frostfs-contract/frostfsid/frostfsid_contract.go

package frostfsid

import (
	"git.frostfs.info/TrueCloudLab/frostfs-contract/common"
	"github.com/nspcc-dev/neo-go/pkg/interop"
	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
	"github.com/nspcc-dev/neo-go/pkg/interop/convert"
	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
	"github.com/nspcc-dev/neo-go/pkg/interop/native/crypto"
	"github.com/nspcc-dev/neo-go/pkg/interop/native/management"
	"github.com/nspcc-dev/neo-go/pkg/interop/native/std"
	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
)

type (
	// Subject represents a subject entity.
	//
	// Fields:
	//   - Namespace: a string representing the namespace of the subject.
	//   - Name: a string representing the name of the subject.
	//     The name must match the following regex pattern: ^[\w+=,.@-]{1,64}$
	// The Subject is stored in the storage as a hash(namespace) + hash(name).
	Subject struct {
		PrimaryKey     interop.PublicKey
		AdditionalKeys []interop.PublicKey
		Namespace      string
		Name           string
		KV             map[string]string
	}

	SubjectExtended struct {
		PrimaryKey     interop.PublicKey
		AdditionalKeys []interop.PublicKey
		Namespace      string
		Name           string
		KV             map[string]string
		Groups         []Group
	}

	// Namespace represents a namespace.
	//
	// Fields:
	//   - Name: a string representing the name of the namespace.
	//     The custom name must match the following regex pattern:
	//     (^$)|(^[a-z0-9]{1,2}$)|(^[a-z0-9][a-z0-9-]{1,48}[a-z0-9]$)
	//     An empty Name is considered the <root> namespace.
	//
	// The Namespace is stored in the storage as a hash(name).
	Namespace struct {
		Name string
	}

	NamespaceExtended struct {
		Name          string
		GroupsCount   int
		SubjectsCount int
	}

	// Group represents a group entity.
	//
	// Fields:
	//   - ID: an integer representing the unique identifier of the group.
	//     The ID is generated upon creation and is the sequential number of the group within the namespace.
	//     It cannot be changed once set.
	//   - Name: a string representing the name of the group.
	//     The name must match the following regex pattern: [\w+=,.@-]{1,128}$
	//   - Namespace: a string representing the namespace of the group.
	//     A group exists only within one namespace.
	//
	// The group is stored in the storage as a hash(namespace) + hash(name).
	Group struct {
		ID        int
		Name      string
		Namespace string
		KV        map[string]string
	}

	GroupExtended struct {
		ID            int
		Name          string
		Namespace     string
		KV            map[string]string
		SubjectsCount int
	}
)

const (
	adminKey                     = 'o'
	subjectKeysPrefix            = 's'
	additionalKeysPrefix         = 'a'
	namespaceKeysPrefix          = 'n'
	namespaceSubjectsKeysPrefix  = 'N'
	namespaceSubjectsNamesPrefix = 'l'
	groupKeysPrefix              = 'g'
	groupSubjectsKeysPrefix      = 'G'
	groupCounterKey              = 'c'
	namespaceGroupsNamesPrefix   = 'm'
)

func _deploy(data any, isUpdate bool) {
	ctx := storage.GetContext()

	args := data.(struct {
		admin interop.Hash160
	})

	if args.admin != nil {
		if len(args.admin) != interop.Hash160Len {
			panic("incorrect length of owner address")
		}
		storage.Put(ctx, adminKey, args.admin)
	}

	storage.Put(ctx, groupCounterKey, 0)
	storage.Put(ctx, namespaceKey(""), std.Serialize(Namespace{}))

	runtime.Log("frostfsid contract initialized")
}

// SetAdmin sets the admin address for the contract.
func SetAdmin(addr interop.Hash160) {
	ctx := storage.GetContext()
	if !common.HasUpdateAccess() {
		panic("not witnessed")
	}

	storage.Put(ctx, adminKey, addr)
}

// ClearAdmin removes the admin address from the contract storage.
func ClearAdmin() {
	ctx := storage.GetContext()
	if !common.HasUpdateAccess() {
		panic("not witnessed")
	}

	storage.Delete(ctx, adminKey)
}

// GetAdmin retrieves the admin address from the contract storage.
func GetAdmin() interop.Hash160 {
	ctx := storage.GetReadOnlyContext()
	return storage.Get(ctx, adminKey).(interop.Hash160)
}

