From b066eafeac5449699fbda3a755c624bd017d9b86 Mon Sep 17 00:00:00 2001
From: Simon THOBY <git@nightmared.fr>
Date: Fri, 6 Nov 2020 15:31:14 +0100
Subject: [PATCH] matrix: send the display name (the nickname in matrix
 parlance) instead of the user name

There is also the option UseUserName (already in use by the discord bridge) to turn back to the old behavior.
---
 bridge/config/config.go  |  2 +-
 bridge/matrix/matrix.go  | 52 ++++++++++++++++++++++++++++++++++++----
 matterbridge.toml.sample |  3 +++
 3 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/bridge/config/config.go b/bridge/config/config.go
index 67a7dc13..7f8d3a4a 100644
--- a/bridge/config/config.go
+++ b/bridge/config/config.go
@@ -154,7 +154,7 @@ type Protocol struct {
 	UseTLS                 bool       // IRC
 	UseDiscriminator       bool       // discord
 	UseFirstName           bool       // telegram
-	UseUserName            bool       // discord
+	UseUserName            bool       // discord, matrix
 	UseInsecureURL         bool       // telegram
 	VerboseJoinPart        bool       // IRC
 	WebhookBindAddress     string     // mattermost, slack
diff --git a/bridge/matrix/matrix.go b/bridge/matrix/matrix.go
index fa2a3f80..edbbbe39 100644
--- a/bridge/matrix/matrix.go
+++ b/bridge/matrix/matrix.go
@@ -22,10 +22,16 @@ var (
 	htmlReplacementTag = regexp.MustCompile("<[^>]*>")
 )
 
+type NicknameCacheEntry struct {
+	nickname    string
+	lastUpdated time.Time
+}
+
 type Bmatrix struct {
-	mc      *matrix.Client
-	UserID  string
-	RoomMap map[string]string
+	mc          *matrix.Client
+	UserID      string
+	NicknameMap map[string]NicknameCacheEntry
+	RoomMap     map[string]string
 	sync.RWMutex
 	*bridge.Config
 }
@@ -60,6 +66,7 @@ func newMatrixUsername(username string) *matrixUsername {
 func New(cfg *bridge.Config) bridge.Bridger {
 	b := &Bmatrix{Config: cfg}
 	b.RoomMap = make(map[string]string)
+	b.NicknameMap = make(map[string]NicknameCacheEntry)
 	return b
 }
 
@@ -296,6 +303,43 @@ func (b *Bmatrix) handleEdit(ev *matrix.Event, rmsg config.Message) bool {
 	return true
 }
 
+func (b *Bmatrix) getUserName(mxid string) string {
+	if b.GetBool("UseUserName") {
+		return mxid[1:]
+	}
+
+	b.RLock()
+	if val, present := b.NicknameMap[mxid]; present {
+		if time.Since(val.lastUpdated) < 10*time.Minute {
+			b.RUnlock()
+			return val.nickname
+		}
+	}
+	b.RUnlock()
+
+	nickname, err := b.mc.GetDisplayName(mxid)
+	if err != nil && err.(matrix.HTTPError).Code != 404 {
+		b.Log.Warnf("Couldn't retrieve the display name for %s", mxid)
+	}
+
+	b.Lock()
+	defer b.Unlock()
+
+	if err != nil {
+		b.NicknameMap[mxid] = NicknameCacheEntry{
+			nickname:    mxid[1:],
+			lastUpdated: time.Now(),
+		}
+	} else {
+		b.NicknameMap[mxid] = NicknameCacheEntry{
+			nickname:    nickname.DisplayName,
+			lastUpdated: time.Now(),
+		}
+	}
+
+	return b.NicknameMap[mxid].nickname
+}
+
 func (b *Bmatrix) handleEvent(ev *matrix.Event) {
 	b.Log.Debugf("== Receiving event: %#v", ev)
 	if ev.Sender != b.UserID {
@@ -309,7 +353,7 @@ func (b *Bmatrix) handleEvent(ev *matrix.Event) {
 
 		// Create our message
 		rmsg := config.Message{
-			Username: ev.Sender[1:],
+			Username: b.getUserName(ev.Sender),
 			Channel:  channel,
 			Account:  b.Account,
 			UserID:   ev.Sender,
diff --git a/matterbridge.toml.sample b/matterbridge.toml.sample
index 6b38580f..fcaac2a4 100644
--- a/matterbridge.toml.sample
+++ b/matterbridge.toml.sample
@@ -1231,6 +1231,9 @@ HTMLDisable=false
 ## RELOADABLE SETTINGS
 ## Settings below can be reloaded by editing the file
 
+# UseUserName shows the username instead of the server nickname
+UseUserName=false
+
 #Whether to prefix messages from other bridges to matrix with the sender's nick.
 #Useful if username overrides for incoming webhooks isn't enabled on the
 #matrix server. If you set PrefixMessagesWithNick to true, each message