apply https://github.com/42wim/matterbridge/pull/1864v1.26.0+0.1.0

5 files changed, 1057 insertions, 650 deletions

diff --git a/bridge/matrix/appservice.go b/bridge/matrix/appservice.go
new file mode 100644
index 00000000..ef172bff
--- /dev/null
+++ b/bridge/matrix/appservice.go
@@ -0,0 +1,147 @@
+package bmatrix
+
+import (
+	"fmt"
+	"regexp"
+
+	"github.com/sirupsen/logrus"
+
+	"maunium.net/go/mautrix/appservice"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
+)
+
+type AppServiceNamespaces struct {
+	rooms     []*regexp.Regexp
+	usernames []*regexp.Regexp
+	prefixes  []string
+}
+
+type AppServiceWrapper struct {
+	appService *appservice.AppService
+	namespaces AppServiceNamespaces
+	stop       chan struct{}
+	stopAck    chan struct{}
+}
+
+func (w *AppServiceWrapper) ParseNamespaces(logger *logrus.Entry) error {
+	if w.appService.Registration != nil {
+		// TODO: handle non-exclusive registrations
+		for _, v := range w.appService.Registration.Namespaces.RoomIDs {
+			re, err := regexp.Compile(v.Regex)
+			if err != nil {
+				logger.Warnf("couldn't parse the appservice regex '%s'", v.Regex)
+				continue
+			}
+
+			w.namespaces.rooms = append(w.namespaces.rooms, re)
+		}
+
+		for _, v := range w.appService.Registration.Namespaces.UserIDs {
+			re, err := regexp.Compile(v.Regex)
+			if err != nil {
+				logger.Warnf("couldn't parse the appservice regex '%s'", v.Regex)
+				continue
+			}
+
+			// we assume that the user regexes will be of the form '@<some prefix>.*'
+			// where '.*' will be replaced by the username we spoof
+			prefix, _ := re.LiteralPrefix()
+			if prefix == "" || prefix == "@" {
+				logger.Warnf("couldn't find an acceptable prefix in the appservice regex '%s'", v.Regex)
+				continue
+			}
+
+			if v.Regex != fmt.Sprintf("%s.*", prefix) {
+				logger.Warnf("complex regexpes are not supported for appServices, the regexp '%s' does not match the format '@<prefix>.*'", v.Regex)
+				continue
+			}
+
+			w.namespaces.usernames = append(w.namespaces.usernames, re)
+			// drop the '@' in the prefix
+			w.namespaces.prefixes = append(w.namespaces.prefixes, prefix[1:])
+		}
+	}
+
+	return nil
+}
+
+func (b *Bmatrix) NewAppService() (*AppServiceWrapper, error) {
+	w := &AppServiceWrapper{
+		appService: appservice.Create(),
+		namespaces: AppServiceNamespaces{
+			rooms:     []*regexp.Regexp{},
+			usernames: []*regexp.Regexp{},
+			prefixes:  []string{},
+		},
+		stop:    make(chan struct{}, 1),
+		stopAck: make(chan struct{}, 1),
+	}
+
+	err := w.appService.SetHomeserverURL(b.mc.HomeserverURL.String())
+	if err != nil {
+		return nil, err
+	}
+
+	_, homeServerDomain, _ := b.mc.UserID.Parse()
+	w.appService.HomeserverDomain = homeServerDomain
+	//nolint:exhaustruct
+	w.appService.Host = appservice.HostConfig{
+		Hostname: b.GetString("AppServiceHost"),
+		Port:     uint16(b.GetInt("AppServicePort")),
+	}
+	w.appService.Registration, err = appservice.LoadRegistration(b.GetString("AppServiceConfigPath"))
+	if err != nil {
+		return nil, err
+	}
+
+	// forward logs from the appService to the matterbridge logger
+	w.appService.Log = NewZerologWrapper(b.Log)
+
+	if err = w.ParseNamespaces(b.Log); err != nil {
+		return nil, err
+	}
+
+	return w, nil
+}
+
+func (a *AppServiceNamespaces) containsRoom(roomID id.RoomID) bool {
+	// no room specified: we check all the rooms
+	if len(a.rooms) == 0 {
+		return true
+	}
+
+	for _, room := range a.rooms {
+		if room.MatchString(roomID.String()) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// nolint: wrapcheck
+func (b *Bmatrix) startAppService() error {
+	wrapper := b.appService
+	// TODO: detect service completion and rerun automatically
+	go wrapper.appService.Start()
+	b.Log.Debug("appservice launched")
+
+	processor := appservice.NewEventProcessor(wrapper.appService)
+	processor.On(event.EventMessage, func(ev *event.Event) {
+		b.handleEvent(originAppService, ev)
+	})
+	go processor.Start()
+	b.Log.Debug("appservice event dispatcher launched")
+
+	// handle service stopping/restarting
+	go func(appService *appservice.AppService, processor *appservice.EventProcessor) {
+		<-wrapper.stop
+
+		appService.Stop()
+		processor.Stop()
+		wrapper.stopAck <- struct{}{}
+	}(wrapper.appService, processor)
+
+	return nil
+}
diff --git a/bridge/matrix/handlers.go b/bridge/matrix/handlers.go
new file mode 100644
index 00000000..8833b0ed
--- /dev/null
+++ b/bridge/matrix/handlers.go
@@ -0,0 +1,344 @@
+package bmatrix
+
+import (
+	"bytes"
+	"fmt"
+	"mime"
+	"regexp"
+	"strings"
+
+	matrix "maunium.net/go/mautrix"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+)
+
+// Determines if the event comes from ourselves, in which case we want to ignore it
+func (b *Bmatrix) ignoreBridgingEvents(ev *event.Event) bool {
+	if ev.Sender == b.UserID {
+		return true
+	}
+
+	// ignore messages we may have sent via the appservice
+	if b.appService != nil {
+		if ev.Sender == b.appService.appService.BotClient().UserID {
+			return true
+		}
+
+		// ignore virtual users messages (we ignore the 'exclusive' field of Namespace for now)
+		for _, username := range b.appService.namespaces.usernames {
+			if username.MatchString(ev.Sender.String()) {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+//nolint: funlen
+func (b *Bmatrix) handleEvent(origin EventOrigin, ev *event.Event) {
+	if b.ignoreBridgingEvents(ev) {
+		return
+	}
+
+	b.RLock()
+	channel, ok := b.RoomMap[ev.RoomID]
+	b.RUnlock()
+	if !ok {
+		// we don't know that room yet, that could be a room returned by an
+		// application service, but matterbridge doesn't handle those just yet
+		b.Log.Debugf("Received event for room %s, not joined yet/not handled", ev.RoomID)
+
+		return
+	}
+
+	if ev.Type == event.EphemeralEventReceipt {
+		// we do not support read receipts across servers, considering that
+		// multiple services (e.g. Discord) doesn't expose that information)
+		return
+	}
+
+	if ev.Type == event.StateMember {
+		b.handleMemberChange(ev)
+
+		return
+	}
+
+	// if we receive appservice events for this room, there is no need to check them with the classical syncer
+	if !channel.appService && origin == originAppService {
+		channel.appService = true
+		b.Lock()
+		b.RoomMap[ev.RoomID] = channel
+		b.Unlock()
+	}
+
+	// if we receive messages both via the classical matrix syncer and appserver, prefer appservice and throw away this duplicate event
+	if channel.appService && origin != originAppService {
+		b.Log.Debugf("Dropping event, should receive it via appservice: %s", ev.ID)
+
+		return
+	}
+
+	b.Log.Debugf("== Receiving event: %#v (appService=%t)", ev, origin == originAppService)
+
+	if ev.Type == event.EphemeralEventTyping {
+		typing := ev.Content.AsTyping()
+		if len(typing.UserIDs) > 0 {
+			//nolint:exhaustruct
+			b.Remote <- config.Message{
+				Event:   config.EventUserTyping,
+				Channel: channel.name,
+				Account: b.Account,
+			}
+		}
+
+		return
+	}
+
+	defer (func(ev *event.Event) {
+		// not crucial, so no ratelimit check here
