// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package windows

import (
	"syscall"
	"unsafe"
)

const (
	STANDARD_RIGHTS_REQUIRED = 0xf0000
	STANDARD_RIGHTS_READ     = 0x20000
	STANDARD_RIGHTS_WRITE    = 0x20000
	STANDARD_RIGHTS_EXECUTE  = 0x20000
	STANDARD_RIGHTS_ALL      = 0x1F0000
)

const (
	NameUnknown          = 0
	NameFullyQualifiedDN = 1
	NameSamCompatible    = 2
	NameDisplay          = 3
	NameUniqueId         = 6
	NameCanonical        = 7
	NameUserPrincipal    = 8
	NameCanonicalEx      = 9
	NameServicePrincipal = 10
	NameDnsDomain        = 12
)

// This function returns 1 byte BOOLEAN rather than the 4 byte BOOL.
// http://blogs.msdn.com/b/drnick/archive/2007/12/19/windows-and-upn-format-credentials.aspx
//sys	TranslateName(accName *uint16, accNameFormat uint32, desiredNameFormat uint32, translatedName *uint16, nSize *uint32) (err error) [failretval&0xff==0] = secur32.TranslateNameW
//sys	GetUserNameEx(nameFormat uint32, nameBuffre *uint16, nSize *uint32) (err error) [failretval&0xff==0] = secur32.GetUserNameExW

// TranslateAccountName converts a directory service
// object name from one format to another.
func TranslateAccountName(username string, from, to uint32, initSize int) (string, error) {
	u, e := UTF16PtrFromString(username)
	if e != nil {
		return "", e
	}
	n := uint32(50)
	for {
		b := make([]uint16, n)
		e = TranslateName(u, from, to, &b[0], &n)
		if e == nil {
			return UTF16ToString(b[:n]), nil
		}
		if e != ERROR_INSUFFICIENT_BUFFER {
			return "", e
		}
		if n <= uint32(len(b)) {
			return "", e
		}
	}
}

const (
	// do not reorder
	NetSetupUnknownStatus = iota
	NetSetupUnjoined
	NetSetupWorkgroupName
	NetSetupDomainName
)

type UserInfo10 struct {
	Name       *uint16
	Comment    *uint16
	UsrComment *uint16
	FullName   *uint16
}

//sys	NetUserGetInfo(serverName *uint16, userName *uint16, level uint32, buf **byte) (neterr error) = netapi32.NetUserGetInfo
//sys	NetGetJoinInformation(server *uint16, name **uint16, bufType *uint32) (neterr error) = netapi32.NetGetJoinInformation
//sys	NetApiBufferFree(buf *byte) (neterr error) = netapi32.NetApiBufferFree

const (
	// do not reorder
	SidTypeUser = 1 + iota
	SidTypeGroup
	SidTypeDomain
	SidTypeAlias
	SidTypeWellKnownGroup
	SidTypeDeletedAccount
	SidTypeInvalid
	SidTypeUnknown
	SidTypeComputer
	SidTypeLabel
)

type SidIdentifierAuthority struct {
	Value [6]byte
}

var (
	SECURITY_NULL_SID_AUTHORITY        = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 0}}
	SECURITY_WORLD_SID_AUTHORITY       = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 1}}
	SECURITY_LOCAL_SID_AUTHORITY       = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 2}}
	SECURITY_CREATOR_SID_AUTHORITY     = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 3}}
	SECURITY_NON_UNIQUE_AUTHORITY      = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 4}}
	SECURITY_NT_AUTHORITY              = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 5}}
	SECURITY_MANDATORY_LABEL_AUTHORITY = SidIdentifierAuthority{[6]byte{0, 0, 0, 0, 0, 16}}
)

const (
	SECURITY_NULL_RID                   = 0
	SECURITY_WORLD_RID                  = 0
	SECURITY_LOCAL_RID                  = 0
	SECURITY_CREATOR_OWNER_RID          = 0
	SECURITY_CREATOR_GROUP_RID          = 1
	SECURITY_DIALUP_RID                 = 1
	SECURITY_NETWORK_RID                = 2
	SECURITY_BATCH_RID                  = 3
	SECURITY_INTERACTIVE_RID            = 4
	SECURITY_LOGON_IDS_RID              = 5
	SECURITY_SERVICE_RID                = 6
	SECURITY_LOCAL_SYSTEM_RID           = 18
	SECURITY_BUILTIN_DOMAIN_RID         = 32
	SECURITY_PRINCIPAL_SELF_RID         = 10
	SECURITY_CREATOR_OWNER_SERVER_RID   = 0x2
	SECURITY_CREATOR_GROUP_SERVER_RID   = 0x3
	SECURITY_LOGON_IDS_RID_COUNT        = 0x3
	SECURITY_ANONYMOUS_LOGON_RID        = 0x7
	SECURITY_PROXY_RID                  = 0x8
	SECURITY_ENTERPRISE_CONTROLLERS_RID = 0x9
	SECURITY_SERVER_LOGON_RID           = SECURITY_ENTERPRISE_CONTROLLERS_RID
	SECURITY_AUTHENTICATED_USER_RID     = 0xb
	SECURITY_RESTRICTED_CODE_RID        = 0xc
	SECURITY_NT_NON_UNIQUE_RID          = 0x15
)

