add matterbridge

8 files changed, 1475 insertions, 0 deletions

diff --git a/teleirc/matterbridge/bridge/discord/discord.go b/teleirc/matterbridge/bridge/discord/discord.go
new file mode 100644
index 0000000..5ae6c57
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/discord.go
@@ -0,0 +1,384 @@
+package bdiscord
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/discord/transmitter"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/bwmarrin/discordgo"
+	lru "github.com/hashicorp/golang-lru"
+)
+
+const (
+	MessageLength = 1950
+	cFileUpload   = "file_upload"
+)
+
+type Bdiscord struct {
+	*bridge.Config
+
+	c *discordgo.Session
+
+	nick    string
+	userID  string
+	guildID string
+
+	channelsMutex  sync.RWMutex
+	channels       []*discordgo.Channel
+	channelInfoMap map[string]*config.ChannelInfo
+
+	membersMutex  sync.RWMutex
+	userMemberMap map[string]*discordgo.Member
+	nickMemberMap map[string]*discordgo.Member
+
+	// Webhook specific logic
+	useAutoWebhooks bool
+	transmitter     *transmitter.Transmitter
+	cache           *lru.Cache
+}
+
+func New(cfg *bridge.Config) bridge.Bridger {
+	newCache, err := lru.New(5000)
+	if err != nil {
+		cfg.Log.Fatalf("Could not create LRU cache: %v", err)
+	}
+
+	b := &Bdiscord{
+		Config: cfg,
+		cache:  newCache,
+	}
+
+	b.userMemberMap = make(map[string]*discordgo.Member)
+	b.nickMemberMap = make(map[string]*discordgo.Member)
+	b.channelInfoMap = make(map[string]*config.ChannelInfo)
+
+	b.useAutoWebhooks = b.GetBool("AutoWebhooks")
+	if b.useAutoWebhooks {
+		b.Log.Debug("Using automatic webhooks")
+	}
+	return b
+}
+
+func (b *Bdiscord) Connect() error {
+	var err error
+	token := b.GetString("Token")
+	b.Log.Info("Connecting")
+	if !strings.HasPrefix(b.GetString("Token"), "Bot ") {
+		token = "Bot " + b.GetString("Token")
+	}
+	// if we have a User token, remove the `Bot` prefix
+	if strings.HasPrefix(b.GetString("Token"), "User ") {
+		token = strings.Replace(b.GetString("Token"), "User ", "", -1)
+	}
+
+	b.c, err = discordgo.New(token)
+	if err != nil {
+		return err
+	}
+	b.Log.Info("Connection succeeded")
+	b.c.AddHandler(b.messageCreate)
+	b.c.AddHandler(b.messageTyping)
+	b.c.AddHandler(b.messageUpdate)
+	b.c.AddHandler(b.messageDelete)
+	b.c.AddHandler(b.messageDeleteBulk)
+	b.c.AddHandler(b.memberAdd)
+	b.c.AddHandler(b.memberRemove)
+	b.c.AddHandler(b.memberUpdate)
+	if b.GetInt("debuglevel") == 1 {
+		b.c.AddHandler(b.messageEvent)
+	}
+	// Add privileged intent for guild member tracking. This is needed to track nicks
+	// for display names and @mention translation
+	b.c.Identify.Intents = discordgo.MakeIntent(discordgo.IntentsAllWithoutPrivileged |
+		discordgo.IntentsGuildMembers)
+
+	err = b.c.Open()
+	if err != nil {
+		return err
+	}
+	guilds, err := b.c.UserGuilds(100, "", "")
+	if err != nil {
+		return err
+	}
+	userinfo, err := b.c.User("@me")
+	if err != nil {
+		return err
+	}
+	serverName := strings.Replace(b.GetString("Server"), "ID:", "", -1)
+	b.nick = userinfo.Username
+	b.userID = userinfo.ID
+
+	// Try and find this account's guild, and populate channels
+	b.channelsMutex.Lock()
+	for _, guild := range guilds {
+		// Skip, if the server name does not match the visible name or the ID
+		if guild.Name != serverName && guild.ID != serverName {
+			continue
+		}
+
+		// Complain about an ambiguous Server setting. Two Discord servers could have the same title!
+		// For IDs, practically this will never happen. It would only trigger if some server's name is also an ID.
+		if b.guildID != "" {
+			return fmt.Errorf("found multiple Discord servers with the same name %#v, expected to see only one", serverName)
+		}
+
+		// Getting this guild's channel could result in a permission error
+		b.channels, err = b.c.GuildChannels(guild.ID)
+		if err != nil {
+			return fmt.Errorf("could not get %#v's channels: %w", b.GetString("Server"), err)
+		}
+
+		b.guildID = guild.ID
+	}
+	b.channelsMutex.Unlock()
+
+	// If we couldn't find a guild, we print extra debug information and return a nice error
+	if b.guildID == "" {
+		err = fmt.Errorf("could not find Discord server %#v", b.GetString("Server"))
+		b.Log.Error(err.Error())
+
+		// Print all of the possible server values
+		b.Log.Info("Possible server values:")
+		for _, guild := range guilds {
+			b.Log.Infof("\t- Server=%#v # by name", guild.Name)
+			b.Log.Infof("\t- Server=%#v # by ID", guild.ID)
+		}
+
+		// If there are no results, we should say that
+		if len(guilds) == 0 {
+			b.Log.Info("\t- (none found)")
+		}
+
+		return err
+	}
+
+	// Legacy note: WebhookURL used to have an actual webhook URL that we would edit,
+	// but we stopped doing that due to Discord making rate limits more aggressive.
+	//
+	// Even older: the same WebhookURL used to be used by every channel, which is usually unexpected.
+	// This is no longer possible.
+	if b.GetString("WebhookURL") != "" {
+		message := "The global WebhookURL setting has been removed. "
+		message += "You can get similar \"webhook editing\" behaviour by replacing this line with `AutoWebhooks=true`. "
+		message += "If you rely on the old-OLD (non-editing) behaviour, can move the WebhookURL to specific channel sections."