+		if err := b.mc.MarkRead(ev.RoomID, ev.ID); err != nil {
+			b.Log.Errorf("couldn't mark message as read %s", err.Error())
+		}
+	})(ev)
+
+	// Create our message
+	//nolint:exhaustruct
+	rmsg := config.Message{
+		Username: b.getDisplayName(ev.RoomID, ev.Sender),
+		Channel:  channel.name,
+		Account:  b.Account,
+		UserID:   string(ev.Sender),
+		ID:       string(ev.ID),
+	}
+
+	// Remove homeserver suffix if configured
+	if b.GetBool("NoHomeServerSuffix") {
+		re := regexp.MustCompile("(.*?):.*")
+		rmsg.Username = re.ReplaceAllString(rmsg.Username, `$1`)
+	}
+
+	// Delete event
+	if ev.Type == event.EventRedaction {
+		rmsg.Event = config.EventMsgDelete
+		rmsg.ID = string(ev.Redacts)
+		rmsg.Text = config.EventMsgDelete
+		b.Remote <- rmsg
+
+		return
+	}
+
+	b.handleMessage(rmsg, ev)
+}
+
+func (b *Bmatrix) handleMemberChange(ev *event.Event) {
+	member := ev.Content.AsMember()
+	if member == nil {
+		b.Log.Errorf("Couldn't process a member event:\n%#v", ev)
+
+		return
+	}
+
+	// Update the displayname on join messages, according to https://spec.matrix.org/v1.3/client-server-api/#events-on-change-of-profile-information
+	if member.Membership == event.MembershipJoin {
+		b.cacheDisplayName(ev.RoomID, ev.Sender, member.Displayname)
+	} else if member.Membership == event.MembershipLeave || member.Membership == event.MembershipBan {
+		b.removeDisplayNameFromCache(ev.Sender)
+	}
+}
+
+func (b *Bmatrix) handleMessage(rmsg config.Message, ev *event.Event) {
+	msg := ev.Content.AsMessage()
+	if msg == nil {
+		b.Log.Errorf("matterbridge don't support this event type: %s", ev.Type.Type)
+		b.Log.Debugf("Full event: %#v", ev)
+
+		return
+	}
+
+	rmsg.Text = msg.Body
+
+	// TODO: cache the avatars
+	avatarURL := b.getAvatarURL(ev.Sender)
+	contentURI, err := id.ParseContentURI(avatarURL)
+	if err == nil {
+		avatarURL = b.mc.GetDownloadURL(contentURI)
+		rmsg.Avatar = avatarURL
+	}
+
+	// Do we have a /me action
+	//nolint: exhaustive
+	switch msg.MsgType {
+	case event.MsgEmote:
+		rmsg.Event = config.EventUserAction
+	case event.MsgImage, event.MsgVideo, event.MsgFile:
+		// Do we have attachments? (we only allow images, videos or files msgtypes)
+		err := b.handleDownloadFile(&rmsg, *msg)
+		if err != nil {
+			b.Log.Errorf("download failed: %#v", err)
+		}
+	default:
+		if msg.RelatesTo == nil {
+			break
+		}
+
+		if msg.RelatesTo.Type == event.RelReplace && msg.NewContent != nil {
+			// Is it an edit?
+			rmsg.ID = string(msg.RelatesTo.EventID)
+			rmsg.Text = msg.NewContent.Body
+		} else if msg.RelatesTo.Type == event.RelReference && msg.RelatesTo.InReplyTo != nil {
+			// Is it a reply?
+			body := msg.Body
+			if !b.GetBool("keepquotedreply") {
+				for strings.HasPrefix(body, "> ") {
+					lineIdx := strings.Index(body, "\n\n")
+					if lineIdx == -1 {
+						break
+					}
+
+					body = body[(lineIdx + 2):]
+				}
+			}
+
+			rmsg.ParentID = string(msg.RelatesTo.EventID)
+			rmsg.Text = body
+		}
+	}
+
+	b.Log.Debugf("<= Sending message from %s on %s to gateway", ev.Sender, b.Account)
+	b.Remote <- rmsg
+}
+
+// handleDownloadFile handles file download
+func (b *Bmatrix) handleDownloadFile(rmsg *config.Message, msg event.MessageEventContent) error {
+	rmsg.Extra = make(map[string][]interface{})
+	if msg.URL == "" || msg.Info == nil {
+		b.Log.Error("couldn't download a file with no URL or no file informations (invalid event ?)")
+		b.Log.Debugf("Full Message content:\n%#v", msg)
+	}
+
+	url := strings.ReplaceAll(string(msg.URL), "mxc://", b.GetString("Server")+"/_matrix/media/v1/download/")
+	filename := msg.Body
+
+	// check if we have an image uploaded without extension
+	if !strings.Contains(filename, ".") {
+		mext, _ := mime.ExtensionsByType(msg.Info.MimeType)
+		if len(mext) > 0 {
+			filename += mext[0]
+		} else if msg.MsgType == event.MsgImage {
+			// just a default .png extension if we don't have mime info
+			filename += ".png"
+		}
+	}
+
+	// check if the size is ok
+	err := helper.HandleDownloadSize(b.Log, rmsg, filename, int64(msg.Info.Size), b.General)
+	if err != nil {
+		return err
+	}
+	// actually download the file
+	data, err := helper.DownloadFile(url)
+	if err != nil {
+		return fmt.Errorf("download %s failed %#v", url, err)
+	}
+	// add the downloaded data to the message
+	helper.HandleDownloadData(b.Log, rmsg, filename, "", url, data, b.General)
+	return nil
+}
+
+// handleUploadFiles handles native upload of files.
+func (b *Bmatrix) handleUploadFiles(msg *config.Message, channel id.RoomID) (string, error) {
+	for _, f := range msg.Extra["file"] {
+		if fi, ok := f.(config.FileInfo); ok {
+			b.handleUploadFile(msg, channel, &fi)
+		}
+	}
+	return "", nil
+}
+
+// handleUploadFile handles native upload of a file.
+//nolint: funlen
+func (b *Bmatrix) handleUploadFile(msg *config.Message, channel id.RoomID, fi *config.FileInfo) {
+	content := bytes.NewReader(*fi.Data)
+	sp := strings.Split(fi.Name, ".")
+	mtype := mime.TypeByExtension("." + sp[len(sp)-1])
+
+	// image and video uploads send no username, we have to do this ourself here #715
+	//nolint:exhaustruct
+	m := event.MessageEventContent{
+		MsgType:       event.MsgText,
+		Body:          fi.Comment,
+		FormattedBody: fi.Comment,
+	}
+
+	_, err := b.sendMessageEventWithRetries(channel, m, msg.Username)
+	if err != nil {
+		b.Log.Errorf("file comment failed: %#v", err)
+	}
+
+	b.Log.Debugf("uploading file: %s %s", fi.Name, mtype)
+
+	var res *matrix.RespMediaUpload
+	//nolint:exhaustruct
+	req := matrix.ReqUploadMedia{
+		Content:       content,
+		ContentType:   mtype,
+		ContentLength: fi.Size,
+	}
+
+	err = b.retry(func() error {
+		res, err = b.mc.UploadMedia(req)
+
+		return err
+	})
+
+	if err != nil {
+		b.Log.Errorf("file upload failed: %#v", err)
+		return
+	}
+
+	b.Log.Debugf("result: %#v", res)
+
+	//nolint:exhaustruct
+	m = event.MessageEventContent{
+		Body: fi.Name,
+		URL:  res.ContentURI.CUString(),
+	}
+
+	switch {
+	case strings.Contains(mtype, "video"):
+		b.Log.Debugf("sendVideo %s", res.ContentURI)
+
+		m.MsgType = event.MsgVideo
+	case strings.Contains(mtype, "image"):
+		b.Log.Debugf("sendImage %s", res.ContentURI)
+
+		m.MsgType = event.MsgImage
+	case strings.Contains(mtype, "audio"):
+		b.Log.Debugf("sendAudio %s", res.ContentURI)
+
+		m.MsgType = event.MsgAudio
+		//nolint:exhaustruct
+		m.Info = &event.FileInfo{
+			MimeType: mtype,
+			Size:     len(*fi.Data),
+		}
+	default:
+		b.Log.Debugf("sendFile %s", res.ContentURI)
+
+		m.MsgType = event.MsgFile
+		//nolint:exhaustruct
+		m.Info = &event.FileInfo{
+			MimeType: mtype,
+			Size:     len(*fi.Data),
+		}
+	}
+
+	_, err = b.sendMessageEventWithRetries(channel, m, msg.Username)
+	if err != nil {
+		b.Log.Errorf("sending the message referencing the uploaded file failed: %#v", err)
+	}
+}
diff --git a/bridge/matrix/helpers.go b/bridge/matrix/helpers.go
index 5a91f748..93031e1d 100644
--- a/bridge/matrix/helpers.go
+++ b/bridge/matrix/helpers.go
@@ -1,16 +1,21 @@
 package bmatrix
 