// Predefined domain-relative RIDs for local groups.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/aa379649(v=vs.85).aspx
const (
	DOMAIN_ALIAS_RID_ADMINS                         = 0x220
	DOMAIN_ALIAS_RID_USERS                          = 0x221
	DOMAIN_ALIAS_RID_GUESTS                         = 0x222
	DOMAIN_ALIAS_RID_POWER_USERS                    = 0x223
	DOMAIN_ALIAS_RID_ACCOUNT_OPS                    = 0x224
	DOMAIN_ALIAS_RID_SYSTEM_OPS                     = 0x225
	DOMAIN_ALIAS_RID_PRINT_OPS                      = 0x226
	DOMAIN_ALIAS_RID_BACKUP_OPS                     = 0x227
	DOMAIN_ALIAS_RID_REPLICATOR                     = 0x228
	DOMAIN_ALIAS_RID_RAS_SERVERS                    = 0x229
	DOMAIN_ALIAS_RID_PREW2KCOMPACCESS               = 0x22a
	DOMAIN_ALIAS_RID_REMOTE_DESKTOP_USERS           = 0x22b
	DOMAIN_ALIAS_RID_NETWORK_CONFIGURATION_OPS      = 0x22c
	DOMAIN_ALIAS_RID_INCOMING_FOREST_TRUST_BUILDERS = 0x22d
	DOMAIN_ALIAS_RID_MONITORING_USERS               = 0x22e
	DOMAIN_ALIAS_RID_LOGGING_USERS                  = 0x22f
	DOMAIN_ALIAS_RID_AUTHORIZATIONACCESS            = 0x230
	DOMAIN_ALIAS_RID_TS_LICENSE_SERVERS             = 0x231
	DOMAIN_ALIAS_RID_DCOM_USERS                     = 0x232
	DOMAIN_ALIAS_RID_IUSERS                         = 0x238
	DOMAIN_ALIAS_RID_CRYPTO_OPERATORS               = 0x239
	DOMAIN_ALIAS_RID_CACHEABLE_PRINCIPALS_GROUP     = 0x23b
	DOMAIN_ALIAS_RID_NON_CACHEABLE_PRINCIPALS_GROUP = 0x23c
	DOMAIN_ALIAS_RID_EVENT_LOG_READERS_GROUP        = 0x23d
	DOMAIN_ALIAS_RID_CERTSVC_DCOM_ACCESS_GROUP      = 0x23e
)

//sys	LookupAccountSid(systemName *uint16, sid *SID, name *uint16, nameLen *uint32, refdDomainName *uint16, refdDomainNameLen *uint32, use *uint32) (err error) = advapi32.LookupAccountSidW
//sys	LookupAccountName(systemName *uint16, accountName *uint16, sid *SID, sidLen *uint32, refdDomainName *uint16, refdDomainNameLen *uint32, use *uint32) (err error) = advapi32.LookupAccountNameW
//sys	ConvertSidToStringSid(sid *SID, stringSid **uint16) (err error) = advapi32.ConvertSidToStringSidW
//sys	ConvertStringSidToSid(stringSid *uint16, sid **SID) (err error) = advapi32.ConvertStringSidToSidW
//sys	GetLengthSid(sid *SID) (len uint32) = advapi32.GetLengthSid
//sys	CopySid(destSidLen uint32, destSid *SID, srcSid *SID) (err error) = advapi32.CopySid
//sys	AllocateAndInitializeSid(identAuth *SidIdentifierAuthority, subAuth byte, subAuth0 uint32, subAuth1 uint32, subAuth2 uint32, subAuth3 uint32, subAuth4 uint32, subAuth5 uint32, subAuth6 uint32, subAuth7 uint32, sid **SID) (err error) = advapi32.AllocateAndInitializeSid
//sys	createWellKnownSid(sidType WELL_KNOWN_SID_TYPE, domainSid *SID, sid *SID, sizeSid *uint32) (err error) = advapi32.CreateWellKnownSid
//sys	isWellKnownSid(sid *SID, sidType WELL_KNOWN_SID_TYPE) (isWellKnown bool) = advapi32.IsWellKnownSid
//sys	FreeSid(sid *SID) (err error) [failretval!=0] = advapi32.FreeSid
//sys	EqualSid(sid1 *SID, sid2 *SID) (isEqual bool) = advapi32.EqualSid
//sys	getSidIdentifierAuthority(sid *SID) (authority *SidIdentifierAuthority) = advapi32.GetSidIdentifierAuthority
//sys	getSidSubAuthorityCount(sid *SID) (count *uint8) = advapi32.GetSidSubAuthorityCount
//sys	getSidSubAuthority(sid *SID, index uint32) (subAuthority *uint32) = advapi32.GetSidSubAuthority
//sys	isValidSid(sid *SID) (isValid bool) = advapi32.IsValidSid

