package db

import (
	"errors"
	"os"

	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db/kv"
)

// ErrNotFound can be used to determine if an error from a method in the database package
// represents a "not found" error. These often require different handling than a low-level
// i/o error. This variable copies the value in the kv package to the same scope as the Database interfaces,
// so that it is available to code paths that do not interact directly with the kv package.
var ErrNotFound = kv.ErrNotFound

// ErrNotFoundState wraps ErrNotFound for an error specific to a state not being found in the database.
var ErrNotFoundState = kv.ErrNotFoundState

// ErrNotFoundOriginBlockRoot wraps ErrNotFound for an error specific to the origin block root.
var ErrNotFoundOriginBlockRoot = kv.ErrNotFoundOriginBlockRoot

// ErrNotFoundBackfillBlockRoot wraps ErrNotFound for an error specific to the backfill block root.
var ErrNotFoundBackfillBlockRoot = kv.ErrNotFoundBackfillBlockRoot

// ErrNotFoundGenesisBlockRoot means no genesis block root was found, indicating the db was not initialized with genesis
var ErrNotFoundGenesisBlockRoot = kv.ErrNotFoundGenesisBlockRoot

// IsNotFound allows callers to treat errors from a flat-file database, where the file record is missing,
// as equivalent to db.ErrNotFound.
func IsNotFound(err error) bool {
	return errors.Is(err, ErrNotFound) || os.IsNotExist(err)
}