feat: Add "Heard X repeats" echo tracking for sent messages

Track how many repeaters heard and forwarded sent channel messages,
similar to the Meshcore mobile app's "Heard X repeats" feature.

- Bridge: Detect GRP_TXT echoes from stdout, track unique paths
- Bridge: New /register_echo and /echo_counts API endpoints
- API: Register messages for echo tracking after send
- API: Merge echo counts into /api/messages response
- Frontend: Display green badge with broadcast icon next to Resend button
- CSS: Echo badge styling with dark mode support

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/routes/api.py

@@ -299,6 +299,30 @@ def get_messages():
             channel_idx=channel_idx
         )
 
+        # Fetch echo counts from bridge (for "Heard X repeats" feature)
+        if not archive_date:  # Only for live messages, not archives
+            try:
+                bridge_url = config.MC_BRIDGE_URL.replace('/cli', '/echo_counts')
+                response = requests.get(bridge_url, timeout=2)
+                if response.ok:
+                    echo_counts = response.json().get('echo_counts', [])
+
+                    # Create lookup by timestamp + channel
+                    echo_lookup = {(ec['timestamp'], ec['channel_idx']): ec['count']
+                                   for ec in echo_counts}
+
+                    # Merge into messages
+                    for msg in messages:
+                        if msg.get('is_own'):
+                            # Find matching echo count (within 5 second window)
+                            msg['echo_count'] = 0
+                            for (ts, ch), count in echo_lookup.items():
+                                if msg.get('channel_idx') == ch and abs(msg['timestamp'] - ts) < 5:
+                                    msg['echo_count'] = count
+                                    break
+            except Exception as e:
+                logger.debug(f"Echo counts fetch failed (non-critical): {e}")
+
         return jsonify({
             'success': True,
             'count': len(messages),
@@ -360,6 +384,17 @@ def send_message():
         success, message = cli.send_message(text, reply_to=reply_to, channel_index=channel_idx)
 
         if success:
+            # Register for echo tracking ("Heard X repeats" feature)
+            try:
+                bridge_url = config.MC_BRIDGE_URL.replace('/cli', '/register_echo')
+                requests.post(
+                    bridge_url,
+                    json={'channel_idx': channel_idx, 'timestamp': time.time()},
+                    timeout=2
+                )
+            except Exception as e:
+                logger.debug(f"Echo registration failed (non-critical): {e}")
+
             return jsonify({
                 'success': True,
                 'message': 'Message sent successfully',

app/static/css/style.css

@@ -1041,3 +1041,29 @@ main {
 .scroll-to-bottom-btn:active {
     transform: scale(0.95);
 }
+
+/* =============================================================================
+   Echo Badge - "Heard X repeats" indicator for sent messages
+   ============================================================================= */
+
+.echo-badge {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.25rem;
+    font-size: 0.7rem;
+    color: #198754;
+    padding: 0.2rem 0.4rem;
+    margin-right: 0.25rem;
+    border-radius: 0.25rem;
+    background-color: rgba(25, 135, 84, 0.1);
+}
+
+.echo-badge i {
+    font-size: 0.65rem;
+}
+
+/* Dark mode support */
+[data-bs-theme="dark"] .echo-badge {
+    color: #75b798;
+    background-color: rgba(117, 183, 152, 0.15);
+}

app/static/js/app.js

@@ -712,6 +712,13 @@ function createMessageElement(msg) {
 
     if (msg.is_own) {
         // Own messages: right-aligned, no avatar
+        // Echo badge shows how many repeaters heard the message
+        const echoDisplay = msg.echo_count > 0
+            ? `<span class="echo-badge" title="Heard by ${msg.echo_count} repeater(s)">
+                 <i class="bi bi-broadcast"></i> ${msg.echo_count}
+               </span>`
+            : '';
+
         wrapper.innerHTML = `
             <div class="message-container">
                 <div class="message-footer own">
@@ -720,6 +727,7 @@ function createMessageElement(msg) {
                 <div class="message own">
                     <div class="message-content">${processMessageContent(msg.content)}</div>
                     <div class="message-actions justify-content-end">
+                        ${echoDisplay}
                         <button class="btn btn-outline-secondary btn-msg-action" onclick='resendMessage(${JSON.stringify(msg.content)})' title="Resend">
                             <i class="bi bi-arrow-repeat"></i>
                         </button>

meshcore-bridge/bridge.py

@@ -146,6 +146,11 @@ class MeshCLISession:
         # Shutdown flag
         self.shutdown_flag = threading.Event()
 
+        # Echo tracking for "Heard X repeats" feature
+        self.pending_echo = None  # {timestamp, channel_idx, pkt_payload}
+        self.echo_counts = {}     # pkt_payload -> {paths: set(), timestamp: float, channel_idx: int}
+        self.echo_lock = threading.Lock()
+
         # Start session
         self._start_session()
 
@@ -308,6 +313,12 @@ class MeshCLISession:
                     self._log_advert(line)
                     continue
 
