UI: Add rate limiting to brightness control

- Add 100ms minimum interval between brightness updates to backend
- Keep UI responsive with immediate local brightness updates
- Prevent backend overload from rapid MIDI CC33 changes
- Add time import for rate limiting functionality
- Add debug output to show when updates are sent vs rate limited
- Improve smoothness and reduce network traffic
- Protect lighting controller from too many rapid parameter changes

src/ui_client.py

@@ -18,6 +18,7 @@ import atexit
 import signal
 import urllib.request
 import urllib.error
+import time
 
 # Single instance locker to prevent multiple UI processes
 class SingleInstanceLocker:
@@ -169,6 +170,10 @@ class MidiController:
         self.knob7 = 0
         self.knob8 = 0
         self.beat_sending_enabled = True
+        
+        # Rate limiting for brightness control
+        self.last_brightness_update = 0
+        self.brightness_update_interval = 0.1  # 100ms minimum between updates
         # Color palette selection state (two selected indices, alternating target)
         self.selected_indices = [0, 1]
         self.next_selected_target = 0  # 0 selects color1 next, 1 selects color2 next
@@ -313,9 +318,20 @@ class MidiController:
             logging.info(f"MIDI CC {control}: {value}")
 
             if control == 33:  # Brightness (0-100)
-                self.brightness = round((value / 127) * 100)
-                if callable(self.on_parameters_change):
-                    self.on_parameters_change({"brightness": self.brightness})
+                current_time = time.time()
+                new_brightness = round((value / 127) * 100)
+                
+                # Rate limiting: only update if enough time has passed
+                if current_time - self.last_brightness_update >= self.brightness_update_interval:
+                    self.brightness = new_brightness
+                    self.last_brightness_update = current_time
+                    print(f"Brightness changed to: {self.brightness}")
+                    if callable(self.on_parameters_change):
+                        self.on_parameters_change({"brightness": self.brightness})
+                else:
+                    # Still update the local value for UI display, but don't send to backend
+                    self.brightness = new_brightness
+                    print(f"Brightness updated locally to: {self.brightness} (rate limited)")
             elif control == 34:  # n1 (0-255)
                 self.n1 = int(value)
                 if callable(self.on_parameters_change):
@@ -1027,12 +1043,15 @@ class UIClient:
     async def persist_parameters(self, params: dict):
         """POST parameter changes via REST to /api/parameters."""
         try:
+            print(f"Sending parameters to backend: {params}")
             data = json.dumps(params).encode('utf-8')
             req = urllib.request.Request(f"{HTTP_BASE}/api/parameters", data=data, method='POST', headers={'Content-Type': 'application/json'})
             with urllib.request.urlopen(req, timeout=2.0) as resp:
                 _ = resp.read()
+            print(f"Successfully sent parameters: {params}")
         except Exception as e:
             logging.debug(f"Failed to persist parameters (REST): {e}")
+            print(f"Failed to send parameters: {e}")
 
     def on_closing(self):
         """Handle application closing."""