 import (
-	"encoding/json"
 	"errors"
 	"fmt"
 	"html"
-	"strings"
+	"sort"
+	"sync"
 	"time"
 
-	matrix "github.com/matterbridge/gomatrix"
+	matrix "maunium.net/go/mautrix"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
 )
 
+// arbitrary limit to determine when to cleanup nickname cache entries
+const MaxNumberOfUsersInCache = 50_000
+
 func newMatrixUsername(username string) *matrixUsername {
 	mUsername := new(matrixUsername)
 
@@ -28,11 +33,11 @@ func newMatrixUsername(username string) *matrixUsername {
 }
 
 // getRoomID retrieves a matching room ID from the channel name.
-func (b *Bmatrix) getRoomID(channel string) string {
+func (b *Bmatrix) getRoomID(channelName string) id.RoomID {
 	b.RLock()
 	defer b.RUnlock()
-	for ID, name := range b.RoomMap {
-		if name == channel {
+	for ID, channel := range b.RoomMap {
+		if channelName == channel.name {
 			return ID
 		}
 	}
@@ -40,31 +45,59 @@ func (b *Bmatrix) getRoomID(channel string) string {
 	return ""
 }
 
-// interface2Struct marshals and immediately unmarshals an interface.
-// Useful for converting map[string]interface{} to a struct.
-func interface2Struct(in interface{}, out interface{}) error {
-	jsonObj, err := json.Marshal(in)
-	if err != nil {
-		return err //nolint:wrapcheck
-	}
+type NicknameCacheEntry struct {
+	displayName               string
+	lastUpdated               time.Time
+	conflictWithOtherUsername bool
+}
 
-	return json.Unmarshal(jsonObj, out)
+type NicknameUserEntry struct {
+	globalEntry *NicknameCacheEntry
+	perChannel  map[id.RoomID]NicknameCacheEntry
 }
 
-// getDisplayName retrieves the displayName for mxid, querying the homeserver if the mxid is not in the cache.
-func (b *Bmatrix) getDisplayName(mxid string) string {
-	if b.GetBool("UseUserName") {
-		return mxid[1:]
+type NicknameCache struct {
+	users map[id.UserID]NicknameUserEntry
+	sync.RWMutex
+}
+
+func NewNicknameCache() *NicknameCache {
+	return &NicknameCache{
+		users:   make(map[id.UserID]NicknameUserEntry),
+		RWMutex: sync.RWMutex{},
 	}
+}
 
-	b.RLock()
-	if val, present := b.NicknameMap[mxid]; present {
-		b.RUnlock()
+// note: cache is not locked here
+func (c *NicknameCache) retrieveDisplaynameFromCache(channelID id.RoomID, mxid id.UserID) string {
+	var cachedEntry *NicknameCacheEntry = nil
+
+	c.RLock()
+	if user, userPresent := c.users[mxid]; userPresent {
+		// try first the name of the user in the room, then globally
+		if roomCachedEntry, roomPresent := user.perChannel[channelID]; roomPresent {
+			cachedEntry = &roomCachedEntry
+		} else if user.globalEntry != nil {
+			cachedEntry = user.globalEntry
+		}
+	}
+	c.RUnlock()
 
-		return val.displayName
+	if cachedEntry == nil {
+		return ""
+	}
+
+	if cachedEntry.conflictWithOtherUsername {
+		// TODO: the current behavior is that only users with clashing usernames and *that have
+		// spoken since the bridge started* will get their mxids shown, and this doesn't
+		// feel right
+		return fmt.Sprintf("%s (%s)", cachedEntry.displayName, mxid)
 	}
-	b.RUnlock()
 
+	return cachedEntry.displayName
+}
+
+func (b *Bmatrix) retrieveGlobalDisplayname(mxid id.UserID) string {
 	displayName, err := b.mc.GetDisplayName(mxid)
 	var httpError *matrix.HTTPError
 	if errors.As(err, &httpError) {
@@ -72,127 +105,198 @@ func (b *Bmatrix) getDisplayName(mxid string) string {
 	}
 
 	if err != nil {
-		return b.cacheDisplayName(mxid, mxid[1:])
+		return string(mxid)[1:]
 	}
 
-	return b.cacheDisplayName(mxid, displayName.DisplayName)
+	return displayName.DisplayName
 }
 
-// cacheDisplayName stores the mapping between a mxid and a display name, to be reused later without performing a query to the homserver.
-// Note that old entries are cleaned when this function is called.
-func (b *Bmatrix) cacheDisplayName(mxid string, displayName string) string {
-	now := time.Now()
+// getDisplayName retrieves the displayName for mxid, querying the homeserver if the mxid is not in the cache.
+func (b *Bmatrix) getDisplayName(channelID id.RoomID, mxid id.UserID) string {
+	if b.GetBool("UseUserName") {
+		return string(mxid)[1:]
+	}
 
-	// scan to delete old entries, to stop memory usage from becoming too high with old entries.
-	// In addition, we also detect if another user have the same username, and if so, we append their mxids to their usernames to differentiate them.
-	toDelete := []string{}
-	conflict := false
+	displayname := b.NicknameCache.retrieveDisplaynameFromCache(channelID, mxid)
+	if displayname != "" {
+		return displayname
+	}
 
-	b.Lock()
-	for mxid, v := range b.NicknameMap {
-		// to prevent username reuse across matrix servers - or even on the same server, append
-		// the mxid to the username when there is a conflict
-		if v.displayName == displayName {
-			conflict = true
-			// TODO: it would be nice to be able to rename previous messages from this user.
-			// The current behavior is that only users with clashing usernames and *that have spoken since the bridge last started* will get their mxids shown, and I don't know if that's the expected behavior.
-			v.displayName = fmt.Sprintf("%s (%s)", displayName, mxid)
-			b.NicknameMap[mxid] = v
+	// retrieve the global display name
+	return b.cacheDisplayName("", mxid, b.retrieveGlobalDisplayname(mxid))
+}
+
+// scan to delete old entries, to stop memory usage from becoming high with obsolete entries.
+// note: assume the cache is already write-locked
+// TODO: should we update the timestamp when the entry is used?
+func (c *NicknameCache) clearObsoleteEntries(mxid id.UserID) {
+	// we have a "off-by-one" to account for when the user being added to the
+	// cache already have obsolete cache entries, as we want to keep it because
+	// we will be refreshing it in a minute
+	if len(c.users) <= MaxNumberOfUsersInCache+1 {
+		return
+	}
+
+	usersLastTimestamp := make(map[id.UserID]int64, len(c.users))
+	// compute the last updated timestamp entry for each user
+	for mxidIter, NicknameCacheIter := range c.users {
+		userLastTimestamp := time.Unix(0, 0)
+		for _, userInChannelCacheEntry := range NicknameCacheIter.perChannel {
+			if userInChannelCacheEntry.lastUpdated.After(userLastTimestamp) {
+				userLastTimestamp = userInChannelCacheEntry.lastUpdated
+			}
 		}
 
-		if now.Sub(v.lastUpdated) > 10*time.Minute {
-			toDelete = append(toDelete, mxid)
+		if NicknameCacheIter.globalEntry != nil {
+			if NicknameCacheIter.globalEntry.lastUpdated.After(userLastTimestamp) {
+				userLastTimestamp = NicknameCacheIter.globalEntry.lastUpdated
+			}
 		}
-	}
 
-	if conflict {
-		displayName = fmt.Sprintf("%s (%s)", displayName, mxid)
+		usersLastTimestamp[mxidIter] = userLastTimestamp.UnixNano()
 	}
 
-	for _, v := range toDelete {
-		delete(b.NicknameMap, v)
+	// get the limit timestamp before which we must clear entries as obsolete
+	sortedTimestamps := make([]int64, 0, len(usersLastTimestamp))
+	for _, value := range usersLastTimestamp {
+		sortedTimestamps = append(sortedTimestamps, value)
 	}
-
-	b.NicknameMap[mxid] = NicknameCacheEntry{
-		displayName: displayName,
-		lastUpdated: now,
+	sort.Slice(sortedTimestamps, func(i, j int) bool { return sortedTimestamps[i] < sortedTimestamps[j] })
+	limitTimestamp := sortedTimestamps[len(sortedTimestamps)-MaxNumberOfUsersInCache]
+
+	// delete entries older than the limit
+	for mxidIter, timestamp := range usersLastTimestamp {
+		// do not clear the user that we are adding to the cache
+		if timestamp <= limitTimestamp && mxidIter != mxid {
+			delete(c.users, mxidIter)
+		}
 	}
-	b.Unlock()
-
-	return displayName
 }
 