+		b.Log.Errorln(message)
+		return fmt.Errorf("use of removed WebhookURL setting")
+	}
+
+	if b.GetInt("debuglevel") == 2 {
+		b.Log.Debug("enabling even more discord debug")
+		b.c.Debug = true
+	}
+
+	// Initialise webhook management
+	b.transmitter = transmitter.New(b.c, b.guildID, "matterbridge", b.useAutoWebhooks)
+	b.transmitter.Log = b.Log
+
+	var webhookChannelIDs []string
+	for _, channel := range b.Channels {
+		channelID := b.getChannelID(channel.Name) // note(qaisjp): this readlocks channelsMutex
+
+		// If a WebhookURL was not explicitly provided for this channel,
+		// there are two options: just a regular bot message (ugly) or this is should be webhook sent
+		if channel.Options.WebhookURL == "" {
+			// If it should be webhook sent, we should enforce this via the transmitter
+			if b.useAutoWebhooks {
+				webhookChannelIDs = append(webhookChannelIDs, channelID)
+			}
+			continue
+		}
+
+		whID, whToken, ok := b.splitURL(channel.Options.WebhookURL)
+		if !ok {
+			return fmt.Errorf("failed to parse WebhookURL %#v for channel %#v", channel.Options.WebhookURL, channel.ID)
+		}
+
+		b.transmitter.AddWebhook(channelID, &discordgo.Webhook{
+			ID:        whID,
+			Token:     whToken,
+			GuildID:   b.guildID,
+			ChannelID: channelID,
+		})
+	}
+
+	if b.useAutoWebhooks {
+		err = b.transmitter.RefreshGuildWebhooks(webhookChannelIDs)
+		if err != nil {
+			b.Log.WithError(err).Println("transmitter could not refresh guild webhooks")
+			return err
+		}
+	}
+
+	// Obtaining guild members and initializing nickname mapping.
+	b.membersMutex.Lock()
+	defer b.membersMutex.Unlock()
+	members, err := b.c.GuildMembers(b.guildID, "", 1000)
+	if err != nil {
+		b.Log.Error("Error obtaining server members: ", err)
+		return err
+	}
+	for _, member := range members {
+		if member == nil {
+			b.Log.Warnf("Skipping missing information for a user.")
+			continue
+		}
+		b.userMemberMap[member.User.ID] = member
+		b.nickMemberMap[member.User.Username] = member
+		if member.Nick != "" {
+			b.nickMemberMap[member.Nick] = member
+		}
+	}
+	return nil
+}
+
+func (b *Bdiscord) Disconnect() error {
+	return b.c.Close()
+}
+
+func (b *Bdiscord) JoinChannel(channel config.ChannelInfo) error {
+	b.channelsMutex.Lock()
+	defer b.channelsMutex.Unlock()
+
+	b.channelInfoMap[channel.ID] = &channel
+	return nil
+}
+
+func (b *Bdiscord) Send(msg config.Message) (string, error) {
+	b.Log.Debugf("=> Receiving %#v", msg)
+
+	channelID := b.getChannelID(msg.Channel)
+	if channelID == "" {
+		return "", fmt.Errorf("Could not find channelID for %v", msg.Channel)
+	}
+
+	if msg.Event == config.EventUserTyping {
+		if b.GetBool("ShowUserTyping") {
+			err := b.c.ChannelTyping(channelID)
+			return "", err
+		}
+		return "", nil
+	}
+
+	// Make a action /me of the message
+	if msg.Event == config.EventUserAction {
+		msg.Text = "_" + msg.Text + "_"
+	}
+
+	// Handle prefix hint for unthreaded messages.
+	if msg.ParentNotFound() {
+		msg.ParentID = ""
+	}
+
+	// Use webhook to send the message
+	useWebhooks := b.shouldMessageUseWebhooks(&msg)
+	if useWebhooks && msg.Event != config.EventMsgDelete && msg.ParentID == "" {
+		return b.handleEventWebhook(&msg, channelID)
+	}
+
+	return b.handleEventBotUser(&msg, channelID)
+}
+
+// handleEventDirect handles events via the bot user
+func (b *Bdiscord) handleEventBotUser(msg *config.Message, channelID string) (string, error) {
+	b.Log.Debugf("Broadcasting using token (API)")
+
+	// Delete message
+	if msg.Event == config.EventMsgDelete {
+		if msg.ID == "" {
+			return "", nil
+		}
+		err := b.c.ChannelMessageDelete(channelID, msg.ID)
+		return "", err
+	}
+
+	// Delete a file
+	if msg.Event == config.EventFileDelete {
+		if msg.ID == "" {
+			return "", nil
+		}
+
+		if fi, ok := b.cache.Get(cFileUpload + msg.ID); ok {
+			err := b.c.ChannelMessageDelete(channelID, fi.(string)) // nolint:forcetypeassert
+			b.cache.Remove(cFileUpload + msg.ID)
+			return "", err
+		}
+
+		return "", fmt.Errorf("file %s not found", msg.ID)
+	}
+
+	// Upload a file if it exists
+	if msg.Extra != nil {
+		for _, rmsg := range helper.HandleExtra(msg, b.General) {
+			rmsg.Text = helper.ClipMessage(rmsg.Text, MessageLength, b.GetString("MessageClipped"))
+			if _, err := b.c.ChannelMessageSend(channelID, rmsg.Username+rmsg.Text); err != nil {
+				b.Log.Errorf("Could not send message %#v: %s", rmsg, err)
+			}
+		}
+		// check if we have files to upload (from slack, telegram or mattermost)
+		if len(msg.Extra["file"]) > 0 {
+			return b.handleUploadFile(msg, channelID)
+		}
+	}
+
+	msg.Text = helper.ClipMessage(msg.Text, MessageLength, b.GetString("MessageClipped"))
+	msg.Text = b.replaceUserMentions(msg.Text)
+
+	// Edit message
+	if msg.ID != "" {
+		_, err := b.c.ChannelMessageEdit(channelID, msg.ID, msg.Username+msg.Text)
+		return msg.ID, err
+	}
+
+	m := discordgo.MessageSend{
+		Content:         msg.Username + msg.Text,
+		AllowedMentions: b.getAllowedMentions(),
+	}
+
+	if msg.ParentValid() {
+		m.Reference = &discordgo.MessageReference{
+			MessageID: msg.ParentID,
+			ChannelID: channelID,
+			GuildID:   b.guildID,
+		}
+	}
+
+	// Post normal message
+	res, err := b.c.ChannelMessageSendComplex(channelID, &m)
+	if err != nil {
+		return "", err
+	}
+
+	return res.ID, nil
+}
+
+// handleUploadFile handles native upload of files
+func (b *Bdiscord) handleUploadFile(msg *config.Message, channelID string) (string, error) {
+	for _, f := range msg.Extra["file"] {
+		fi := f.(config.FileInfo)
+		file := discordgo.File{
+			Name:        fi.Name,
+			ContentType: "",
+			Reader:      bytes.NewReader(*fi.Data),
+		}
+		m := discordgo.MessageSend{
+			Content:         msg.Username + fi.Comment,
