merged from gramsrv upstream

internal/domain/welcome_message.go

@@ -1,9 +1,13 @@
 package domain
 
 import (
+	"crypto/sha256"
+	"encoding/json"
+	"errors"
 	"fmt"
 	"math"
 	"strings"
+	"time"
 )
 
 const officialWelcomeMessageTemplate = "👋 Welcome to OwpenGram!\n\nYou just signed in via %s.\n\nIf this wasn't you, revoke this session from \"Settings > Privacy and Security > Active sessions\" immediately."
@@ -40,3 +44,202 @@ func SignInMethodLabel(u User) string {
 	}
 	return "phone number"
 }
+
+const (
+	MaxWelcomeMessagesPerPeer     = 5
+	MaxWelcomeMessageContentBytes = 4 << 20
+	InitialWelcomeRevision        = int64(1)
+	WelcomeMessageDeliveryTTL     = 24 * time.Hour
+)
+
+var (
+	ErrWelcomeMessageInvalid          = errors.New("welcome message invalid")
+	ErrWelcomeMessagePeerInvalid      = errors.New("welcome message peer invalid")
+	ErrWelcomeMessageForbidden        = errors.New("welcome message forbidden")
+	ErrWelcomeMessageNotFound         = errors.New("welcome message not found")
+	ErrWelcomeMessageNotModified      = errors.New("welcome message not modified")
+	ErrWelcomeMessageLimit            = errors.New("welcome message limit exceeded")
+	ErrWelcomeMessageRandomIDConflict = errors.New("welcome message random id conflict")
+	ErrWelcomeMessageRevisionOverflow = errors.New("welcome message revision overflow")
+)
+
+// WelcomeMessageContent is a durable peer template. It intentionally does not
+// contain transient receiver, device, callback, report, TTL or reply fields.
+type WelcomeMessageContent struct {
+	Message     string
+	Entities    []MessageEntity
+	Media       *MessageMedia
+	ReplyMarkup *MessageReplyMarkup
+	RichMessage *MessageRichMessage
+	InvertMedia bool
+	NoForwards  bool
+}
+
+func (c WelcomeMessageContent) Validate() error {
+	if err := ValidateEphemeralContent(EphemeralContent{
+		Message: c.Message, Entities: c.Entities, Media: c.Media,
+		ReplyMarkup: c.ReplyMarkup, RichMessage: c.RichMessage,
+	}); err != nil {
+		return ErrWelcomeMessageInvalid
+	}
+	if c.InvertMedia && c.Media == nil {
+		return ErrWelcomeMessageInvalid
+	}
+	raw, err := json.Marshal(c)
+	if err != nil || len(raw) > MaxWelcomeMessageContentBytes {
+		return ErrWelcomeMessageInvalid
+	}
+	return nil
+}
+
+type WelcomeMessage struct {
+	ID                int
+	Peer              Peer
+	CreatorUserID     int64
+	Date              int
+	EditDate          int
+	RandomID          int64
+	Content           WelcomeMessageContent
+	CreateFingerprint [32]byte
+	Version           uint64
+}
+
+func (m WelcomeMessage) ValidateStored() error {
+	if m.ID <= 0 || m.ID > MaxMessageBoxID || m.Peer.Type != PeerTypeChannel || m.Peer.ID <= 0 ||
+		m.CreatorUserID <= 0 || m.Date <= 0 || m.RandomID == 0 || m.Version == 0 ||
+		(m.EditDate != 0 && m.EditDate < m.Date) || m.CreateFingerprint == ([32]byte{}) {
+		return ErrWelcomeMessageInvalid
+	}
+	return m.Content.Validate()
+}
+
+type CreateWelcomeMessageRequest struct {
+	Peer              Peer
+	CreatorUserID     int64
+	Date              int
+	RandomID          int64
+	Content           WelcomeMessageContent
+	CreateFingerprint [32]byte
+}
+
+func (r CreateWelcomeMessageRequest) Validate() error {
+	if r.Peer.Type != PeerTypeChannel || r.Peer.ID <= 0 || r.CreatorUserID <= 0 ||