// Update method updates contract source code and manifest. It can be invoked
// only by committee.
func Update(script []byte, manifest []byte, data any) {
	if !common.HasUpdateAccess() {
		panic("only committee can update contract")
	}

	management.UpdateWithData(script, manifest, common.AppendVersion(data))
	runtime.Log("frostfsid contract updated")
}

// Version returns the version of the contract.
func Version() int {
	return common.Version
}

// CreateSubject creates a new subject in the specified namespace with the provided public key.
func CreateSubject(ns string, key interop.PublicKey) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(key) != interop.PublicKeyCompressedLen {
		panic("incorrect public key length")
	}

	addr := contract.CreateStandardAccount(key)
	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data != nil {
		panic("subject already exists")
	}

	saPrefix := subjectAdditionalPrefix(key)
	it := storage.Find(ctx, saPrefix, storage.KeysOnly)
	for iterator.Next(it) {
		panic("key is occupied")
	}

	nsKey := namespaceKey(ns)
	data = storage.Get(ctx, nsKey).([]byte)
	if data == nil {
		panic("namespace not found")
	}

	subj := Subject{
		PrimaryKey: key,
		Namespace:  ns,
	}

	storage.Put(ctx, sKey, std.Serialize(subj))

	nsSubjKey := namespaceSubjectKey(ns, addr)
	storage.Put(ctx, nsSubjKey, []byte{1})

	runtime.Notify("CreateSubject", interop.Hash160(addr))
}

// AddSubjectKey adds an additional public key to a subject with the specified address.
func AddSubjectKey(addr interop.Hash160, key interop.PublicKey) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}
	if len(key) != interop.PublicKeyCompressedLen {
		panic("incorrect public key length")
	}

	saKey := subjectAdditionalKey(key, addr)
	data := storage.Get(ctx, saKey).([]byte)
	if data != nil {
		panic("key already added")
	}

	storage.Put(ctx, saKey, []byte{1})

	sKey := subjectKeyFromAddr(addr)
	data = storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("address not found")
	}
	subject := std.Deserialize(data).(Subject)
	subject.AdditionalKeys = append(subject.AdditionalKeys, key)

	storage.Put(ctx, sKey, std.Serialize(subject))
	runtime.Notify("AddSubjectKey", addr, key)
}

// RemoveSubjectKey removes an additional public key from the subject with the specified address.
func RemoveSubjectKey(addr interop.Hash160, key interop.PublicKey) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}
	if len(key) != interop.PublicKeyCompressedLen {
		panic("incorrect public key length")
	}

	saKey := subjectAdditionalKey(key, addr)
	data := storage.Get(ctx, saKey).([]byte)
	if data == nil {
		panic("key already removed")
	}

	storage.Delete(ctx, saKey)

	sKey := subjectKeyFromAddr(addr)
	data = storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("address not found")
	}
	subject := std.Deserialize(data).(Subject)

	var additionalKeys []interop.PublicKey
	for i := 0; i < len(subject.AdditionalKeys); i++ {
		if !common.BytesEqual(subject.AdditionalKeys[i], key) {
			additionalKeys = append(additionalKeys, subject.AdditionalKeys[i])
		}
	}
	subject.AdditionalKeys = additionalKeys

	storage.Put(ctx, sKey, std.Serialize(subject))
	runtime.Notify("RemoveSubjectKey", addr, key)
}

// SetSubjectName sets a new name for the subject with the specified address.
func SetSubjectName(addr interop.Hash160, name string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}

	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("subject not found")
	}

	subject := std.Deserialize(data).(Subject)
	oldName := subject.Name
	subject.Name = name
	storage.Put(ctx, sKey, std.Serialize(subject))

	updateNamespaceSubjectName(ctx, subject, oldName)

	runtime.Notify("SetSubjectName", addr, name)
}

// SetSubjectKV sets a key-value pair for the subject with the specified address.
func SetSubjectKV(addr interop.Hash160, key, val string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}

