Enhance command handling: implement monotonic ID for deduplication and improve acknowledgment process

web/server/server.js

@@ -49,6 +49,7 @@ if (lastUpdate > 0) {
 
 // Pending commands for bridge HTTP polling (fallback)
 let pendingCommands = [];
+let nextCommandId = 1;  // Monotonic ID for deduplication
 
 // ========== Helpers ==========
 
@@ -70,9 +71,10 @@ function pushCommandToBridge(command) {
     }
   }
   if (!sent) {
-    // Fallback: queue for HTTP polling
-    pendingCommands.push({ ...command, timestamp: Date.now() });
-    console.log(`[Bridge] Queued command via HTTP poll (no WS bridge)`);
+    // Fallback: queue for HTTP polling with monotonic ID
+    const id = nextCommandId++;
+    pendingCommands.push({ ...command, id, timestamp: Date.now() });
+    console.log(`[Bridge] Queued command #${id} via HTTP poll (no WS bridge)`);
   }
 }
 
@@ -413,12 +415,24 @@ app.get('/api/bridge/commands', (req, res) => {
   }
 });
 
-// Bridge acknowledges commands
+// Bridge acknowledges commands by last processed ID
+// Only removes commands with id <= lastProcessedId, preventing
+// race conditions where new commands arrive between GET and ACK.
 app.post('/api/bridge/commands/ack', (req, res) => {
   try {
-    const cleared = pendingCommands.length;
-    pendingCommands = [];
-    res.json({ success: true, cleared });
+    const { lastProcessedId } = req.body || {};
+    if (lastProcessedId !== undefined && lastProcessedId !== null) {
+      // Remove only commands that have been processed
+      const before = pendingCommands.length;
+      pendingCommands = pendingCommands.filter(cmd => (cmd.id || 0) > lastProcessedId);
+      const cleared = before - pendingCommands.length;
+      res.json({ success: true, cleared });
+    } else {
+      // Legacy: clear all (backwards-compatible)
+      const cleared = pendingCommands.length;
+      pendingCommands = [];
+      res.json({ success: true, cleared });
+    }
   } catch (error) {
     res.status(500).json({ error: error.message });
   }