Reaction rendering

Reactions can now be rendered inline. This can be toggled via the
`ShowReactionsInline` configuration field.

config/config.go

@@ -145,6 +145,9 @@ type Config struct {
 	// application, as there are some childish goons that deem it funny
 	// to impersonate people or change their name every 5 minutes.
 	ShowNicknames bool
+	// ShowReactionsInline decides whether reactions are displayed below a
+	// message.
+	ShowReactionsInline bool
 
 	// FileHandlers allow registering specific file-handers for certain
 	FileOpenHandlers map[string]string
@@ -208,6 +211,7 @@ func createDefaultConfig() *Config {
 		IndicateChannelAccessRestriction:            false,
 		ShowBottomBar:                               true,
 		ShowNicknames:                               true,
+		ShowReactionsInline:                         true,
 		FileOpenHandlers:                            make(map[string]string),
 		FileOpenSaveFilesPermanently:                false,
 		FileDownloadSaveLocation:                    "~/Downloads",

discordutil/message.go

@@ -245,3 +245,51 @@ func ReplaceMentions(message *discordgo.Message) string {
 	}
 	return strings.NewReplacer(replaceInstructions...).Replace(message.Content)
 }
+
+// HandleReactionAdd adds a new reaction to a message or updates the count if
+// that message already has a reaction with that same emoji.
+func HandleReactionAdd(state *discordgo.State,
+	message *discordgo.Message,
+	newReaction *discordgo.MessageReactionAdd) {
+	for _, reaction := range message.Reactions {
+		//Only custom emojis have IDs and non custom unes have unique names.
+		if reaction.Emoji.ID == newReaction.Emoji.ID && reaction.Emoji.Name == newReaction.Emoji.Name {
+			//Match found, so we can add one to the count.
+			reaction.Count++
+			return
+		}
+	}
+
+	//FIXME Better look up emoji in cache if possible?
+	message.Reactions = append(message.Reactions, &discordgo.MessageReactions{
+		Count: 1,
+		Emoji: &newReaction.Emoji,
+		Me:    newReaction.UserID == state.User.ID,
+	})
+}
+
+// HandleReactionRemove removes an existing reaction to a message or updates
+// the count if the same message still has reactions with the same emoji left.
+func HandleReactionRemove(state *discordgo.State,
+	message *discordgo.Message,
+	newReaction *discordgo.MessageReactionRemove) {
+	for index, reaction := range message.Reactions {
+		//Only custom emojis have IDs and non custom unes have unique names.
+		if reaction.Emoji.ID == newReaction.Emoji.ID && reaction.Emoji.Name == newReaction.Emoji.Name {
+			if reaction.Count <= 1 {
+				message.Reactions = append(message.Reactions[:index], message.Reactions[index+1:]...)
+				//No more reactions of that emoji would be left, therefore we remove the array entry.
+			} else {
+				//Only a single user removed his reaction, so we keep the array entry.
+				reaction.Count--
+			}
+			return
+		}
+	}
+}
+
+// HandleReactionRemoveAll removes all reactions from all users in a message.
+func HandleReactionRemoveAll(state *discordgo.State,
+	message *discordgo.Message) {
+	message.Reactions = message.Reactions[0:0]
+}

ui/chatview.go

@@ -714,8 +714,32 @@ func (chatView *ChatView) formatDefaultMessageText(message *discordgo.Message) s
 		}
 	}
 
+	var reactionText string
+	if len(message.Reactions) > 0 {
+		var reactionBuilder strings.Builder
+		reactionBuilder.Grow(10 + len(message.Reactions)*8)
+		reactionBuilder.WriteString("\nReactions: ")
+		for rIndex, reaction := range message.Reactions {
+			if reaction.Emoji.Name != "" {
+				reactionBuilder.WriteString(tviewutil.Escape(reaction.Emoji.Name))
+				if reaction.Me {
+					reactionBuilder.WriteString("[::r]")
+				}
+				reactionBuilder.WriteRune('-')
+				reactionBuilder.WriteString(strconv.FormatInt(int64(reaction.Count), 10))
+				if reaction.Me {
+					reactionBuilder.WriteString("[::-]")
+				}
+				if rIndex != len(message.Reactions)-1 {
+					reactionBuilder.WriteRune(' ')
+				}
+			}
+		}
+		reactionText = reactionBuilder.String()
+	}
+
 	if !hasRichEmbed {
-		return messageText
+		return messageText + reactionText
 	}
 