	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("subject not found")
	}

	subject := std.Deserialize(data).(Subject)
	if subject.KV == nil {
		subject.KV = map[string]string{}
	}
	subject.KV[key] = val

	storage.Put(ctx, sKey, std.Serialize(subject))
	runtime.Notify("SetSubjectKV", addr, key, val)
}

// DeleteSubjectKV deletes a key-value pair from the subject with the specified address.
func DeleteSubjectKV(addr interop.Hash160, key string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}

	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("subject not found")
	}

	subject := std.Deserialize(data).(Subject)
	delete(subject.KV, key)

	storage.Put(ctx, sKey, std.Serialize(subject))
	runtime.Notify("DeleteSubjectKV", addr, key)
}

// DeleteSubject deletes the subject with the specified address.
func DeleteSubject(addr interop.Hash160) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}

	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		return
	}
	subj := std.Deserialize(data).(Subject)

	for i := 0; i < len(subj.AdditionalKeys); i++ {
		storage.Delete(ctx, subjectAdditionalKey(subj.AdditionalKeys[i], addr))
	}
	storage.Delete(ctx, sKey)

	removeSubjectFromNamespace(ctx, subj.Namespace, addr)
	deleteNamespaceSubjectName(ctx, subj.Namespace, subj.Name)

	runtime.Notify("DeleteSubject", addr)
}

// GetSubject retrieves the subject with the specified address.
func GetSubject(addr interop.Hash160) Subject {
	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}

	ctx := storage.GetReadOnlyContext()
	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("subject not found")
	}

	return std.Deserialize(data).(Subject)
}

// GetSubjectExtended retrieves the extended information of the subject with the specified address.
func GetSubjectExtended(addr interop.Hash160) SubjectExtended {
	subj := GetSubject(addr)
	ctx := storage.GetReadOnlyContext()

	var groups []Group
	nsHash := ripemd160Hash(subj.Namespace)
	it := storage.Find(ctx, groupPrefixFromHash(nsHash), storage.KeysOnly|storage.RemovePrefix)
	for iterator.Next(it) {
		groupHash := iterator.Value(it).([]byte)
		data := storage.Get(ctx, groupSubjectKeyFromHashes(nsHash, groupHash, addr)).([]byte)
		if data != nil {
			data = storage.Get(ctx, groupKeyFromHashes(nsHash, groupHash)).([]byte)
			if data == nil {
				panic("group not found")
			}
			groups = append(groups, std.Deserialize(data).(Group))
		}
	}

	subjExt := SubjectExtended{
		PrimaryKey:     subj.PrimaryKey,
		AdditionalKeys: subj.AdditionalKeys,
		Namespace:      subj.Namespace,
		Name:           subj.Name,
		KV:             subj.KV,
		Groups:         groups,
	}

	return subjExt
}

// GetSubjectByKey retrieves the subject associated with the provided public key.
func GetSubjectByKey(key interop.PublicKey) Subject {
	if len(key) != interop.PublicKeyCompressedLen {
		panic("incorrect key length")
	}

	ctx := storage.GetReadOnlyContext()

	sKey := subjectKey(key)
	data := storage.Get(ctx, sKey).([]byte)
	if data != nil {
		return std.Deserialize(data).(Subject)
	}

	saPrefix := subjectAdditionalPrefix(key)
	it := storage.Find(ctx, saPrefix, storage.KeysOnly|storage.RemovePrefix)
	for iterator.Next(it) {
		addr := iterator.Value(it).([]byte)
		sKey = subjectKeyFromAddr(addr)
		data = storage.Get(ctx, sKey).([]byte)
		if data != nil {
			return std.Deserialize(data).(Subject)
		}
		break
	}

	panic("subject not found")
}

// GetSubjectByName retrieves the subject with the specified name within the given namespace.
func GetSubjectByName(ns, name string) Subject {
	key := GetSubjectKeyByName(ns, name)
	addr := contract.CreateStandardAccount(key)
	return GetSubject(addr)
}