// The security identifier (SID) structure is a variable-length
// structure used to uniquely identify users or groups.
type SID struct{}

// StringToSid converts a string-format security identifier
// SID into a valid, functional SID.
func StringToSid(s string) (*SID, error) {
	var sid *SID
	p, e := UTF16PtrFromString(s)
	if e != nil {
		return nil, e
	}
	e = ConvertStringSidToSid(p, &sid)
	if e != nil {
		return nil, e
	}
	defer LocalFree((Handle)(unsafe.Pointer(sid)))
	return sid.Copy()
}

// LookupSID retrieves a security identifier SID for the account
// and the name of the domain on which the account was found.
// System specify target computer to search.
func LookupSID(system, account string) (sid *SID, domain string, accType uint32, err error) {
	if len(account) == 0 {
		return nil, "", 0, syscall.EINVAL
	}
	acc, e := UTF16PtrFromString(account)
	if e != nil {
		return nil, "", 0, e
	}
	var sys *uint16
	if len(system) > 0 {
		sys, e = UTF16PtrFromString(system)
		if e != nil {
			return nil, "", 0, e
		}
	}
	n := uint32(50)
	dn := uint32(50)
	for {
		b := make([]byte, n)
		db := make([]uint16, dn)
		sid = (*SID)(unsafe.Pointer(&b[0]))
		e = LookupAccountName(sys, acc, sid, &n, &db[0], &dn, &accType)
		if e == nil {
			return sid, UTF16ToString(db), accType, nil
		}
		if e != ERROR_INSUFFICIENT_BUFFER {
			return nil, "", 0, e
		}
		if n <= uint32(len(b)) {
			return nil, "", 0, e
		}
	}
}

// String converts SID to a string format
// suitable for display, storage, or transmission.
func (sid *SID) String() (string, error) {
	var s *uint16
	e := ConvertSidToStringSid(sid, &s)
	if e != nil {
		return "", e
	}
	defer LocalFree((Handle)(unsafe.Pointer(s)))
	return UTF16ToString((*[256]uint16)(unsafe.Pointer(s))[:]), nil
}

// Len returns the length, in bytes, of a valid security identifier SID.
func (sid *SID) Len() int {
	return int(GetLengthSid(sid))
}

// Copy creates a duplicate of security identifier SID.
func (sid *SID) Copy() (*SID, error) {
	b := make([]byte, sid.Len())
	sid2 := (*SID)(unsafe.Pointer(&b[0]))
	e := CopySid(uint32(len(b)), sid2, sid)
	if e != nil {
		return nil, e
	}
	return sid2, nil
}

// IdentifierAuthority returns the identifier authority of the SID.
func (sid *SID) IdentifierAuthority() SidIdentifierAuthority {
	return *getSidIdentifierAuthority(sid)
}

// SubAuthorityCount returns the number of sub-authorities in the SID.
func (sid *SID) SubAuthorityCount() uint8 {
	return *getSidSubAuthorityCount(sid)
}

// SubAuthority returns the sub-authority of the SID as specified by
// the index, which must be less than sid.SubAuthorityCount().
func (sid *SID) SubAuthority(idx uint32) uint32 {
	if idx >= uint32(sid.SubAuthorityCount()) {
		panic("sub-authority index out of range")
	}
	return *getSidSubAuthority(sid, idx)
}

// IsValid returns whether the SID has a valid revision and length.
func (sid *SID) IsValid() bool {
	return isValidSid(sid)
}

// Equals compares two SIDs for equality.
func (sid *SID) Equals(sid2 *SID) bool {
	return EqualSid(sid, sid2)
}