-// handleError converts errors into httpError.
-//nolint:exhaustivestruct
-func handleError(err error) *httpError {
-	var mErr matrix.HTTPError
-	if !errors.As(err, &mErr) {
-		return &httpError{
-			Err: "not a HTTPError",
+// to prevent username reuse across matrix rooms - or even inside the same room, if a user uses multiple servers -
+// identify users with naming conflicts
+func (c *NicknameCache) detectConflict(mxid id.UserID, displayName string) bool {
+	conflict := false
+
+	for mxidIter, NicknameCacheIter := range c.users {
+		// skip conflict detection against ourselves, obviously
+		if mxidIter == mxid {
+			continue
 		}
-	}
 
-	var httpErr httpError
+		for channelID, userInChannelCacheEntry := range NicknameCacheIter.perChannel {
+			if userInChannelCacheEntry.displayName == displayName {
+				userInChannelCacheEntry.conflictWithOtherUsername = true
+				c.users[mxidIter].perChannel[channelID] = userInChannelCacheEntry
+				conflict = true
+			}
+		}
 
-	if err := json.Unmarshal(mErr.Contents, &httpErr); err != nil {
-		return &httpError{
-			Err: "unmarshal failed",
+		if NicknameCacheIter.globalEntry != nil && NicknameCacheIter.globalEntry.displayName == displayName {
+			c.users[mxidIter].globalEntry.conflictWithOtherUsername = true
+			conflict = true
 		}
 	}
 
-	return &httpErr
+	return conflict
 }
 
-func (b *Bmatrix) containsAttachment(content map[string]interface{}) bool {
-	// Skip empty messages
-	if content["msgtype"] == nil {
-		return false
+// cacheDisplayName stores the mapping between a mxid and a display name, to be reused
+// later without performing a query to the homeserver.
+// Note that old entries are cleaned when this function is called.
+func (b *Bmatrix) cacheDisplayName(channelID id.RoomID, mxid id.UserID, displayName string) string {
+	now := time.Now()
+
+	cache := b.NicknameCache
+
+	cache.Lock()
+	defer cache.Unlock()
+
+	conflict := cache.detectConflict(mxid, displayName)
+
+	cache.clearObsoleteEntries(mxid)
+
+	var newEntry NicknameUserEntry
+	if user, userPresent := cache.users[mxid]; userPresent {
+		newEntry = user
+	} else {
+		newEntry = NicknameUserEntry{
+			globalEntry: nil,
+			perChannel:  make(map[id.RoomID]NicknameCacheEntry),
+		}
 	}
 
-	// Only allow image,video or file msgtypes
-	if !(content["msgtype"].(string) == "m.image" ||
-		content["msgtype"].(string) == "m.video" ||
-		content["msgtype"].(string) == "m.file") {
-		return false
+	cacheEntry := NicknameCacheEntry{
+		displayName:               displayName,
+		lastUpdated:               now,
+		conflictWithOtherUsername: conflict,
 	}
 
-	return true
+	// this is a local (room-specific) display name, let's cache it as such
+	if channelID == "" {
+		newEntry.globalEntry = &cacheEntry
+	} else {
+		globalDisplayName := b.retrieveGlobalDisplayname(mxid)
+		// updating the global display name or resetting the room name to the global name
+		if globalDisplayName == displayName {
+			delete(newEntry.perChannel, channelID)
+			newEntry.globalEntry = &cacheEntry
+		} else {
+			newEntry.perChannel[channelID] = cacheEntry
+		}
+	}
+
+	cache.users[mxid] = newEntry
+
+	return displayName
 }
 
-// getAvatarURL returns the avatar URL of the specified sender.
-func (b *Bmatrix) getAvatarURL(sender string) string {
-	urlPath := b.mc.BuildURL("profile", sender, "avatar_url")
+func (b *Bmatrix) removeDisplayNameFromCache(mxid id.UserID) {
+	cache := b.NicknameCache
 
-	s := struct {
-		AvatarURL string `json:"avatar_url"`
-	}{}
+	cache.Lock()
+	defer cache.Unlock()
 
-	err := b.mc.MakeRequest("GET", urlPath, nil, &s)
-	if err != nil {
-		b.Log.Errorf("getAvatarURL failed: %s", err)
+	delete(cache.users, mxid)
+}
 
+// getAvatarURL returns the avatar URL of the specified sender.
+func (b *Bmatrix) getAvatarURL(sender id.UserID) string {
+	url, err := b.mc.GetAvatarURL(sender)
+	if err != nil {
+		b.Log.Errorf("Couldn't retrieve the URL of the avatar for MXID %s", sender)
 		return ""
 	}
 
-	url := strings.ReplaceAll(s.AvatarURL, "mxc://", b.GetString("Server")+"/_matrix/media/r0/thumbnail/")
-	if url != "" {
-		url += "?width=37&height=37&method=crop"
-	}
-
-	return url
+	return url.String()
 }
 
 // handleRatelimit handles the ratelimit errors and return if we're ratelimited and the amount of time to sleep
 func (b *Bmatrix) handleRatelimit(err error) (time.Duration, bool) {
-	httpErr := handleError(err)
-	if httpErr.Errcode != "M_LIMIT_EXCEEDED" {
+	var mErr matrix.HTTPError
+	if !errors.As(err, &mErr) {
+		b.Log.Errorf("Received a non-HTTPError, don't know what to make of it:\n%#v", err)
+		return 0, false
+	}
+
+	if mErr.RespError.ErrCode != "M_LIMIT_EXCEEDED" {
 		return 0, false
 	}
 
-	b.Log.Debugf("ratelimited: %s", httpErr.Err)
-	b.Log.Infof("getting ratelimited by matrix, sleeping approx %d seconds before retrying", httpErr.RetryAfterMs/1000)
+	b.Log.Debugf("ratelimited: %s", mErr.RespError.Err)
+
+	// fallback to a one-second delay
+	retryDelayMs := 1000
+
+	if retryDelayString, present := mErr.RespError.ExtraData["retry_after_ms"]; present {
+		if retryDelayInt, correct := retryDelayString.(int); correct && retryDelayInt > retryDelayMs {
+			retryDelayMs = retryDelayInt
+		}
+	}
+
+	b.Log.Infof("getting ratelimited by matrix, sleeping approx %d seconds before retrying", retryDelayMs/1000)
 
-	return time.Duration(httpErr.RetryAfterMs) * time.Millisecond, true
+	return time.Duration(retryDelayMs) * time.Millisecond, true
 }
 
 // retry function will check if we're ratelimited and retries again when backoff time expired
@@ -213,3 +317,66 @@ func (b *Bmatrix) retry(f func() error) error {
 		}
 	}
 }
+
+type SendMessageEventWrapper struct {
+	inner *matrix.Client
+}
+
+//nolint: wrapcheck
+func (w SendMessageEventWrapper) SendMessageEvent(roomID id.RoomID, eventType event.Type, contentJSON interface{}) (*matrix.RespSendEvent, error) {
+	return w.inner.SendMessageEvent(roomID, eventType, contentJSON)
+}
+
+//nolint: wrapcheck
+func (b *Bmatrix) sendMessageEventWithRetries(channel id.RoomID, message event.MessageEventContent, username string) (string, error) {
+	var (
+		resp   *matrix.RespSendEvent
+		client interface {
+			SendMessageEvent(roomID id.RoomID, eventType event.Type, contentJSON interface{}) (resp *matrix.RespSendEvent, err error)
+		}
+		err error
+	)
+
+	b.RLock()
+	appservice := b.RoomMap[channel].appService
+	b.RUnlock()
+
+	client = SendMessageEventWrapper{inner: b.mc}
+
+	// only try to send messages through the app Service *once* we have received
+	// events through it (otherwise we don't really know if the appservice works)
+	// Additionally, even if we're receiving messages in that room via the appService listener,
+	// let's check that the appservice "covers" that room
+	if appservice && b.appService.namespaces.containsRoom(channel) && len(b.appService.namespaces.prefixes) > 0 {
+		b.Log.Debugf("Sending with appService")
+		// we take the first prefix
+		bridgeUserID := fmt.Sprintf("@%s%s:%s", b.appService.namespaces.prefixes[0], id.EncodeUserLocalpart(username), b.appService.appService.HomeserverDomain)
+		intent := b.appService.appService.Intent(id.UserID(bridgeUserID))
+		// if we can't change the display name it's not great but not the end of the world either, ignore it
+		// TODO: do not perform this action on every message, with an in-memory cache or something
+		_ = intent.SetDisplayName(username)
+		client = intent
+	} else {
+		applyUsernametoMessage(&message, username)
+	}
+
+	err = b.retry(func() error {
+		resp, err = client.SendMessageEvent(channel, event.EventMessage, message)
+
+		return err
+	})
+	if err != nil {
+		return "", err
+	}
+
+	return string(resp.EventID), err
+}
+
+func applyUsernametoMessage(newMsg *event.MessageEventContent, username string) {
+	matrixUsername := newMatrixUsername(username)
+
+	newMsg.Body = matrixUsername.plain + newMsg.Body
+	if newMsg.FormattedBody != "" {
+		newMsg.FormattedBody = matrixUsername.formatted + newMsg.FormattedBody
+	}
+}
diff --git a/bridge/matrix/matrix.go b/bridge/matrix/matrix.go
index 49fc33b3..ee2081ff 100644
--- a/bridge/matrix/matrix.go
+++ b/bridge/matrix/matrix.go
@@ -1,18 +1,18 @@
+// nolint: exhaustivestruct
 package bmatrix
 
 import (
-	"bytes"
 	"fmt"
-	"mime"
 	"regexp"
-	"strings"
 	"sync"
-	"time"
+
+	matrix "maunium.net/go/mautrix"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
 