// GetSubjectKeyByName retrieves the public key of the subject with the specified namespace and name.
func GetSubjectKeyByName(ns, name string) interop.PublicKey {
	if name == "" {
		panic("invalid or name")
	}

	ctx := storage.GetReadOnlyContext()

	nsSubjNameKey := namespaceSubjectNameKey(ns, name)
	subjKey := storage.Get(ctx, nsSubjNameKey).(interop.PublicKey)
	if subjKey == nil {
		panic("subject not found")
	}

	return subjKey
}

// GetValueForSubjectKey GetSubjectKey returns the value associated with the key for the subject.
func GetValueForSubjectKey(addr interop.Hash160, name string) string {
	if len(addr) != interop.Hash160Len {
		panic("incorrect address length")
	}

	ctx := storage.GetReadOnlyContext()
	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		return ""
	}

	sbj := std.Deserialize(data).(Subject)

	for k, v := range sbj.KV {
		if k == name {
			return v
		}
	}

	return ""
}

func ListSubjects() iterator.Iterator {
	ctx := storage.GetReadOnlyContext()
	return storage.Find(ctx, []byte{subjectKeysPrefix}, storage.KeysOnly|storage.RemovePrefix)
}

// CreateNamespace creates a new namespace with the specified name.
func CreateNamespace(ns string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	nsKey := namespaceKey(ns)
	data := storage.Get(ctx, nsKey).([]byte)
	if data != nil {
		panic("namespace already exists")
	}

	namespace := Namespace{
		Name: ns,
	}

	storage.Put(ctx, nsKey, std.Serialize(namespace))
	runtime.Notify("CreateNamespace", ns)
}

// GetNamespace retrieves the namespace with the specified name.
func GetNamespace(ns string) Namespace {
	ctx := storage.GetReadOnlyContext()
	nsKey := namespaceKey(ns)
	data := storage.Get(ctx, nsKey).([]byte)
	if data == nil {
		panic("namespace not found")
	}

	return std.Deserialize(data).(Namespace)
}

// GetNamespaceExtended retrieves extended information about the namespace.
func GetNamespaceExtended(ns string) NamespaceExtended {
	ctx := storage.GetReadOnlyContext()
	nsKey := namespaceKey(ns)
	data := storage.Get(ctx, nsKey).([]byte)
	if data == nil {
		panic("namespace not found")
	}
	namespace := std.Deserialize(data).(Namespace)

	nsExtended := NamespaceExtended{
		Name: namespace.Name,
	}

	it := storage.Find(ctx, groupPrefix(ns), storage.KeysOnly)
	for iterator.Next(it) {
		nsExtended.GroupsCount += 1
	}

	it = storage.Find(ctx, namespaceSubjectPrefix(ns), storage.KeysOnly)
	for iterator.Next(it) {
		nsExtended.SubjectsCount += 1
	}

	return nsExtended
}

func ListNamespaces() iterator.Iterator {
	ctx := storage.GetReadOnlyContext()
	return storage.Find(ctx, []byte{namespaceKeysPrefix}, storage.ValuesOnly|storage.DeserializeValues)
}

func ListNamespaceSubjects(ns string) iterator.Iterator {
	ctx := storage.GetReadOnlyContext()
	return storage.Find(ctx, namespaceSubjectPrefix(ns), storage.KeysOnly|storage.RemovePrefix)
}

// CreateGroup creates a new group within the specified namespace.
func CreateGroup(ns, group string) int {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if group == "" {
		panic("invalid group name")
	}

	nsKey := namespaceKey(ns)
	data := storage.Get(ctx, nsKey).([]byte)
	if data == nil {
		panic("namespace not found")
	}

	groupCountID := storage.Get(ctx, groupCounterKey).(int)
	groupCountID++
	storage.Put(ctx, groupCounterKey, groupCountID)

	gr := Group{
		ID:        groupCountID,
		Name:      group,
		Namespace: ns,
	}

	setNamespaceGroupName(ctx, gr)

	gKey := groupKey(ns, groupCountID)
	storage.Put(ctx, gKey, std.Serialize(gr))

	runtime.Notify("CreateGroup", ns, group)

	return groupCountID
}

// GetGroup retrieves the group with the specified ID within the given namespace.
func GetGroup(ns string, groupID int) Group {
	ctx := storage.GetReadOnlyContext()
	gKey := groupKey(ns, groupID)
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}

