.LayoutUtils.GetImageManifests(repo)
	if err != nil {
		digestinfo.Log.Error().Err(err).Msg("unable to read image manifests")

		return uniqueTags, err
	}

	for _, manifest := range manifests {
		imageDigest := manifest.Digest

		val, ok := manifest.Annotations[ispec.AnnotationRefName]
		if ok {
			imageBlobManifest, err := digestinfo.LayoutUtils.GetImageBlobManifest(repo, imageDigest)
			if err != nil {
				digestinfo.Log.Error().Err(err).Msg("unable to read image blob manifest")

				return uniqueTags, err
			}

			tags := []*string{}

			// Check the image manigest in index.json matches the search digest
			// This is a blob with mediaType application/vnd.oci.image.manifest.v1+json
			if strings.Contains(manifest.Digest.String(), digest) {
				tags = append(tags, &val)
			}

			// Check the image config matches the search digest
			// This is a blob with mediaType application/vnd.oci.image.config.v1+json
			if strings.Contains(imageBlobManifest.Config.Digest.Algorithm+":"+imageBlobManifest.Config.Digest.Hex, digest) {
				tags = append(tags, &val)
			}

			// Check to see if the individual layers in the oci image manifest match the digest
			// These are blobs with mediaType application/vnd.oci.image.layer.v1.tar+gzip
			for _, layer := range imageBlobManifest.Layers {
				if strings.Contains(layer.Digest.Algorithm+":"+layer.Digest.Hex, digest) {
					tags = append(tags, &val)
				}
			}

			keys := make(map[string]bool)

			for _, entry := range tags {
				if _, value := keys[*entry]; !value {
					uniqueTags = append(uniqueTags, entry)
					keys[*entry] = true
				}
			}
		}
	}

	return uniqueTags, nil
}