feat: implement GuildStickersUpdate event (#1614)

---------

Co-authored-by: Fedor Lapshin <fe.lap.prog@gmail.com>

eventhandlers.go

@@ -41,6 +41,7 @@ const (
 	guildScheduledEventUpdateEventType           = "GUILD_SCHEDULED_EVENT_UPDATE"
 	guildScheduledEventUserAddEventType          = "GUILD_SCHEDULED_EVENT_USER_ADD"
 	guildScheduledEventUserRemoveEventType       = "GUILD_SCHEDULED_EVENT_USER_REMOVE"
+	guildStickersUpdateEventType                 = "GUILD_STICKERS_UPDATE"
 	guildUpdateEventType                         = "GUILD_UPDATE"
 	integrationCreateEventType                   = "INTEGRATION_CREATE"
 	integrationDeleteEventType                   = "INTEGRATION_DELETE"
@@ -746,6 +747,26 @@ func (eh guildScheduledEventUserRemoveEventHandler) Handle(s *Session, i interfa
 	}
 }
 
+// guildStickersUpdateEventHandler is an event handler for GuildStickersUpdate events.
+type guildStickersUpdateEventHandler func(*Session, *GuildStickersUpdate)
+
+// Type returns the event type for GuildStickersUpdate events.
+func (eh guildStickersUpdateEventHandler) Type() string {
+	return guildStickersUpdateEventType
+}
+
+// New returns a new instance of GuildStickersUpdate.
+func (eh guildStickersUpdateEventHandler) New() interface{} {
+	return &GuildStickersUpdate{}
+}
+
+// Handle is the handler for GuildStickersUpdate events.
+func (eh guildStickersUpdateEventHandler) Handle(s *Session, i interface{}) {
+	if t, ok := i.(*GuildStickersUpdate); ok {
+		eh(s, t)
+	}
+}
+
 // guildUpdateEventHandler is an event handler for GuildUpdate events.
 type guildUpdateEventHandler func(*Session, *GuildUpdate)
 
@@ -1573,6 +1594,8 @@ func handlerForInterface(handler interface{}) EventHandler {
 		return guildScheduledEventUserAddEventHandler(v)
 	case func(*Session, *GuildScheduledEventUserRemove):
 		return guildScheduledEventUserRemoveEventHandler(v)
+	case func(*Session, *GuildStickersUpdate):
+		return guildStickersUpdateEventHandler(v)
 	case func(*Session, *GuildUpdate):
 		return guildUpdateEventHandler(v)
 	case func(*Session, *IntegrationCreate):
@@ -1686,6 +1709,7 @@ func init() {
 	registerInterfaceProvider(guildScheduledEventUpdateEventHandler(nil))
 	registerInterfaceProvider(guildScheduledEventUserAddEventHandler(nil))
 	registerInterfaceProvider(guildScheduledEventUserRemoveEventHandler(nil))
+	registerInterfaceProvider(guildStickersUpdateEventHandler(nil))
 	registerInterfaceProvider(guildUpdateEventHandler(nil))
 	registerInterfaceProvider(integrationCreateEventHandler(nil))
 	registerInterfaceProvider(integrationDeleteEventHandler(nil))

events.go

@@ -181,6 +181,12 @@ type GuildEmojisUpdate struct {
 	Emojis  []*Emoji `json:"emojis"`
 }
 
+// A GuildStickersUpdate is the data for a GuildStickersUpdate event.
+type GuildStickersUpdate struct {
+	GuildID  string     `json:"guild_id"`
+	Stickers []*Sticker `json:"stickers"`
+}
+
 // A GuildMembersChunk is the data for a GuildMembersChunk event.
 type GuildMembersChunk struct {
 	GuildID    string      `json:"guild_id"`

state.go

@@ -42,6 +42,7 @@ type State struct {
 	TrackChannels      bool
 	TrackThreads       bool
 	TrackEmojis        bool
+	TrackStickers      bool
 	TrackMembers       bool
 	TrackThreadMembers bool
 	TrackRoles         bool
@@ -63,6 +64,7 @@ func NewState() *State {
 		TrackChannels:      true,
 		TrackThreads:       true,
 		TrackEmojis:        true,
+		TrackStickers:      true,
 		TrackMembers:       true,
 		TrackThreadMembers: true,
 		TrackRoles:         true,
@@ -175,8 +177,8 @@ func (s *State) GuildRemove(guild *Guild) error {
 
 // Guild gets a guild by ID.
 // Useful for querying if @me is in a guild:
-//     _, err := discordgo.Session.State.Guild(guildID)
+//    _, err := discordgo.Session.State.Guild(guildID)
-//     isInGuild := err == nil
+//	  isInGuild := err == nil
 func (s *State) Guild(guildID string) (*Guild, error) {
 	if s == nil {
 		return nil, ErrNilState
@@ -1050,6 +1052,17 @@ func (s *State) OnInterface(se *Session, i interface{}) (err error) {
 			defer s.Unlock()
 			guild.Emojis = t.Emojis
 		}
+	case *GuildStickersUpdate:
+		if s.TrackStickers {
+			var guild *Guild
+			guild, err = s.Guild(t.GuildID)
+			if err != nil {
+				return err
+			}
+			s.Lock()
+			defer s.Unlock()
+			guild.Stickers = t.Stickers
+		}
 	case *ChannelCreate:
 		if s.TrackChannels {
 			err = s.ChannelAdd(t.Channel)