Split Discord bridge in multiple files (#632)

4 files changed, 412 insertions, 257 deletions

diff --git a/bridge/discord/discord.go b/bridge/discord/discord.go
index 3a11a504..16ce8c05 100644
--- a/bridge/discord/discord.go
+++ b/bridge/discord/discord.go
@@ -2,9 +2,7 @@ package bdiscord
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
-	"regexp"
 	"strings"
 	"sync"
 
@@ -17,18 +15,23 @@ import (
 const MessageLength = 1950
 
 type Bdiscord struct {
-	c              *discordgo.Session
-	Channels       []*discordgo.Channel
-	Nick           string
-	UseChannelID   bool
-	userMemberMap  map[string]*discordgo.Member
-	nickMemberMap  map[string]*discordgo.Member
-	guildID        string
-	webhookID      string
-	webhookToken   string
-	channelInfoMap map[string]*config.ChannelInfo
-	sync.RWMutex
 	*bridge.Config
+
+	c *discordgo.Session
+
+	nick         string
+	useChannelID bool
+	guildID      string
+	webhookID    string
+	webhookToken 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
 }
 
 func New(cfg *bridge.Config) bridge.Bridger {
@@ -77,28 +80,40 @@ func (b *Bdiscord) Connect() error {
 		return err
 	}
 	serverName := strings.Replace(b.GetString("Server"), "ID:", "", -1)
-	b.Nick = userinfo.Username
+	b.nick = userinfo.Username
+	b.channelsMutex.Lock()
 	for _, guild := range guilds {
 		if guild.Name == serverName || guild.ID == serverName {
-			b.Channels, err = b.c.GuildChannels(guild.ID)
+			b.channels, err = b.c.GuildChannels(guild.ID)
 			b.guildID = guild.ID
 			if err != nil {
-				return err
+				break
 			}
 		}
 	}
-	for _, channel := range b.Channels {
+	b.channelsMutex.Unlock()
+	if err != nil {
+		return err
+	}
+	b.channelsMutex.RLock()
+	for _, channel := range b.channels {
 		b.Log.Debugf("found channel %#v", channel)
 	}
-	// obtaining guild members and initializing nickname mapping
-	b.Lock()
-	defer b.Unlock()
+	b.channelsMutex.RUnlock()
+
+	// 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 guild 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 != "" {
@@ -113,10 +128,13 @@ func (b *Bdiscord) Disconnect() error {
 }
 
 func (b *Bdiscord) JoinChannel(channel config.ChannelInfo) error {
+	b.channelsMutex.Lock()
+	defer b.channelsMutex.Unlock()
+
 	b.channelInfoMap[channel.ID] = &channel
 	idcheck := strings.Split(channel.Name, "ID:")
 	if len(idcheck) > 1 {
-		b.UseChannelID = true
+		b.useChannelID = true
 	}
 	return nil
 }
@@ -139,11 +157,13 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
 	wToken := b.webhookToken
 
 	// check if have a channel specific webhook
+	b.channelsMutex.RLock()
 	if ci, ok := b.channelInfoMap[msg.Channel+b.Account]; ok {
 		if ci.Options.WebhookURL != "" {
 			wID, wToken = b.splitURL(ci.Options.WebhookURL)
 		}
 	}
+	b.channelsMutex.RUnlock()
 
 	// Use webhook to send the message
 	if wID != "" {
@@ -196,7 +216,9 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
 	if msg.Extra != nil {
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {
 			rmsg.Text = helper.ClipMessage(rmsg.Text, MessageLength)
-			b.c.ChannelMessageSend(channelID, rmsg.Username+rmsg.Text)
+			if _, err := b.c.ChannelMessageSend(channelID, rmsg.Username+rmsg.Text); err != nil {
+				b.Log.Errorf("Could not send message %#v: %v", rmsg, err)
+			}
 		}
 		// check if we have files to upload (from slack, telegram or mattermost)
 		if len(msg.Extra["file"]) > 0 {
@@ -221,246 +243,15 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
 	return res.ID, err
 }
 