// IsWellKnown determines whether the SID matches the well-known sidType.
func (sid *SID) IsWellKnown(sidType WELL_KNOWN_SID_TYPE) bool {
	return isWellKnownSid(sid, sidType)
}

// LookupAccount retrieves the name of the account for this SID
// and the name of the first domain on which this SID is found.
// System specify target computer to search for.
func (sid *SID) LookupAccount(system string) (account, domain string, accType uint32, err error) {
	var sys *uint16
	if len(system) > 0 {
		sys, err = UTF16PtrFromString(system)
		if err != nil {
			return "", "", 0, err
		}
	}
	n := uint32(50)
	dn := uint32(50)
	for {
		b := make([]uint16, n)
		db := make([]uint16, dn)
		e := LookupAccountSid(sys, sid, &b[0], &n, &db[0], &dn, &accType)
		if e == nil {
			return UTF16ToString(b), UTF16ToString(db), accType, nil
		}
		if e != ERROR_INSUFFICIENT_BUFFER {
			return "", "", 0, e
		}
		if n <= uint32(len(b)) {
			return "", "", 0, e
		}
	}
}

// Various types of pre-specified SIDs that can be synthesized and compared at runtime.
type WELL_KNOWN_SID_TYPE uint32

const (
	WinNullSid                                    = 0
	WinWorldSid                                   = 1
	WinLocalSid                                   = 2
	WinCreatorOwnerSid                            = 3
	WinCreatorGroupSid                            = 4
	WinCreatorOwnerServerSid                      = 5
	WinCreatorGroupServerSid                      = 6
	WinNtAuthoritySid                             = 7
	WinDialupSid                                  = 8
	WinNetworkSid                                 = 9
	WinBatchSid                                   = 10
	WinInteractiveSid                             = 11
	WinServiceSid                                 = 12
	WinAnonymousSid                               = 13
	WinProxySid                                   = 14
	WinEnterpriseControllersSid                   = 15
	WinSelfSid                                    = 16
	WinAuthenticatedUserSid                       = 17
	WinRestrictedCodeSid                          = 18
	WinTerminalServerSid                          = 19
	WinRemoteLogonIdSid                           = 20
	WinLogonIdsSid                                = 21
	WinLocalSystemSid                             = 22
	WinLocalServiceSid                            = 23
	WinNetworkServiceSid                          = 24
	WinBuiltinDomainSid                           = 25
	WinBuiltinAdministratorsSid                   = 26
	WinBuiltinUsersSid                            = 27
	WinBuiltinGuestsSid                           = 28
	WinBuiltinPowerUsersSid                       = 29
	WinBuiltinAccountOperatorsSid                 = 30
	WinBuiltinSystemOperatorsSid                  = 31
	WinBuiltinPrintOperatorsSid                   = 32
	WinBuiltinBackupOperatorsSid                  = 33
	WinBuiltinReplicatorSid                       = 34
	WinBuiltinPreWindows2000CompatibleAccessSid   = 35
	WinBuiltinRemoteDesktopUsersSid               = 36
	WinBuiltinNetworkConfigurationOperatorsSid    = 37
	WinAccountAdministratorSid                    = 38
	WinAccountGuestSid                            = 39
	WinAccountKrbtgtSid                           = 40
	WinAccountDomainAdminsSid                     = 41
	WinAccountDomainUsersSid                      = 42
	WinAccountDomainGuestsSid                     = 43
	WinAccountComputersSid                        = 44
	WinAccountControllersSid                      = 45
	WinAccountCertAdminsSid                       = 46
	WinAccountSchemaAdminsSid                     = 47
	WinAccountEnterpriseAdminsSid                 = 48
	WinAccountPolicyAdminsSid                     = 49
	WinAccountRasAndIasServersSid                 = 50
	WinNTLMAuthenticationSid                      = 51
	WinDigestAuthenticationSid                    = 52
	WinSChannelAuthenticationSid                  = 53
	WinThisOrganizationSid                        = 54
	WinOtherOrganizationSid                       = 55
	WinBuiltinIncomingForestTrustBuildersSid      = 56
	WinBuiltinPerfMonitoringUsersSid              = 57
	WinBuiltinPerfLoggingUsersSid                 = 58
	WinBuiltinAuthorizationAccessSid              = 59
	WinBuiltinTerminalServerLicenseServersSid     = 60
	WinBuiltinDCOMUsersSid                        = 61
	WinBuiltinIUsersSid                           = 62
	WinIUserSid                                   = 63
	WinBuiltinCryptoOperatorsSid                  = 64
	WinUntrustedLabelSid                          = 65
	WinLowLabelSid                                = 66
	WinMediumLabelSid                             = 67
	WinHighLabelSid                               = 68
	WinSystemLabelSid                             = 69
	WinWriteRestrictedCodeSid                     = 70
	WinCreatorOwnerRightsSid                      = 71
	WinCacheablePrincipalsGroupSid                = 72
	WinNonCacheablePrincipalsGroupSid             = 73
	WinEnterpriseReadonlyControllersSid           = 74
	WinAccountReadonlyControllersSid              = 75
	WinBuiltinEventLogReadersGroup                = 76
	WinNewEnterpriseReadonlyControllersSid        = 77
	WinBuiltinCertSvcDComAccessGroup              = 78
	WinMediumPlusLabelSid                         = 79
	WinLocalLogonSid                              = 80
	WinConsoleLogonSid                            = 81
	WinThisOrganizationCertificateSid             = 82
	WinApplicationPackageAuthoritySid             = 83
	WinBuiltinAnyPackageSid                       = 84
	WinCapabilityInternetClientSid                = 85
	WinCapabilityInternetClientServerSid          = 86
	WinCapabilityPrivateNetworkClientServerSid    = 87
	WinCapabilityPicturesLibrarySid               = 88
	WinCapabilityVideosLibrarySid                 = 89
	WinCapabilityMusicLibrarySid                  = 90
	WinCapabilityDocumentsLibrarySid              = 91
	WinCapabilitySharedUserCertificatesSid        = 92
	WinCapabilityEnterpriseAuthenticationSid      = 93
	WinCapabilityRemovableStorageSid              = 94
	WinBuiltinRDSRemoteAccessServersSid           = 95
	WinBuiltinRDSEndpointServersSid               = 96
	WinBuiltinRDSManagementServersSid             = 97
	WinUserModeDriversSid                         = 98
	WinBuiltinHyperVAdminsSid                     = 99
	WinAccountCloneableControllersSid             = 100
	WinBuiltinAccessControlAssistanceOperatorsSid = 101
	WinBuiltinRemoteManagementUsersSid            = 102
	WinAuthenticationAuthorityAssertedSid         = 103
	WinAuthenticationServiceAssertedSid           = 104
	WinLocalAccountSid                            = 105
	WinLocalAccountAndAdministratorSid            = 106
	WinAccountProtectedUsersSid                   = 107
	WinCapabilityAppointmentsSid                  = 108
	WinCapabilityContactsSid                      = 109
	WinAccountDefaultSystemManagedSid             = 110
	WinBuiltinDefaultSystemManagedGroupSid        = 111
	WinBuiltinStorageReplicaAdminsSid             = 112
	WinAccountKeyAdminsSid                        = 113
	WinAccountEnterpriseKeyAdminsSid              = 114
	WinAuthenticationKeyTrustSid                  = 115
	WinAuthenticationKeyPropertyMFASid            = 116
	WinAuthenticationKeyPropertyAttestationSid    = 117
	WinAuthenticationFreshKeyAuthSid              = 118
	WinBuiltinDeviceOwnersSid                     = 119
)