+			Files:           []*discordgo.File{&file},
+			AllowedMentions: b.getAllowedMentions(),
+		}
+		res, err := b.c.ChannelMessageSendComplex(channelID, &m)
+		if err != nil {
+			return "", fmt.Errorf("file upload failed: %s", err)
+		}
+
+		// link file_upload_nativeID (file ID from the original bridge) to our upload id
+		// so that we can remove this later when it eg needs to be deleted
+		b.cache.Add(cFileUpload+fi.NativeID, res.ID)
+	}
+
+	return "", nil
+}
diff --git a/teleirc/matterbridge/bridge/discord/handlers.go b/teleirc/matterbridge/bridge/discord/handlers.go
new file mode 100644
index 0000000..34cef55
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/handlers.go
@@ -0,0 +1,281 @@
+package bdiscord
+
+import (
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/bwmarrin/discordgo"
+	"github.com/davecgh/go-spew/spew"
+)
+
+func (b *Bdiscord) messageDelete(s *discordgo.Session, m *discordgo.MessageDelete) { //nolint:unparam
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring messageDelete because it originates from a different guild")
+		return
+	}
+	rmsg := config.Message{Account: b.Account, ID: m.ID, Event: config.EventMsgDelete, Text: config.EventMsgDelete}
+	rmsg.Channel = b.getChannelName(m.ChannelID)
+
+	b.Log.Debugf("<= Sending message from %s to gateway", b.Account)
+	b.Log.Debugf("<= Message is %#v", rmsg)
+	b.Remote <- rmsg
+}
+
+// TODO(qaisjp): if other bridges support bulk deletions, it could be fanned out centrally
+func (b *Bdiscord) messageDeleteBulk(s *discordgo.Session, m *discordgo.MessageDeleteBulk) { //nolint:unparam
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring messageDeleteBulk because it originates from a different guild")
+		return
+	}
+	for _, msgID := range m.Messages {
+		rmsg := config.Message{
+			Account: b.Account,
+			ID:      msgID,
+			Event:   config.EventMsgDelete,
+			Text:    config.EventMsgDelete,
+			Channel: b.getChannelName(m.ChannelID),
+		}
+
+		b.Log.Debugf("<= Sending message from %s to gateway", b.Account)
+		b.Log.Debugf("<= Message is %#v", rmsg)
+		b.Remote <- rmsg
+	}
+}
+
+func (b *Bdiscord) messageEvent(s *discordgo.Session, m *discordgo.Event) {
+	b.Log.Debug(spew.Sdump(m.Struct))
+}
+
+func (b *Bdiscord) messageTyping(s *discordgo.Session, m *discordgo.TypingStart) {
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring messageTyping because it originates from a different guild")
+		return
+	}
+	if !b.GetBool("ShowUserTyping") {
+		return
+	}
+
+	// Ignore our own typing messages
+	if m.UserID == b.userID {
+		return
+	}
+
+	rmsg := config.Message{Account: b.Account, Event: config.EventUserTyping}
+	rmsg.Channel = b.getChannelName(m.ChannelID)
+	b.Remote <- rmsg
+}
+
+func (b *Bdiscord) messageUpdate(s *discordgo.Session, m *discordgo.MessageUpdate) { //nolint:unparam
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring messageUpdate because it originates from a different guild")
+		return
+	}
+	if b.GetBool("EditDisable") {
+		return
+	}
+	// only when message is actually edited
+	if m.Message.EditedTimestamp != nil {
+		b.Log.Debugf("Sending edit message")
+		m.Content += b.GetString("EditSuffix")
+		msg := &discordgo.MessageCreate{
+			Message: m.Message,
+		}
+		b.messageCreate(s, msg)
+	}
+}
+
+func (b *Bdiscord) messageCreate(s *discordgo.Session, m *discordgo.MessageCreate) { //nolint:unparam
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring messageCreate because it originates from a different guild")
+		return
+	}
+	var err error
+
+	// not relay our own messages
+	if m.Author.Username == b.nick {
+		return
+	}
+	// if using webhooks, do not relay if it's ours
+	if m.Author.Bot && b.transmitter.HasWebhook(m.Author.ID) {
+		return
+	}
+
+	// add the url of the attachments to content
+	if len(m.Attachments) > 0 {
+		for _, attach := range m.Attachments {
+			m.Content = m.Content + "\n" + attach.URL
+		}
+	}
+
+	rmsg := config.Message{Account: b.Account, Avatar: "https://cdn.discordapp.com/avatars/" + m.Author.ID + "/" + m.Author.Avatar + ".jpg", UserID: m.Author.ID, ID: m.ID}
+
+	b.Log.Debugf("== Receiving event %#v", m.Message)
+
+	if m.Content != "" {
+		m.Message.Content = b.replaceChannelMentions(m.Message.Content)
+		rmsg.Text, err = m.ContentWithMoreMentionsReplaced(b.c)
+		if err != nil {
+			b.Log.Errorf("ContentWithMoreMentionsReplaced failed: %s", err)
+			rmsg.Text = m.ContentWithMentionsReplaced()
+		}
+	}
+
+	// set channel name
+	rmsg.Channel = b.getChannelName(m.ChannelID)
+
+	fromWebhook := m.WebhookID != ""
+	if !fromWebhook && !b.GetBool("UseUserName") {
+		rmsg.Username = b.getNick(m.Author, m.GuildID)
+	} else {
+		rmsg.Username = m.Author.Username
+		if !fromWebhook && b.GetBool("UseDiscriminator") {
+			rmsg.Username += "#" + m.Author.Discriminator
+		}
+	}
+
+	// if we have embedded content add it to text
+	if b.GetBool("ShowEmbeds") && m.Message.Embeds != nil {
+		for _, embed := range m.Message.Embeds {
+			rmsg.Text += handleEmbed(embed)
+		}
+	}
+
+	// no empty messages
+	if rmsg.Text == "" {
+		return
+	}
+
+	// do we have a /me action
+	var ok bool
+	rmsg.Text, ok = b.replaceAction(rmsg.Text)
+	if ok {
+		rmsg.Event = config.EventUserAction
+	}
+
+	// Replace emotes
+	rmsg.Text = replaceEmotes(rmsg.Text)
+
+	// Add our parent id if it exists, and if it's not referring to a message in another channel
+	if ref := m.MessageReference; ref != nil && ref.ChannelID == m.ChannelID {
+		rmsg.ParentID = ref.MessageID
+	}
+
+	b.Log.Debugf("<= Sending message from %s on %s to gateway", m.Author.Username, b.Account)
+	b.Log.Debugf("<= Message is %#v", rmsg)
+	b.Remote <- rmsg
+}
+
+func (b *Bdiscord) memberUpdate(s *discordgo.Session, m *discordgo.GuildMemberUpdate) {