 	"github.com/42wim/matterbridge/bridge"
 	"github.com/42wim/matterbridge/bridge/config"
 	"github.com/42wim/matterbridge/bridge/helper"
-	matrix "github.com/matterbridge/gomatrix"
 )
 
 var (
@@ -20,25 +20,30 @@ var (
 	htmlReplacementTag = regexp.MustCompile("<[^>]*>")
 )
 
-type NicknameCacheEntry struct {
-	displayName string
-	lastUpdated time.Time
+type EventOrigin int
+
+const (
+	originClassicSyncer EventOrigin = iota
+	originAppService
+)
+
+type RoomInfo struct {
+	name       string
+	appService bool
 }
 
 type Bmatrix struct {
-	mc          *matrix.Client
-	UserID      string
-	NicknameMap map[string]NicknameCacheEntry
-	RoomMap     map[string]string
-	rateMutex   sync.RWMutex
+	mc            *matrix.Client
+	UserID        id.UserID
+	appService    *AppServiceWrapper
+	NicknameCache *NicknameCache
+	RoomMap       map[id.RoomID]RoomInfo
+	rateMutex     sync.RWMutex
+	joinedRooms   []id.RoomID
 	sync.RWMutex
 	*bridge.Config
-}
-
-type httpError struct {
-	Errcode      string `json:"errcode"`
-	Err          string `json:"error"`
-	RetryAfterMs int    `json:"retry_after_ms"`
+	stopNormalSync    chan struct{}
+	stopNormalSyncAck chan struct{}
 }
 
 type matrixUsername struct {
@@ -46,44 +51,12 @@ type matrixUsername struct {
 	formatted string
 }
 
-// SubTextMessage represents the new content of the message in edit messages.
-type SubTextMessage struct {
-	MsgType       string `json:"msgtype"`
-	Body          string `json:"body"`
-	FormattedBody string `json:"formatted_body,omitempty"`
-	Format        string `json:"format,omitempty"`
-}
-
-// MessageRelation explains how the current message relates to a previous message.
-// Notably used for message edits.
-type MessageRelation struct {
-	EventID string `json:"event_id"`
-	Type    string `json:"rel_type"`
-}
-
-type EditedMessage struct {
-	NewContent SubTextMessage  `json:"m.new_content"`
-	RelatedTo  MessageRelation `json:"m.relates_to"`
-	matrix.TextMessage
-}
-
-type InReplyToRelationContent struct {
-	EventID string `json:"event_id"`
-}
-
-type InReplyToRelation struct {
-	InReplyTo InReplyToRelationContent `json:"m.in_reply_to"`
-}
-
-type ReplyMessage struct {
-	RelatedTo InReplyToRelation `json:"m.relates_to"`
-	matrix.TextMessage
-}
-
 func New(cfg *bridge.Config) bridge.Bridger {
 	b := &Bmatrix{Config: cfg}
-	b.RoomMap = make(map[string]string)
-	b.NicknameMap = make(map[string]NicknameCacheEntry)
+	b.RoomMap = make(map[id.RoomID]RoomInfo)
+	b.NicknameCache = NewNicknameCache()
+	b.stopNormalSync = make(chan struct{}, 1)
+	b.stopNormalSyncAck = make(chan struct{}, 1)
 	return b
 }
 
@@ -91,13 +64,13 @@ func (b *Bmatrix) Connect() error {
 	var err error
 	b.Log.Infof("Connecting %s", b.GetString("Server"))
 	if b.GetString("MxID") != "" && b.GetString("Token") != "" {
+		b.UserID = id.UserID(b.GetString("MxID"))
 		b.mc, err = matrix.NewClient(
-			b.GetString("Server"), b.GetString("MxID"), b.GetString("Token"),
+			b.GetString("Server"), b.UserID, b.GetString("Token"),
 		)
 		if err != nil {
 			return err
 		}
-		b.UserID = b.GetString("MxID")
 		b.Log.Info("Using existing Matrix credentials")
 	} else {
 		b.mc, err = matrix.NewClient(b.GetString("Server"), "", "")
@@ -105,102 +78,150 @@ func (b *Bmatrix) Connect() error {
 			return err
 		}
 		resp, err := b.mc.Login(&matrix.ReqLogin{
-			Type:       "m.login.password",
-			User:       b.GetString("Login"),
-			Password:   b.GetString("Password"),
-			Identifier: matrix.NewUserIdentifier(b.GetString("Login")),
+			Type:             matrix.AuthTypePassword,
+			Password:         b.GetString("Password"),
+			Identifier:       matrix.UserIdentifier{Type: matrix.IdentifierTypeUser, User: b.GetString("Login")}, //nolint: exhaustruct
+			StoreCredentials: true,
 		})
 		if err != nil {
 			return err
 		}
-		b.mc.SetCredentials(resp.UserID, resp.AccessToken)
 		b.UserID = resp.UserID
 		b.Log.Info("Connection succeeded")
 	}
-	go b.handlematrix()
+
+	b.Log.Debug("Retrieving the list of rooms we have already joined")
+	joinedRooms, err := b.mc.JoinedRooms()
+	if err != nil {
+		b.Log.Errorf("couldn't list the joined rooms")
+
+		return err
+	}
+	b.joinedRooms = joinedRooms.JoinedRooms
+	for _, roomID := range joinedRooms.JoinedRooms {
+		// leave the channel name (usually a channel alias - in the matrix sense)
+		// unresolved for now, it will be completed when JoinChannel() is called
+		b.RoomMap[roomID] = RoomInfo{name: "", appService: false}
+	}
+
 	return nil
 }
 
 func (b *Bmatrix) Disconnect() error {
+	// tell the Sync() loop to exit
+	b.stopNormalSync <- struct{}{}
+	b.mc.StopSync()
+
+	// wait for both the syncer and the appservice to terminate
+	<-b.stopNormalSyncAck
+	if b.appService != nil {
+		b.appService.stop <- struct{}{}
+		<-b.appService.stopAck
+	}
+
 	return nil
 }
 
 func (b *Bmatrix) JoinChannel(channel config.ChannelInfo) error {
-	return b.retry(func() error {
-		resp, err := b.mc.JoinRoom(channel.Name, "", nil)
+	resolvedAlias, err := b.mc.ResolveAlias(id.RoomAlias(channel.Name))
+	if err != nil {
+		b.Log.Errorf("couldn't retrieve the room ID for the alias '%s'", channel.Name)
+
+		return err
+	}
+
+	roomInfo := RoomInfo{name: channel.Name, appService: false}
+	alreadyJoined := false
+	for _, roomID := range b.joinedRooms {
+		// we have already joined this room (e.g. in a previous execution of matterbridge)
+		// => we only update the room alias, but do not attempt to join it again
+		if roomID == resolvedAlias.RoomID {
+			alreadyJoined = true
+			break
+		}
+	}
+
+	if !alreadyJoined {
+		err = b.retry(func() error {
+			_, innerErr := b.mc.JoinRoom(channel.Name, "", nil)
+			return innerErr
+		})
+
 		if err != nil {
 			return err
 		}
+	}
 
-		b.Lock()
-		b.RoomMap[resp.RoomID] = channel.Name
-		b.Unlock()
+	b.Lock()
+	b.RoomMap[resolvedAlias.RoomID] = roomInfo
+	b.Unlock()
 
-		return nil
-	})
+	return nil
 }
 
-func (b *Bmatrix) Send(msg config.Message) (string, error) {
-	b.Log.Debugf("=> Receiving %#v", msg)
-
-	channel := b.getRoomID(msg.Channel)
-	b.Log.Debugf("Channel %s maps to channel id %s", msg.Channel, channel)
+func (b *Bmatrix) Start() error {
+	// at this point, JoinChannel() has been called on all the channels
+	// declared in the configuration, so we can exit every other joined room
+	// in order to stop receiving events from rooms we no longer follow
+	b.RLock()
+	for _, roomID := range b.joinedRooms {
+		if _, present := b.RoomMap[roomID]; !present {
+			// we deliberately ignore the return value,
+			// because the bridge will still work even if we couln't exit the room
+			_, _ = b.mc.LeaveRoom(roomID, &matrix.ReqLeave{Reason: "No longer bridged"})
+		}
+	}
+	b.RUnlock()
 