-func (b *Bdiscord) messageDelete(s *discordgo.Session, m *discordgo.MessageDelete) {
-	rmsg := config.Message{Account: b.Account, ID: m.ID, Event: config.EventMsgDelete, Text: config.EventMsgDelete}
-	rmsg.Channel = b.getChannelName(m.ChannelID)
-	if b.UseChannelID {
-		rmsg.Channel = "ID:" + 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) messageUpdate(s *discordgo.Session, m *discordgo.MessageUpdate) {
-	if b.GetBool("EditDisable") {
-		return
-	}
-	// only when message is actually edited
-	if m.Message.EditedTimestamp != "" {
-		b.Log.Debugf("Sending edit message")
-		m.Content += b.GetString("EditSuffix")
-		b.messageCreate(s, (*discordgo.MessageCreate)(m))
-	}
-}
-
-func (b *Bdiscord) messageCreate(s *discordgo.Session, m *discordgo.MessageCreate) {
-	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 b.useWebhook() && m.Author.Bot && b.isWebhookID(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}
-
-	if m.Content != "" {
-		b.Log.Debugf("== Receiving event %#v", m.Message)
-		m.Message.Content = b.stripCustomoji(m.Message.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)
-	if b.UseChannelID {
-		rmsg.Channel = "ID:" + m.ChannelID
-	}
-
-	// set username
-	if !b.GetBool("UseUserName") {
-		rmsg.Username = b.getNick(m.Author)
-	} else {
-		rmsg.Username = m.Author.Username
-	}
-
-	// 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 = rmsg.Text + "embed: " + embed.Title + " - " + embed.Description + " - " + embed.URL + "\n"
-		}
-	}
-
-	// 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
-	}
-
-	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) {
-	b.Lock()
-	if _, 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)
-	}
-	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
-	}
-	b.Unlock()
-}
-
-func (b *Bdiscord) getNick(user *discordgo.User) string {
-	var err error
-	b.Lock()
-	defer b.Unlock()
-	if _, ok := b.userMemberMap[user.ID]; ok {
-		if b.userMemberMap[user.ID] != nil {
-			if b.userMemberMap[user.ID].Nick != "" {
-				// only return if nick is set
-				return b.userMemberMap[user.ID].Nick
-			}
-			// otherwise return username
-			return user.Username
-		}
-	}
-	// if we didn't find nick, search for it
-	member, err := b.c.GuildMember(b.guildID, user.ID)
-	if err != nil {
-		return user.Username
-	}
-	b.userMemberMap[user.ID] = member
-	// only return if nick is set
-	if b.userMemberMap[user.ID].Nick != "" {
-		return b.userMemberMap[user.ID].Nick
-	}
-	return user.Username
-}
-
-func (b *Bdiscord) getGuildMemberByNick(nick string) (*discordgo.Member, error) {
-	b.Lock()
-	defer b.Unlock()
-	if _, ok := b.nickMemberMap[nick]; ok {
-		if b.nickMemberMap[nick] != nil {
-			return b.nickMemberMap[nick], 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 {
-	idcheck := strings.Split(name, "ID:")
-	if len(idcheck) > 1 {
-		return idcheck[1]
-	}
-	for _, channel := range b.Channels {
-		if channel.Name == name {
-			return channel.ID
-		}
-	}
-	return ""
-}
-
-func (b *Bdiscord) getChannelName(id string) string {
-	for _, channel := range b.Channels {
-		if channel.ID == id {
-			return channel.Name
-		}
-	}
-	return ""
-}
-
-func (b *Bdiscord) replaceChannelMentions(text string) string {
-	var err error
-	re := regexp.MustCompile("<#[0-9]+>")
-	text = re.ReplaceAllStringFunc(text, func(m string) string {
-		channel := b.getChannelName(m[2 : len(m)-1])
-		// if at first don't succeed, try again
-		if channel == "" {
