import (
	"encoding/binary"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"time"

	"github.com/cespare/xxhash/v2"
	jsoniter "github.com/json-iterator/go"
)

// XL constants.
const (
	// XL metadata file carries per object metadata.
	xlStorageFormatFileV1 = "xl.json"
)

// Valid - tells us if the format is sane by validating
// format version and erasure coding information.
func (m *xlMetaV1Object) valid() bool {

func RegisterDefaultKVS(kvsMap map[string]KVS) {
	for subSys, kvs := range kvsMap {
		DefaultKVS[subSys] = kvs
	}
}

// HelpSubSysMap - help for all individual KVS for each sub-systems
// also carries a special empty sub-system which dumps
// help for each sub-system key.
var HelpSubSysMap = map[string]HelpKVS{}

// RegisterHelpSubSys - this function saves
// input help KVS for each sub-system globally,

### Upgrade Checklist

- Test all upgrades in a lower environment (DEV, QA, UAT) before applying to production. Performing blind upgrades in production environments carries significant risk.

//
// Internally this function creates 'uploads.json' associated for the
// incoming object at
// '.minio.sys/multipart/bucket/object/uploads.json' on all the
// disks. `uploads.json` carries metadata regarding on-going multipart
// operation(s) on the object.
func (er erasureObjects) newMultipartUpload(ctx context.Context, bucket string, object string, opts ObjectOptions) (*NewMultipartUploadResult, error) {

This file is the source of truth for each `version` at rest. `xl.meta` is a msgpack file serialized from a
well defined data structure. To understand `xl.meta` here are the few things to start with

`xl.meta` carries first 8 bytes an XL header which describes the current format and the format version,
allowing the unmarshaller's to automatically use the right data structures to parse the subsequent content in the stream.

### v1.0

>
> ```
> mc admin config set myminio/ notify_postgres[:name] connection_string="host=hostname port=2832 username=psqluser password=psqlpass database=bucketevents"
> ```
>
> Please make sure this step is carried out, without this step PostgreSQL notification targets will not work,
> an error message will be shown on the console upon server upgrade/restart, make sure to follow the above

				Kind:     kind,
				KeyID:    keyID,
				KmsCtx:   kmsCtx,
				Checksum: checksum,
			}
		}
	}

	if len(fanOutEntries) > 0 {
		// Fan-out requires no copying, and must be carried from original source
		// https://en.wikipedia.org/wiki/Copy_protection so the incoming stream
		// is always going to be in-memory as we cannot re-read from what we

}

// xlMetaV2Version describes the journal entry, Type defines
// the current journal entry type other types might be nil based
// on what Type field carries, it is imperative for the caller
// to verify which journal type first before accessing rest of the fields.
type xlMetaV2Version struct {
	Type             VersionType           `json:"Type" msg:"Type"`

	// Group is used to group (or *not* to group) different services
	// together. Services with an identical Group are returned in
	// the same answer.
	Group string `json:"group,omitempty"`

	// Key carries the original key used during Put().
	Key string `json:"-"`

}

// ObjectV object version key/versionId
type ObjectV struct {
	ObjectName string `xml:"Key"`
	VersionID  string `xml:"VersionId"`
}

// ObjectToDelete carries key name for the object to delete.
type ObjectToDelete struct {
	ObjectV
	// Replication status of DeleteMarker
	DeleteMarkerReplicationStatus string `xml:"DeleteMarkerReplicationStatus"`