-	username := newMatrixUsername(msg.Username)
+	go b.handlematrix()
 
-	body := username.plain + msg.Text
-	formattedBody := username.formatted + helper.ParseMarkdown(msg.Text)
+	if b.GetBool("UseAppService") {
+		appService, err := b.NewAppService()
+		if err != nil {
+			b.Log.Errorf("couldn't load the app service configuration: %#v", err)
 
-	if b.GetBool("SpoofUsername") {
-		// https://spec.matrix.org/v1.3/client-server-api/#mroommember
-		type stateMember struct {
-			AvatarURL   string `json:"avatar_url,omitempty"`
-			DisplayName string `json:"displayname"`
-			Membership  string `json:"membership"`
+			return err
 		}
 
-		// TODO: reset username afterwards with DisplayName: null ?
-		m := stateMember{
-			AvatarURL:   "",
-			DisplayName: username.plain,
-			Membership:  "join",
-		}
+		b.appService = appService
+		err = b.startAppService()
+		if err != nil {
+			b.Log.Errorf("couldn't start the application service: %#v", err)
 
-		_, err := b.mc.SendStateEvent(channel, "m.room.member", b.UserID, m)
-		if err == nil {
-			body = msg.Text
-			formattedBody = helper.ParseMarkdown(msg.Text)
+			return err
 		}
 	}
 
-	// Make a action /me of the message
-	if msg.Event == config.EventUserAction {
-		m := matrix.TextMessage{
-			MsgType:       "m.emote",
-			Body:          body,
-			FormattedBody: formattedBody,
-			Format:        "org.matrix.custom.html",
-		}
+	return nil
+}
 
-		if b.GetBool("HTMLDisable") {
-			m.Format = ""
-			m.FormattedBody = ""
-		}
+func (b *Bmatrix) Send(msg config.Message) (string, error) {
+	b.Log.Debugf("=> Sending %#v", msg)
 
-		msgID := ""
+	channel := b.getRoomID(msg.Channel)
+	if channel == "" {
+		return "", fmt.Errorf("got message for unknown channel '%s'", msg.Channel)
+	}
 
-		err := b.retry(func() error {
-			resp, err := b.mc.SendMessageEvent(channel, "m.room.message", m)
-			if err != nil {
-				return err
-			}
+	if msg.Event == config.EventUserTyping && b.GetBool("ShowUserTyping") {
+		_, err := b.mc.UserTyping(channel, true, 15000)
+		return "", err
+	}
 
-			msgID = resp.EventID
+	// Make a action /me of the message
+	if msg.Event == config.EventUserAction {
+		//nolint:exhaustruct
+		m := event.MessageEventContent{
+			MsgType: event.MsgEmote,
+			Body:    msg.Text,
+		}
 
-			return err
-		})
+		if !b.GetBool("HTMLDisable") {
+			m.FormattedBody = helper.ParseMarkdown(msg.Text)
+			m.Format = event.FormatHTML
+		}
 
-		return msgID, err
+		return b.sendMessageEventWithRetries(channel, m, msg.Username)
 	}
 
 	// Delete message
@@ -212,12 +233,10 @@ func (b *Bmatrix) Send(msg config.Message) (string, error) {
 		msgID := ""
 
 		err := b.retry(func() error {
-			resp, err := b.mc.RedactEvent(channel, msg.ID, &matrix.ReqRedact{})
-			if err != nil {
-				return err
-			}
+			//nolint:exhaustruct
+			resp, err := b.mc.RedactEvent(channel, id.EventID(msg.ID), matrix.ReqRedact{})
 
-			msgID = resp.EventID
+			msgID = string(resp.EventID)
 
 			return err
 		})
@@ -228,13 +247,13 @@ func (b *Bmatrix) Send(msg config.Message) (string, error) {
 	// Upload a file if it exists
 	if msg.Extra != nil {
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {
-			rmsg := rmsg
-
-			err := b.retry(func() error {
-				_, err := b.mc.SendText(channel, rmsg.Username+rmsg.Text)
+			//nolint:exhaustruct
+			m := event.MessageEventContent{
+				MsgType: event.MsgText,
+				Body:    rmsg.Text,
+			}
 
-				return err
-			})
+			_, err := b.sendMessageEventWithRetries(channel, m, msg.Username)
 			if err != nil {
 				b.Log.Errorf("sendText failed: %s", err)
 			}
@@ -247,472 +266,159 @@ func (b *Bmatrix) Send(msg config.Message) (string, error) {
 
 	// Edit message if we have an ID
 	if msg.ID != "" {
-		rmsg := EditedMessage{
-			TextMessage: matrix.TextMessage{
-				Body:          body,
-				MsgType:       "m.text",
-				Format:        "org.matrix.custom.html",
-				FormattedBody: formattedBody,
-			},
+		//nolint:exhaustruct
+		rmsg := event.MessageEventContent{
+			MsgType: event.MsgText,
+			Body:    msg.Text,
 		}
-
-		rmsg.NewContent = SubTextMessage{
-			Body:          rmsg.TextMessage.Body,
-			FormattedBody: rmsg.TextMessage.FormattedBody,
-			Format:        rmsg.TextMessage.Format,
-			MsgType:       "m.text",
+		//nolint:exhaustruct
+		rmsg.NewContent = &event.MessageEventContent{
+			Body:    rmsg.Body,
+			MsgType: event.MsgText,
 		}
-
 		if b.GetBool("HTMLDisable") {
-			rmsg.TextMessage.Format = ""
-			rmsg.TextMessage.FormattedBody = ""
-			rmsg.NewContent.Format = ""
-			rmsg.NewContent.FormattedBody = ""
+			rmsg.FormattedBody = "* " + msg.Text
+		} else {
+			rmsg.Format = event.FormatHTML
+			rmsg.FormattedBody = "* " + helper.ParseMarkdown(msg.Text)
+			rmsg.NewContent.Format = rmsg.Format
+			rmsg.NewContent.FormattedBody = rmsg.FormattedBody
 		}
 
-		rmsg.RelatedTo = MessageRelation{
-			EventID: msg.ID,
-			Type:    "m.replace",
+		//nolint:exhaustruct
+		rmsg.RelatesTo = &event.RelatesTo{
+			EventID: id.EventID(msg.ID),
+			Type:    event.RelReplace,
 		}
 
-		err := b.retry(func() error {
-			_, err := b.mc.SendMessageEvent(channel, "m.room.message", rmsg)
+		return b.sendMessageEventWithRetries(channel, rmsg, msg.Username)
+	}
 
-			return err
-		})
-		if err != nil {
-			return "", err
-		}
+	//nolint:exhaustruct
+	m := event.MessageEventContent{
+		Body: msg.Text,
+	}
 
-		return msg.ID, nil
+	if !b.GetBool("HTMLDisable") {
+		m.Format = event.FormatHTML
+		m.FormattedBody = msg.Text
 	}
 
 	// Use notices to send join/leave events
 	if msg.Event == config.EventJoinLeave {
-		m := matrix.TextMessage{
-			MsgType:       "m.notice",
-			Body:          body,
-			FormattedBody: formattedBody,
-			Format:        "org.matrix.custom.html",
-		}
-
+		m.MsgType = event.MsgNotice
+	} else {
+		m.MsgType = event.MsgText
 		if b.GetBool("HTMLDisable") {
-			m.Format = ""
 			m.FormattedBody = ""
+		} else {
+			m.FormattedBody = helper.ParseMarkdown(msg.Text)
 		}
 