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring memberUpdate because it originates from a different guild")
+		return
+	}
+	if m.Member == nil {
+		b.Log.Warnf("Received member update with no member information: %#v", m)
+	}
+
+	b.membersMutex.Lock()
+	defer b.membersMutex.Unlock()
+
+	if currMember, ok := b.userMemberMap[m.Member.User.ID]; ok {
+		b.Log.Debugf(
+			"%s: memberupdate: user %s (nick %s) changes nick to %s",
+			b.Account,
+			m.Member.User.Username,
+			b.userMemberMap[m.Member.User.ID].Nick,
+			m.Member.Nick,
+		)
+		delete(b.nickMemberMap, currMember.User.Username)
+		delete(b.nickMemberMap, currMember.Nick)
+		delete(b.userMemberMap, m.Member.User.ID)
+	}
+	b.userMemberMap[m.Member.User.ID] = m.Member
+	b.nickMemberMap[m.Member.User.Username] = m.Member
+	if m.Member.Nick != "" {
+		b.nickMemberMap[m.Member.Nick] = m.Member
+	}
+}
+
+func (b *Bdiscord) memberAdd(s *discordgo.Session, m *discordgo.GuildMemberAdd) {
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring memberAdd because it originates from a different guild")
+		return
+	}
+	if b.GetBool("nosendjoinpart") {
+		return
+	}
+	if m.Member == nil {
+		b.Log.Warnf("Received member update with no member information: %#v", m)
+		return
+	}
+	username := m.Member.User.Username
+	if m.Member.Nick != "" {
+		username = m.Member.Nick
+	}
+
+	rmsg := config.Message{
+		Account:  b.Account,
+		Event:    config.EventJoinLeave,
+		Username: "system",
+		Text:     username + " joins",
+	}
+	b.Log.Debugf("<= Sending message from %s to gateway", b.Account)
+	b.Log.Debugf("<= Message is %#v", rmsg)
+	b.Remote <- rmsg
+}
+
+func (b *Bdiscord) memberRemove(s *discordgo.Session, m *discordgo.GuildMemberRemove) {
+	if m.GuildID != b.guildID {
+		b.Log.Debugf("Ignoring memberRemove because it originates from a different guild")
+		return
+	}
+	if b.GetBool("nosendjoinpart") {
+		return
+	}
+	if m.Member == nil {
+		b.Log.Warnf("Received member update with no member information: %#v", m)
+		return
+	}
+	username := m.Member.User.Username
+	if m.Member.Nick != "" {
+		username = m.Member.Nick
+	}
+
+	rmsg := config.Message{
+		Account:  b.Account,
+		Event:    config.EventJoinLeave,
+		Username: "system",
+		Text:     username + " leaves",
+	}
+	b.Log.Debugf("<= Sending message from %s to gateway", b.Account)
+	b.Log.Debugf("<= Message is %#v", rmsg)
+	b.Remote <- rmsg
+}
+
+func handleEmbed(embed *discordgo.MessageEmbed) string {
+	var t []string
+	var result string
+
+	t = append(t, embed.Title)
+	t = append(t, embed.Description)
+	t = append(t, embed.URL)
+
+	i := 0
+	for _, e := range t {
+		if e == "" {
+			continue
+		}
+
+		i++
+		if i == 1 {
+			result += " embed: " + e
+			continue
+		}
+
+		result += " - " + e
+	}
+
+	if result != "" {
+		result += "\n"
+	}
+
+	return result
+}
diff --git a/teleirc/matterbridge/bridge/discord/handlers_test.go b/teleirc/matterbridge/bridge/discord/handlers_test.go
new file mode 100644
index 0000000..915d9b1
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/handlers_test.go
@@ -0,0 +1,58 @@
+package bdiscord
+
+import (
+	"testing"
+
+	"github.com/bwmarrin/discordgo"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHandleEmbed(t *testing.T) {
+	testcases := map[string]struct {
+		embed  *discordgo.MessageEmbed
+		result string
+	}{
+		"allempty": {
+			embed:  &discordgo.MessageEmbed{},
+			result: "",
+		},
+		"one": {
+			embed: &discordgo.MessageEmbed{
+				Title: "blah",
+			},
+			result: " embed: blah\n",
+		},
+		"two": {
+			embed: &discordgo.MessageEmbed{
+				Title:       "blah",
+				Description: "blah2",
+			},
+			result: " embed: blah - blah2\n",
+		},
+		"three": {
+			embed: &discordgo.MessageEmbed{
+				Title:       "blah",
+				Description: "blah2",
+				URL:         "blah3",
+			},
+			result: " embed: blah - blah2 - blah3\n",
+		},
+		"twob": {
+			embed: &discordgo.MessageEmbed{
+				Description: "blah2",
+				URL:         "blah3",
+			},
+			result: " embed: blah2 - blah3\n",
+		},
+		"oneb": {
+			embed: &discordgo.MessageEmbed{
+				URL: "blah3",
+			},
+			result: " embed: blah3\n",
+		},
+	}
+
+	for name, tc := range testcases {
+		assert.Equalf(t, tc.result, handleEmbed(tc.embed), "Testcases %s", name)
+	}
+}
diff --git a/teleirc/matterbridge/bridge/discord/helpers.go b/teleirc/matterbridge/bridge/discord/helpers.go
new file mode 100644
index 0000000..2e18f46
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/helpers.go
@@ -0,0 +1,269 @@
+package bdiscord
+
+import (
+	"errors"
+	"regexp"
+	"strings"
+	"unicode"
+
+	"github.com/bwmarrin/discordgo"
+)
+
+func (b *Bdiscord) getAllowedMentions() *discordgo.MessageAllowedMentions {
+	// If AllowMention is not specified, then allow all mentions (default Discord behavior)
+	if !b.IsKeySet("AllowMention") {
+		return nil
+	}
+
+	// Otherwise, allow only the mentions that are specified
+	allowedMentionTypes := make([]discordgo.AllowedMentionType, 0, 3)
+	for _, m := range b.GetStringSlice("AllowMention") {
+		switch m {
+		case "everyone":
+			allowedMentionTypes = append(allowedMentionTypes, discordgo.AllowedMentionTypeEveryone)
+		case "roles":
+			allowedMentionTypes = append(allowedMentionTypes, discordgo.AllowedMentionTypeRoles)
+		case "users":
+			allowedMentionTypes = append(allowedMentionTypes, discordgo.AllowedMentionTypeUsers)
+		}
+	}
+
+	return &discordgo.MessageAllowedMentions{
+		Parse: allowedMentionTypes,
+	}
+}
+
+func (b *Bdiscord) getNick(user *discordgo.User, guildID string) string {
+	b.membersMutex.RLock()
+	defer b.membersMutex.RUnlock()
+
+	if member, ok := b.userMemberMap[user.ID]; ok {
+		if member.Nick != "" {
+			// Only return if nick is set.
