State: Added Reaction state handlers

discord/message.go

@@ -14,10 +14,6 @@ type Message struct {
 	// message object.
 	Author User `json:"author"`
 
-	// The member object exists in MESSAGE_CREATE and MESSAGE_UPDATE
-	// events from text-based guild channels.
-	Member *Member `json:"member,omitempty"`
-
 	Content string `json:"content"`
 
 	Timestamp       Timestamp `json:"timestamp,omitempty"`

gateway/events.go

@@ -173,8 +173,14 @@ func (u GuildMemberUpdateEvent) Update(m *discord.Member) {
 
 // https://discordapp.com/developers/docs/topics/gateway#messages
 type (
-	MessageCreateEvent discord.Message
-	MessageUpdateEvent discord.Message
+	MessageCreateEvent struct {
+		discord.Message
+		Member *discord.Member `json:"member,omitempty"`
+	}
+	MessageUpdateEvent struct {
+		discord.Message
+		Member *discord.Member `json:"member,omitempty"`
+	}
 	MessageDeleteEvent struct {
 		ID        discord.Snowflake `json:"id"`
 		ChannelID discord.Snowflake `json:"channel_id"`
@@ -200,13 +206,19 @@ type (
 		UserID    discord.Snowflake `json:"user_id"`
 		ChannelID discord.Snowflake `json:"channel_id"`
 		MessageID discord.Snowflake `json:"message_id"`
-
-		Emoji discord.Emoji `json:"emoji"`
-
-		GuildID discord.Snowflake `json:"guild_id,omitempty"`
+		Emoji     discord.Emoji     `json:"emoji"`
+		GuildID   discord.Snowflake `json:"guild_id,omitempty"`
 	}
 	MessageReactionRemoveAllEvent struct {
 		ChannelID discord.Snowflake `json:"channel_id"`
+		MessageID discord.Snowflake `json:"message_id"`
+		GuildID   discord.Snowflake `json:"guild_id,omitempty"`
+	}
+	MessageReactionRemoveEmoji struct {
+		ChannelID discord.Snowflake `json:"channel_id"`
+		MessageID discord.Snowflake `json:"message_id"`
+		Emoji     discord.Emoji     `json:"emoji"`
+		GuildID   discord.Snowflake `json:"guild_id,omitempty"`
 	}
 
 	MessageAckEvent struct {

state/state_events.go

@@ -134,14 +134,15 @@ func (s *State) onEvent(iface interface{}) {
 			s.stateErr(err, "Failed to remove a channel in state")
 		}
 
-		// *gateway.ChannelPinsUpdateEvent is not tracked.
+	case *gateway.ChannelPinsUpdateEvent:
+		// not tracked.
 
 	case *gateway.MessageCreateEvent:
-		if err := s.Store.MessageSet((*discord.Message)(ev)); err != nil {
+		if err := s.Store.MessageSet(&ev.Message); err != nil {
 			s.stateErr(err, "Failed to add a message in state")
 		}
 	case *gateway.MessageUpdateEvent:
-		if err := s.Store.MessageSet((*discord.Message)(ev)); err != nil {
+		if err := s.Store.MessageSet(&ev.Message); err != nil {
 			s.stateErr(err, "Failed to update a message in state")
 		}
 	case *gateway.MessageDeleteEvent:
@@ -154,6 +155,62 @@ func (s *State) onEvent(iface interface{}) {
 				s.stateErr(err, "Failed to delete bulk meessages in state")
 			}
 		}
+	case *gateway.MessageReactionAddEvent:
+		s.editMessage(ev.ChannelID, ev.MessageID, func(m *discord.Message) bool {
+			if i := findReaction(m.Reactions, ev.Emoji); i > -1 {
+				m.Reactions[i].Count++
+			} else {
+				u, err := s.Store.Me()
+				if err != nil {
+					s.stateErr(err, "Failed to get self for reaction add")
+					return false
+				}
+				m.Reactions = append(m.Reactions, discord.Reaction{
+					Count: 1,
+					Me:    ev.UserID == u.ID,
+					Emoji: ev.Emoji,
+				})
+			}
+			return true
+		})
+	case *gateway.MessageReactionRemoveEvent:
+		s.editMessage(ev.ChannelID, ev.MessageID, func(m *discord.Message) bool {
+			var i = findReaction(m.Reactions, ev.Emoji)
+			if i < 0 {
+				return false
+			}
+
+			r := &m.Reactions[i]
+			r.Count--
+
+			switch {
+			case r.Count < 1: // If the count is 0:
+				// Remove the reaction.
+				m.Reactions = append(m.Reactions[:i], m.Reactions[i+1:]...)
+
+			case r.Me: // If reaction removal is the user's
+				u, err := s.Store.Me()
+				if err == nil && ev.UserID == u.ID {
+					r.Me = false
+				}
+			}
+
+			return true
+		})
+	case *gateway.MessageReactionRemoveAllEvent:
+		s.editMessage(ev.ChannelID, ev.MessageID, func(m *discord.Message) bool {
+			m.Reactions = nil
+			return true
+		})
+	case *gateway.MessageReactionRemoveEmoji:
+		s.editMessage(ev.ChannelID, ev.MessageID, func(m *discord.Message) bool {
+			var i = findReaction(m.Reactions, ev.Emoji)
+			if i < 0 {
+				return false
+			}
+			m.Reactions = append(m.Reactions[:i], m.Reactions[i+1:]...)
+			return true
+		})
 
 	case *gateway.PresenceUpdateEvent:
 		presence := (*discord.Presence)(ev)
@@ -201,6 +258,28 @@ func (s *State) batchLog(errors ...error) {
 
 // Helper functions
 
+func (s *State) editMessage(ch, msg discord.Snowflake, fn func(m *discord.Message) bool) {
+	m, err := s.Store.Message(ch, msg)
+	if err != nil {
+		return
+	}
+	if !fn(m) {
+		return
+	}
+	if err := s.Store.MessageSet(m); err != nil {
+		s.stateErr(err, "Failed to save message in reaction add")
+	}
+}
+
+func findReaction(rs []discord.Reaction, emoji discord.Emoji) int {
+	for i := range rs {
+		if rs[i].Emoji.ID == emoji.ID && rs[i].Emoji.Name == emoji.Name {
+			return i
+		}
+	}
+	return -1
+}
+
 func handleGuildCreate(store Store, guild *gateway.GuildCreateEvent) []error {
 	// If a guild is unavailable, don't populate it in the state, as the guild
 	// data is very incomplete.