-		var (
-			resp *matrix.RespSendEvent
-			err  error
-		)
-
-		err = b.retry(func() error {
-			resp, err = b.mc.SendMessageEvent(channel, "m.room.message", m)
-
-			return err
-		})
-		if err != nil {
-			return "", err
-		}
-
-		return resp.EventID, err
-	}
-
-	if msg.ParentValid() {
-		m := ReplyMessage{
-			TextMessage: matrix.TextMessage{
-				MsgType:       "m.text",
-				Body:          body,
-				FormattedBody: formattedBody,
-				Format:        "org.matrix.custom.html",
-			},
-		}
-
-		if b.GetBool("HTMLDisable") {
-			m.TextMessage.Format = ""
-			m.TextMessage.FormattedBody = ""
-		}
-
-		m.RelatedTo = InReplyToRelation{
-			InReplyTo: InReplyToRelationContent{
-				EventID: msg.ParentID,
-			},
-		}
-
-		var (
-			resp *matrix.RespSendEvent
-			err  error
-		)
-
-		err = b.retry(func() error {
-			resp, err = b.mc.SendMessageEvent(channel, "m.room.message", m)
-
-			return err
-		})
-		if err != nil {
-			return "", err
-		}
-
-		return resp.EventID, err
-	}
-
-	if b.GetBool("HTMLDisable") {
-		var (
-			resp *matrix.RespSendEvent
-			err  error
-		)
-
-		err = b.retry(func() error {
-			resp, err = b.mc.SendText(channel, body)
-
-			return err
-		})
-		if err != nil {
-			return "", err
-		}
-
-		return resp.EventID, err
-	}
-
-	// Post normal message with HTML support (eg riot.im)
-	var (
-		resp *matrix.RespSendEvent
-		err  error
-	)
-
-	err = b.retry(func() error {
-		resp, err = b.mc.SendFormattedText(channel, body, formattedBody)
-
-		return err
-	})
-	if err != nil {
-		return "", err
-	}
-
-	return resp.EventID, err
-}
-
-func (b *Bmatrix) handlematrix() {
-	syncer := b.mc.Syncer.(*matrix.DefaultSyncer)
-	syncer.OnEventType("m.room.redaction", b.handleEvent)
-	syncer.OnEventType("m.room.message", b.handleEvent)
-	syncer.OnEventType("m.room.member", b.handleMemberChange)
-	go func() {
-		for {
-			if b == nil {
-				return
-			}
-			if err := b.mc.Sync(); err != nil {
-				b.Log.Println("Sync() returned ", err)
+		if msg.ParentValid() {
+			m.RelatesTo = &event.RelatesTo{
+				EventID: "",
+				Type:    event.RelReference,
+				InReplyTo: &event.InReplyTo{
+					EventID: id.EventID(msg.ParentID),
+				},
+				Key: "",
 			}
 		}
-	}()
-}
-
-func (b *Bmatrix) handleEdit(ev *matrix.Event, rmsg config.Message) bool {
-	relationInterface, present := ev.Content["m.relates_to"]
-	newContentInterface, present2 := ev.Content["m.new_content"]
-	if !(present && present2) {
-		return false
 	}
 
-	var relation MessageRelation
-	if err := interface2Struct(relationInterface, &relation); err != nil {
-		b.Log.Warnf("Couldn't parse 'm.relates_to' object with value %#v", relationInterface)
-		return false
-	}
-
-	var newContent SubTextMessage
-	if err := interface2Struct(newContentInterface, &newContent); err != nil {
-		b.Log.Warnf("Couldn't parse 'm.new_content' object with value %#v", newContentInterface)
-		return false
-	}
-
-	if relation.Type != "m.replace" {
-		return false
-	}
-
-	rmsg.ID = relation.EventID
-	rmsg.Text = newContent.Body
-	b.Remote <- rmsg
-
-	return true
+	return b.sendMessageEventWithRetries(channel, m, msg.Username)
 }
 
-func (b *Bmatrix) handleReply(ev *matrix.Event, rmsg config.Message) bool {
-	relationInterface, present := ev.Content["m.relates_to"]
-	if !present {
-		return false
-	}
-
-	var relation InReplyToRelation
-	if err := interface2Struct(relationInterface, &relation); err != nil {
-		// probably fine
-		return false
-	}
-
-	body := rmsg.Text
-
-	if !b.GetBool("keepquotedreply") {
-		for strings.HasPrefix(body, "> ") {
-			lineIdx := strings.IndexRune(body, '\n')
-			if lineIdx == -1 {
-				body = ""
-			} else {
-				body = body[(lineIdx + 1):]
+// DontProcessOldEvents returns true if a sync event should be considered for further processing.
+// We use that function to filter out events we have already read.
+func (b *Bmatrix) DontProcessOldEvents(resp *matrix.RespSync, since string) bool {
+	// we only filter old events in the initial sync(), because subsequent sync()
+	// (where since != "") should only return new events
+	if since != "" {
+		return true
+	}
+
+	for joinedRoom, roomData := range resp.Rooms.Join {
+		var readTimestamp int64 = 0
+		// retrieve the timestamp of the last read receipt
+		// note: we're not sure some events will not be thrown away in this
+		// initial sync, as the server may not have received some events yet when
+		// the read receipt was sent: there is a mix of timestamps between
+		// the read receipt on the target homeserver and the timestamps when
+		// events were *created* on the homeserver peers
+		for _, evt := range roomData.Ephemeral.Events {
+			if evt.Type != event.EphemeralEventReceipt {
+				continue
 			}
-		}
-	}
-
-	rmsg.Text = body
-	rmsg.ParentID = relation.InReplyTo.EventID
-	b.Remote <- rmsg
-
-	return true
-}
-
-func (b *Bmatrix) handleMemberChange(ev *matrix.Event) {
-	// Update the displayname on join messages, according to https://matrix.org/docs/spec/client_server/r0.6.1#events-on-change-of-profile-information
-	if ev.Content["membership"] == "join" {
-		if dn, ok := ev.Content["displayname"].(string); ok {
-			b.cacheDisplayName(ev.Sender, dn)
-		}
-	}
-}
-
-func (b *Bmatrix) handleEvent(ev *matrix.Event) {
-	b.Log.Debugf("== Receiving event: %#v", ev)
-	if ev.Sender != b.UserID {
-		b.RLock()
-		channel, ok := b.RoomMap[ev.RoomID]
-		b.RUnlock()
-		if !ok {
-			b.Log.Debugf("Unknown room %s", ev.RoomID)
-			return
-		}
-
-		// Create our message
-		rmsg := config.Message{
-			Username: b.getDisplayName(ev.Sender),
-			Channel:  channel,
-			Account:  b.Account,
-			UserID:   ev.Sender,
-			ID:       ev.ID,
-			Avatar:   b.getAvatarURL(ev.Sender),
-		}
-
-		// Remove homeserver suffix if configured
-		if b.GetBool("NoHomeServerSuffix") {
-			re := regexp.MustCompile("(.*?):.*")
-			rmsg.Username = re.ReplaceAllString(rmsg.Username, `$1`)
-		}
-
-		// Delete event
-		if ev.Type == "m.room.redaction" {
-			rmsg.Event = config.EventMsgDelete
-			rmsg.ID = ev.Redacts
-			rmsg.Text = config.EventMsgDelete
-			b.Remote <- rmsg
-			return
-		}
-
-		// Text must be a string
-		if rmsg.Text, ok = ev.Content["body"].(string); !ok {
-			b.Log.Errorf("Content[body] is not a string: %T\n%#v",
-				ev.Content["body"], ev.Content)
-			return
-		}
-
-		// Do we have a /me action
-		if ev.Content["msgtype"].(string) == "m.emote" {
-			rmsg.Event = config.EventUserAction
-		}
-
-		// Is it an edit?
-		if b.handleEdit(ev, rmsg) {
-			return
-		}
-
-		// Is it a reply?
-		if b.handleReply(ev, rmsg) {
-			return
-		}
 
-		// Do we have attachments
-		if b.containsAttachment(ev.Content) {
-			err := b.handleDownloadFile(&rmsg, ev.Content)
+			err := evt.Content.ParseRaw(evt.Type)
 			if err != nil {
-				b.Log.Errorf("download failed: %#v", err)
+				b.Log.Warnf("couldn't parse receipt event %#v", evt.Content)
+			}
+			receipts := *evt.Content.AsReceipt()
+			for _, receiptByType := range receipts {
+				for _, receiptsByUser := range receiptByType {
+					for userID, userReceipt := range receiptsByUser {
+						// ignore read receipts of other users
+						if userID != b.UserID {
+							continue
+						}
+
+						readTimestamp = userReceipt.Timestamp.UnixNano()
+					}
+				}
 			}
 		}
 
