package writecachebadger

import (
	"fmt"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/internal/metaerr"
	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
	"github.com/dgraph-io/badger/v4"
)

// IterateDB iterates over all objects stored in badger.DB instance and passes them to f until error return.
// It is assumed that db is an underlying database of some WriteCache instance.
//
// DB must not be nil and should be opened.
func IterateDB(db *badger.DB, f func(oid.Address) error) error {
	return metaerr.Wrap(db.View(func(tx *badger.Txn) error {
		opts := badger.DefaultIteratorOptions
		opts.PrefetchValues = false
		it := tx.NewIterator(opts)
		for it.Rewind(); it.Valid(); it.Next() {
			var key internalKey
			if got, want := len(it.Item().Key()), len(key); got != want {
				return fmt.Errorf("invalid db key len: got %d, want %d", got, want)
			}
			copy(key[:], it.Item().Key())
			if err := f(key.address()); err != nil {
				return err
			}
		}
		return nil
	}))
}