 	var messageBuffer strings.Builder
@@ -808,7 +832,7 @@ func (chatView *ChatView) formatDefaultMessageText(message *discordgo.Message) s
 		embedBuffer.WriteRune('\n')
 	}
 
-	return messageBuffer.String()
+	return messageBuffer.String() + reactionText
 }
 
 func parseCustomEmojis(text string) string {

ui/window.go

@@ -742,6 +742,7 @@ func NewWindow(app *tview.Application, session *discordgo.Session, readyEvent *d
 
 	window.registerMessageEventHandler(messageInputChan, messageEditChan, messageDeleteChan, messageBulkDeleteChan)
 	window.startMessageHandlerRoutines(messageInputChan, messageEditChan, messageDeleteChan, messageBulkDeleteChan)
+	window.registerReactionEventHandlers()
 
 	window.userList = NewUserTree(window.session.State)
 
@@ -1653,6 +1654,73 @@ func (window *Window) registerMessageEventHandler(input, edit, delete chan *disc
 	})
 }
 
+// registerReactionEventHandlers are responsible for updating the cache if
+// reactions are added or removed and updating the chatview if needed.
+func (window *Window) registerReactionEventHandlers() {
+	window.session.AddHandler(func(s *discordgo.Session, m *discordgo.MessageReactionAdd) {
+		message, stateError := s.State.Message(m.ChannelID, m.MessageID)
+		if message != nil && stateError == nil {
+			s.State.Lock()
+			defer func() {
+				selectedChannel := window.selectedChannel
+				if selectedChannel != nil && selectedChannel.ID == m.ChannelID {
+					window.app.QueueUpdateDraw(func() {
+						window.chatView.Lock()
+						defer window.chatView.Unlock()
+
+						window.chatView.UpdateMessage(message)
+					})
+				}
+			}()
+			defer s.State.Unlock()
+
+			discordutil.HandleReactionAdd(s.State, message, m)
+		}
+	})
+
+	window.session.AddHandler(func(s *discordgo.Session, m *discordgo.MessageReactionRemove) {
+		message, stateError := s.State.Message(m.ChannelID, m.MessageID)
+		if message != nil && stateError == nil {
+			s.State.Lock()
+			defer func() {
+				selectedChannel := window.selectedChannel
+				if selectedChannel != nil && selectedChannel.ID == m.ChannelID {
+					window.app.QueueUpdateDraw(func() {
+						window.chatView.Lock()
+						defer window.chatView.Unlock()
+
+						window.chatView.UpdateMessage(message)
+					})
+				}
+			}()
+			defer s.State.Unlock()
+
+			discordutil.HandleReactionRemove(s.State, message, m)
+		}
+	})
+
+	window.session.AddHandler(func(s *discordgo.Session, m *discordgo.MessageReactionRemoveAll) {
+		message, stateError := s.State.Message(m.ChannelID, m.MessageID)
+		if message != nil && stateError == nil {
+			s.State.Lock()
+			defer func() {
+				selectedChannel := window.selectedChannel
+				if selectedChannel != nil && selectedChannel.ID == m.ChannelID {
+					window.app.QueueUpdateDraw(func() {
+						window.chatView.Lock()
+						defer window.chatView.Unlock()
+
+						window.chatView.UpdateMessage(message)
+					})
+				}
+			}()
+			defer s.State.Unlock()
+
+			discordutil.HandleReactionRemoveAll(s.State, message)
+		}
+	})
+}
+
 // QueueUpdateDrawSynchronized is meant to be used by goroutines that aren't
 // the main goroutine in order to wait for the UI-Thread to execute the given
 // If this method is ever called from the main thread, the application will