// Creates a SID for a well-known predefined alias, generally using the constants of the form
// Win*Sid, for the local machine.
func CreateWellKnownSid(sidType WELL_KNOWN_SID_TYPE) (*SID, error) {
	return CreateWellKnownDomainSid(sidType, nil)
}

// Creates a SID for a well-known predefined alias, generally using the constants of the form
// Win*Sid, for the domain specified by the domainSid parameter.
func CreateWellKnownDomainSid(sidType WELL_KNOWN_SID_TYPE, domainSid *SID) (*SID, error) {
	n := uint32(50)
	for {
		b := make([]byte, n)
		sid := (*SID)(unsafe.Pointer(&b[0]))
		err := createWellKnownSid(sidType, domainSid, sid, &n)
		if err == nil {
			return sid, nil
		}
		if err != ERROR_INSUFFICIENT_BUFFER {
			return nil, err
		}
		if n <= uint32(len(b)) {
			return nil, err
		}
	}
}

const (
	// do not reorder
	TOKEN_ASSIGN_PRIMARY = 1 << iota
	TOKEN_DUPLICATE
	TOKEN_IMPERSONATE
	TOKEN_QUERY
	TOKEN_QUERY_SOURCE
	TOKEN_ADJUST_PRIVILEGES
	TOKEN_ADJUST_GROUPS
	TOKEN_ADJUST_DEFAULT
	TOKEN_ADJUST_SESSIONID