+			return member.Nick
+		}
+		// Otherwise return username.
+		return user.Username
+	}
+
+	// If we didn't find nick, search for it.
+	member, err := b.c.GuildMember(guildID, user.ID)
+	if err != nil {
+		b.Log.Warnf("Failed to fetch information for member %#v on guild %#v: %s", user, guildID, err)
+		return user.Username
+	} else if member == nil {
+		b.Log.Warnf("Got no information for member %#v", user)
+		return user.Username
+	}
+	b.userMemberMap[user.ID] = member
+	b.nickMemberMap[member.User.Username] = member
+	if member.Nick != "" {
+		b.nickMemberMap[member.Nick] = member
+		return member.Nick
+	}
+	return user.Username
+}
+
+func (b *Bdiscord) getGuildMemberByNick(nick string) (*discordgo.Member, error) {
+	b.membersMutex.RLock()
+	defer b.membersMutex.RUnlock()
+
+	if member, ok := b.nickMemberMap[nick]; ok {
+		return member, nil
+	}
+	return nil, errors.New("Couldn't find guild member with nick " + nick) // This will most likely get ignored by the caller
+}
+
+func (b *Bdiscord) getChannelID(name string) string {
+	if strings.Contains(name, "/") {
+		return b.getCategoryChannelID(name)
+	}
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+
+	idcheck := strings.Split(name, "ID:")
+	if len(idcheck) > 1 {
+		return idcheck[1]
+	}
+	for _, channel := range b.channels {
+		if channel.Name == name && channel.Type == discordgo.ChannelTypeGuildText {
+			return channel.ID
+		}
+	}
+	return ""
+}
+
+func (b *Bdiscord) getCategoryChannelID(name string) string {
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+	res := strings.Split(name, "/")
+	// shouldn't happen because function should be only called from getChannelID
+	if len(res) != 2 {
+		return ""
+	}
+	catName, chanName := res[0], res[1]
+	for _, channel := range b.channels {
+		// if we have a parentID, lookup the name of that parent (category)
+		// and if it matches return it
+		if channel.Name == chanName && channel.ParentID != "" {
+			for _, cat := range b.channels {
+				if cat.ID == channel.ParentID && cat.Name == catName {
+					return channel.ID
+				}
+			}
+		}
+	}
+	return ""
+}
+
+func (b *Bdiscord) getChannelName(id string) string {
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+
+	for _, c := range b.channelInfoMap {
+		if c.Name == "ID:"+id {
+			// if we have ID: specified in our gateway configuration return this
+			return c.Name
+		}
+	}
+
+	for _, channel := range b.channels {
+		if channel.ID == id {
+			return b.getCategoryChannelName(channel.Name, channel.ParentID)
+		}
+	}
+	return ""
+}
+
+func (b *Bdiscord) getCategoryChannelName(name, parentID string) string {
+	var usesCat bool
+	// do we have a category configuration in the channel config
+	for _, c := range b.channelInfoMap {
+		if strings.Contains(c.Name, "/") {
+			usesCat = true
+			break
+		}
+	}
+	// configuration without category, return the normal channel name
+	if !usesCat {
+		return name
+	}
+	// create a category/channel response
+	for _, c := range b.channels {
+		if c.ID == parentID {
+			name = c.Name + "/" + name
+		}
+	}
+	return name
+}
+
+var (
+	// See https://discordapp.com/developers/docs/reference#message-formatting.
+	channelMentionRE = regexp.MustCompile("<#[0-9]+>")
+	userMentionRE    = regexp.MustCompile("@[^@\n]{1,32}")
+	emoteRE          = regexp.MustCompile(`<a?(:\w+:)\d+>`)
+)
+
+func (b *Bdiscord) replaceChannelMentions(text string) string {
+	replaceChannelMentionFunc := func(match string) string {
+		channelID := match[2 : len(match)-1]
+		channelName := b.getChannelName(channelID)
+
+		// If we don't have the channel refresh our list.