	return std.Deserialize(data).(Group)
}

// GetGroupExtended retrieves extended information about the group, including the count of subjects in the group.
func GetGroupExtended(ns string, groupID int) GroupExtended {
	ctx := storage.GetReadOnlyContext()
	gKey := groupKey(ns, groupID)
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}

	gr := std.Deserialize(data).(Group)

	grExtended := GroupExtended{
		ID:        gr.ID,
		Name:      gr.Name,
		Namespace: gr.Namespace,
		KV:        gr.KV,
	}

	it := storage.Find(ctx, groupSubjectPrefix(ns, groupID), storage.KeysOnly)
	for iterator.Next(it) {
		grExtended.SubjectsCount += 1
	}

	return grExtended
}

// GetGroupIDByName retrieves the ID of the group with the specified name within the given namespace.
func GetGroupIDByName(ns, name string) int {
	if name == "" {
		panic("invalid name")
	}

	ctx := storage.GetReadOnlyContext()

	nsGroupNameKey := namespaceGroupNameKey(ns, name)
	groupIDRaw := storage.Get(ctx, nsGroupNameKey).([]byte)
	if groupIDRaw == nil {
		panic("group not found")
	}

	return std.Deserialize(groupIDRaw).(int)
}

// GetGroupByName retrieves the group with the specified name within the given namespace.
func GetGroupByName(ns, name string) Group {
	groupID := GetGroupIDByName(ns, name)
	gKey := groupKey(ns, groupID)

	ctx := storage.GetReadOnlyContext()
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}

	return std.Deserialize(data).(Group)
}

// SetGroupName sets a new name for the group with the specified ID within the given namespace.
func SetGroupName(ns string, groupID int, name string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	gKey := groupKey(ns, groupID)
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}

	gr := std.Deserialize(data).(Group)
	oldName := gr.Name
	gr.Name = name
	storage.Put(ctx, gKey, std.Serialize(gr))

	updateNamespaceGroupName(ctx, gr, oldName)

	runtime.Notify("SetGroupName", ns, groupID, name)
}

// SetGroupKV sets a key-value pair for the group with the specified ID within the given namespace.
func SetGroupKV(ns string, groupID int, key, val string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	gKey := groupKey(ns, groupID)
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}

	gr := std.Deserialize(data).(Group)
	if gr.KV == nil {
		gr.KV = map[string]string{}
	}
	gr.KV[key] = val

	storage.Put(ctx, gKey, std.Serialize(gr))
	runtime.Notify("SetGroupKV", ns, groupID, key, val)
}

// DeleteGroupKV deletes a key-value pair from the group with the specified ID within the given namespace.
func DeleteGroupKV(ns string, groupID int, key string) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	gKey := groupKey(ns, groupID)
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}

	gr := std.Deserialize(data).(Group)
	delete(gr.KV, key)

	storage.Put(ctx, gKey, std.Serialize(gr))
	runtime.Notify("DeleteGroupKV", ns, groupID, key)
}

func ListGroups(ns string) iterator.Iterator {
	ctx := storage.GetReadOnlyContext()
	return storage.Find(ctx, groupPrefix(ns), storage.ValuesOnly|storage.DeserializeValues)
}

// AddSubjectToGroup adds a subject to a group with the specified ID.
func AddSubjectToGroup(addr interop.Hash160, groupID int) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("invalid address length")
	}

	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("subject not found")
	}
	subject := std.Deserialize(data).(Subject)

	gKey := groupKey(subject.Namespace, groupID)
	data = storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}
	group := std.Deserialize(data).(Group)

	if group.Namespace != subject.Namespace {
		panic("subject and group must be in the same namespace")
	}

	gsKey := groupSubjectKey(subject.Namespace, groupID, addr)
	storage.Put(ctx, gsKey, []byte{1})

	runtime.Notify("AddSubjectToGroup", addr, subject.Namespace, groupID)
}

// RemoveSubjectFromGroup removes a subject from a group with the specified ID.
func RemoveSubjectFromGroup(addr interop.Hash160, groupID int) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	if len(addr) != interop.Hash160Len {
		panic("invalid address length")
	}

	sKey := subjectKeyFromAddr(addr)
	data := storage.Get(ctx, sKey).([]byte)
	if data == nil {
		panic("subject not found")
	}