-			b.Channels, err = b.c.GuildChannels(b.guildID)
-			if err != nil {
-				return "#unknownchannel"
-			}
-			channel = b.getChannelName(m[2 : len(m)-1])
-			return "#" + channel
-		}
-		return "#" + channel
-	})
-	return text
-}
-
-func (b *Bdiscord) replaceUserMentions(text string) string {
-	re := regexp.MustCompile("@[^@]{1,32}")
-	text = re.ReplaceAllStringFunc(text, func(m string) string {
-		mention := strings.TrimSpace(m[1:])
-		var member *discordgo.Member
-		var err error
-		for {
-			b.Log.Debugf("Testing mention: '%s'", mention)
-			member, err = b.getGuildMemberByNick(mention)
-			if err != nil {
-				lastSpace := strings.LastIndex(mention, " ")
-				if lastSpace == -1 {
-					break
-				}
-				mention = strings.TrimSpace(mention[0:lastSpace])
-			} else {
-				break
-			}
-		}
-		if err != nil {
-			return m
-		}
-		return strings.Replace(m, "@"+mention, member.User.Mention(), -1)
-	})
-	b.Log.Debugf("Message with mention replaced: %s", text)
-	return text
-}
-
-func (b *Bdiscord) replaceAction(text string) (string, bool) {
-	if strings.HasPrefix(text, "_") && strings.HasSuffix(text, "_") {
-		return strings.Replace(text, "_", "", -1), true
-	}
-	return text, false
-}
-
-func (b *Bdiscord) stripCustomoji(text string) string {
-	// <:doge:302803592035958784>
-	re := regexp.MustCompile("<(:.*?:)[0-9]+>")
-	return re.ReplaceAllString(text, `$1`)
-}
-
-// splitURL splits a webhookURL and returns the id and token
-func (b *Bdiscord) splitURL(url string) (string, string) {
-	webhookURLSplit := strings.Split(url, "/")
-	if len(webhookURLSplit) != 7 {
-		b.Log.Fatalf("%s is no correct discord WebhookURL", url)
-	}
-	return webhookURLSplit[len(webhookURLSplit)-2], webhookURLSplit[len(webhookURLSplit)-1]
-}
-
 // useWebhook returns true if we have a webhook defined somewhere
 func (b *Bdiscord) useWebhook() bool {
 	if b.GetString("WebhookURL") != "" {
 		return true
 	}
+
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+
 	for _, channel := range b.channelInfoMap {
 		if channel.Options.WebhookURL != "" {
 			return true
@@ -477,6 +268,10 @@ func (b *Bdiscord) isWebhookID(id string) bool {
 			return true
 		}
 	}
+
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+
 	for _, channel := range b.channelInfoMap {
 		if channel.Options.WebhookURL != "" {
 			wID, _ := b.splitURL(channel.Options.WebhookURL)
diff --git a/bridge/discord/handlers.go b/bridge/discord/handlers.go
new file mode 100644
index 00000000..79c32015
--- /dev/null
+++ b/bridge/discord/handlers.go
@@ -0,0 +1,125 @@
+package bdiscord
+
+import (
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/bwmarrin/discordgo"
+)
+
+func (b *Bdiscord) messageDelete(s *discordgo.Session, m *discordgo.MessageDelete) {
+	rmsg := config.Message{Account: b.Account, ID: m.ID, Event: config.EventMsgDelete, Text: config.EventMsgDelete}
+	rmsg.Channel = b.getChannelName(m.ChannelID)
+	if b.useChannelID {
+		rmsg.Channel = "ID:" + 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) messageUpdate(s *discordgo.Session, m *discordgo.MessageUpdate) {
+	if b.GetBool("EditDisable") {
+		return
+	}
+	// only when message is actually edited
+	if m.Message.EditedTimestamp != "" {
+		b.Log.Debugf("Sending edit message")
+		m.Content += b.GetString("EditSuffix")
+		b.messageCreate(s, (*discordgo.MessageCreate)(m))
+	}
+}
+
+func (b *Bdiscord) messageCreate(s *discordgo.Session, m *discordgo.MessageCreate) {