	TOKEN_ALL_ACCESS = STANDARD_RIGHTS_REQUIRED |
		TOKEN_ASSIGN_PRIMARY |
		TOKEN_DUPLICATE |
		TOKEN_IMPERSONATE |
		TOKEN_QUERY |
		TOKEN_QUERY_SOURCE |
		TOKEN_ADJUST_PRIVILEGES |
		TOKEN_ADJUST_GROUPS |
		TOKEN_ADJUST_DEFAULT |
		TOKEN_ADJUST_SESSIONID
	TOKEN_READ  = STANDARD_RIGHTS_READ | TOKEN_QUERY
	TOKEN_WRITE = STANDARD_RIGHTS_WRITE |
		TOKEN_ADJUST_PRIVILEGES |
		TOKEN_ADJUST_GROUPS |
		TOKEN_ADJUST_DEFAULT
	TOKEN_EXECUTE = STANDARD_RIGHTS_EXECUTE
)

const (
	// do not reorder
	TokenUser = 1 + iota
	TokenGroups
	TokenPrivileges
	TokenOwner
	TokenPrimaryGroup
	TokenDefaultDacl
	TokenSource
	TokenType
	TokenImpersonationLevel
	TokenStatistics
	TokenRestrictedSids
	TokenSessionId
	TokenGroupsAndPrivileges
	TokenSessionReference
	TokenSandBoxInert
	TokenAuditPolicy
	TokenOrigin
	TokenElevationType
	TokenLinkedToken
	TokenElevation
	TokenHasRestrictions
	TokenAccessInformation
	TokenVirtualizationAllowed
	TokenVirtualizationEnabled
	TokenIntegrityLevel
	TokenUIAccess
	TokenMandatoryPolicy
	TokenLogonSid
	MaxTokenInfoClass
)

// Group attributes inside of Tokengroups.Groups[i].Attributes
const (
	SE_GROUP_MANDATORY          = 0x00000001
	SE_GROUP_ENABLED_BY_DEFAULT = 0x00000002
	SE_GROUP_ENABLED            = 0x00000004
	SE_GROUP_OWNER              = 0x00000008
	SE_GROUP_USE_FOR_DENY_ONLY  = 0x00000010
	SE_GROUP_INTEGRITY          = 0x00000020
	SE_GROUP_INTEGRITY_ENABLED  = 0x00000040
	SE_GROUP_LOGON_ID           = 0xC0000000
	SE_GROUP_RESOURCE           = 0x20000000
	SE_GROUP_VALID_ATTRIBUTES   = SE_GROUP_MANDATORY | SE_GROUP_ENABLED_BY_DEFAULT | SE_GROUP_ENABLED | SE_GROUP_OWNER | SE_GROUP_USE_FOR_DENY_ONLY | SE_GROUP_LOGON_ID | SE_GROUP_RESOURCE | SE_GROUP_INTEGRITY | SE_GROUP_INTEGRITY_ENABLED
)

// Privilege attributes
const (
	SE_PRIVILEGE_ENABLED_BY_DEFAULT = 0x00000001
	SE_PRIVILEGE_ENABLED            = 0x00000002
	SE_PRIVILEGE_REMOVED            = 0x00000004
	SE_PRIVILEGE_USED_FOR_ACCESS    = 0x80000000
	SE_PRIVILEGE_VALID_ATTRIBUTES   = SE_PRIVILEGE_ENABLED_BY_DEFAULT | SE_PRIVILEGE_ENABLED | SE_PRIVILEGE_REMOVED | SE_PRIVILEGE_USED_FOR_ACCESS
)

// Token types
const (
	TokenPrimary       = 1
	TokenImpersonation = 2
)

// Impersonation levels
const (
	SecurityAnonymous      = 0
	SecurityIdentification = 1
	SecurityImpersonation  = 2
	SecurityDelegation     = 3
)

type LUID struct {
	LowPart  uint32
	HighPart int32
}

type LUIDAndAttributes struct {
	Luid       LUID
	Attributes uint32
}

type SIDAndAttributes struct {
	Sid        *SID
	Attributes uint32
}

type Tokenuser struct {
	User SIDAndAttributes
}

type Tokenprimarygroup struct {
	PrimaryGroup *SID
}

type Tokengroups struct {
	GroupCount uint32
	Groups     [1]SIDAndAttributes
}

type Tokenprivileges struct {
	PrivilegeCount uint32
	Privileges     [1]LUIDAndAttributes
}

type Tokenmandatorylabel struct {
	Label SIDAndAttributes
}

func (tml *Tokenmandatorylabel) Size() uint32 {
	return uint32(unsafe.Sizeof(Tokenmandatorylabel{})) + GetLengthSid(tml.Label.Sid)
}

