/*
 * Copyright 2026 Oleg Borodin <onborodin@gmail.com>
 */
package imageoper

import (
	"context"
	"encoding/json"
	"io"
	"net/http"

	"mstore/pkg/descr"

	ocidigest "github.com/opencontainers/go-digest"
	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)

type CheckImagesParams struct {
	Name string
}
type CheckImagesResult struct {
	Repositories []string `json:"repositories"`
}

func (oper *Operator) CheckImages(ctx context.Context, params *CheckImagesParams) (*CheckImagesResult, int, error) {
	var err error
	res := &CheckImagesResult{
		Repositories: make([]string, 0),
	}

	var manDescrs []descr.Manifest
	if params.Name == "" {
		manDescrs, err = oper.mdb.ListAllManifests(ctx)
		if err != nil {
			return res, http.StatusInternalServerError, err
		}
	} else {
		manDescrs, err = oper.mdb.ListManifestsByName(ctx, params.Name)
		if err != nil {
			return res, http.StatusInternalServerError, err
		}
	}
	for _, manDescr := range manDescrs {
		incorrectImage, err := oper.checkImage(ctx, manDescr)
		if err != nil {
			return res, http.StatusInternalServerError, err
		}
		if incorrectImage {
			repo := manDescr.Name + ":" + manDescr.Reference
			res.Repositories = append(res.Repositories, repo)
		}
	}
	return res, http.StatusOK, err
}

func (oper *Operator) checkImage(ctx context.Context, manDescr descr.Manifest) (bool, error) {

	resName := manDescr.Name
	oper.iLock.WaitAndLock(resName)
	defer oper.iLock.Done(resName)

	var err error
	incorrectImage := false
	oper.logg.Debugf("Check image %s:%s", manDescr.Name, manDescr.Reference)
	man := &ocispec.Manifest{}
	err = json.Unmarshal([]byte(manDescr.Payload), man)
	if err != nil {
		return incorrectImage, err
	}
	blobs := make([]ocispec.Descriptor, 0)
	blobs = append(blobs, man.Config)
	blobs = append(blobs, man.Layers...)
	for _, blob := range blobs {
		oper.logg.Debugf("Check blob %s", blob.Digest.String())
		blobExists, blobDescr, err := oper.mdb.GetBlobByNameRefDigest(ctx, manDescr.Name, manDescr.Reference, blob.Digest.String())
		if err != nil {
			return incorrectImage, err
		}
		blobExists, blobSize, err := oper.store.BlobExists(blobDescr.Name, blobDescr.Digest)
		if err != nil {
			return incorrectImage, err
		}
		if !blobExists || blobSize != blobDescr.Size {
			incorrectImage = true
		} else {
			digstr := blobDescr.Digest
			digobj, err := ocidigest.Parse(digstr)
			if err != nil {
				oper.logg.Debugf("Incorrect blob name: %s", digstr)
				incorrectImage = true
			}
			_, blobReadCloser, err := oper.store.BlobReader(blobDescr.Name, blobDescr.Digest)
			if err != nil {
				return incorrectImage, err
			}
			defer blobReadCloser.Close()
			verifier := digobj.Verifier()
			_, err = io.Copy(verifier, blobReadCloser)
			if !verifier.Verified() {
				oper.logg.Debugf("Incorrect blob digest: %s", digstr)
				incorrectImage = true
			}
		}
	}
	if incorrectImage {
		repo := manDescr.Name + ":" + manDescr.Reference
		oper.logg.Debugf("Delete incomplete image: %s", repo)
		err = oper.deleteManifestObjects(ctx, manDescr.Name, manDescr.Reference)
		if err != nil {
			return incorrectImage, err
		}
	}
	return incorrectImage, err
}