+	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 b.useWebhook() && m.Author.Bot && b.isWebhookID(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}
+
+	if m.Content != "" {
+		b.Log.Debugf("== Receiving event %#v", m.Message)
+		m.Message.Content = b.stripCustomoji(m.Message.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)
+	if b.useChannelID {
+		rmsg.Channel = "ID:" + m.ChannelID
+	}
+
+	// set username
+	if !b.GetBool("UseUserName") {
+		rmsg.Username = b.getNick(m.Author)
+	} else {
+		rmsg.Username = m.Author.Username
+	}
+
+	// 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 = rmsg.Text + "embed: " + embed.Title + " - " + embed.Description + " - " + embed.URL + "\n"
+		}
+	}
+
+	// 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
+	}
+
+	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.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
+	}
+}
diff --git a/bridge/discord/helpers.go b/bridge/discord/helpers.go
new file mode 100644
index 00000000..e693498c
--- /dev/null
+++ b/bridge/discord/helpers.go
@@ -0,0 +1,189 @@
+package bdiscord
+
+import (
+	"errors"
+	"regexp"
+	"strings"
+	"unicode"
+
+	"github.com/bwmarrin/discordgo"
+)
+
+func (b *Bdiscord) getNick(user *discordgo.User) 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(b.guildID, user.ID)
+	if err != nil {
+		b.Log.Warnf("Failed to fetch information for member %#v: %#v", user, 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 {
+	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 {
+			return channel.ID
+		}
+	}
+	return ""
+}
+
+func (b *Bdiscord) getChannelName(id string) string {
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+
+	for _, channel := range b.channels {
+		if channel.ID == id {
+			return channel.Name
+		}
+	}
+	return ""
+}
+
+var (
+	// See https://discordapp.com/developers/docs/reference#message-formatting.
+	channelMentionRE = regexp.MustCompile("<#[0-9]+>")
+	emojiRE          = regexp.MustCompile("<(:.*?:)[0-9]+>")
+	userMentionRE    = regexp.MustCompile("@[^@\n]{1,32}")
+)
+
+func (b *Bdiscord) replaceChannelMentions(text string) string {
+	replaceChannelMentionFunc := func(match string) string {
+		var err error
+		channelID := match[2 : len(match)-1]
+
+		channelName := b.getChannelName(channelID)
+		// If we don't have the channel refresh our list.
+		if channelName == "" {
+			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 (b *Bdiscord) stripCustomoji(text string) string {
+	return emojiRE.ReplaceAllString(text, `$1`)
+}
+
+func (b *Bdiscord) replaceAction(text string) (string, bool) {
+	if strings.HasPrefix(text, "_") && strings.HasSuffix(text, "_") {
+		return text[1:], true
+	}
+	return text, false
+}
+
+// splitURL splits a webhookURL and returns the ID and token.
+func (b *Bdiscord) splitURL(url string) (string, string) {
+	const (
+		expectedWebhookSplitCount = 7
+		webhookIdxID              = 5
+		webhookIdxToken           = 6
+	)
+	webhookURLSplit := strings.Split(url, "/")
+	if len(webhookURLSplit) != expectedWebhookSplitCount {
+		b.Log.Fatalf("%s is no correct discord WebhookURL", url)
+	}
+	return webhookURLSplit[webhookIdxID], webhookURLSplit[webhookIdxToken]
+}
+
+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/bridge/discord/helpers_test.go b/bridge/discord/helpers_test.go
new file mode 100644
index 00000000..0f196d9a
--- /dev/null
+++ b/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)
+	}
+}