	subject := std.Deserialize(data).(Subject)

	gKey := groupKey(subject.Namespace, groupID)
	data = storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}
	group := std.Deserialize(data).(Group)

	if group.Namespace != subject.Namespace {
		panic("subject and group must be in the same namespace")
	}

	gsKey := groupSubjectKey(subject.Namespace, groupID, addr)
	storage.Delete(ctx, gsKey)

	runtime.Notify("RemoveSubjectFromGroup", addr, subject.Namespace, groupID)
}

func ListGroupSubjects(ns string, groupID int) iterator.Iterator {
	ctx := storage.GetReadOnlyContext()
	return storage.Find(ctx, groupSubjectPrefix(ns, groupID), storage.KeysOnly|storage.RemovePrefix)
}

// DeleteGroup deletes the group with the specified ID within the given namespace.
func DeleteGroup(ns string, groupID int) {
	ctx := storage.GetContext()
	checkContractOwner(ctx)

	gKey := groupKey(ns, groupID)
	data := storage.Get(ctx, gKey).([]byte)
	if data == nil {
		panic("group not found")
	}
	gr := std.Deserialize(data).(Group)

	storage.Delete(ctx, gKey)

	it := storage.Find(ctx, groupSubjectPrefix(ns, groupID), storage.KeysOnly)
	for iterator.Next(it) {
		gsKey := iterator.Value(it).([]byte)
		storage.Delete(ctx, gsKey)
	}

	deleteNamespaceGroupName(ctx, ns, gr.Name)

	runtime.Notify("DeleteGroup", ns, groupID)
}

func checkContractOwner(ctx storage.Context) {
	addr := storage.Get(ctx, adminKey)
	if addr != nil && runtime.CheckWitness(addr.(interop.Hash160)) {
		return
	}
	if common.HasUpdateAccess() {
		return
	}
	panic("not witnessed")
}

func removeSubjectFromNamespace(ctx storage.Context, ns string, addr interop.Hash160) {
	nsSubjKey := namespaceSubjectKey(ns, addr)
	storage.Delete(ctx, nsSubjKey)

	nsHash := ripemd160Hash(ns)
	it := storage.Find(ctx, groupPrefixFromHash(nsHash), storage.KeysOnly|storage.RemovePrefix)
	for iterator.Next(it) {
		groupHash := iterator.Value(it).([]byte)
		storage.Delete(ctx, groupSubjectKeyFromHashes(nsHash, groupHash, addr))
	}
}

func setNamespaceSubjectName(ctx storage.Context, subj Subject) {
	if subj.Name == "" {
		return
	}

	nsSubjNameKey := namespaceSubjectNameKey(subj.Namespace, subj.Name)
	subjKey := storage.Get(ctx, nsSubjNameKey).(interop.PublicKey)
	if subjKey == nil {
		storage.Put(ctx, nsSubjNameKey, subj.PrimaryKey)
	} else if !common.BytesEqual(subjKey, subj.PrimaryKey) {
		panic("subject name is not available in the current namespace")
	}
}

func deleteNamespaceSubjectName(ctx storage.Context, ns, subjName string) {
	if subjName == "" {
		return
	}

	nsSubjNameKey := namespaceSubjectNameKey(ns, subjName)
	storage.Delete(ctx, nsSubjNameKey)
}

func updateNamespaceSubjectName(ctx storage.Context, subj Subject, oldName string) {
	if subj.Name == oldName {
		return
	}

	deleteNamespaceSubjectName(ctx, subj.Namespace, oldName)
	setNamespaceSubjectName(ctx, subj)
}

func updateNamespaceGroupName(ctx storage.Context, gr Group, oldName string) {
	if gr.Name == oldName {
		return
	}

	deleteNamespaceGroupName(ctx, gr.Namespace, oldName)
	setNamespaceGroupName(ctx, gr)
}

func deleteNamespaceGroupName(ctx storage.Context, ns, grName string) {
	if grName == "" {
		return
	}

	nsGroupNameKey := namespaceGroupNameKey(ns, grName)
	storage.Delete(ctx, nsGroupNameKey)
}

func setNamespaceGroupName(ctx storage.Context, gr Group) {
	if gr.Name == "" {
		return
	}

