Escape @room in reply fallback to avoid unintentional pings

Closes https://github.com/SchildiChat/SchildiChat-android/issues/178

Change-Id: I8a545dd80d29802d1b35b0315fca89125c997f15

FEATURES.md

@@ -34,6 +34,7 @@ Here you can find some extra features and changes compared to Element Android (w
 - Render image reactions
 - Send freeform reactions
 - Render media captions ([MSC2530](https://github.com/matrix-org/matrix-spec-proposals/pull/2530))
+- Escape @room in the reply fallback to avoid unintentional room pings when replying
 
 - Branding (name, app icon, links)
 - Show a toast instead of a snackbar after copying text, in order to not block the input area right after copying

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/send/LocalEchoEventFactory.kt

@@ -637,7 +637,7 @@ internal class LocalEchoEventFactory @Inject constructor(
                 permalink,
                 userLink,
                 userId,
-                bodyFormatted,
+                bodyFormatted.escapeRoomPings(),
                 finalReplyTextFormatted
         )
         //
@@ -726,7 +726,7 @@ internal class LocalEchoEventFactory @Inject constructor(
             append(originalSenderId)
             append(">")
 
-            val lines = body.text.split("\n")
+            val lines = body.text.escapeRoomPings().split("\n")
             lines.forEachIndexed { index, s ->
                 if (index == 0) {
                     append(" $s")
@@ -739,6 +739,11 @@ internal class LocalEchoEventFactory @Inject constructor(
         }
     }
 
+    private fun String.escapeRoomPings(): String {
+        // Escape @room, so replying as moderator will not ping the whole room
+        return replace("@room", "@\u2060room")
+    }
+
     private fun bodyForReply(timelineEvent: TimelineEvent, isRedactedEvent: Boolean = false): TextContent {
         val content = when (timelineEvent.root.getClearType()) {
             in EventType.POLL_END.values -> {