package writecache

import (
	"errors"
	"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/cockroachdb/pebble"
)

// ErrNoDefaultBucket is returned by IterateDB when default bucket for objects is missing.
var ErrNoDefaultBucket = errors.New("no default bucket")

// IterateDB iterates over all objects stored in bbolt.DB instance and passes them to f until error return.
// It is assumed that db is an underlying database of some WriteCache instance.
//
// Returns ErrNoDefaultBucket if there is no default bucket in db.
//
// DB must not be nil and should be opened.
func IterateDB(db *pebble.DB, f func(oid.Address) error) error {
	it, err := db.NewIter(nil)
	if err != nil {
		return metaerr.Wrap(err)
	}
	for v := it.First(); v; v = it.Next() {
		var addr oid.Address
		err := addr.DecodeString(string(it.Key()))
		if err != nil {
			_ = it.Close()
			return fmt.Errorf("could not parse object address: %w", err)
		}

		if err := f(addr); err != nil {
			_ = it.Close()
			return err
		}
	}
	return metaerr.Wrap(it.Close())
}