+		r.Date <= 0 || r.RandomID == 0 || r.CreateFingerprint == ([32]byte{}) {
+		return ErrWelcomeMessageInvalid
+	}
+	return r.Content.Validate()
+}
+
+type WelcomeMessageEditFields struct {
+	SetMessage     bool
+	Message        string
+	SetEntities    bool
+	Entities       []MessageEntity
+	SetMedia       bool
+	Media          *MessageMedia
+	SetReplyMarkup bool
+	ReplyMarkup    *MessageReplyMarkup
+	SetRichMessage bool
+	RichMessage    *MessageRichMessage
+	SetInvertMedia bool
+	InvertMedia    bool
+}
+
+func (f WelcomeMessageEditFields) Empty() bool {
+	return !f.SetMessage && !f.SetEntities && !f.SetMedia && !f.SetReplyMarkup &&
+		!f.SetRichMessage && !f.SetInvertMedia
+}
+
+func (f WelcomeMessageEditFields) Apply(current WelcomeMessageContent) (WelcomeMessageContent, error) {
+	if f.Empty() {
+		return WelcomeMessageContent{}, ErrWelcomeMessageInvalid
+	}
+	if f.SetMessage {
+		current.Message = f.Message
+	}
+	if f.SetEntities {
+		current.Entities = f.Entities
+	}
+	if f.SetMedia {
+		current.Media = f.Media
+	}
+	if f.SetReplyMarkup {
+		current.ReplyMarkup = f.ReplyMarkup
+	}
+	if f.SetRichMessage {
+		current.RichMessage = f.RichMessage
+	}
+	if f.SetInvertMedia {
+		current.InvertMedia = f.InvertMedia
+	}
+	if err := current.Validate(); err != nil {
+		return WelcomeMessageContent{}, err
+	}
+	return current, nil
+}
+
+type EditWelcomeMessageRequest struct {
+	Peer     Peer
+	ID       int
+	EditDate int
+	Fields   WelcomeMessageEditFields
+}
+
+func (r EditWelcomeMessageRequest) Validate() error {
+	if r.Peer.Type != PeerTypeChannel || r.Peer.ID <= 0 || r.ID <= 0 ||
+		r.ID > MaxMessageBoxID || r.EditDate <= 0 || r.Fields.Empty() {
+		return ErrWelcomeMessageInvalid
+	}
+	return nil
+}
+
+type WelcomeMessageList struct {
+	Hash        int64
+	Messages    []WelcomeMessage
+	NotModified bool
+}
+
+// WelcomeMessageDelivery is a short-lived, non-PTS snapshot created in the
+// same transaction as one inactive->active membership transition. It is not a
+// message-history row and must be physically removed no later than ExpiresAt.
+type WelcomeMessageDelivery struct {
+	ID           int64
+	JoinEventID  int64
+	ChannelID    int64
+	TargetUserID int64
+	TemplateID   int
+	EphemeralID  int
+	JoinedAt     int
+	Content      WelcomeMessageContent
+	AttemptCount int
+	ExpiresAt    time.Time
+}
+
+func (d WelcomeMessageDelivery) ValidateStored(now time.Time) error {
+	if d.ID <= 0 || d.JoinEventID <= 0 || d.ChannelID <= 0 || d.TargetUserID <= 0 ||
+		d.TemplateID <= 0 || d.EphemeralID <= 0 || d.EphemeralID > MaxMessageBoxID ||
+		d.JoinedAt <= 0 || d.AttemptCount <= 0 || d.ExpiresAt.IsZero() || !d.ExpiresAt.After(now) {
+		return ErrWelcomeMessageInvalid
+	}
+	return d.Content.Validate()
+}
+
+func WelcomeCreateFingerprint(peer Peer, creatorUserID, randomID int64, content WelcomeMessageContent) ([32]byte, error) {
+	raw, err := json.Marshal(struct {
+		Peer          Peer
+		CreatorUserID int64
+		RandomID      int64
+		Content       WelcomeMessageContent
+	}{peer, creatorUserID, randomID, content})
+	if err != nil {
+		return [32]byte{}, err
+	}
+	return sha256.Sum256(raw), nil
+}
+
+func NextWelcomeRevision(current int64) (int64, error) {
+	if current < InitialWelcomeRevision || current == math.MaxInt64 {
+		return 0, ErrWelcomeMessageRevisionOverflow
+	}
+	return current + 1, nil
+}