// Authorization Functions
//sys	checkTokenMembership(tokenHandle Token, sidToCheck *SID, isMember *int32) (err error) = advapi32.CheckTokenMembership
//sys	OpenProcessToken(process Handle, access uint32, token *Token) (err error) = advapi32.OpenProcessToken
//sys	OpenThreadToken(thread Handle, access uint32, openAsSelf bool, token *Token) (err error) = advapi32.OpenThreadToken
//sys	ImpersonateSelf(impersonationlevel uint32) (err error) = advapi32.ImpersonateSelf
//sys	RevertToSelf() (err error) = advapi32.RevertToSelf
//sys	SetThreadToken(thread *Handle, token Token) (err error) = advapi32.SetThreadToken
//sys	LookupPrivilegeValue(systemname *uint16, name *uint16, luid *LUID) (err error) = advapi32.LookupPrivilegeValueW
//sys	AdjustTokenPrivileges(token Token, disableAllPrivileges bool, newstate *Tokenprivileges, buflen uint32, prevstate *Tokenprivileges, returnlen *uint32) (err error) = advapi32.AdjustTokenPrivileges
//sys	AdjustTokenGroups(token Token, resetToDefault bool, newstate *Tokengroups, buflen uint32, prevstate *Tokengroups, returnlen *uint32) (err error) = advapi32.AdjustTokenGroups
//sys	GetTokenInformation(token Token, infoClass uint32, info *byte, infoLen uint32, returnedLen *uint32) (err error) = advapi32.GetTokenInformation
//sys	SetTokenInformation(token Token, infoClass uint32, info *byte, infoLen uint32) (err error) = advapi32.SetTokenInformation
//sys	DuplicateTokenEx(existingToken Token, desiredAccess uint32, tokenAttributes *SecurityAttributes, impersonationLevel uint32, tokenType uint32, newToken *Token) (err error) = advapi32.DuplicateTokenEx
//sys	GetUserProfileDirectory(t Token, dir *uint16, dirLen *uint32) (err error) = userenv.GetUserProfileDirectoryW
//sys	getSystemDirectory(dir *uint16, dirLen uint32) (len uint32, err error) = kernel32.GetSystemDirectoryW

// An access token contains the security information for a logon session.
// The system creates an access token when a user logs on, and every
// process executed on behalf of the user has a copy of the token.
// The token identifies the user, the user's groups, and the user's
// privileges. The system uses the token to control access to securable
// objects and to control the ability of the user to perform various
// system-related operations on the local computer.
type Token Handle

// OpenCurrentProcessToken opens the access token
// associated with current process. It is a real
// token that needs to be closed, unlike
// GetCurrentProcessToken.
func OpenCurrentProcessToken() (Token, error) {
	p, e := GetCurrentProcess()
	if e != nil {
		return 0, e
	}
	var t Token
	e = OpenProcessToken(p, TOKEN_QUERY, &t)
	if e != nil {
		return 0, e
	}
	return t, nil
}

// GetCurrentProcessToken returns the access token associated with
// the current process. It is a pseudo token that does not need
// to be closed.
func GetCurrentProcessToken() Token {
	return Token(^uintptr(4 - 1))
}

// GetCurrentThreadToken return the access token associated with
// the current thread. It is a pseudo token that does not need
// to be closed.
func GetCurrentThreadToken() Token {
	return Token(^uintptr(5 - 1))
}

// GetCurrentThreadEffectiveToken returns the effective access token
// associated with the current thread. It is a pseudo token that does
// not need to be closed.
func GetCurrentThreadEffectiveToken() Token {
	return Token(^uintptr(6 - 1))
}

// Close releases access to access token.
func (t Token) Close() error {
	return CloseHandle(Handle(t))
}

// getInfo retrieves a specified type of information about an access token.
func (t Token) getInfo(class uint32, initSize int) (unsafe.Pointer, error) {
	n := uint32(initSize)
	for {
		b := make([]byte, n)
		e := GetTokenInformation(t, class, &b[0], uint32(len(b)), &n)
		if e == nil {
			return unsafe.Pointer(&b[0]), nil
		}
		if e != ERROR_INSUFFICIENT_BUFFER {
			return nil, e
		}
		if n <= uint32(len(b)) {
			return nil, e
		}
	}
}

// GetTokenUser retrieves access token t user account information.
func (t Token) GetTokenUser() (*Tokenuser, error) {
	i, e := t.getInfo(TokenUser, 50)
	if e != nil {
		return nil, e
	}
	return (*Tokenuser)(i), nil
}