+		if channelName == "" {
+			var err error
+			b.channels, err = b.c.GuildChannels(b.guildID)
+			if err != nil {
+				return "#unknownchannel"
+			}
+			channelName = b.getChannelName(channelID)
+		}
+		return "#" + channelName
+	}
+	return channelMentionRE.ReplaceAllStringFunc(text, replaceChannelMentionFunc)
+}
+
+func (b *Bdiscord) replaceUserMentions(text string) string {
+	replaceUserMentionFunc := func(match string) string {
+		var (
+			err      error
+			member   *discordgo.Member
+			username string
+		)
+
+		usernames := enumerateUsernames(match[1:])
+		for _, username = range usernames {
+			b.Log.Debugf("Testing mention: '%s'", username)
+			member, err = b.getGuildMemberByNick(username)
+			if err == nil {
+				break
+			}
+		}
+		if member == nil {
+			return match
+		}
+		return strings.Replace(match, "@"+username, member.User.Mention(), 1)
+	}
+	return userMentionRE.ReplaceAllStringFunc(text, replaceUserMentionFunc)
+}
+
+func replaceEmotes(text string) string {
+	return emoteRE.ReplaceAllString(text, "$1")
+}
+
+func (b *Bdiscord) replaceAction(text string) (string, bool) {
+	length := len(text)
+	if length > 1 && text[0] == '_' && text[length-1] == '_' {
+		return text[1 : length-1], true
+	}
+	return text, false
+}
+
+// splitURL splits a webhookURL and returns the ID and token.
+func (b *Bdiscord) splitURL(url string) (string, string, bool) {
+	const (
+		expectedWebhookSplitCount = 7
+		webhookIdxID              = 5
+		webhookIdxToken           = 6
+	)
+	webhookURLSplit := strings.Split(url, "/")
+	if len(webhookURLSplit) != expectedWebhookSplitCount {
+		return "", "", false
+	}
+	return webhookURLSplit[webhookIdxID], webhookURLSplit[webhookIdxToken], true
+}
+
+func enumerateUsernames(s string) []string {
+	onlySpace := true
+	for _, r := range s {
+		if !unicode.IsSpace(r) {
+			onlySpace = false
+			break
+		}
+	}
+	if onlySpace {
+		return nil
+	}
+
+	var username, endSpace string
+	var usernames []string
+	skippingSpace := true
+	for _, r := range s {
+		if unicode.IsSpace(r) {
+			if !skippingSpace {
+				usernames = append(usernames, username)
+				skippingSpace = true
+			}
+			endSpace += string(r)
+			username += string(r)
+		} else {
+			endSpace = ""
+			username += string(r)
+			skippingSpace = false
+		}
+	}
+	if endSpace == "" {
+		usernames = append(usernames, username)
+	}
+	return usernames
+}
diff --git a/teleirc/matterbridge/bridge/discord/helpers_test.go b/teleirc/matterbridge/bridge/discord/helpers_test.go
new file mode 100644
index 0000000..0f196d9
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/helpers_test.go
@@ -0,0 +1,46 @@
+package bdiscord
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEnumerateUsernames(t *testing.T) {
+	testcases := map[string]struct {
+		match             string
+		expectedUsernames []string
+	}{
+		"only space": {
+			match:             "  \t\n \t",
+			expectedUsernames: nil,
+		},
+		"single word": {
+			match:             "veni",
+			expectedUsernames: []string{"veni"},
+		},
+		"single word with preceeding space": {
+			match:             " vidi",
+			expectedUsernames: []string{" vidi"},
+		},
+		"single word with suffixed space": {
+			match:             "vici ",
+			expectedUsernames: []string{"vici"},
+		},
+		"multi-word with varying whitespace": {
+			match: "just me  and\tmy friends \t",
+			expectedUsernames: []string{
+				"just",
+				"just me",
+				"just me  and",
+				"just me  and\tmy",
+				"just me  and\tmy friends",
+			},
+		},
+	}
+
+	for testname, testcase := range testcases {
+		foundUsernames := enumerateUsernames(testcase.match)
+		assert.Equalf(t, testcase.expectedUsernames, foundUsernames, "Should have found the expected usernames for testcase %s", testname)
+	}
+}
diff --git a/teleirc/matterbridge/bridge/discord/transmitter/transmitter.go b/teleirc/matterbridge/bridge/discord/transmitter/transmitter.go
new file mode 100644
index 0000000..71407a1
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/transmitter/transmitter.go
@@ -0,0 +1,257 @@
+// Package transmitter provides functionality for transmitting
+// arbitrary webhook messages to Discord.
+//
+// The package provides the following functionality:
+//
+// - Creating new webhooks, whenever necessary
+// - Loading webhooks that we have previously created
+// - Sending new messages
+// - Editing messages, via message ID
+// - Deleting messages, via message ID
+//
+// The package has been designed for matterbridge, but with other
+// Go bots in mind. The public API should be matterbridge-agnostic.
+package transmitter
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/bwmarrin/discordgo"
+	log "github.com/sirupsen/logrus"
+)
+
+// A Transmitter represents a message manager for a single guild.
+type Transmitter struct {
+	session    *discordgo.Session
+	guild      string
+	title      string
+	autoCreate bool
+
+	// channelWebhooks maps from a channel ID to a webhook instance
+	channelWebhooks map[string]*discordgo.Webhook
+
+	mutex sync.RWMutex
+
+	Log *log.Entry
+}
+
+// ErrWebhookNotFound is returned when a valid webhook for this channel/message combination does not exist
+var ErrWebhookNotFound = errors.New("webhook for this channel and message does not exist")
+
+// ErrPermissionDenied is returned if the bot does not have permission to manage webhooks.
+//
+// Bots can be granted a guild-wide permission and channel-specific permissions to manage webhooks.
+// Despite potentially having guild-wide permission, channel specific overrides could deny a bot's permission to manage webhooks.
+var ErrPermissionDenied = errors.New("missing 'Manage Webhooks' permission")
+
+// New returns a new Transmitter given a Discord session, guild ID, and title.
+func New(session *discordgo.Session, guild string, title string, autoCreate bool) *Transmitter {
+	return &Transmitter{
+		session:    session,
+		guild:      guild,
+		title:      title,
+		autoCreate: autoCreate,
+
+		channelWebhooks: make(map[string]*discordgo.Webhook),
+
+		Log: log.NewEntry(log.StandardLogger()),
+	}
+}
+
+// Send transmits a message to the given channel with the provided webhook data, and waits until Discord responds with message data.
+func (t *Transmitter) Send(channelID string, params *discordgo.WebhookParams) (*discordgo.Message, error) {
+	wh, err := t.getOrCreateWebhook(channelID)
+	if err != nil {
+		return nil, err
+	}
+
+	msg, err := t.session.WebhookExecute(wh.ID, wh.Token, true, params)
+	if err != nil {
+		return nil, fmt.Errorf("execute failed: %w", err)
+	}
+
+	return msg, nil
+}
+
+// Edit will edit a message in a channel, if possible.