	nsGroupNameKey := namespaceGroupNameKey(gr.Namespace, gr.Name)
	groupIDRaw := storage.Get(ctx, nsGroupNameKey).([]byte)
	if groupIDRaw == nil {
		storage.Put(ctx, nsGroupNameKey, std.Serialize(gr.ID))
		return
	}

	groupID := std.Deserialize(groupIDRaw).(int)
	if groupID != gr.ID {
		panic("group name is not available in the current namespace")
	}
}

func subjectKey(key interop.PublicKey) []byte {
	addr := contract.CreateStandardAccount(key)
	return subjectKeyFromAddr(addr)
}

func subjectKeyFromAddr(addr interop.Hash160) []byte {
	return append([]byte{subjectKeysPrefix}, addr...)
}

func subjectAdditionalKey(additionalKey interop.PublicKey, primeAddr interop.Hash160) []byte {
	return append(subjectAdditionalPrefix(additionalKey), primeAddr...)
}

func subjectAdditionalPrefix(additionalKey interop.PublicKey) []byte {
	addr := contract.CreateStandardAccount(additionalKey)
	return append([]byte{additionalKeysPrefix}, addr...)
}

func namespaceKey(ns string) []byte {
	return namespaceKeyFromHash(ripemd160Hash(ns))
}

func namespaceKeyFromHash(ns []byte) []byte {
	return append([]byte{namespaceKeysPrefix}, ns...)
}

func groupKey(ns string, groupID int) []byte {
	prefix := groupPrefix(ns)
	return append(prefix, idToBytes(groupID)...)
}

func groupKeyFromHashes(nsHash []byte, groupIDBytes []byte) []byte {
	prefix := groupPrefixFromHash(nsHash)
	return append(prefix, groupIDBytes...)
}

func groupPrefix(ns string) []byte {
	return groupPrefixFromHash(ripemd160Hash(ns))
}

func groupPrefixFromHash(nsHash []byte) []byte {
	return append([]byte{groupKeysPrefix}, nsHash...)
}

func ripemd160Hash(data string) []byte {
	return crypto.Ripemd160([]byte(data))
}

func namespaceSubjectKey(ns string, addr interop.Hash160) []byte {
	prefix := namespaceSubjectPrefix(ns)
	return append(prefix, addr...)
}

func namespaceSubjectPrefix(ns string) []byte {
	nsHash := ripemd160Hash(ns)
	return append([]byte{namespaceSubjectsKeysPrefix}, nsHash...)
}

func namespaceSubjectNameKey(ns, subjName string) []byte {
	nsHash := ripemd160Hash(ns)
	nameHash := ripemd160Hash(subjName)
	return append([]byte{namespaceSubjectsNamesPrefix}, append(nsHash, nameHash...)...)
}

func namespaceGroupNameKey(ns, groupName string) []byte {
	nsHash := ripemd160Hash(ns)
	nameHash := ripemd160Hash(groupName)
	return append([]byte{namespaceGroupsNamesPrefix}, append(nsHash, nameHash...)...)
}

func groupSubjectKey(ns string, groupID int, addr interop.Hash160) []byte {
	prefix := groupSubjectPrefix(ns, groupID)
	return append(prefix, addr...)
}

func groupSubjectKeyFromHashes(nsHash, groupHash []byte, addr interop.Hash160) []byte {
	prefix := groupSubjectPrefixFromHashes(nsHash, groupHash)
	return append(prefix, addr...)
}

func groupSubjectPrefix(ns string, groupID int) []byte {
	nsHash := ripemd160Hash(ns)
	return groupSubjectPrefixFromHashes(nsHash, idToBytes(groupID))
}

func groupSubjectPrefixFromHashes(nsHash, groupIDBytes []byte) []byte {
	return append([]byte{groupSubjectsKeysPrefix}, append(nsHash, groupIDBytes...)...)
}

// idToBytes converts i64 value to BE bytes. Panics if value is bigger than i64.
func idToBytes(itemID int) []byte {
	b := convert.ToBytes(itemID)
	ln := len(b)
	if ln > 8 {
		panic("item ID exceeds 8 byte limit")
	}
	zeros := make([]byte, 8-ln)
	return append(b, zeros...)
}