// GetTokenGroups retrieves group accounts associated with access token t.
func (t Token) GetTokenGroups() (*Tokengroups, error) {
	i, e := t.getInfo(TokenGroups, 50)
	if e != nil {
		return nil, e
	}
	return (*Tokengroups)(i), nil
}

// GetTokenPrimaryGroup retrieves access token t primary group information.
// A pointer to a SID structure representing a group that will become
// the primary group of any objects created by a process using this access token.
func (t Token) GetTokenPrimaryGroup() (*Tokenprimarygroup, error) {
	i, e := t.getInfo(TokenPrimaryGroup, 50)
	if e != nil {
		return nil, e
	}
	return (*Tokenprimarygroup)(i), nil
}

// GetUserProfileDirectory retrieves path to the
// root directory of the access token t user's profile.
func (t Token) GetUserProfileDirectory() (string, error) {
	n := uint32(100)
	for {
		b := make([]uint16, n)
		e := GetUserProfileDirectory(t, &b[0], &n)
		if e == nil {
			return UTF16ToString(b), nil
		}
		if e != ERROR_INSUFFICIENT_BUFFER {
			return "", e
		}
		if n <= uint32(len(b)) {
			return "", e
		}
	}
}

// IsElevated returns whether the current token is elevated from a UAC perspective.
func (token Token) IsElevated() bool {
	var isElevated uint32
	var outLen uint32
	err := GetTokenInformation(token, TokenElevation, (*byte)(unsafe.Pointer(&isElevated)), uint32(unsafe.Sizeof(isElevated)), &outLen)
	if err != nil {
		return false
	}
	return outLen == uint32(unsafe.Sizeof(isElevated)) && isElevated != 0
}

// GetLinkedToken returns the linked token, which may be an elevated UAC token.
func (token Token) GetLinkedToken() (Token, error) {
	var linkedToken Token
	var outLen uint32
	err := GetTokenInformation(token, TokenLinkedToken, (*byte)(unsafe.Pointer(&linkedToken)), uint32(unsafe.Sizeof(linkedToken)), &outLen)
	if err != nil {
		return Token(0), err
	}
	return linkedToken, nil
}

// GetSystemDirectory retrieves path to current location of the system
// directory, which is typically, though not always, C:\Windows\System32.
func GetSystemDirectory() (string, error) {
	n := uint32(MAX_PATH)
	for {
		b := make([]uint16, n)
		l, e := getSystemDirectory(&b[0], n)
		if e != nil {
			return "", e
		}
		if l <= n {
			return UTF16ToString(b[:l]), nil
		}
		n = l
	}
}

// IsMember reports whether the access token t is a member of the provided SID.
func (t Token) IsMember(sid *SID) (bool, error) {
	var b int32
	if e := checkTokenMembership(t, sid, &b); e != nil {
		return false, e
	}
	return b != 0, nil
}

const (
	WTS_CONSOLE_CONNECT        = 0x1
	WTS_CONSOLE_DISCONNECT     = 0x2
	WTS_REMOTE_CONNECT         = 0x3
	WTS_REMOTE_DISCONNECT      = 0x4
	WTS_SESSION_LOGON          = 0x5
	WTS_SESSION_LOGOFF         = 0x6
	WTS_SESSION_LOCK           = 0x7
	WTS_SESSION_UNLOCK         = 0x8
	WTS_SESSION_REMOTE_CONTROL = 0x9
	WTS_SESSION_CREATE         = 0xa
	WTS_SESSION_TERMINATE      = 0xb
)

const (
	WTSActive       = 0
	WTSConnected    = 1
	WTSConnectQuery = 2
	WTSShadow       = 3
	WTSDisconnected = 4
	WTSIdle         = 5
	WTSListen       = 6
	WTSReset        = 7
	WTSDown         = 8
	WTSInit         = 9
)

type WTSSESSION_NOTIFICATION struct {
	Size      uint32
	SessionID uint32
}

type WTS_SESSION_INFO struct {
	SessionID         uint32
	WindowStationName *uint16
	State             uint32
}

//sys WTSQueryUserToken(session uint32, token *Token) (err error) = wtsapi32.WTSQueryUserToken
//sys WTSEnumerateSessions(handle Handle, reserved uint32, version uint32, sessions **WTS_SESSION_INFO, count *uint32) (err error) = wtsapi32.WTSEnumerateSessionsW
//sys WTSFreeMemory(ptr uintptr) = wtsapi32.WTSFreeMemory