+func (t *Transmitter) Edit(channelID string, messageID string, params *discordgo.WebhookParams) error {
+	wh := t.getWebhook(channelID)
+
+	if wh == nil {
+		return ErrWebhookNotFound
+	}
+
+	uri := discordgo.EndpointWebhookToken(wh.ID, wh.Token) + "/messages/" + messageID
+	_, err := t.session.RequestWithBucketID("PATCH", uri, params, discordgo.EndpointWebhookToken("", ""))
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// HasWebhook checks whether the transmitter is using a particular webhook.
+func (t *Transmitter) HasWebhook(id string) bool {
+	t.mutex.RLock()
+	defer t.mutex.RUnlock()
+
+	for _, wh := range t.channelWebhooks {
+		if wh.ID == id {
+			return true
+		}
+	}
+
+	return false
+}
+
+// AddWebhook allows you to register a channel's webhook with the transmitter.
+func (t *Transmitter) AddWebhook(channelID string, webhook *discordgo.Webhook) bool {
+	t.Log.Debugf("Manually added webhook %#v to channel %#v", webhook.ID, channelID)
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	_, replaced := t.channelWebhooks[channelID]
+	t.channelWebhooks[channelID] = webhook
+	return replaced
+}
+
+// RefreshGuildWebhooks loads "relevant" webhooks into the transmitter, with careful permission handling.
+//
+// Notes:
+//
+// - A webhook is "relevant" if it was created by this bot -- the ApplicationID should match the bot's ID.
+// - The term "having permission" means having the "Manage Webhooks" permission. See ErrPermissionDenied for more information.
+// - This function is additive and will not unload previously loaded webhooks.
+// - A nil channelIDs slice is treated the same as an empty one.
+//
+// If the bot has guild-wide permission:
+//
+// 1. it will load any "relevant" webhooks from the entire guild
+// 2. the given slice is ignored
+//
+// If the bot does not have guild-wide permission:
+//
+// 1. it will load any "relevant" webhooks in each channel
+// 2. a single error will be returned if any error occurs (incl. if there is no permission for any of these channels)
+//
+// If any channel has more than one "relevant" webhook, it will randomly pick one.
+func (t *Transmitter) RefreshGuildWebhooks(channelIDs []string) error {
+	t.Log.Debugln("Refreshing guild webhooks")
+
+	botID, err := getDiscordUserID(t.session)
+	if err != nil {
+		return fmt.Errorf("could not get current user: %w", err)
+	}
+
+	// Get all existing webhooks
+	hooks, err := t.session.GuildWebhooks(t.guild)
+	if err != nil {
+		switch {
+		case isDiscordPermissionError(err):
+			// We fallback on manually fetching hooks from individual channels
+			// if we don't have the "Manage Webhooks" permission globally.
+			// We can only do this if we were provided channelIDs, though.
+			if len(channelIDs) == 0 {
+				return ErrPermissionDenied
+			}
+			t.Log.Debugln("Missing global 'Manage Webhooks' permission, falling back on per-channel permission")
+			return t.fetchChannelsHooks(channelIDs, botID)
+		default:
+			return fmt.Errorf("could not get webhooks: %w", err)
+		}
+	}
+
+	t.Log.Debugln("Refreshing guild webhooks using global permission")
+	t.assignHooksByAppID(hooks, botID, false)
+	return nil
+}
+
+// createWebhook creates a webhook for a specific channel.
+func (t *Transmitter) createWebhook(channel string) (*discordgo.Webhook, error) {
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	wh, err := t.session.WebhookCreate(channel, t.title+time.Now().Format(" 3:04:05PM"), "")
+	if err != nil {
+		return nil, err
+	}
+
+	t.channelWebhooks[channel] = wh
+	return wh, nil
+}
+
+func (t *Transmitter) getWebhook(channel string) *discordgo.Webhook {
+	t.mutex.RLock()
+	defer t.mutex.RUnlock()
+
+	return t.channelWebhooks[channel]
+}
+
+func (t *Transmitter) getOrCreateWebhook(channelID string) (*discordgo.Webhook, error) {
+	// If we have a webhook for this channel, immediately return it
+	wh := t.getWebhook(channelID)
+	if wh != nil {
+		return wh, nil
+	}
+
+	// Early exit if we don't want to automatically create one
+	if !t.autoCreate {
+		return nil, ErrWebhookNotFound
+	}
+
+	t.Log.Infof("Creating a webhook for %s\n", channelID)
+	wh, err := t.createWebhook(channelID)
+	if err != nil {
+		return nil, fmt.Errorf("could not create webhook: %w", err)
+	}
+
+	return wh, nil
+}
+
+// fetchChannelsHooks fetches hooks for the given channelIDs and calls assignHooksByAppID for each channel's hooks
+func (t *Transmitter) fetchChannelsHooks(channelIDs []string, botID string) error {
+	// For each channel, search for relevant hooks
+	var failedHooks []string
+	for _, channelID := range channelIDs {
+		hooks, err := t.session.ChannelWebhooks(channelID)
+		if err != nil {
+			failedHooks = append(failedHooks, "\n- "+channelID+": "+err.Error())
+			continue
+		}
+		t.assignHooksByAppID(hooks, botID, true)
+	}
+
+	// Compose an error if any hooks failed
+	if len(failedHooks) > 0 {
+		return errors.New("failed to fetch hooks:" + strings.Join(failedHooks, ""))
+	}
+
+	return nil
+}
+
+func (t *Transmitter) assignHooksByAppID(hooks []*discordgo.Webhook, appID string, channelTargeted bool) {
+	logLine := "Picking up webhook"
+	if channelTargeted {
+		logLine += " (channel targeted)"
+	}
+
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	for _, wh := range hooks {
+		if wh.ApplicationID != appID {
+			continue
+		}
+
+		t.channelWebhooks[wh.ChannelID] = wh
+		t.Log.WithFields(log.Fields{
+			"id":      wh.ID,
+			"name":    wh.Name,