-		b.Log.Debugf("<= Sending message from %s on %s to gateway", ev.Sender, b.Account)
-		b.Remote <- rmsg
-
-		// not crucial, so no ratelimit check here
-		if err := b.mc.MarkRead(ev.RoomID, ev.ID); err != nil {
-			b.Log.Errorf("couldn't mark message as read %s", err.Error())
-		}
-	}
-}
-
-// handleDownloadFile handles file download
-func (b *Bmatrix) handleDownloadFile(rmsg *config.Message, content map[string]interface{}) error {
-	var (
-		ok                        bool
-		url, name, msgtype, mtype string
-		info                      map[string]interface{}
-		size                      float64
-	)
-
-	rmsg.Extra = make(map[string][]interface{})
-	if url, ok = content["url"].(string); !ok {
-		return fmt.Errorf("url isn't a %T", url)
-	}
-	url = strings.Replace(url, "mxc://", b.GetString("Server")+"/_matrix/media/v1/download/", -1)
-
-	if info, ok = content["info"].(map[string]interface{}); !ok {
-		return fmt.Errorf("info isn't a %T", info)
-	}
-	if size, ok = info["size"].(float64); !ok {
-		return fmt.Errorf("size isn't a %T", size)
-	}
-	if name, ok = content["body"].(string); !ok {
-		return fmt.Errorf("name isn't a %T", name)
-	}
-	if msgtype, ok = content["msgtype"].(string); !ok {
-		return fmt.Errorf("msgtype isn't a %T", msgtype)
-	}
-	if mtype, ok = info["mimetype"].(string); !ok {
-		return fmt.Errorf("mtype isn't a %T", mtype)
-	}
-
-	// check if we have an image uploaded without extension
-	if !strings.Contains(name, ".") {
-		if msgtype == "m.image" {
-			mext, _ := mime.ExtensionsByType(mtype)
-			if len(mext) > 0 {
-				name += mext[0]
+		newEventList := make([]*event.Event, 0, len(roomData.Timeline.Events))
+		for _, evt := range roomData.Timeline.Events {
+			// remove old event, except for state changes
+			if evt.Timestamp > readTimestamp || evt.Type.Class == event.StateEventType {
+				newEventList = append(newEventList, evt)
 			}
-		} else {
-			// just a default .png extension if we don't have mime info
-			name += ".png"
 		}
-	}
-
-	// check if the size is ok
-	err := helper.HandleDownloadSize(b.Log, rmsg, name, int64(size), b.General)
-	if err != nil {
-		return err
-	}
-	// actually download the file
-	data, err := helper.DownloadFile(url)
-	if err != nil {
-		return fmt.Errorf("download %s failed %#v", url, err)
-	}
-	// add the downloaded data to the message
-	helper.HandleDownloadData(b.Log, rmsg, name, "", url, data, b.General)
-	return nil
-}
 
-// handleUploadFiles handles native upload of files.
-func (b *Bmatrix) handleUploadFiles(msg *config.Message, channel string) (string, error) {
-	for _, f := range msg.Extra["file"] {
-		if fi, ok := f.(config.FileInfo); ok {
-			b.handleUploadFile(msg, channel, &fi)
-		}
+		roomData.Timeline.Events = newEventList
+		resp.Rooms.Join[joinedRoom] = roomData
 	}
-	return "", nil
+	return true
 }
 
-// handleUploadFile handles native upload of a file.
-func (b *Bmatrix) handleUploadFile(msg *config.Message, channel string, fi *config.FileInfo) {
-	username := newMatrixUsername(msg.Username)
-	content := bytes.NewReader(*fi.Data)
-	sp := strings.Split(fi.Name, ".")
-	mtype := mime.TypeByExtension("." + sp[len(sp)-1])
-	// image and video uploads send no username, we have to do this ourself here #715
-	err := b.retry(func() error {
-		_, err := b.mc.SendFormattedText(channel, username.plain+fi.Comment, username.formatted+fi.Comment)
-
-		return err
-	})
-	if err != nil {
-		b.Log.Errorf("file comment failed: %#v", err)
-	}
-
-	b.Log.Debugf("uploading file: %s %s", fi.Name, mtype)
-
-	var res *matrix.RespMediaUpload
-
-	err = b.retry(func() error {
-		res, err = b.mc.UploadToContentRepo(content, mtype, int64(len(*fi.Data)))
-
-		return err
-	})
+func (b *Bmatrix) handlematrix() {
+	syncer, ok := b.mc.Syncer.(*matrix.DefaultSyncer)
+	if !ok {
+		b.Log.Errorf("couldn't convert the Syncer object to a DefaultSyncer structure, the matrix bridge won't work")
 
-	if err != nil {
-		b.Log.Errorf("file upload failed: %#v", err)
 		return
 	}
 
-	switch {
-	case strings.Contains(mtype, "video"):
-		b.Log.Debugf("sendVideo %s", res.ContentURI)
-		err = b.retry(func() error {
-			_, err = b.mc.SendVideo(channel, fi.Name, res.ContentURI)
+	// register our custom filtering function
+	syncer.OnSync(b.DontProcessOldEvents)
 
-			return err
+	eventsTypes := []event.Type{event.EventRedaction, event.EventMessage, event.StateMember, event.EphemeralEventReceipt}
+	if b.GetBool("ShowUserTyping") {
+		eventsTypes = append(eventsTypes, event.EphemeralEventTyping)
+	}
+	for _, evType := range eventsTypes {
+		syncer.OnEventType(evType, func(source matrix.EventSource, ev *event.Event) {
+			b.handleEvent(originClassicSyncer, ev)
 		})
-		if err != nil {
-			b.Log.Errorf("sendVideo failed: %#v", err)
-		}
-	case strings.Contains(mtype, "image"):
-		b.Log.Debugf("sendImage %s", res.ContentURI)
-		err = b.retry(func() error {
-			_, err = b.mc.SendImage(channel, fi.Name, res.ContentURI)
+	}
 
-			return err
-		})
-		if err != nil {
-			b.Log.Errorf("sendImage failed: %#v", err)
-		}
-	case strings.Contains(mtype, "audio"):
-		b.Log.Debugf("sendAudio %s", res.ContentURI)
-		err = b.retry(func() error {
-			_, err = b.mc.SendMessageEvent(channel, "m.room.message", matrix.AudioMessage{
-				MsgType: "m.audio",
-				Body:    fi.Name,
-				URL:     res.ContentURI,
-				Info: matrix.AudioInfo{
-					Mimetype: mtype,
-					Size:     uint(len(*fi.Data)),
-				},
-			})
+	go func() {
+		for {
+			select {
+			case <-b.stopNormalSync:
+				b.stopNormalSyncAck <- struct{}{}
 
-			return err
-		})
-		if err != nil {
-			b.Log.Errorf("sendAudio failed: %#v", err)
-		}
-	default:
-		b.Log.Debugf("sendFile %s", res.ContentURI)
-		err = b.retry(func() error {
-			_, err = b.mc.SendMessageEvent(channel, "m.room.message", matrix.FileMessage{
-				MsgType: "m.file",
-				Body:    fi.Name,
-				URL:     res.ContentURI,
-				Info: matrix.FileInfo{
-					Mimetype: mtype,
-					Size:     uint(len(*fi.Data)),
-				},
-			})
+				return
+			default:
 
-			return err
-		})
-		if err != nil {
-			b.Log.Errorf("sendFile failed: %#v", err)
+				if err := b.mc.Sync(); err != nil {
+					b.Log.Warningf("Sync() returned %#v", err)
+				}
+			}
 		}
-	}
-	b.Log.Debugf("result: %#v", res)
+	}()
 }
diff --git a/bridge/matrix/zerolog_abstraction.go b/bridge/matrix/zerolog_abstraction.go
new file mode 100644
index 00000000..3d74a4e0
--- /dev/null
+++ b/bridge/matrix/zerolog_abstraction.go
@@ -0,0 +1,43 @@
+package bmatrix
+
+import (
+	"errors"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/rs/zerolog"
+)
+
+var levels_zerolog2logrus = map[zerolog.Level]logrus.Level{
+	zerolog.DebugLevel: logrus.DebugLevel,
+	zerolog.InfoLevel:  logrus.InfoLevel,
+	zerolog.WarnLevel:  logrus.WarnLevel,
+	zerolog.FatalLevel: logrus.FatalLevel,
+	zerolog.PanicLevel: logrus.PanicLevel,
+	zerolog.ErrorLevel: logrus.ErrorLevel,
+	zerolog.TraceLevel: logrus.TraceLevel,
+}
+
+// an abstraction for zerolog so we can pipe its output to logrus.Entry, that is used in matterbridge
+type zerologWrapper struct {
+	inner *logrus.Entry
+}
+
+func (w zerologWrapper) Write(p []byte) (n int, err error) {
+	return w.inner.Logger.Writer().Write(p)
+}
+
+func (w zerologWrapper) WriteLevel(level zerolog.Level, p []byte) (n int, err error) {
+	if logrus_level, present := levels_zerolog2logrus[level]; present {
+		return w.inner.Logger.WriterLevel(logrus_level).Write(p)
+	}
+	// drop the message if we haven't a matching level
+	return 0, errors.New("Unsupported logging level")
+}
+
+func NewZerologWrapper(entry *logrus.Entry) zerolog.Logger {
+	wrapper := zerologWrapper{inner: entry}
+	log := zerolog.New(wrapper)
+
+	return log
+}