+                # Try to parse as GRP_TXT echo (for "Heard X repeats" feature)
+                echo_data = self._parse_grp_txt_echo(line)
+                if echo_data:
+                    self._process_echo(echo_data[0], echo_data[1])
+                    continue
+
                 # Otherwise, append to current CLI response
                 self._append_to_current_response(line)
 
@@ -471,6 +482,67 @@ class MeshCLISession:
         except (json.JSONDecodeError, ValueError):
             return False
 
+    def _parse_grp_txt_echo(self, line):
+        """Parse GRP_TXT JSON echo, return (pkt_payload, path) or None."""
+        try:
+            data = json.loads(line)
+            if isinstance(data, dict) and data.get("payload_typename") == "GRP_TXT":
+                return (data.get('pkt_payload'), data.get('path', ''))
+        except (json.JSONDecodeError, ValueError):
+            pass
+        return None
+
+    def _process_echo(self, pkt_payload, path):
+        """Process a GRP_TXT echo and track unique paths."""
+        if not pkt_payload:
+            return
+
+        with self.echo_lock:
+            current_time = time.time()
+
+            # If this pkt_payload is already tracked, add path
+            if pkt_payload in self.echo_counts:
+                self.echo_counts[pkt_payload]['paths'].add(path)
+                logger.debug(f"Echo: added path {path} to existing payload, total: {len(self.echo_counts[pkt_payload]['paths'])}")
+                return
+
+            # If we have a pending message waiting for correlation
+            if self.pending_echo and self.pending_echo.get('pkt_payload') is None:
+                # Check time window (60 seconds)
+                if current_time - self.pending_echo['timestamp'] < 60:
+                    # Associate this pkt_payload with the pending message
+                    self.pending_echo['pkt_payload'] = pkt_payload
+                    self.echo_counts[pkt_payload] = {
+                        'paths': {path},
+                        'timestamp': self.pending_echo['timestamp'],
+                        'channel_idx': self.pending_echo['channel_idx']
+                    }
+                    logger.info(f"Echo: correlated pkt_payload with sent message, first path: {path}")
+
+    def register_pending_echo(self, channel_idx, timestamp):
+        """Register a sent message for echo tracking."""
+        with self.echo_lock:
+            self.pending_echo = {
+                'timestamp': timestamp,
+                'channel_idx': channel_idx,
+                'pkt_payload': None
+            }
+            # Cleanup old echo counts (> 1 hour)
+            cutoff = time.time() - 3600
+            self.echo_counts = {k: v for k, v in self.echo_counts.items()
+                               if v['timestamp'] > cutoff}
+            logger.debug(f"Registered pending echo for channel {channel_idx}")
+
+    def get_echo_count(self, timestamp, channel_idx):
+        """Get echo count for a message by timestamp and channel."""
+        with self.echo_lock:
+            for pkt_payload, data in self.echo_counts.items():
+                # Match within 5 second window
+                if (abs(data['timestamp'] - timestamp) < 5 and
+                    data['channel_idx'] == channel_idx):
+                    return len(data['paths'])
+        return 0
+
     def _log_advert(self, json_line):
         """Log advert JSON to .jsonl file with timestamp"""
         try:
@@ -1023,6 +1095,67 @@ def set_manual_add_contacts():
         }), 500
 
 
+# =============================================================================
+# Echo tracking endpoints for "Heard X repeats" feature
+# =============================================================================
+
+@app.route('/register_echo', methods=['POST'])
+def register_echo():
+    """
+    Register a sent message for echo tracking.
+
+    Called after successfully sending a channel message to start
+    tracking repeater echoes for that message.
+
+    Request JSON:
+        {
+            "channel_idx": 0,
+            "timestamp": 1706500000.123
+        }
+    """
+    if not meshcli_session:
+        return jsonify({'success': False, 'error': 'Not initialized'}), 503
+
+    data = request.get_json()
+    channel_idx = data.get('channel_idx', 0)
+    timestamp = data.get('timestamp', time.time())
+
+    meshcli_session.register_pending_echo(channel_idx, timestamp)
+    return jsonify({'success': True}), 200
+
+
+@app.route('/echo_counts', methods=['GET'])
+def get_echo_counts():
+    """
+    Get all echo counts for recent messages.
+
+    Returns echo counts grouped by timestamp and channel, allowing
+    the caller to match with their sent messages.
+
+    Response JSON:
+        {
+            "success": true,
+            "echo_counts": [
+                {"timestamp": 1706500000.123, "channel_idx": 0, "count": 3},
+                ...
+            ]
+        }
+    """
+    if not meshcli_session:
+        return jsonify({'success': False, 'error': 'Not initialized'}), 503
+
+    with meshcli_session.echo_lock:
+        result = []
+        for pkt_payload, data in meshcli_session.echo_counts.items():
+            result.append({
+                'timestamp': data['timestamp'],
+                'channel_idx': data['channel_idx'],
+                'count': len(data['paths'])
+            })
+
+    return jsonify({'success': True, 'echo_counts': result}), 200
+
+
 # =============================================================================
 # WebSocket handlers for console
 # =============================================================================