+			"channel": wh.ChannelID,
+		}).Println(logLine)
+	}
+}
diff --git a/teleirc/matterbridge/bridge/discord/transmitter/utils.go b/teleirc/matterbridge/bridge/discord/transmitter/utils.go
new file mode 100644
index 0000000..042aa50
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/transmitter/utils.go
@@ -0,0 +1,32 @@
+package transmitter
+
+import (
+	"github.com/bwmarrin/discordgo"
+)
+
+// isDiscordPermissionError returns false for nil, and true if a Discord RESTError with code discordgo.ErrorCodeMissionPermissions
+func isDiscordPermissionError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	restErr, ok := err.(*discordgo.RESTError)
+	if !ok {
+		return false
+	}
+
+	return restErr.Message != nil && restErr.Message.Code == discordgo.ErrCodeMissingPermissions
+}
+
+// getDiscordUserID gets own user ID from state, and fallback on API request
+func getDiscordUserID(session *discordgo.Session) (string, error) {
+	if user := session.State.User; user != nil {
+		return user.ID, nil
+	}
+
+	user, err := session.User("@me")
+	if err != nil {
+		return "", err
+	}
+	return user.ID, nil
+}
diff --git a/teleirc/matterbridge/bridge/discord/webhook.go b/teleirc/matterbridge/bridge/discord/webhook.go
new file mode 100644
index 0000000..c34fc94
--- /dev/null
+++ b/teleirc/matterbridge/bridge/discord/webhook.go
@@ -0,0 +1,148 @@
+package bdiscord
+
+import (
+	"bytes"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/bwmarrin/discordgo"
+)
+
+// shouldMessageUseWebhooks checks if have a channel specific webhook, if we're not using auto webhooks
+func (b *Bdiscord) shouldMessageUseWebhooks(msg *config.Message) bool {
+	if b.useAutoWebhooks {
+		return true
+	}
+
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+	if ci, ok := b.channelInfoMap[msg.Channel+b.Account]; ok {
+		if ci.Options.WebhookURL != "" {
+			return true
+		}
+	}
+	return false
+}
+
+// maybeGetLocalAvatar checks if UseLocalAvatar contains the message's
+// account or protocol, and if so, returns the Discord avatar (if exists)
+func (b *Bdiscord) maybeGetLocalAvatar(msg *config.Message) string {
+	for _, val := range b.GetStringSlice("UseLocalAvatar") {
+		if msg.Protocol != val && msg.Account != val {
+			continue
+		}
+
+		member, err := b.getGuildMemberByNick(msg.Username)
+		if err != nil {
+			return ""
+		}
+
+		return member.User.AvatarURL("")
+	}
+	return ""
+}
+
+// webhookSend send one or more message via webhook, taking care of file
+// uploads (from slack, telegram or mattermost).
+// Returns messageID and error.
+func (b *Bdiscord) webhookSend(msg *config.Message, channelID string) (*discordgo.Message, error) {
+	var (
+		res *discordgo.Message
+		err error
+	)
+
+	// If avatar is unset, mutate the message to include the local avatar (but only if settings say we should do this)
+	if msg.Avatar == "" {
+		msg.Avatar = b.maybeGetLocalAvatar(msg)
+	}
+
+	// WebhookParams can have either `Content` or `File`.
+
+	// We can't send empty messages.
+	if msg.Text != "" {
+		res, err = b.transmitter.Send(
+			channelID,
+			&discordgo.WebhookParams{
+				Content:         msg.Text,
+				Username:        msg.Username,
+				AvatarURL:       msg.Avatar,
+				AllowedMentions: b.getAllowedMentions(),
+			},
+		)
+		if err != nil {
+			b.Log.Errorf("Could not send text (%s) for message %#v: %s", msg.Text, msg, err)
+		}
+	}
+
+	if msg.Extra != nil {
+		for _, f := range msg.Extra["file"] {
+			fi := f.(config.FileInfo)
+			file := discordgo.File{
+				Name:        fi.Name,
+				ContentType: "",
+				Reader:      bytes.NewReader(*fi.Data),
+			}
+			content := fi.Comment
+
+			_, e2 := b.transmitter.Send(
+				channelID,
+				&discordgo.WebhookParams{
+					Username:        msg.Username,
+					AvatarURL:       msg.Avatar,
+					Files:           []*discordgo.File{&file},
+					Content:         content,
+					AllowedMentions: b.getAllowedMentions(),
+				},
+			)
+			if e2 != nil {
+				b.Log.Errorf("Could not send file %#v for message %#v: %s", file, msg, e2)
+			}
+		}
+	}
+	return res, err
+}
+
+func (b *Bdiscord) handleEventWebhook(msg *config.Message, channelID string) (string, error) {
+	// skip events
+	if msg.Event != "" && msg.Event != config.EventUserAction && msg.Event != config.EventJoinLeave && msg.Event != config.EventTopicChange {
+		return "", nil
+	}
+
+	// skip empty messages
+	if msg.Text == "" && (msg.Extra == nil || len(msg.Extra["file"]) == 0) {
+		b.Log.Debugf("Skipping empty message %#v", msg)
+		return "", nil
+	}
+
+	msg.Text = helper.ClipMessage(msg.Text, MessageLength, b.GetString("MessageClipped"))
+	msg.Text = b.replaceUserMentions(msg.Text)
+	// discord username must be [0..32] max
+	if len(msg.Username) > 32 {
+		msg.Username = msg.Username[0:32]
+	}
+
+	if msg.ID != "" {
+		b.Log.Debugf("Editing webhook message")
+		err := b.transmitter.Edit(channelID, msg.ID, &discordgo.WebhookParams{
+			Content:         msg.Text,
+			Username:        msg.Username,
+			AllowedMentions: b.getAllowedMentions(),
+		})
+		if err == nil {
+			return msg.ID, nil
+		}
+		b.Log.Errorf("Could not edit webhook message: %s", err)
+	}
+
+	b.Log.Debugf("Processing webhook sending for message %#v", msg)
+	discordMsg, err := b.webhookSend(msg, channelID)
+	if err != nil {
+		b.Log.Errorf("Could not broadcast via webhook for message %#v: %s", msg, err)
+		return "", err
+	}
+	if discordMsg == nil {
+		return "", nil
+	}
+
+	return discordMsg.ID, nil
+}